There are about 40 Hydra species found in the world. 3 species of hydra are found in Bangladesh. Colorless or yellow-brown Hydra vulgaris, brown Hydra oligactis (Hydra fusca) and green Hydra viridissima. Hydra vulgaris is found in abundance in freshwater reservoirs in Bangladesh. Dr. Siddiq Publications

Hydra is carnivorous animal. Hydra feeds on insect larvae, small insects, cyclops, daphnia/crustacea, small worms, annelids, fish eggs, frogs etc. But the main diet is crustacean joints. Absorption and excretion are accomplished by contraction and expansion of the body wall. Hydra only preys on animals that have glutathione in their collars.

Different species of hydra are found all over the world. Lives in freshwater bodies such as ponds, ponds, canals, bilges, lakes, springs etc. They are not found in turbid, high and moving water. They hang downwards on a submerged solid object or plant leaf. Hydra vulgaris (orange-red), Hydra oligactis and Hydra viridissima (green) are found in freshwater bodies of Asia, Europe and America, including Bangladesh.

(i) Their bodies are long, cylindrical and slender.
(ii) The upper part of the body is open and the lower part is closed.
(iii) Twisted hypostome is located at the free end of the body.
(iv) Hypostome has 6–8 scutes.
(v) One or more buds are present on the body
(vi) At the lower end of the body is the foot-disc.

Hydra is a well-known small animal of the order Cnidaria. They are diploblastic animals. They are free-living animals and are known as freshwater polyps. Swiss scientist Abraham Trembley (1700-1784) discovered Hydra. Carolus Linnaeus (1758) named it Hydra after the nine-headed dragon Hydra in Greek mythology. Cutting off one head of the dragon hydra would produce two heads. If any part of it was torn off, a new hydra would be created from that part. That is, hydra has the ability to regenerate. Mahavir Hercules killed the monster Hydra. Dr. Siddiq Publications

Hydra is a well-known small animal of the order Cnidaria. They are diploblastic animals. They are free-living animals and are known as freshwater polyps. Swiss scientist Abraham Trembley (1700-1784) discovered Hydra. Carolus Linnaeus (1758) named it Hydra after the nine-headed dragon Hydra in Greek mythology. Cutting off one head of the dragon hydra would produce two heads. If any part of it was torn off, a new hydra would be created from that part. That is, hydra has the ability to regenerate. Mahavir Hercules killed the monster Hydra. Dr. Siddiq Publications

Hydra’s identifying features
(i) Their bodies are long, cylindrical and slender.
(ii) The upper part of the body is open and the lower part is closed.
(iii) Twisted hypostome is located at the free end of the body.
(iv) Hypostome has 6–8 scutes.
(v) One or more buds are present on the body
(vi) At the lower end of the body is the foot-disc.

Habitat of Hydra
Different species of hydra are found all over the world. Lives in freshwater bodies such as ponds, ponds, canals, bilges, lakes, springs etc. They are not found in turbid, high and moving water. They hang downwards on a submerged solid object or plant leaf. Hydra vulgaris (orange-red), Hydra oligactis and Hydra viridissima (green) are found in freshwater bodies of Asia, Europe and America, including Bangladesh.

Food of Hydra
Hydra is carnivorous animal. Hydra feeds on insect larvae, small insects, cyclops, daphnia/crustacea, small worms, annelids, fish eggs, frogs etc. But the main diet is crustacean joints. Absorption and excretion are accomplished by contraction and expansion of the body wall. Hydra only preys on animals that have glutathione in their collars.

Hydra species of Bangladesh
There are about 40 Hydra species found in the world. 3 species of hydra are found in Bangladesh. Colorless or yellow-brown Hydra vulgaris, brown Hydra oligactis (Hydra fusca) and green Hydra viridissima. Hydra vulgaris is found in abundance in freshwater reservoirs in Bangladesh. Dr. Siddiq Publications

External structure of Hydra
Hydra is a small tube-shaped animal. When expanded they are about 1-3 cm long and 1 mm wide. When removed from the water, they turn into a soft and shapeless lump. Hydra’s body consists of three parts. Hypostome, body stem and foot.
1. Hypostome: The word Hypostome is formed from hypo meaning below and stoma meaning mouth. The upper part of the body has a mouth opening. The small and twisted contractile organ below the stoma is called the hypostome. Stomata receive food, water and oxygen. It expels undigested or waste material.
2. Body: The entire body except the hypostome and the base is called the body. Different parts of the body-
(i) Sterile: At the base of the hypostome there are 6-10 slender, long, hollow and contractile-expanding sturgeon. Each karshika is twice or thrice as long as the body. The outer wall of Karshika consists of batteries of small nematocysts like tumors. Karshikas are arranged in a circle. It participates in food intake, movement and self-defense.
(ii) Mukul: Favorable environment or environment with sufficient food during summer. Hydra gains physical growth by consuming food. As a result, one or more buds are formed in the middle region of the body. Each bud matures and gives birth to a new hydra. This is one of hydra’s asexual reproduction methods. Dr. Siddiq Publications
(iii) Genitalia: During hibernation and winter, temporary genitalia are formed on the body of the metamorphosed hydra. The upper part of the body contains the spermatozoa and the lower part the ovary. The testicles produce sperm and the ovaries produce eggs. Participates in sperm and egg production.
(iv) Pedicel: The part between the stem and the foot is the petiole. It is narrow, narrow and contractile. It connects the body and the foot.
3. Padachakti: The round and pressed part in the lower part of the body is the sole of the foot. A sticky substance secreted from the soles of the feet keeps the hydra attached to objects. Bubbles help float in water. It helps the hydra to move by forming a membrane. Hydra displays gliding movements with the help of discs. Dr. Siddiq Publications
Internal structure of Hydra
Longitudinal or transverse section of Hydra showing the body wall and gastrovascular or coelenteron. The body wall consists of two cell layers. Epidermis (embryonic ectoderm) and gastrodermis (embryonic endoderm).
The outermost cell layer of the body wall is called the epidermis. The thickness of the epidermis is one-third that of the body wall. It contains seven types of cells. Muscle sheath cells, interstitial cells, sensory cells, nerve cells, glandular cells, germ cells and nidoblasts.
1. Musculo-Epithelial cells: Musculo-epithelial cells are located throughout the epidermis. The cells look columnar. The outside of each cell is wide and free and the inside is closed and narrow. There are two muscle enhancers on the inside. It is also called muscle tail. Within the muscle tail are the contractile fibers myoneme. The cytoplasm of the cell contains a nucleus, mucous material and granular glands. The cells lining the musculature are large, flattened and contain nidocytes. Mucin is secreted from the mucous material and granules from the granular glands. Muscle sheath cells are interconnected to form an integral sheath.
Musculoskeletal function
(i) Musculature protects the body by creating a body covering.
(ii) Myoneme causes contraction-expansion of the body.
(iii) Mucous gland secretion keeps the body slippery.
(iv) It bears nematocysts.
(v) It helps in movement by contraction-expansion.
(vi) Mucous granules secreting sap form the cuticle.
(vii) It contains nidoblasts.
(viii) Keeps the body attached to an object.
(ix) Part rich in mucous granules participates in digestion.
2. Interstitial cell: Interstitial cells are located in clusters between muscle cells. It is called Reserve cell or Stem cell or multipotent cell. The cells appear round, oval or triangular in shape. Each cell contains a nucleus, numerous mitochondria, endoplasmic reticulum, lysosomes, ribosomes etc. It has totipotency capability. So it transforms into any other cell as needed. The diameter of the cells is 5 μm.
Function of interstitial cells
(i) A cell can transform into any other cell.
(ii) It participates in hydra regeneration, growth, gonad and bud formation.
(iiii) After 45 days, when body cells are destroyed, interstitial cells fill the space.
3. Sensory cell: Sensory cells are scattered in the spaces between the muscle covering cells. However, it is numerous in karshika, hypostome, feet. The cells appear narrow, elongated and spindle-shaped. That is, the middle part is wide and both ends are narrow. Each cell has cytoplasm and a swollen nucleus. It has contractile membranes on the outside and sensory nerves on the inside. It is sensitive to light, heat, touch, chemicals etc. Dr. Siddiq Publications
Function of sensory cells
(i) It receives different types of stimuli from the environment.
(ii) It participates in self-defense.
(iii) It helps in selection of accommodation.
(iv) It selects food.
4. Nerve cells: Nerve cells are located under the epidermis near the mesoglia. The cells appear maculate or polygonal. Cytoplasm and nucleus are present in the cell. Each cell has two or more branched nervous systems. Nervous systems combine to form the neural network. Dr. Siddiq Publications
Nerve cell function
(i) It receives nerve impulses from sensory cells and generates reports.
(ii) It facilitates coordination between different cells.
5. Gland cell: Gland cells are located in the peduncle, hypostome and peduncle. Cells may appear cylindrical, granular, or oval. It contains mucous glands, enzyme glands and glands that secrete mucus.
Function of glandular cells
(i) A cell helps in digestion of food.
(ii) The secreted sticky juice keeps the hydra attached to an object.
(iii) It helps in locomotion by creating momentum.
(iv) Helps hydra to float in water by creating bubbles.
6. Germ cell: During the reproductive season, spermatozoa and ovum are formed from interstitial cells in the hydra body stem. The testes are above and the ovaries are below. The testicles produce sperm and the ovaries produce eggs. Sperm are very small and nucleated. It consists of head, midsection and movable tail. Eggs are large, round and have three polar bodies.
Function of reproductive cells: Sperm and egg participate in reproductive function.
7. Cnidocyte cell: Nidoblast cells are widespread everywhere except the soles of hydra. It is located in the spaces between the muscle cells. The cells look round, oval, flax-shaped, cupped or pear-shaped. Each cell is bilayered and contains only one nucleus. There are nematocysts with twisted threads inside the cells.
Nidoblast function
(i) It helps in food intake.
(ii) It helps in locomotion.
(iii) Participates in self-defence.
(iv) Captures and traps prey.
(v) Helps the animal to cling to an object.
(vi) It carries taxonomic importance.
Gastrodermis of Hydra
The innermost cell layer of the body wall is called the gastrodermis. The thickness of the gastrodermis is two-thirds that of the body wall. It contains 5 types of cells. Nutrient cells, glandular cells, interstitial cells, nerve cells and sensory cells.
1. Nutritive cells: Nutritive cells are located throughout most of the gastrodermis. It looks stunning. Each cell has a large nucleus and cavity. It forms contractile fibrous fascicles. Nutrient cells can be divided into two types. Flagellar cells and transient cells. Dr. Siddiq Publications
(i) Flagellar cells: These cells have 1-4 thread-like flagella at the free end.
(ii) Transient cells: The free end of this cell has transient cells.
Nutrients are cell functions
(i) It thins and thickens the body by contraction-expansion.
(ii) Flagella transform the food material into particles.
(iii) Acts like a sphincter to open and close the mouth.
(iv) It allows water to enter the mouth.
(v) Digests food.

2. Interstitial cell: Interstitial cells are located in clusters between muscle cells. It is called Reserve cell or Stem cell or multipotent cell. The cells appear round, oval or triangular in shape. Each cell contains a nucleus, numerous mitochondria, endoplasmic reticulum, lysosomes, ribosomes etc. It has totipotency capability. So it transforms into any other cell as needed. The diameter of the cells is 5 μm.
Function of interstitial cells
(i) A cell can transform into any other cell.
(ii) It participates in hydra regeneration, growth, gonad and bud formation.
(iiii) After 45 days, when body cells are destroyed, interstitial cells fill the space.
3. Sensory cell: Sensory cells are scattered in the spaces between the muscle covering cells. However, it is numerous in karshika, hypostome, feet. The cells appear narrow, elongated and spindle-shaped. That is, the middle part is wide and both ends are narrow. Each cell has cytoplasm and a swollen nucleus. It has contractile membranes on the outside and sensory nerves on the inside. It is sensitive to light, heat, touch, chemicals etc. Dr. Siddiq Publications
Function of sensory cells
(i) It receives different types of stimuli from the environment.
(ii) It participates in self-defense.
(iii) It helps in selection of accommodation.
(iv) It selects food.
4. Nerve cells: Nerve cells are located under the epidermis near the mesoglia. The cells appear maculate or polygonal. Cells have cytoplasm and nucleus. Each cell has two or more branched nervous systems. Nervous systems combine to form the neural network. Dr. Siddiq Publications
Nerve cell function
(i) It receives nerve impulses from sensory cells and generates reports.
(ii) It facilitates coordination between different cells.
5. Gland cell: Gland cells are located in the peduncle, hypostome and peduncle. Cells may appear cylindrical, granular, or oval. It contains mucous glands, enzyme glands and glands that secrete mucus.
Function of glandular cells
(i) A cell helps in digestion of food.
(ii) The secreted sticky juice keeps the hydra attached to an object.
(iii) It helps in locomotion by creating momentum.
(iv) Helps hydra to float in water by creating bubbles.

Mesogloea
The jelly-like sticky extracellular layer between the epidermis and gastrodermis of Nidaria is called mesoglia. It is thin, colorless and elastic. Its diameter is 0.1 micron. Dr. Siddiq Publications
Function of mesoglia
1. Mesoglia serve as the foundation of the epidermis and endoderm.
2. It acts as an attachment point.
3. It makes the body contract and expand.
4. Acts as a flexible skeleton of the body.
5. It contains myofibrils.
Cnidoblast or Cnidocyte
The word Cnidoblast is derived from the Greek words knide meaning nettle and blastos meaning germ. The goblet or flax-shaped cells on the exterior of hydra are called nidoblast cells. It can be round, oval, pear-shaped, cup-shaped or oval-shaped. Nidoblast cells are found everywhere in the body except the soles of the feet. But its number is more in Karshika. Sometimes the cells are arranged in clusters. A group of them is called a battery.
1. Integument: Each nidoblast cell is covered by a bilayered envelope. Outer cover and inner cover. It is composed of proteins and lipids. Between the two envelopes are granular cytoplasm, a nucleus, mitochondria, lysosomes, ribosomes, etc.
2. Nematocyst: Small cysts with twisted secretions present in nidoblast cells are called nematocysts. The sac of nematocyst is called capsule. Capsules contain the poisonous liquid hypnotoxin. Hypnotoxin is composed of proteins and phenols. Hypnotoxin poison is neurotoxic in nature. That is, it acts on the victim’s nervous system. The level of this venom is 75% similar to that of a gokra or cobra snake. The nematocyst has a long and hollow filament at its tip. The broad part of the base of the sutraka is called the butt or shaft. The butt has three large spines called barbs. The butt consists of spirally arranged small barbule spines. Normally, the nematocyst is inserted into the sac with butts and spines. A nematocyst once shed never reenters.Dr. Siddiq Publications
3. Operculum: The mouth of nematocyst has a lid like part. It is called operculum. It moves sideways when exposed.
4. Nidocile: The free end of the nidocyte cell consists of a tough, firm, tiny and hypersensitive hollow spine. It is called nidosil. It is a transformed cilium. It works like a trigger. As a result, patched sutraka is thrown out. Dr. Siddiq Publications
5. Muscle fibers and lasso: Several muscle fibers emerge from the lower end of the nematocyst. Besides, there is a twisted thread called lasso at the lower end.
Nidoblast function
1. Defense: Nematocysts contain a poisonous substance called hypnotoxin. Hydra defends itself with this toxic substance.
2. Prey capture: Hydra captures food by means of nematocysts. Then paralyze the victim. Dr. Siddiq Publications
3. Movement: Nematocyst cells help the hydra to move. Different types of movements occur in hydra. Dr. Siddiq Publications
4. Clogging the body: Nematocysts secrete sticky substances. By this, the hydra is stuck to an object. Dr. Siddiq Publications

Different types of Nematocysts in Hydra
Nematocysts are small sacs with patchy filaments located in nidocyte cells. Normally the sutraka is inserted into a sac or capsule with a butt and a fork. A nematocyst once shed never reenters. In 1965, scientist Werner identified 23 types of nematocysts in the bodies of Nideria animals. However, four types of nematocysts can be seen in Hydra. Dr. Siddiq Publications
1. Stenotile or penetrant: Stenotile is the largest of the four types of nematocysts of Hydra. Its capsule is filled with a poisonous liquid called hypnotoxin. Its butt is fat. The butt has three large spines. It’s called a barb. Butt has three rows of barbules.
Work of stenotil or penetrant
(i) It paralyzes prey with hypnotoxin.
(ii) Its trigger grips the prey.
2. Streptolin Glutinant or Holotrichus isorhiza: Streptolin Glutinant medium type nematocyst. Its capsule is small and the butt is not well formed. It lacks barbs, but has barbules. Its stems are long, spiny and open at the apex.
Action of Streptolin Glutinant
(i) It traps prey.
(ii) Helps in locomotion.
(iii) secretes sticky substances.
3. Steriolin glutinant or Atrichus isorhiza: Steriolin glutinant is the smallest nematocyst. Their butt is not well formed. Barbs and barbules are absent. Its stems are short, thornless and open at the apex. Dr. Siddiq Publications
Action of stearoline glutenin
(i) It helps in locomotion.
(ii) binds the hydra to an object.
(iii) secretes sticky substances.
(iv) Capture the victim.
4. Volvent or Desmonym: Volvent is a relatively small nematocyst. They do not have butts, barbs and barbules. Its stem is thick, short, elastic, spineless and closed at the apex. There is only one patch of Sutra inside its capsule. The sutraka remains patchy even when thrown. As soon as it is thrown, it creates many screws like a cork-screw.
Volvent’s work
(i) It grasps the prey.
(ii) It helps in locomotion.
Nematocyst initiation technique
Nematocyst initiation is a chemical and mechanical process. When a prey comes close to the hydra’s attractor, the trigger is thrown. Chemicals in the prey’s body increase the water permeability of the hydra’s nematocyst wall. The osmotic pressure or hydrostatic pressure of the capsule increases. Water quickly enters the bag. A chemical called poly-ℽ-glutamate is secreted inside the sac. The operculum opens as soon as the prey touches the nidocile. Sutraka is thrown out with lightning speed. This entire event takes place in just 3 milliseconds.
Once the nematocyst is released, it cannot be returned to the nematocyst. That is, once thrown, it cannot be used again. No more nematocysts are formed in the same nidocyte. Such nidocytes slowly enter the gastrointestinal tract and are mixed with food and digested. Within 48 hours new nidocytes are generated and used.

Coelenteron
The body cavity of animals of the order Nidaria is called a coelenteron. The body cavity of the Hydra is the Cilantron. Archenteron transforms into Cilenteron. It is covered by gastrodermis. It involves extracellular digestion. Food and excreta are transported through it. Hence it is called Gastrovascular cavity. Cilantron is sometimes called blind gut or blind sac. It is exposed through the stoma. Takes food and leaves waste through mouth. Dr. Siddiq Publications

Why cilantro is called digestive circulation
Both alimentary canal and body cavity functions of Nidaria are carried out by cilantrones. Cilenterone performs physiological functions such as digestion, transport of nutrients, respiration, excretion, excretion of waste products, etc. Food material is taken up in the cilantro and extracellular and intracellular digestion is carried out. Undigested food and waste products are excreted through the stomata. So Cilenteron is called Gastrovascular cavity or Gastrovascular cavity. Dr. Siddiq Publications
Importance of cilantro
1. Cilantron contains food.
2. It causes extracellular digestion.
3. Food and excreta are transported through it.
4. It excretes waste through the stoma.

Food intake and digestion of hydra
Nutrition: The biochemical process in which complex food is converted into simple and soluble food and the undigested part is excreted is called nutrition. Nutrients absorbed by the body replenish, grow and produce energy.

Foraging techniques
Hungry hydra grips the base with the soles and floats the body and gills to catch prey. The nematocysts of the attractor are activated when prey approaches. Different types of nematocysts are ejected as the prey touches the attractor.
Volute nematocyst inhibits prey movement. Glutinants trap prey by secreting sticky juices. The stenotil nematocyst injects a poison called hypnotoxin into the victim’s body and paralyzes the victim. Then the food is brought to the mouth. The stomata are swollen and wide and food enters the mouth. Mucus secreted from glandular cells makes food moist and slippery. As a result of contraction and expansion of the hypostome and body wall, food enters the cilantro.
Process of digestion
The biochemical process in which various types of enzymes break down complex food into simple and absorbable food is called digestion. Hydra can digest food such as proteins, fats and simple carbohydrates. They cannot digest starch or complex carbohydrates. Undigested food comes out through the mouth. Hydra digestion takes place in two stages. Extracellular digestion and intracellular digestion.
1. Extracellular digestion: The process in which food is digested outside the cells inside the stomach, alimentary canal and celandine is called extracellular digestion. As soon as the food material reaches the cilentron, the mouth pore closes. The prey or food is killed by the action of the enzyme. The contraction and expansion of the body wall breaks the prey into smaller particles. Food is digested under the influence of enzymes secreted from glandular cells. Proteins are broken down into polypeptides. Lipid food is not digested here. Dr. Siddiq Publications
2. Intracellular digestion: The process in which food is digested inside the cytoplasm of the cell is called intracellular digestion.
Partially digested food particles in the cilantro are converted into smaller particles by the contraction-expansion of the body. Some of the food particles turn into liquid with the help of the passage. The food particles then enter the food cavity in the cytoplasm. Enzymes secreted from the cytoplasm digest food. Food is digested first in an acidic and then in an alkaline phase. Proteins are broken down into amino acids and lipids are broken down into fatty acids and glycerol. Dr. Siddiq Publications
Absorption
Extracellular and intracellular digestion occur in hydra. The digested food is absorbed into the cytoplasm of the transient cells. Absorption of amino acid, glucose, fatty acid, glycerol etc. in the cytoplasm.

Assimilation and exclusion
The digested part of food is called digesta. Nutrients are absorbed in the cytoplasm and transported to different parts of the body by the process of diffusion. Undigested food particles reach the stomata by contraction and expansion of the body wall and flagellar circulation. After that, it is mixed with the stream of water from the mouth. Dr. Siddiq Publications
Different movements of Hydra
The process by which the organism moves under its own efforts due to biological needs is called locomotion.
Movement of hydra: Different types of movement of hydra are looping, somersaulting, gliding, floating, swimming, crawling, stooping, diving and contraction-expansion of the body.
1. Looping
The process by which hydra moves by creating loops is called looping movement. Hydra exhibits looping movements to cover long distances.
(i) In this process the hydra stands upright on the trajectory by the foot.
(ii) Bends the head forward and touches the trajectory by the Karshika.
(iii) A loop is formed between the sole and the head when the base is touched by the nematocyst of Karshika.
(iv) Then pull the feet closer to the head.
(v) Retouches the trajectory by treading.
(vi) Stands straight again with the head raised on the floor.
(vii) Then moves forward bending the head forward.
By forming a loop like this, the hydra moves forward.
2. Somersaulting
Hydra’s fast movement mechanism is somersaulting. Each run creates two loops.
(i) In this process the hydra touches the trajectory by the sole.
(ii) Standing upright by resting on the floor.
(iii) Touches the trajectory by the Karshika with the head facing forward.
(iv) Stand upside down by lifting the feet on the karshika.
(v) Release Karshika by resting on the floor and stand upright with the head up.
Thus the hydra moves forward through digbazi.
3. Gliding or amoeboid movement: Hydra moves by gliding process to cover very short distances. In this process the hydra moves as slowly as the amoeba. A slippery sap is secreted from the cells of the epidermis of the soles of hydra. It creates a moment from the place of the feet. Momentarily moves forward on smooth ground. At the same time, the Hydra moves forward very slowly. In this way, the hydra very slowly crosses a very small distance.
4. Floating: The hydra moves upside down by freeing the feet. That is, the foot is on the top and the oral floor is on the bottom. Gas and mucus are secreted from the glands of the soles of the feet. The released gas and mucus combine to form bubbles. Hydra floats in water with the help of bubbles. During this time, it floats from one place to another due to the pull of the current or the impact of the waves.
5. Swimming: The hydra frees the body and positions itself horizontally. Makes the karshikas move like waves. At the same time, it also moves the body. In this way, it swims by creating a wave-like movement.
6. Walking: Hydra moves upside down by freeing the soles. That is, the foot is on the top and the oral floor is on the bottom. Places the entire weight of the body on the Karshika. Using Karshika as a foot moves slowly. Dr. Siddiq Publications
7. Climbing: Hydra clings to branches of submerged plants by tentacles. Releases and shrinks the soles. Then put the floor in a new place. Thus changes the space through contraction.
8. Contraction and expansion: Hydra relaxes the body and causes contraction and expansion of muscle cells. In this the body size becomes shorter and longer. As a result, a kind of movement is created and the place changes.
9. Drawing: If bubbles are not created in the body, the body becomes heavy. The body sinks faster due to its heaviness. It is called submerged movement. Dr. Siddiq Publications
Respiration
Hydra has no specific respiratory organs. It causes the exchange of gaseous substances through the epidermis and gastrodermis.
1. Epidermis: Dissolved oxygen from the water around the body enters the epidermal cells by diffusion. The absorbed oxygen reaches the various cells of the body and completes the respiration process. Carbon dioxide produced as a result of respiration is released outside the body in the process of diffusion. Dr. Siddiq Publications
2. Gastrodermis: Gastrodermis consists of flagellated cells. Flagellar movement causes a constant flow of water into the stomata. Dissolved oxygen from water enters the gastrodermal cells by the process of diffusion. The absorbed oxygen reaches the various cells of the body and completes the respiration process. Carbon dioxide produced as a result of respiration is released outside the body in the process of diffusion.

Excretion of Hydra
Hydra has no specific excretory organs. Metabolism in cells produces nitrogenous waste products. The waste material generated is released into the water during the diffusion process.
Nerve system of hydra
Hydra is a suborder of animals. Their bodies have a weak nervous system. In the animal world, hydra or nidarians developed the first nervous system. Nervous system emerges from their afferent neurons and joins to form neural network. Neurons do not have axons or dendrites and never form synapses. Mesoglia has one nerve plexus on either side. Nerves are attached to the epidermis and gastrodermis. Nerves are densely located in the mouth and foot. Neurons are connected to each other and to sensory cells and muscle cells. Sensory cells receive light, touch and chemical stimuli from the environment. Then through the nerve network sent to the muscle cells. Dr. Siddiq Publications
Irritability of Hydra
1. Touch: Pricking the hydra with a needle causes the body to contract. Leaves, aquatic plants, objects, etc. are stuck by hydra treads.
2. Hunger: A hungry hydra contracts and expands its muscles. Moves the body at a very fast speed to search for food. If they are not hungry, they slow down.
3. Temperature: Hydra always prefers cool water with a temperature of 20 degrees Celsius. When the surface temperature of the reservoir rises, the hydra slowly moves down. Dr. Siddiq Publications
4. Light: Hydra does not like either too much light or darkness. Always like moderate light. Dr. Siddiq Publications
5. Current: A continuous current causes the hydride body to bend towards the anode. Later, the whole body contracts. Dr. Siddiq Publications

Reproduction of Hydra
The process by which organisms reproduce is called reproduction. Hydra reproduces in two ways. Asexual reproduction and sexual reproduction. Dr. Siddiq Publications

Asexual reproduction: The reproduction that takes place without the union of sperm and egg is called asexual. Asexual reproduction in hydra is – budding and fission.
1. Budding: Budding is an asexual reproductive process in Hydra. This process does not require male or female hydra to reproduce. So it is a simple method. During summer, the environment has more food. Hydra grows physically by consuming food. Then budding occurs in hydra. The higher the number of buds, the faster the number of hydra will grow.
(i) During summer, hydra grows by taking food from the environment and increases in size. Siddique Publications
(ii) Interstitial cells in the middle or lower part of the body divide rapidly to form a small swollen area.
(iii) The swollen part enlarges into a hollow and cylindrical bud.
(iv) Epidermis, mesoglia and gastrodermis gradually develop in bud.
(v) Cilantron gradually expands from mother hydra to bud.
(vi) The bud grows by receiving nutrients from the mother hydra.
(vii) The bud consists of stomata, hypostome and karshika.
(viii) A circular groove is formed at the junction of mother hydra and bud.
(ix) The furrow gradually deepens to separate the offspring hydra from the mother hydra.
(x) Padatal is formed after the disintegration of Aptya Hydra. It then attaches itself to submerged objects and lives independently.
A hydra can produce several buds simultaneously. New buds can be formed from each bud. At this time the matrihydra seems to be a gregarious animal. It takes about three weeks to hatch and live independently from the mother hydra.
2. Fission
When a hydra’s body splits into two or more segments, a new hydra grows from each segment. This is called regeneration. Hydra is divided in two ways. Longitudinal division and transverse division. Dr. Siddiq Publications
(i) Longitudinal division: When the hydra body is divided longitudinally into two or more segments, a new hydra is formed from each segment.
(ii) Transverse division: When the body of hydra is divided transversely into two or more segments, new hydra originates from each segment.

Hydra Sexual reproduction
The process by which sperm and egg unite to form a zygote is called sex. Sexual reproduction in hydra takes place in two stages. Gametogenesis and fertilization.
1. Gametogenesis: The process by which gametes i.e. sperm and egg are produced is called gametogenesis. It is of two types. Spermatogenesis and oogenesis. Dr. Siddiq Publications
(i) Spermatogenesis: The process by which sperm are produced is called spermatogenesis. Spermatozoa are formed on the upper side of the hydra’s body. The interstitial cells of the testis divide repeatedly in the process of mitosis to form spermatogonia. Each spermatogonia enlarges in size by taking food and develops into spermatocytes. Each spermatocyte divides by meiosis to produce 4 spermatids. Each spermatid is transformed into a sperm in the process of spermiogenesis.
(ii) Oogenesis: The process by which eggs are produced is called oogenesis. Ovaries are formed on the underside of the hydra’s body. Ovarian interstitial cells divide repeatedly in the process of mitosis to form oogonia. Each oogonia grows in size by taking food and turns into an oocyte. Each oocyte divides by meiosis to produce 3 small polar bodies and one oocyte. The oocyte transforms into an egg. Ovum is covered with a slippery coat of gelatin.
2. Fertilization: The union of sperm and egg is called fertilization. The spermatozoa break through the nipple of the spermatic cord and come out and swim in the water in swarms. Within 24-48 hours, the sperm unites with the egg to form a zygote.

Development of Hydra
Development: The zygote divides repeatedly and turns into a full-fledged organism is called development. The division of the zygote in Hydra is holoblastic or complete. The stages of its development are as follows.
1. Morula stage: The zygote divides repeatedly by cleavage to become multicellular, sterile and round cells. This is called Marula Dasha. Two types of cells are formed in marula dasha. Micromere and macromere. Dr. Siddiq Publications
2. Blastula stage: In the blastulation process, the cells of the morula stage are arranged in a certain layer and form a hollow spherical structure. This is called blastula dasha. The cavity in the center of the blastula is called the blastocell. The blastular wall is called blastoderm and the cells are called blastomere.
3. Gastrula Stage: In the process of gastulation, the cells of the blastomere form a two-layered nerate and spherical structure. This is called gastrula dasha. The gastrula of hydra is called stereogastula because it is attached to the mother body. The outer layer of the gastrula is called ectoderm and the inner layer is called endoderm. Between the ectoderm and endoderm are jelly-like acellular mesoglia. The gastrular cavity is called the primitive cilenteron.
4. Cyst: Gastula is surrounded by spiny sheath made of chitin. It is called a cyst.
5. Hydrilla: Embryo elongates inside the cyst at favorable temperatures during spring. In the embryo, the mouth opening, hypostome, trachea and foot wheel are formed. This condition of the fetus is called hydrula. Dr. Siddiq Publications
Although hydra is bisexual, self-fertilization does not occur
Most hydra are dioecious, but some hydra are monoecious. Self-indulgence is a sexual process. The union of sperm and ovum of the same animal is called insemination. Even though hydra is bisexual, self-fertilization does not occur. In the same hydra, spermatozoa and ova are produced in two different seasons. In hydra the eggs are immature at the time when the sperm are mature. Again, when the egg is mature the sperm is immature. Therefore sperm and egg of the same hydra can never meet. This is why self-fertilization does not occur in hydra. In hydra, only purification occurs. Dr. Siddiq Publications

Symbiosis
The Greek word Symbioum means live together. The close co-existence of two organisms of different species that benefit from each other is called mytosymbiosis. Algae Zoochlorella and green hydra Chlorohydra viridissima form mitotic organisms. Again, sea urchins and clownfish form a symbiotic relationship. Algae parts are transmitted to the next generation along with hydra eggs. So algae is called lifelong paying guest. How hydra and algae benefit is discussed below.Dr. Siddiq Publications
How Algae Benefit
1. Shelter: Algae take shelter in hydra’s endodermal muscle cells.
2. CO2 Acquisition: Algae use the CO2 produced in hydra respiration for photosynthesis.
3. Nitrogen acquisition: The nitrogenous waste products of hydra metabolism are used by algae to produce carnivorous food.
4. Protection from environmental stress: Algae take shelter in hydra’s body. So it is protected from heat, stress, dryness etc. Dr. Siddiq Publications
How does Hydra benefit?
1. Food: Hydra consumes excess food produced by algae in the process of photosynthesis. When the algae die, the corpse is used by the hydra as food.
2. Obtaining O2: Hydra uses the O2 produced by algae in the process of photosynthesis. Dr. Siddiq Publications
3. Excretion of waste products: Hydra produces nitrogenous waste products in the process of respiration. Algae consume these waste materials and free the hydra waste.

Why is the hydra called a mythical creature?
The close coexistence of two organisms of different species that benefit from each other is called symbionts. Hydra obtains food and oxygen from algae. The CO2 and waste products produced by hydra growth are fed to the algae. As a result, Hydra benefits and life becomes easier. Hence hydra is called a mythic organism. Green hydra called Chlorohydra viridissima forms mitosis.

Hydra Division of Labor
In multicellular organisms, when specific cells, organs or organs perform specific tasks, it is called division of labor. In the animal kingdom, division of labor is first seen in the Nidarians or Hydra. Physiological and cellular division of labor can be seen in Hydra.
Physical division of labor
1. Mouth: Controls intake of food, excretion of waste and flow of water.
2. Traction: Used for locomotion, catching prey, climbing and self-defense.
3. Body: Aids in locomotion and contains buds and genitals.
4. Epidermis: Structures and protects the body.
5. Mesoglia: Forms the base and structure and helps in contraction and expansion of the body.
6. Cilantron: Works on digestion and circulation.
7. Padachakti: Helps to move and keep the body bound.

Cellular division of labor
1. Musculoskeletal Cells: Helps build body armor, locomotion and capture prey.
2. Interstitial cells: Any cell or organ that forms the body.
3. Sensory and nerve cells: Receive and report stimuli.
4. Nutrient cells: carry out extracellular and intracellular digestion.
5. Gland cells: secrete enzymes and sticky substances.
Hydra’s Regeneration ability
Reconstruction of lost or damaged body parts is called regeneration. Hydra has great regenerative capacity due to its totipotency. The Swiss scientist Abraham Tremley (1744) was the first to observe the hydra’s ability to regenerate. Cutting a hydra into pieces creates a hydra from each piece. Karshika and hypostome are formed from the oral end and padachakati from the non-oral end. Dr. Siddiq Publications
1. If the hydra is divided into several segments transversely, each segment creates a complete hydra. Each segment maintains polarity. That is, from the oral end, karshika and hypostome are formed and from the non-oral end, the foot-disc is formed.
2. If the hydra body is divided lengthwise into two parts, a complete hydra is created from each part.
3. If the head of hydra is divided into two parts vertically, one head is created from each part.
The creature is named Hydra after the mythical monster Hydra in Greek mythology. This monster had nine heads. If the strong human Hercules cut off the head of the monster, two heads grew in that place. Dr. Siddiq Publications

Reasons for including Hydra in the phylum Cnidaria
1. In the embryonic stage, the hydra body is divided into ectoderm and endoderm layers. In mature animals, ectoderm transforms into epidermis and endoderm transforms into gastrodermis.
2. In the center of the body is the cilantern or gastrovascular cavity. It is exposed to the outside through the mouth.
3. The body wall consists of interstitial cells. It can be transformed into any other cell. Dr. Siddiq Publications
4. Epidermis consists of nidoblast or nidocyte cells. Nidocyte cells contain nematocysts.
5. Cellular division of labor can be seen.
Hydra is included in the Cnidaria phylum due to the above characteristics.

Why is Hydra called the simplest multicellular animal?
1. Hydra is a bivalve. Its body wall consists of epidermis and gastrodermis. Between the epidermis and the gastrodermis are the acellular mesoglia.
2. Interstitial cells in the body can transform into any other cell.
3. Nervous system emerges from nerve cells to form neural network. It is widespread throughout the body. Dr. Siddique Publications
4. Cilenteron or gastrovascular cavity is present in the body. It acts as a body cavity and digestive tract.
5. Open to the outside through the gastrovascular orifice.
6. Intracellular and extracellular digestion takes place in the body.
7. Absorption and excretion occur in the process of diffusion and absorption.
8. Division of labor is observed for performing physiological and mechanical tasks.
9. Asexual reproduction and sexual reproduction occur in the body.
Hydra is called the simplest multicellular animal due to the above characteristics.

1. Diet: Animals are parasitoids. Their food intake occurs in the process of digestion.

2. Nutrition: Their nutrition is Holozoic.

3. Locomotion: Most animals are capable of locomotion.

4. Cell Division: Cell division occurs through mitosis and meiosis.

5. Circulation: Blood and other fluids circulate inside the body.

6. Reproductive System: Their reproductive system can be ovipositor, ovipositor and uterus.

7. Cells without cell walls: Animal cells do not have cell walls.

8. Protective covering: Outside the animal cell there are protective coverings such as cell layer, skin, hair, feathers, scales etc.

9. Stimulus: They respond to any stimulus.

10. Excretion: Animals excrete harmful wastes from the body.

11. Respiration: They respire.

12. Bearing: They can bear.

The Chordata phase is divided into three subphases. namely Urochordata, Cephalochordata and Vertebrata. Urochordata and Cephalochordata together are called Protochordata. Chordates have three unique characteristics. These are – elastic notochord, dorsal hollow nerve cord and pharyngeal gill opening. All these characteristics are present in protochordata at any stage of life or for life. But all these characteristics of vertebrates are present in embryo but not in later life. In vertebrates, the notochord transforms into the spinal cord, the hollow nerve cords form the brain and spinal cord, and the gills close to form the lungs. From all this it can be understood that all the characteristics of chordates are present in vertebrates, but not all the characteristics of vertebrates are present in chordates. So it can be said that all vertebrates are chordates, but not all chordates are vertebrates.

1. Vertebral Cord: Chordates have a notochord in embryo or throughout life. In advanced animals the notochord is replaced by the spinal cord.

2. Brain: Chordates have nerve cords. The anterior end of the nerve cord forms the brain.

3. Symmetry: The posterior part of the nerve cord of Chordata animals forms the symphysis.

4. Pharyngeal gill slits: Chordates have pharyngeal gill slits at any stage of life or throughout life.

5. Heart: Cordata animals have a well-formed heart. The heart is always located at the apex of the intestine.

6. Endostyle: Chordata animals have endostyle. The endostyle later transforms into the thyroid gland.

7. Digestive system: Chordata have complete digestive system. It contains intracellular and extracellular digestive glands.

8. Tail: Cordatas have a post-anal segment elastic tail. Sometimes the tail can get lost during the transition.

9. Circulatory system: Chordates have a closed circulatory system. It is made up of blood, blood vessels and blood vessels. It has hepatic portal system.

10. Excretory system: The main excretory system of chordates consists of a pair of kidneys. Through this, nitrogenous wastes are removed from the body.

11. Body skin: The body skin of chordata animals consists of epidermis (derived from ectoderm) and dermis (derived from mesoderm).

12. Endoskeleton: The endoskeleton of chordates is made up of bone or cartilage.

13. Eyes: Cordatas eyes are simple in nature. It originates from the brain.

14. Genus: Chordata are unisexual. They have sex. Asexual reproduction is absent.

15. Osmoregulation: Osmoregulation of chordates occurs through the kidneys.

16. Silome: True silome is present in the body of chordates. Surrounding the heart is the pericardial cavity.

From the above discussion, it can be understood that the animals of this phase are at the highest level of the biosphere through evolution. As their brains are developed, they are establishing dominance everywhere. As the age of the earth increases, their structural characteristics will develop. As a result, they can control the world with their hands.

Carbohydrates
All the organic compounds made up of carbon, hydrogen and oxygen in which the ratio of carbon, hydrogen and oxygen is 1:2:1 are called carbohydrates or sugars. There are also many compounds that do not have a 1:2:1 ratio, including carbohydrates. According to the modern definition, all aldehyde and ketone compounds containing hydroxyl groups are called carbohydrates. Or, polyhydroxy aldehydes, polyhydroxyketones and their derivatives are collectively called carbohydrates.

Nomenclature of carbohydrates
The word carbohydrate is derived from the French word hydrate de carbon. It means hydrate of carbon or hydration of carbon. Carbohydrates are called carbs or saccharides or staff of life.

Source of carbohydrates
The main source of carbohydrates is plants. Most plant bodies contain 50-80% of their dry weight as carbohydrates. Major carbohydrate producing plants are – rice, wheat, sugarcane, bhutra, barley, cow, sugar, beet, carrot, date, grape, apple, mango, banana etc. Roots, stems, leaves, fruits and seeds of plants contain carbohydrates. Carbohydrates are found in guava, apple, onion, mango, pineapple, lichen, moss etc. Animal liver, muscle and milk contain carbohydrates.

Physical characteristics of carbohydrates
1. Carbohydrates are granular, fibrous and powdery solids.
2. It is sweet or tasteless.
3. It is insoluble in water, but monosaccharides are soluble in water.
4. Its molecular weight ranges from 10,000 to several hundred thousand daltons.
5. They turn into carbon or embers on high heat.
6. It is light active and light tolerant.

Chemical characteristics of carbohydrates
1. Carbohydrates are made up of carbon, hydrogen and oxygen.
2. It contains more hydroxyl group (-OH).
3. They combine with acids to form esters.
4. Moist analysis of this yields aldehydes and ketones.
5. Carbohydrates must contain hydroxyl and carbonyl groups.
6. Carbohydrates are attached to lipids to form glycolipids and proteins to form glycoproteins.
7. It stores short term energy.
8. Cellulose is the structural component of plant cell walls and chitin is the cell wall of fungi.

Classification of Carbohydrates
1. Classification based on taste
Carbohydrates are divided into two categories based on taste. These are-
(i) Sugar: Carbohydrates that are sweet, granular and soluble in water are called sugars. Such as glucose, fructose, sucrose etc.
(ii) Non-sugar: Carbohydrates which are not sweet, granular and insoluble in water are called non-sugars. Such as starch, cellulose, glycogen etc.

2. Classification based on oxidation potential
Carbohydrates are divided into two categories based on their oxidative capacity. These are-
(i) Reducing or reducing sugars: Those carbohydrates which have aldehyde and ketone radicals in free form and react with Fehling’s reagent, Benedict’s reagent and Burford’s reagent are called reducing or reducing carbohydrates. All monosaccharides are monosaccharides. Because the aldehyde group (-CHO) or ketone group (-CO) of monosaccharides are free. For example, glucose, fructose, galactose, glyceraldehyde, ribose, xylose etc.
(ii) Non-reducing or non-reducing sugars: Those carbohydrates which do not have aldehyde and ketone radicals in free form and do not react with Fehling’s reagent, Benedict’s reagent and Burford’s reagent are called non-reducing or non-reducing carbohydrates. Eg Sucrose, Starch, Cellulose, Glycogen, Trehalose etc. Dr. Siddiq Publications

3. Structural classification
Carbohydrates are divided into four categories based on structure. These are-
(i) Monosaccharides, (ii) Disaccharide, (iii) Oligosaccharide, (iv) Polysaccharide

Monosaccharides
Monosaccharide is formed from the Greek word mono meaning one and saccharin meaning sugar. Monosaccharide means a single sugar. Carbohydrates that do not yield any other simple carbohydrate units when broken down or analyzed are called monosaccharides. Their common symbol is CnH2nOn. Monosaccharides have 3-10 carbons. Monosaccharides have a free aldehyde group (-CHO) at carbon 1 or a ketone group (>C=O) at carbon 2, so they are called reducing sugars or reducing sugars. Monosaccharides with aldehyde groups are called aldoses and monosaccharides with ketone groups are called ketoses. Aldehyde and ketone groups are reducing groups and sugars containing reducing groups are called reducing sugars.

Characteristics of monosaccharides
(i) It is a simple sugar.
(ii) It is photoactive.
(iii) It is a small molecule.
(iv) Its molecular weight is less than 10,000 daltons.
(v) It has a sweet taste.
(vi) It is granular and soluble in water.
(vii) It contains aldehyde and ketone groups.
(viii) It is called aldose or ketose sugar.
(ix) It is a repulsive sugar.

Classification of Monosaccharides
Monosaccharides can be divided into two groups based on the aldehyde or ketone group.
1. Aldose: Monosaccharides containing aldehyde groups are called aldoses. Such as glucose, erythrose, ribose, mannose etc. Dr. Siddiq Publications
2. Ketose: Monosaccharides containing ketone group are called ketose. Such as fructose, erythrulose, ribulose, dihydroxyacetone etc.

The different types of monosaccharides based on the number of carbons are-
1. Triose: Monosaccharides with three carbons are called triose. A triose with an aldehyde group is called an aldotriose and a ketone group with a ketotriose. Its molecular symbol is C3H6O3. For example, glyceraldehyde, dihydroxy acetone etc.
2. Tetrose: A four-membered monosaccharide is called a tetrose. Its molecular symbol is C4H8O4. A tetrose with a four-carbon aldehyde group is called an aldotetrose and a ketone group with a ketotetrose. Eg-Erythrose, Thirose, Erythrolose etc. Dr. Siddiq Publications
3. Pentose: Five carbon monosaccharides are called pentoses. Its molecular symbol is C5H10O5. Ribose and deoxyribose are pentose sugars and form nucleotides and nucleic acids. Examples – ribulose, xylulose, arabinose, lyxose, ribose, deoxyribose etc. Dr. Siddiq Publications
4. Hexose: Monosaccharides with six carbons are called hexoses. Its molecular symbol is C6H12O6. Hexoses of aldehyde groups are called aldohexoses and hexoses of ketone groups are called ketohexoses. They are known as blood sugar. There are 16 types of hexoses. The abundant hexose is the glucose that provides energy to living cells. Examples – glucose, fructose, galactose, mannose etc.
5. Heptose: A monosaccharide with seven carbons is called heptose. Its molecular symbol is C7H14O7. Its number is very less. It plays an important role in photosynthesis. Pseudoheptulose, monoheptulose etc.
6. Octose: An eight carbon monosaccharide is called octose. Its molecular symbol is C8H26O8. eg glucooctose. Dr. Siddiq Publications
7. Nenose: A monosaccharide having nine carbons is called nenose. Its molecular symbol is C9H18O9. eg gluconanose.
8. Decose: A ten carbon monosaccharide is called decose. Its molecular symbol is C10H30O10. E.g. Glucodecose.

Disaccharide
Carbohydrates that break down or break down into two molecules of monosaccharides are called disaccharides. Their chemical symbol is C12H22O11. A condensation reaction between two monosaccharide molecules results in the removal of one molecule of H2O from two –OH groups to form a disaccharide. Both monosaccharide molecules of the disaccharide form new C-O-C bonds. The C-O-C bond formed is called a glycosidic bond. Disaccharides such as sucrose (table sugar), maltose, isomaltose, lactose (milk sugar), cellobiose, trehalose etc. When sucrose or sugar is broken down, glucose and fructose are obtained. Again, lactose is broken down to glucose and galactose. Dr. Siddiq Publications

Oligosaccharide
The word oligosaccharide is formed from the Greek words oligo meaning few and saccharin meaning sugar. Oligosaccharide means few sugars. Carbohydrates that break down or break down into a few molecules of monosaccharides (3-10 molecules) are called oligosaccharides. Monosaccharides or monomers are linked by glycosidic bonds to form oligosaccharides. The attachment of the hydroxyl group of one monosaccharide to the hydroxyl group of another monosaccharide is called glycosidic linkage. Dr. Siddiq Publications

Properties of oligosaccharides
(i) Oligosaccharides are simple sugars.
(ii) It can be wet analyzed.
(iii) It is a small molecule.
(iv) Its molecular weight is less than 10,000 daltons.
(v) It has a sweet taste.
(vi) It is granular and soluble in water.
(vii) It is an insoluble sugar.

Some oligosaccharides
(i) Trisaccharides: Carbohydrates which break down or break down into three molecule monosaccharides are called trisaccharides. Such as – raffinose, rabinose, raminose and malizitose. Breaking down raffinose yields glucose, fructose and galactose. Dr. Siddiq Publications
(ii) Tetrasaccharides: Carbohydrates which break down or break down into four molecules of monosaccharides are called tetrasaccharides. Its chemical symbol is C24H42O21. Eg – Stachyose, Skardose etc. When stachyose is broken down, glucose, fructose and two molecules of galactose are obtained. Tetrasaccharides are found in plants of the Leguminosae and Labiatae families. Cucurbita pepo plant contains tetrasaccharides.
(iii) Pentasaccharides: Carbohydrates which break down or break down into monosaccharides of five molecules are called pentasaccharides. For example, verbose. The root of Verbescus thepus plant contains pentasaccharides.
(iv) Hexasaccharide: Carbohydrates composed of six monosaccharide molecules are called hexasaccharides. For example, α-Cyclodextrin.
(v) Heptasaccharides: Carbohydrates which are made up of seven molecules of monosaccharides are called heptasaccharides.
(vi) Octasaccharides: Carbohydrates which are composed of eight molecules of monosaccharides are called octasaccharides.
(vii) Nanasaccharides: Non-carbohydrate molecules composed of monosaccharides are called Nanasaccharides.
(viii) Decasaccharides: Carbohydrates which are composed of ten molecules of monosaccharides are called Decasaccharides.

Polysaccharide
Polysaccharide is formed from the Greek words poly meaning many and saccharin meaning sugar. Carbohydrates that break down or break down into many molecules (more than 10) of monosaccharides are called polysaccharides. Their common symbol is (C6H10O5)n. where 10 ≥ n ≤ 3000|

Properties of polysaccharides
(i) It is a complex sugar.
(ii) Its wet analysis yields numerous monosaccharide molecules.
(iii) It is a large molecule.
(iv) Its molecular weight is more than 10,000 daltons.
(v) It is not sweet in taste.
(vi) It is non-granular and insoluble in water.
(vii) It does not contain aldehyde and ketone groups.
(viii) It is an insoluble sugar.

1. Classification based on work
Polysaccharides are divided into three categories based on function.
(i) Stored polysaccharides: All the carbohydrates that are stored in the body as stored food are called stored polysaccharides. For example, starch, glycogen, inulin, dextin, paramylam, livan etc. Starch is the main stored food in plants and glycogen in animals. Dr. Siddiq Publications
(ii) Structural polysaccharides: Carbohydrates which form the cell walls of plants are called structural polysaccharides. For example, cellulose, hemicellulose, pectic acid, chitin, keratin sulfate etc. Cellulose is the main structural component of the cell wall.
(iii) Complex polysaccharides: Those polysaccharides which are composed of sugars and non-sugars are called complex polysaccharides. Such as mucopolysaccharide, agar, hyaluronic acid, chondroitin sulfate, heparin etc. Dr. Siddiq Publications
2. Structural classification
Polysaccharides are divided into two categories based on structure.
(i) Homopolysaccharides or Homoglycans: Carbohydrates that are composed of monosaccharides of the same type are called homopolysaccharides or homoglycans. For example, starch, cellulose, glycogen, inulin etc.
(ii) Heteropolysaccharides or Heteroglycans: Carbohydrates composed of two or more types of monosaccharides are called heteropolysaccharides or heteroglycans. Such as hemicellulose, mucopolysaccharide, pectin, chitin, agar etc.
3. Unit Based Classification: On the basis of structural unit polysaccharides are of several types-
(i) Glucosan: The polysaccharide formed from glucose is called glucosan.
(ii) Fructosan: The polysaccharide formed by fructose is called fructosan.
(iii) Galactasan: The polysaccharide formed by galactose is called galactasan.
(iv) Hexosan: A polysaccharide composed of six carbon monosaccharides is called hexosan.

1. Ribose
Ribose is a monosaccharide with five carbons. It is called D-ribose. Ribose was discovered by scientist Emil Fisher in 1891. Its molecular symbol is C5H10O5. Its melting point is 95 degrees Celsius. It is a reducing sugar. It is called aldopentose sugar as it contains aldehyde group. Capable of ribose oxidation. It reacts with Hcl to produce furfuric acid. Ribose acts as the building block of RNA. A purine or pyrimidine base combines with ribose to form a nucleoside. Nucleosides combine with inorganic phosphates to form nucleotides. Nucleotides are then combined to form RNA. Ribose helps in the formation of sugars in the photophosphorylation process. Ribose is attached to biomolecules like ATP, NAD+, NADP+, FAD, Co-A etc. Dr. Siddiq Publications
2. Ribulose
Ribulose is a five-carbon monosaccharide. It is a reducing sugar. Its molecular symbol is C5H10O5. Since it contains a keto group, it is called a ketopentose sugar. Ribulose acts as a CO2 consumer in photosynthesis and produces ribulose 1, 5 bisphosphate. Ribulose 1, 5 bisphosphate is oxidized to form carboxyl compounds. Dr. Siddiq Publications
3. Deoxyribose
Deoxyribose is a five-carbon monosaccharide. It is a reducing sugar. Its molecular signaling
C5H10O4. It was discovered by scientist Phoebus Levene in 1929. It is called aldopentose sugar as it contains aldehyde group. Capable of deoxyribose oxidation. It is named deoxyribose because there is no oxygen attached to its 2nd carbon. Deoxyribose acts as a building block for DNA. A purine or pyrimidine base attaches to the 1st carbon of deoxyribose to form a deoxynucleoside. Deoxynucleosides and inorganic phosphate combine to form deoxynucleotides. Deoxynucleotides combine to form DNA. DNA transfers the hereditary characteristics of organisms through generations.

4. Glucose
Glucose is a six-carbon monosaccharide. It is a reducing sugar. Its molecular signal. It is called aldohexose as it contains aldehyde group. Ripe fruits and honey contain high amounts of glucose. As the ripe fruit contains 12-30% glucose, it is called grape sugar. It is called dextrose, corn sugar, grape sugar, blood sugar and D-glucose. Its relative sweetness is 74. Glucose is produced in the plant body in the process of photosynthesis. However, sugars are never stored in plant bodies. It acts as the primary component of respiration.

Properties of Glucose
(i) Glucose is a simple sugar.
(ii) It is a white granular substance.
(iii) It has a sweet taste.
(iv) It is soluble in water.
(v) It is slightly soluble in alcohol, but insoluble in ether.
(vi) It contains aldehyde group. Dr. Siddiq Publications
(vii) It is called aldose sugar.
(viii) It is a reactive sugar.
(ix) Glucose binds to proteins in the animal body to form glycoproteins.
(x) It reacts with phosphoric acid to form esters.
(xi) Its melting point is 146 degrees Celsius. (α- D glucose) and 150 degrees C. (β-D glucose).

Different types of glucose
(i) D Glucose (Dextrorotatory): If the hydroxyl (OH) group is attached to the right side of the 5th carbon of glucose.
It is called dextrorotatory or D glucose. Its rotation direction is to the right of the chiral center. It is a light activator. All natural glucose is D glucose. Dr. Siddique Publications
(ii) L Glucose (Laevorotatory): If the hydroxyl (OH) group is attached to the left side of the 5th carbon of glucose, it is called Laevorotatory or L glucose. Its rotation direction is to the left of the chiral center. It is a light activator. L-glucose is synthetically produced for use in diabetes medication and endoscopy. (The center along which the carbon molecules are linked is called the chiral center). Dr. Siddique Publications
(iii) α-D glucose and β-D glucose: Carbon 1 of glucose forms an oxygen bridge near carbon 5. A ring structure is formed as a result. An -OH group is generated due to the ring structure. If the -OH group is below the 1st carbon of glucose, it is called α-D glucose and if it is above the 1st carbon of glucose, it is called β-D glucose. α-glucose forms starch and β-glucose forms cellulose. D glucose is always present in the plant body.

Use of glucose
(i) Glucose is used as patient food. Quickly energizes the patient.
(ii) It is used in fruit preservation. Prevents fruit rot.
(iii) D-glucose is used to produce vitamin C from bacteria in the Richstein process.
(iv) Glucose is used in the preparation of calcium gluconate drugs.
(v) It plays a role in carbohydrate metabolism in the organism.
(vi) It is used to make citric acid, gluconic acid, bio-ethanol, sorbital etc.
(vii) It acts as a source of energy for sick people. Dr. Siddique Publications
(viii) Glycoproteins and glycolipids are formed from glucose.
(ix) Glucose is used in the process of glycolysis to generate energy.

5. Fuctose
Fructose is a six carbon monosaccharide. It is a reducing sugar. Since it contains a keto group, it is called a ketohexose. Fructose is so named because it was first identified from fruit. Sugarcane, beets, ripe fruits, nectar and honey contain high amounts of fructose. Ripe fruits contain a lot of fructose, so it is called fruit sugar or levulose. Its relative sweetness is 173. Fructose is the largest source of fructose in plants. Augustin Pierre Dubrunfaut discovered it in 1847. 2,40,000 tons of fructose are produced in the world every year. Dr. Siddiq Publications

Properties of fructose
(i) Fructose is a simple sugar.
(ii) It is a white granular substance.
(iii) It has a sweet taste.
(iv) It is soluble in water.
(v) It is soluble in hot alcohol.
(vi) It contains keto group.
(vii) It is called ketose sugar.
(viii) It is a reactive sugar.

Use of fructose
(i) Fructose is used in making sweets.
(ii) Used in making beverages, cakes, juices etc.
(iii) It acts as a source of energy.
(iv) It is used as delicacy for sick people.
(v) Fructose is used as a substitute for glucose in diabetic patients.
(vi) It combines with phosphoric acid to form esters.
(vii) It is used to prepare culture medium.
(viii) Male semen contains fructose. Therefore, sexual harassment can be proven by checking the presence of fructose in the genitals of women. Dr. Siddiq Publications

Chemical structure of fructose
Fructose is a six-carbon chemical compound with the molecular symbol C6H12O6. Fructose can be of two types based on the position of the -OH group. These are D and L fructose. If the -OH group on the 5th carbon of fructose is on the right side, it is called dextrorotatory or D fructose and if the -OH group on the 5th carbon of fructose is on the left side, it is called Laevorotatory or L fructose. Dr. Siddiq Publications

Why is fructose harmful to the human body?
A certain amount of fructose is metabolized in human liver cells. The liver cannot metabolize all the fructose when consuming high-calorie and high-fructose foods. Excess fructose is converted to fat and stored. Accumulated fat causes obesity, type-2 diabetes, cancer, heart disease, etc. in humans. So fructose is harmful to human body. Dr. Siddiq Publications

* Pyranose: Pyranose is hexagonal and has 5 carbons and 1 oxygen in its ring.
* Furanose: Furanose is pentagonal and has 4 carbons and 1 oxygen in its ring.

Relative Sweetness: Lactose-16, Maltose-32, Glucose-74, Sucrose-100, Fructose-173, Saccharin-500, Monaleline-2000. Dr. Siddiq Publications

6. Mannose: Mannose is a monosaccharide. It is an aldohexose sugar. It is the C-2 epimer of glucose. The molecular symbol for mannose is C5H10O5. It works metabolically in the human body. It plays an important role in glycosylation of proteins.
7. Galactose: Galactose is a monosaccharide. It is an aldohexose sugar. It is the C-2 epimer of glucose. The molecular symbol for galactose is C6H12O6. It is used to prepare culture media.

8. Sucrose : Definition, structure, characteristics and uses
The Latin word Sucrose means Sugar. Sucrose is a disaccharide. It is a non-reducing sugar. Sucrose is called sugar or beet sugar. Sugarcane, beets, carrots, flower nectar, pineapple etc. contain sucrose. The main raw material of honey is sucrose. Sugarcane contains 15% sucrose. It is twice as sweet as glucose. Carbohydrates are produced in plant leaves during photosynthesis and transported to various organs as sucrose. That is, sucrose is transported throughout the plant body. Sugar is sucrose. Analyzing sugar produces glucose and fructose. About 170 million tons of sugar are produced every year. English chemist William Miller (1857) coined the term sucrose.

Chemical structure of sucrose
Sucrose is a disaccharide and its molecular symbol is C12H24O11. Glucose and fructose combine to form sucrose molecules. The -OH group on the 1st carbon of α-D glucose and the OH group on the 2nd carbon of β-D glucose form a glycosidic bond. A molecule of water is released during the formation of the glycosidic bond. As a result, aldehyde and ketone groups are destroyed. So while glucose and fructose are reducing sugars, sucrose is a non-reducing sugar.

Characteristics of sucrose
(i) Sucrose is a white granular solid.
(ii) It is soluble in water, but insoluble in pure alcohol and ether.
(iii) It is twice as sweet in taste as glucose.
(iv) Its melting point is 188°C.
(v) Its wet analysis gives glucose and fructose.
(vi) It is a reactive sugar.
(vii) It is a non-reducing sugar.

Use of sucrose
(i) As Sweetener: Sucrose is most widely used in the preparation of sweetened foods.
(ii) Energy producing: It produces energy as a component of respiration.
(iii) Soap making: It is used to make transparent soap.
(iv) Commercial use: Sucrose is used commercially to make glucose and oxalic acid.
(v) Formation of polysaccharides: It helps in formation of polysaccharides. Dr. Siddique Publications
(vi) Stored energy: Sucrose acts as a reservoir of stored energy in the plant body.
(vii) As Bait: Flies, cockroaches, ants and other harmful insects are attracted by sucrose. Sucrose is used as poison bait to kill them. Dr. Siddique Publications
(viii) Acid making: Sucrose is used to make oxalic acid.
(ix) Production of honey: The main raw material of honey is sucrose.
(x) As a preservative: Sucrose is a natural preservative. It is used in food preservation.
(xi) Fermentation process: Sucrose is the main food of fungi. Fungi accelerate the fermentation process. This is why sugar is used along with the raw material in the fermentation process. Dr. Siddique Publications
(xii) In Horticulture: Sucrose creates an inhospitable environment for nematode worms in the soil. So sucrose is used in garden soil.

9. Lactose
Lactose is a disaccharide. Its molecular symbol is C12H22O11. Milk contains 2-4% lactose. One molecule of glucose and one molecule of galactose are joined by a glycosidic bond to form lactose. Lactase enzyme breaks down lactose into glucose and galactose. Dr. Siddiq Publications
10. Cellobiose
Cellobiose is a disaccharide. It is a reducing sugar. Its molecular symbol is C12H22O11. Cellobiose is produced by the partial breakdown of cellulose or lignin. Two molecules of glucose are joined by β-1,4 linkage to form cellobiose. Cellobiose is broken down into glucose under the influence of emulsin enzymes and acids. Bromine oxidizes cellobiose with water to form cellobionic acid. Dr. Siddique Publications
Function: Cellobiose acts as a structural component of cell wall.
11. Maltose
Maltose is a disaccharide. It is a reducing sugar. Its molecular symbol is C12H22O11. It is sweet in taste and its sweetness is 30-60% of sugar. Maltose is produced by partial distillation of sugar. Maltose is formed by the partial breakdown of starch. Two molecules of glucose are joined by α-1,4 linkage to form maltose. Maltose is used in malting barley to make beer.

12. Cellulose
Cellulose is a complex homopolysaccharide. The cell wall of autophagous plants is composed of cellulose. Cellulose is the most abundant organic material on Earth. Glucose is obtained by wet analysis of cellulose with hydrochloric acid or sulfuric acid or sodium hydroxide. Cellulose molecules contain β-1-4 glycosidic linkages. Neither animals nor humans can digest cellulose because they have no enzymes to break these β-1-4 glycosidic bonds. French chemist Anselme Payen (1838) discovered cellulose. Kobayashi & Shoda (1992) first produced synthetic cellulose. Dr. Siddiq Publications

Amount of cellulose
94% in cotton, 90% in linen or linseed, 90% in cellulose, 30-40% in grass, 60% in wood, 45% in dry hemp fiber, 58% in jute, 40% in sugarcane bagasse, 42% in wheat straw and 40-70% in organic soil. remains

Properties of Cellulose
(i) Cellulose is a tasteless, odorless and colorless substance.
(ii) It is chemically inert, but converts to glucose on wet analysis with strong acids.
(iii) It is insoluble in water and organic solvents. Dr. Siddique Publications
(iv) Its molecular weight ranges from 2 lakh to several lakh daltons.
(v) It is non-toxic and non-oxidizing.
(vi) It shows no color in iodine solution.
(vii) It is tough and fibrous.
(viii) It has no nutritional value.
(ix) Cellulose contains 44.41% carbon, 44.4% oxygen and 6.2% hydrogen.

Chemical structure of cellulose
Cellulose is a complex polysaccharide. It is composed of glucose molecules. Numerous glucose molecules are linked by β 1-4 glycosidic bonds to form cellulose. Cellulose is converted to glucose by hydrolysis with H2SO4 or HCl or NaOH.

Uses of cellulose
(i) Textile industry: Cellulose is used as the main raw material for textile industry. Rayon is made from cellulose as the raw material of the fabric.
(ii) As an explosive: It is used as a nitrate explosive. Cellulose is used as raw material for making nitrocellulose. Dr. Siddique Publications
(iii) For making furniture: Cellulose is the main material of wood and bamboo. Various types of furniture are made from bamboo and wood.
(iv) In paper industry: It is used to make filter paper and tissue paper. Cellulose insulators are made from newsprint paper in a recycling process. Cellulose insulator is an environmentally friendly coating.
(v) Digestion: Wood-boring insects use cellulose to digest wood.
(vi) In making gum: Methyl cellulose is used in making gum. Pure cellulose is mixed with water to make glue.
(vii) For making photographic film: It is used for making photographic, cellophane and celluloid.
(viii) In Biotechnology: Cellulose produced from fungi and bacteria is being used in biotechnology.
(ix) As Structural Material: Cellulose acts as the main structural material of plants. It forms leaves, stems and branches of plants. Dr. Siddiq Publications
(x) Skeletal system of plants: Cellulose provides strength and protection to plants. Cellulose is therefore called the skeletal system of plants.
(xi) Faecal formation: Most of the cellulose ingested with animal feed is excreted as faeces. Rafez relieves constipation. Cellulose is therefore essential for animal life. Dr. Siddiq Publications
(xii) Stationary phase: Cellulose is used as the stationary phase in thin layer chromatography.

Why can’t people digest cellulose?
Cellulase, the enzyme that digests cellulose, is not produced in the mammalian digestive system. However, a type of mitotic bacteria lives in the digestive system of cows, buffaloes, goats, deer, sheep etc. All these bacteria produce cellulose digesting enzyme cellulase. This enzyme aids in cellulose digestion by cleaving the β, 1-4 glycosidic bonds of cellulose. Humans cannot digest cellulose because the human digestive system lacks such mitotic bacteria. But the human diet must contain cellulose-type food. Because cellulose is essential for the production of stool. Dr. Siddiq Publications

13. Starch
The German word Starch means strong or hard or hard or rigid. Starch is a complex homopolysaccharide. Its molecular symbol is (C6H10O5)n. Carbohydrates or sugars produced in the process of photosynthesis are converted into starch and stored. Rice, wheat, potato, sorghum, banana, barley etc. are the main sources of starch. All these ingredients contain 70-80% starch. Round potato starch particles are the largest and 100µm. Rice starch particles are smallest and 2µm. The first reference to the extraction of starch from plants is found in the Natural History of Pliny the Elder (77-78 AD). Dr. Siddiq Publications

Properties of Starch /Religion
(i) Starch is tasteless, odorless and colorless substance.
(ii) It is a white granular powdery organic chemical substance.
(iii) It is insoluble in water, alcohol and ether.
(iv) Starch turns blue in iodine solution.
(v) It breaks down at high temperature into large dextin particles.
(vi) Starch cannot oxidize Fehling’s solution.
(vii) Iodine reacts with amylose of starch to produce black or black-blue color.
(viii) Iodine reacts with amylopectin of starch to produce red or purple color.

Chemical structure of starch
Starch is a complex polysaccharide. Starch is made up of amylose and amylopectin. It contains 22% amylose and 78% amylopectin. Amylose is composed of 200-1000 molecules and amylopectin is composed of 2000-200,000 molecules of glucose. Numerous glucose molecules are linked by α-1-4 glycosidic bonds to form starch. However, glucose molecules can be joined by α-1-6 bonds. Starch is hydrolyzed to glucose.

Use of starch
(i) Stored food: Starch is stored in the plant body as stored food. Starch in plant seeds, fruits and tubers serves as stored food. Starch stored in rice, wheat, bhutra, cassava, corn and round potato is used as human food.
(ii) Source of energy: It acts as a source of energy in the organism. Starch is converted into glucose to provide energy and carbon molecules to the body. Dr. Siddiq Publications
(iii) Respiration: It generates heat and energy in respiration.
(iv) Research: Starch is used in the laboratory to produce glucose and alcohol.
(v) In Paper Industry: Starch is the main ingredient in paper industry.
(vi) Preparation of glue: Pure starch is mixed with hot water to make glue. It is used to make corrugated board glue.
(vii) In titration: Starch is used as indicator during titration.
(viii) Textile use: Warp seizing agent is produced from starch. Warp shrinking agents reduce the rate of yarn tearing during fabric weaving. Starch is used for beating (laundry) cloth. Dr. Siddiq Publications
(ix) Oil exploration: Starch is used to increase the viscosity of drilling fluids, which are slippery fluids in oil exploration.
(x) Manufacture of cosmetics: Starch is used in the manufacture of talcum powder and other cosmetics.
(xi) Food processing: Starch is used to increase the density of food during food processing.
(xii) Production of Polymers: Starch is used to make eco-friendly bioplastics and other synthetic polymers.
(xiii) Fuel production: Biofuel corn ethanol is produced from starch in a fermentation process.
(xiv) Reproduction: Starch stored in the fruits, seeds, rhizomes and corms of the plant participates in the production of offspring in the next season.
(xv) In pharmaceutical industry: Starch is used as active ingredient carrier, tablet disintegrant and binder in pharmaceutical industry.
(xvi) Clothing starch: Liquid clothing starch is prepared by mixing pure starch with water. It is used in garments and laundry.

14. Glycogen
Glycogen is a nutrient complex homopolysaccharide. Glycogen is the main stored food in the animal body. Glycogen is stored in the liver, muscles, brain and stomach of vertebrates. But the liver has the most. Human liver contains about 100-120 grams of glycogen. Cyanobacteria or blue-green algae and some fungi (yeasts) have glycogen as stored food. Glycogen is called animal starch. French scientist Claude Bernard (1857) discovered glycogen.

Glycogen Properties/Religions
(i) Glycogen is a white powdery biochemical substance.
(ii) It is soluble in water. Dr. Siddiq Publications
(iii) It forms suspension in cold water.
(iv) Its molecular weight is 50 lakh daltons.
(v) On wet analysis it converts first to maltose and then to α-glucose.
(vi) It reacts with iodine solution to acquire a reddish violet color.
(vii) Heat removes its red color.
(viii) It reverts to black color on cooling.
(ix) Partially hydrolyzed to maltose and fully hydrolyzed to α-D glucose.
(x) It is converted into glucose in the process of glycolysis.
(xi) It keeps blood glucose levels normal.

Chemical structure of glycogen
Glycogen is a complex polysaccharide. It is composed of numerous α-glucose molecules. In the process of glycogenesis, 30,000 molecules of glucose combine to form glycogen. Glucose molecules are linked by α-1-4 glycosidic bonds to form glycogen. Branching of glycogen occurs through α-1-6 linkage. Each branch contains 10-20 glucose molecules. Their molecular weight is 106-107 daltons. Glycogen is hydrolyzed into glucose. Glycogen is converted to glucose when needed to provide carbon and energy. For this reason, glycogen is called animal starch.

Utilization of glycogen
(i) Stored food: Glycogen is stored in the animal body as stored food.
(ii) Glucose production: Glucose is produced from liver glycogen in the process of glycogenesis.
(iii) Muscle energy: Glycogen stored in skeletal and cardiac muscles provides extra energy to muscles.
(iv) Regulation of blood volume: It regulates blood volume in the body. Increases blood glucose levels by breaking down liver glycogen. Dr. Siddiq Publications
(v) Formation of suspension: It forms colloidal suspension in water.
(vi) Production of Surfactant: Glycogen begins to accumulate in the pulmonary cells of the fetal baby at 23 weeks of gestation. Stored glycogen produces lung surfactant.
(vii) Energy storage: Glycogen production and storage takes place in the liver cells of animals. It acts as a stored energy reservoir secondary to the glucose cycle in the animal body. Dr. Siddiq Publications
(viii) Energy supply to the brain: A small amount of glycogen is stored in brain cells. It powers the conscious brain.

15. Inulin
Inulin is a polysaccharide. It is dissolved in cells. It contains 30-35 fructose units. Plants of the family Asteraceae such as dahlia, chicory, Jerusalem artichoke etc. contain inulin. Inulin is found in onions and garlic.
16. Chitin
Chitin is a polysaccharide. A simple linear homopolymer of N-acetyl-D-glucosamine residues is called chitin. Chitin is one of the most abundant substances on earth. It is the second most important polymer in the world. Its chemical symbol is (C8H13O5)n. Numerous D amino monomers are joined by β-1, 4 glycosidic bonds to form chitin.
Properties of chitin
(i) Chitin is insoluble in water, organic acids and weak acids.
(ii) It is soluble in strong formic acid and methane sulphonic acid.
(iii) It is stronger and more stable than cellulose.
(iv) Chitin is decomposed by strong acids to acetic acid and u-amino glucose.
(v) It is similar to keratin protein.
Source of Chitin: Chitin forms the exoskeleton or shell of animals like moths, crabs, shrimps, lobsters, squids. The cell walls of yeast and fungi are made of chitin. Dr. Siddique Publications
Uses of chitin: Chitin has uses in herbal, industrial and biotechnology.

Carbohydrate derivatives
New substances that are produced from carbohydrates are called derivatives. Carbohydrates are sugar-like substances and most are natural. Some of the carbohydrates are:
1. Saccharin or Sweet-N-Low: Saccharin or Sweet-N-Low is a primitive artificial sweetener. It is 300 times sweeter than sugar.
2. Glucosamine: Glucosamine is a well-known amino sugar in the human body. It is used in the production of glycosylated lipids and proteins. It polymerizes to form chitin. Fungi and arthropods contain chitin.
3. Galactosamine: Galactosamine plays a role in cell-to-cell interactions. It is the main component of cartilage.
4. Galactosamine adenosine: Galactosamine adenosine is an important component of DNA and RNA.
5. Sugar alcohol: Sugar alcohol is a sweet substance. Diabetics use it instead of sugar.
6. Amino sugar heparin: Amino sugar heparin is a granular substance. It resides in the mast cells of the arterial wall. It prevents blood clotting. Dr. Abu Bakr Siddiq
7. Sialic acid: Sialic acid is a sugar amine. It keeps people physically and mentally healthy.
8. Chondroitin sulfate: Chondroitin sulfate is a component of cartilage. It prevents stress.
9. Ascorbic acid or vitamin-C: Ascorbic acid or vitamin-C prevents scurvy.
10. Sucralose or Spinda: Sucralose or Spinda is an artificial sweetener. It is 600 times sweeter than sugar.

Functions/Importance of Carbohydrates
1. Source of Energy: Green plants convert solar energy into chemical energy in the process of photosynthesis. chemical
Uses energy to produce carbohydrates. These sugars then come from plants to animals. For this reason sugar is called bio-fuel. Dr. Abu Bakr Siddiq
2. stored food
(i) Starch is the main stored food in the plant body. Carbohydrates are stored in the form of starch in the seeds, fruits and tubers of plants.
(ii) Sucrose, fructose, raffinose etc. are stored as stored food in the plant body.
(iv) Glycogen is stored as stored food in all animal, bacterial and fungal cells.
(v) Excess carbohydrates are stored as glycogen in the liver and muscles.
(vi) Onion, garlic and dalia contain carbohydrates in the form of inulin.
3. structural elements
(i) Carbohydrates 50-80% of dry weight of plant body. It is the main constituent of the plant body.
(ii) Cellulose, hemicellulose, pectic acid etc. form the cell wall of plants.
(iii) Chitin forms the cell wall of fungi and the body wall of arthropods.
(iv) Peptidoglycan forms the cell wall of bacteria and cyanobacteria.
4. Formation of organic compounds: Pentose sugars act as building blocks of organic molecules such as DNA, RNA, ATP, ADP, NAD, NADP, FAD, GTP, GDP etc. Dr. Abu Bakr Siddiq
5. Industry: Sugar is used to make raw materials for various industries including paper and textile industries.
6. Fulfillment of basic needs: It plays an important role in fulfilling the basic needs of people like food, material, medical care, shelter etc.
7. Strengthening the body: The main component of xylem tissue is sugar. Xylem provides rigidity to the plant body. Due to this, the plant does not break in storms. Cellulose gives plants strength and protection and carries loads.
8. Metabolism: Carbohydrates help in the metabolism of amino acids and fatty acids in the body. It speeds up the process of peristalsis. Fatty oxidation does not occur in the absence of carbohydrates.
9. As a lubricant: Hyaluronic acid is used as a lubricant or lubricant in bone joints.
10. Anticoagulants: Heparin is a polysaccharide. Heparin acts as an anticoagulant factor in the body. It prevents blood clotting. So blood can move inside the blood vessels.
11. Excretion of waste products: Carbohydrates like fiber help in the elimination of waste products from the body. Faeces play an important role in fertilization. Dr. Abu Bakr Siddiq
12. Regulation of brain function: Carbohydrates give energy to the brain to think, act and function.
13. Nucleic Acids: Ribose and deoxyribose are pentose sugars. Pentose sugars form DNA and RNA.
14. Formation of glycocalyx: Carbohydrates are attached to proteins to form glycoproteins and lipids to form glycolipids. Glycoproteins and glycolipids together are called glycocalyx.
15. Antigen production: Different antigens of human blood group are produced from carbohydrates. Antigens are made up of glycoproteins and enhance immunity. Dr. Abu Bakr Siddiq
16. Biofuels: Carbohydrates are the main source of energy in the body. It acts as bio-fuel in the body. Carbohydrates are oxidized by oxygen to form water and CO2. It provides energy to cells. 50-80% of the body’s energy source is carbohydrates. This energy content is 4.1 Kcal/gm.
17. Co-enzymes: ATP, FAD, NAD, NADP etc. are the structural parts of co-enzymes.
18. Body building and repair: Carbohydrates provide extra protein to the body. Excess protein builds and repairs the organism’s body.
19. Hormones and reproduction: Follicular stimulating hormone (FSH) and Leutinizing hormone (LH) are formed by glycoproteins. It participates in animal reproduction.
20. Fatty Oxidation: Fatty oxidation is very important for the organism. Carbohydrate Op for Fatty Oxidation