Chapter 1 LIFE PROCESSES

Food is the basic requirement of all living organisms to get energy and to carry out their activities.

To perform vital life processes like respiration, chemical energy is used by living organisms.

Green plants are autotrophs because they can make their food themselves.

Inorganic substances such as CO2 and water are used by autotrophs to synthesize their food.

Fungi obtain their food from dead and decaying plants and animals. Such type of mode of nutrition is called saprotrophic nutrition.

Fungi have saprophytic mode of nutrition.

Leech has parasitic mode of nutrition.

Amoeba has holozoic mode of nutrition.

The process by which green plants make their own food is called photosynthesis.

In addition to carbon dioxide and water, plants need sunlight and chlorophyll for the process of photosynthesis.

Apart from sunlight and chlorophyll, plants need water and carbon dioxide to make food by the process of photosynthesis.

In the process of Photosynthesis, Carbon dioxide gas is used.

In the process of Photosynthesis, Oxygen gas is produced.

The food prepared in the plant by the process of photosynthesis is glucose (A) then it gets stored in plant leaves in the form of starch (B).

We use the alcohol to remove chlorophyll from the leaves during the photosynthesis experiments.

To remove chlorophyll from the leaves, we boil the leaf in alcohol.

Chlorophyll absorbs the light energy from the sun that is required to derive photosynthesis.

The colour of chlorophyll pigment is green.

Chloroplast contains a green pigment called chlorophyll. Chlorophyll absorbs the solar energy from the sun and converts it into chemical energy.

Chloroplasts are the plant cell organelles where the process of photosynthesis takes place.

Apart from carbon dioxide and water, nitrogen, magnesium, iron and phosphorus are needed by the plants. Plants take these raw materials from the soil.

Chlorophyll is present in the chloroplast and chloroplast is mainly present in the leaves of the plant.

Each stomata is surrounded by a pair of guard cells. Guard cells regulate the opening and closing of stomata.

The mode of nutrition in amoeba is holozoic and the process of obtaining food is called phagocytosis.

All animals, on the basis of their food habits, can be divided into three groups:-

• Herbivores

• Carnivores

• Omnivores

(i) The term carnivore is related to only flesh eating animals.

(ii) The term herbivore is related to only plant eating animals.

(iii) The term omnivore is related to both plant and meat eating animals.

Chlorophyll is the green pigment present in the leaves of plants. It is necessary for the process of photosynthesis in plants.

The correct order of processes involved in the nutrition in animals are-

Ingestion, digestion, absorption, assimilation, egestion.

Amoeba has no mouth for ingestion of food. Amoeba engulfs the food particles by forming finger-like projections called pseudopodia.

In amoeba, digestive enzyme digests the food in the food vacuole. The enzymes enter into the food vacuole from outer cytoplasm and break down the food into small molecules.

Amoeba has no fixed place for egestion. When sufficient amount of undigested food gets collected inside the cell, it is thrown out of the body by rupturing the cell membrane.

Paramecium, a unicellular animal, has tiny hair-like structures, called cilia around its body. It uses cilia to sweep the food particles from water into its mouth.

Saliva is a watery fluid which contains an enzyme called salivary amylase. Salivary amylase acts on starch and breaks down it into sugar.

(i) The absorption of digested food takes place in the small intestine.

(ii) The absorption of water from remaining indigestible food takes place in the large intestine.

Peristaltic movement is the contraction and relaxation of the muscles of the digestive tract to move the food through the digestive system.

Food pipe is also called oesophagus. Oesophagus is a long muscular tube that runs from the mouth to the stomach.

Salivary glands secrete saliva into the mouth which is mixed with the food. Saliva makes the food slippery so that it is easy to swallow.

The inner surface of small intestine has numerous finger-like projections called villi. Villi increase the surface area which helps in absorption of the digested food.

The walls of the large intestine absorb water from the remaining indigestible food materials.

Anus is the opening at the end of the alimentary canal through which undigested food is thrown out.

Digested food is absorbed in the small intestine. The digested food passes through the walls of small intestine and goes into our blood stream.

Enzymes are biological catalysts which increase the rate of chemical reactions that take place inside the living body. Examples: Pepsin, trypsin, amylase, etc.

(a) All green plants are autotrophs.

(b) All non-green plants and animals are Heterotrophs.

(c) Heterotrophs depend on autotrophs and other heterotrophs for food.

(d) Green plants use carbon dioxide and water to make food.

(e) Iodine turns blue-black on reacting with starch.

Chlorophyll is a green coloured pigment present in the leaves of plants. Chlorophyll absorbs the solar energy from the sunlight during the process of photosynthesis.

(i) The food prepared in the plant by the process of photosynthesis is in the form of sugar called glucose.

(ii) Extra glucose gets stored in plant leaves in the form of starch.

The most important factor that decides whether something is alive is movement.

All living organisms perform some basic functions to maintain their lives are called life processes. These life processes are: Nutrition and Respiration, Transportation and Excretion, Control and Co-ordination, Growth, Movement and Reproduction.

Those organisms which can make their own food from inorganic substances like carbon dioxide and water are called autotrophs. All green plants are the example of autotrophs.

Sunlight, chlorophyll, carbon dioxide and water are the necessary conditions required for autotrophic nutrition.

Those organisms which cannot make their own food from inorganic substances like carbon dioxide and water and depend on other organisms for their food are called heterotrophs. All the animals, fungi, and bacteria are examples of heterotrophs.

The nutrient is a chemical substance which is essential for growth and energy for various metabolic activities in living organisms.

Carbohydrates, proteins, fats and minerals are main nutrients present in our body.

Heterotrophic mode of nutrition if of three types:

I. Saprotrophic (saprophytic) nutrition

II. Parasitic nutrition

III. Holozoic nutrition

Photosynthesis is a process in which light energy (X) is converted into chemical energy (Y).

The process of photosynthesis takes place in the following three steps:

• Absorption of light energy by chlorophyll

• Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.

• Reduction of carbon dioxide to carbohydrates.

Plants are autotrophs so they can make their own food from inorganic substances like carbon dioxide and water by the process of photosynthesis.

Nitrogen is essential element for plants which is used to make proteins and other compounds. Plants take up nitrogen from the soil in the form of inorganic salts called nitrates (or nitrites), or in the form of organic compounds which are prepared by bacteria from the atmospheric nitrogen.

(i) Saprophytic Nutrition: Saprophytic nutrition is that nutrition in which organisms obtain their food from dead and decaying organisms (plants and animals).

Examples: Fungi (mushrooms), and many bacteria.

(ii) Parasitic Nutrition: Parasitic nutrition is that nutrition in which organisms obtain their food from other living organisms (called host).

Examples: Leech, mosquito.

(iii) Holozoic Nutrition: In this mode of nutrition, the digestion happens inside the body of the organism. Most of the animals follow this mode of nutrition.

Example: Human beings

(i) Saprophytes obtain their food from dead and decaying organisms. Fungi and many bacteria are examples of saprophytes.

(ii) Parasites live on or in other organisms and obtain their food from them. Leech, mosquito, plasmodium are examples of parasites.

Plants need carbon dioxide for the process of photosynthesis. They take carbon dioxide from the air. Carbon dioxide enters the leaves through tiny pores present on the leaves’ surface called stomata.

Water is important factor required for photosynthesis. Plants take water from the soil through their roots by the process of osmosis. The xylem vessels then transport the water to the leaves where it reaches the chloroplast containing cells and is utilized in photosynthesis.

The stomach walls secrete gastric juice which contains three substances: Hydrochloric acid, pepsin enzyme and mucus.

Functions:

(a) Hydrochloric acid kills the germs. It makes acidic medium inside the stomach which is necessary for pepsin enzymes to work.

(b) The enzyme pepsin does partial digestion of protein.

(c) The mucus helps to protect the stomach wall from its own secretions of hydrochloric acid.

Pancreas secretes pancreatic juice which contains digestive enzymes like pancreatic amylase, trypsin and lipase.

Functions:

(a) Pancreatic amylase breaks down the starch.

(b) Trypsin digests the proteins.

(c) Lipase breaks down emulsified fats.

Hydrochloric acid makes acidic medium inside the stomach which is necessary for pepsin enzymes to work. In acidic medium, pepsin breaks down proteins into peptones.

Another function of hydrochloric acid is to kill germs that entered the stomach along with food.

The function of enzymes in the digestive system is to help in the breaking down of complex organic food materials into simpler forms.

Bile is a greenish-yellow liquid that is secreted by liver and stored in gall bladder. It contains bile pigments and bile salts.

Functions: The bile performs two functions:

(i) Bile makes acidic food, coming from stomach, alkaline so that pancreatic enzymes act on it.

(ii) Bile salts break down the fat present in the food into smaller globules. This increases the efficiency of enzyme to act and digest the food.

Trypsin is a pancreatic enzyme which is secreted by pancreas. It digests the proteins.

Liver secretes bile which contains bile pigments and bile salts. Bile helps in the emulsification of fats present in the food.

Pancreas secretes pancreatic juice in the small intestine. Pancreatic juice contains digestive enzymes which help in the digestion of proteins, fats and starch.

(i) c (ii) a (iii) d (iv) b

(a) Photosynthesis is the process by which green plants convert light energy (Sunlight) into chemical energy (Carbohydrates).

(b) Heterotrophs organisms cannot make their own food and depends on other organisms for their food.

(c) Autotrophs organisms can make their own food from carbon dioxide and water.

(d) The process of photosynthesis takes place in Chloroplasts.

(e) A stomata consists a pair of guard cells surrounding a opening called Stomatal pore.

(f) Pepsin is a protein digestive enzyme that is secreted by gastric glands in stomach and breaks down proteins into peptones.

(i) c (ii) d (iii) a (iv) b

All are parasites because they derive their food from other living organisms without killing them.

(b) -

(i) Trypsin is a pancreatic enzyme which digests protein into amino acids.

(ii) Amylase acts on carbohydrates (starch) and converts it into sucrose.

(iii) Pepsin is a digestive enzyme which digests the proteins and converts them into smaller molecules.

(iv) The enzyme lipase digests fat into fatty acids and glycerol.

The inner surface of small intestine has numerous finger-like structures, called Villi. Villi increase the surface area of small intestine so that optimal absorption takes place.

Cellulose is a carbohydrate that is digested with difficulty. Herbivores animals like cow, ox, and buffalo that eat only plants (grass) have a longer small intestine to allow the cellulose, present in the plants to be digested completely.

The mucus helps to protect the stomach wall from the secretion of hydrochloric acid. If mucus is not secreted by gastric glands, hydrochloric acid will cause the erosion of inner lining of stomach leading to the formation of ulcers in the stomach.

The contraction and expansion movements of the oesophagus called peristaltic movements push the food down inside the alimentary canal.

The guard cells regulate the opening and closing of stomatal pores. They swell, when water flows into the guard cells and stomatal pores get opens. Similarly, when the guard cells lose water, they shrink, become straight and the stomatal pores get closed.

Plant which is placed in continuous light will live longer because it can do the process of photosynthesis by using light and produce oxygen which is required for the respiration. While plant which is placed in dark does not do the process of photosynthesis due to lack of light.

Green plants are the source of food for all living organisms. So, if all the green plants disappear from the earth, then all the organisms will die because of starvation.

If plant is releasing CO₂ and taking in O₂, it doesn’t mean that no photosynthesis is happening in the plant. In day time, plants perform both respiration and photosynthesis simultaneously. Plants use up all carbon dioxide released by respiration in the process of photosynthesis. Similarly, some of the oxygen produced during photosynthesis is used up in respiration.

The plant whose leaves are coated with vaseline will not remain healthy for long because vaseline will make a coating on the leaves. This will close the stomata due to which plant will stop exchange of gases and transpiration. This plant won’t be able to get carbon dioxide for photosynthesis. Thus, the plant will not be able to prepare its food. As a result, plant will die.

(i) The rate of photosynthesis decreases in cloudy day in morning but increases in bright sunshine in the afternoon.

(ii) The rate of photosynthesis decreases in the area where there is no rainfall for a considerable time.

(iii) The rate of photosynthesis decreases when dust gathers on the leaves.

The process by which green plants make their food in the presence of sunlight and chlorophyll with the help of inorganic substances like carbon dioxide and water, is called photosynthesis.

The process of photosynthesis can be represented as:

The process of photosynthesis takes place in the green leaves of a plant. Plants need carbon dioxide and water for the process of photosynthesis. Plants take carbon dioxide from the air. Carbon dioxide enters the leaves through tiny pores present on the leaves’ surface called stomata. Plants take water from the soil through their roots by the process of osmosis. The xylem vessels then transport the water to the leaves where it reaches the chloroplast containing cells and is utilized in photosynthesis. The process of photosynthesis takes place in the presence of sunlight. The sunlight provides energy required to carry out the chemical reactions involved in the preparation of food. This sunlight energy is absorbed by the green pigment called chlorophyll. The process of photosynthesis takes place in the following three steps:

• Absorption of light energy by chlorophyll

• Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.

• Reduction of carbon dioxide to carbohydrates.

The raw materials for photosynthesis are carbon dioxide and water. Plants need carbon dioxide and water for the process of photosynthesis. Plants take carbon dioxide from the air. Carbon dioxide enters the leaves through tiny pores present on the leaves’ surface called stomata. Plants take water from the soil through their roots by the process of osmosis. The xylem vessels then transport the water to the leaves where it reaches the chloroplast containing cells and is utilized in photosynthesis.

Sunlight, chlorophyll, carbon dioxide and water are the necessary conditions required for photosynthesis.

The rate of photosynthesis is affected by:

•Light

•Carbon dioxide

•Water

•Temperature

•Mineral elements

Nutrition is a physical process by which living organisms obtain raw materials (nutrients) to sustain their life. Carbohydrates, fats, proteins, minerals, vitamins and water are examples of nutrients which organisms obtain from their surroundings. Nutrition is necessary for organisms as it provides energy to them for metabolic activities, growth and tissue repair.

There are mainly two modes of nutrition:

(i) Autotrophic Nutrition

(ii) Heterotrophic Nutrition

(i) Autotrophic Nutrition: Autotrophic nutrition is that mode of nutrition in which organisms prepare their own food from inorganic substances like carbon dioxide and water in the presence of sunlight and chlorophyll. All green plants obtain their food by autotrophic nutrition.

(ii) Heterotrophic nutrition: Heterotrophic nutrition is that mode of nutrition in which organisms cannot prepare their own food from inorganic substances like carbon dioxide and water and depend on other organisms for their food. All the animals, fungi, and bacteria have heterotrophic mode of nutrition.

The mode of nutrition in (i) round worm and (ii) plasmodium is parasitic nutrition. Parasitic nutrition is that nutrition in which organisms obtain their food from other living organisms (called host).

(i) Herbivores: Animals which eat only plants or their parts like grass, leaves, frutis, etc are called herbivores. Cow, goat, dear, camel are examples of herbivorus animals.

(ii) Carnivores: Animals which eat only flesh of other animlas are called carnivores. Tiger and lion are examples of carnivores.

(iii) Omnivores: Animals that eat both plants and animals are known as omnivores. Example: Human being, crow, dog, sparrow, etc.

Herbivores Carnivores Omnivores

Goat Lion Man

Elephant Snake Dog

Rabbit Hawk Crow

Deer

There are five steps in the process of nutriton in Animals:

(i) Ingestion: It is the process of taking in food.

(ii) Digestion: The process of breaking complex food substances into simple molecules.

(iii) Absorption: It is the process of absorption of digested food.

(iv) Assimilation: It is the process of utilization of digested food; for energy, growth and repair.

(v) Egestion: It is the process of throwing out faecal matter out of the body

Nutrition in amoeba

Nutrition in amoeba involves the following steps-

(i) Ingestion: Amoeba is a unicellular organism which feeds on microscopic plants and animals which flowt on water. The mode of nutrition in Amoeba is holozoic. Amoeba has no mouth for ingestion of food. It ingests the food by using finger-like extension of cell surface called pseudopodia. The food is engulfed with little water to form a food vacuole.

(ii) Digestion: The food is digested in the food vacuole by digestive enzymes which break down the food into small and soluble molecules by chemical reactions.

(iii) Absorption: The digested food, present in the food vacuole is absorbed directly into the cytoplasm by diffusion. The digested food spreads out from the food vacuole into the whole amoeba cell. After absorption, the food vacuole shrinks and disappears.

(iv) Assimilation: In this step, the absorbed food is used to obtain energy through respiration and other metabolic activities which lead to the growth of Amoeba.

(v) Egestion: Amoeba has no particular point from which the egestion takes place. When considerable amount of undigested food collects inside the cell, then its cell membrane ruptures at any place. Through this, the undigested food is thrown out of the body.

The mode of nutrition in Amoeba is Holozoic.

The process by which Amoeba obtains food is called phagocytosis which means cell feeding.

Digestion of food in the human beings:

In human beings, digestion of food starts from the mouth. Mouth opens into a chamber or cavity called buccal cavity. The buccal cavity contains teeth, tongue and salivary glands. The teeth cut the food into small pieces, chew and grind it. Thus, teeth help in physical digestion. Salivary glands produce saliva which mixes with the food. Saliva is a watery fluid that makes the food slippery for swallowing. These glands help in chemical digestion of food.

The saliva contains an enzyme called salivary amylase which digests the starch into maltose sugar. Buccal cavity opens into pharynx which leads to a long tube called oesophagus. The walls of oesophagus are highly muscular. Digestion does not occur in the oesophagus. It carries the food down into the stomach. When the slightly digested food enters the oesophagus, its walls starts contraction and expansion movements called peristaltic movements. These movements push the food from the oesophagus into the stomach.

The glands present on the walls of the stomach secrete gastric juice that contains three substances: hydrochloric acid, the protein digesting-enzyme, called pepsin and mucus. Hydrochloric acid makes acidic medium inside the stomach which is necessary for pepsin enzymes to work. In acidic medium, pepsin breaks down proteins into peptones. Another function of hydrochloric acid is to kill germs that entered the stomach along with food. The mucus helps to protect the stomach wall from its own secretions of hydrochloric acid.

From the stomach, the partially digested food goes into the small intestine through sphincter muscle. In humans, small intestine is the site of complete digestion of food like carbohydrates, proteins and fats. It receives the secretions of two glands, liver and pancreas through a common duct. Liver secretes bile which is alkaline and contains bile salts and bile pigments. Bile salts helps to emulsify the fats. The bile secreted by the liver is stored in the gall bladder. Pancreas secretes pancreatic juice which contains trypsin, lipase and pancreatic amylase. Trypsin digests the proteins, lipase emulsifies the fats and pancreatic amylase breaks down the starch. The wall of small intestine contains glands which secrete intestinal juice. Intestinal juice contains a number of enzyme which complete the digestion process.

Human Digestive System

The inner surface of small intestine has numerous finger-like structures, called Villi. Villi increase the surface area of small intestine so that optimal absorption takes place.

Peristaltic movements.

Teeth help us to cut the food into small pieces, chew and grind. The outermost part of the tooth is enamel. Enamel is the hardest tissue in the body. Below the enamel is dentin which surrounds the pulp cavity. The pulp cavity contains nerves and blood vessels.

Dental caries is tooth decay which is caused by the action of acid forming bacteria and improper dental care. It is most common form of oral disease.

It generally happens when we eat sugary food. Such food, when acted upon by the bacteria in the mouth, produces acids. The acids, thus produced, lead the loss of calcium and phosphate from the enamel and, subsequently, from the dentine which leads to cavities in the tooth.

Plaque is the sticky, yellowish film of bacteria and food particles that forms on the teeth. It is most noticeable when teeth are not brushed. It causes tooth decay.

To prevent plaque, teeth must be brushed twice a day.

The various organs of the human digestive system in sequence are: Mouth, Oesophagus, Stomach, Small intestine and Large intestine.

The glands which are associated with the human digestive system are: Salivary glands, Liver and Pancreas.

(i) Carbohydrates - The digestion of carbohydrates occurs in the mouth, stomach and small intestine. In the mouth, saliva mixes with the food. Saliva contains an enzyme called salivary amylase which partially digests the carbohydrate and converts it into maltose sugar. When the slightly digested food reaches into the small intestine, pancreatic amylase present in the pancreatic juice breaks down the starch. The walls of the small intestine secrete the intestinal juice which finally converts it into glucose and completes the digestion of carbohydrates.

(ii) Fats - The digestion of fats begins in the stomach. In the stomach, gastric glands secrete a small amount of gastric lipase that breaks down the fats present in the food. In the small intestine, the pancreatic lipase breaks down the emulsified fats. The intestinal juice, secreted by the walls of small intestine, finally converts the fats into fatty acids and glycerol.

(iii) Proteins - The digestion of proteins begins in the stomach. In the stomach, gastric glands secrete gastric juice which contains an enzyme called pepsin which converts the proteins into peptones. Pancreatic juice contains trypsin which digests the proteins into peptides and the intestinal juice completes the process of digestion of proteins thus converting it into amino acids.

Herbivores animals like cow, ox, and buffalo that eat only plants (grass) have a longer small intestine to allow the cellulose, present in the plants to be digested completely.

Amoeba is a unicellular organism which float on water. The process of obtaining food by Amoeba is called phagocytosis.

Plasmodium obtains food by parasitic nutrition. Parasitic nutrition is that nutrition in which organisms obtain their food from other living organisms (called host).

Mushroom has a saprophytic mode of nutrition as it obtain its food from dead and decaying organic matter.

The small intestine is the largest part of the alimentary canal. It is about 6.5 m long. Small intestine is a highly-coiled tube.

Digestion of food begins in the mouth. The mouth cavity contains teeth, tongue and salivary glands. The teeth cut the food into small pieces, chew and grind it. This is called physical digestion.

The small intestine in the human is the site of complete digestion of food materials like carbohydrates, proteins and fats. It receives secretion of liver and pancreas for this purpose.

Bile is a greenish-yellow liquid that is secreted by liver and stored in gall bladder. It contains bile pigments and bile salts.

Holozoic mode of nutrition is found in Parakeet and Paramecium.

Sunlight, chlorophyll, carbon dioxide and water are the necessary conditions required for autotrophic nutrition.

There are five steps in the process of nutrition in Amoeba:

(i) Ingestion: It is the process of taking in food.

(ii) Digestion: The process of breaking complex food substances into simple molecules.

(iii) Absorption: It is the process of absorption of digested food.

(iv) Assimilation: It is the process of utilization of digested food; for energy, growth and repair.

(v) Egestion: It is the process of throwing out faecal matter out of the body

In human digestive system, the enzymes pepsin and trypsin are secreted stomach and pancreas respectively.

We use the alcohol to remove chlorophyll from the leaves during the photosynthesis experiments.

Pancreas secretes pancreatic juice which contains trypsin, lipase and pancreatic amylase. Trypsin digests the proteins, lipase emulsifies the fats and pancreatic amylase breaks down the starch.

The bile secreted by the liver is stored in the gall bladder. Bile contains bile salts and bile pigments.

The digestion of proteins starts in the stomach. The glands present on the walls of the stomach secrete gastric juice that contains an enzyme called pepsin. Pepsin breaks down proteins into peptones.

The mucus helps to protect the stomach wall from its own secretions of hydrochloric acid.

In humans, small intestine is the site of complete digestion of food like carbohydrates, proteins and fats. It receives the secretions of two glands, liver and pancreas through a common duct.

The digestion of carbohydrates begins in the mouth, stomach and small intestine. Saliva contains an enzyme called salivary amylase which partially digests the starch and converts it into maltose sugar. When the slightly digested food reaches into the small intestine, pancreatic amylase present in the pancreatic juice breaks down the starch.

In the mouth, salivary glands secrete saliva. Saliva is a watery fluid which contains an enzyme called salivary amylase which partially digests the starch and converts it into maltose sugar.

Pancreas secretes pancreatic juice which contains trypsin, lipase and pancreatic amylase. Trypsin digests the proteins, lipase emulsifies the fats and pancreatic amylase breaks down the starch.

The oxygen liberated during photosynthesis by green plants comes from water.

All living organisms are made up of cells. Similarly, the organization of cells into tissue, tissue into organs and organs into systems is dependent upon the movement of molecules.

The food prepared in the plant(autotroph) by the process of photosynthesis is glucose then it gets stored in plant leaves in the form of starch.

The process of photosynthesis takes place in the following three steps:

• Absorption of light energy by chlorophyll

• Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.

• Reduction of carbon dioxide to carbohydrates.

A. The guard cells regulate the opening and closing of stomatal pores. They swell, when water flows into the guard cells and stomatal pores get opens. Similarly, when the guard cells lose water, they shrink, become straight and the stomatal pores get closed.

Plants take up nitrogen from the soil in the form of inorganic salts called nitrates (or nitrites), or in the form of organic compounds which are produced by bacteria from the atmospheric nitrogen.

Saliva is a watery fluid which contains an enzyme called salivary amylase. Salivary amylase acts on starch and breaks down it into sugar.

Those organisms which cannot make their own food from inorganic substances like carbon dioxide and water and depend on other organisms for their food are called heterotrophs. All the animals, fungi, and bacteria are examples of heterotrophs.

Saprophytes obtain their food from dead and decaying organisms by secreting hydrolytic enzymes over food. Examples: Yeast, mushroom, bread mould.

The various organs of the human digestive system in sequence are: Mouth, Oesophagus, Stomach, Small intestine and Large intestine.

(a) (i) Organisms A ---Bacteria

(ii) Bacteria (A), present in the mouth act on sugar and produce acid (B).

(b) (i) The topmost part of the tooth is enamel (C). It is the hardest tissue in the body.

(ii) The middle part of the tooth is known as dentine (D).

(c) Dental caries (E) is tooth decay.

(d) The lower part of the tooth is known as pulp cavity (F) which contains nerves and blood vessels.

(e) If bacteria (A) reach the pulp cavity (F) of the tooth it would cause inflammation and infection which would then lead to severe pain.

(a) W is Dental Plaque. (b) (i) X is Saliva (ii) Y is Salivary Glands. (c) Z are Bacteria. (d) Layer W can be removed by brushing teeth after eating.

(a) (i) Salivary glands (A) present in the mouth and secrete saliva.

(ii) Salivary glands(A) secrete saliva (B) which contains an enzyme called salivary amylase (C).

(b) D is Oesophagus. Oesophagus is a long, thin and muscular tube that connects the throat (pharynx) to the stomach.

(c) Peristaltic movement (E) is a wave of contraction and expansion which occurs in the alimentary canal and helps to push the food forward.

(d) (i) Hydrochloric acid (ii) Mucus (iii) Enzyme pepsin

The stomach wall secretes gastric juice which contains three substances: Hydrochloric acid (F), the enzyme pepsin (G) and mucus (H).

(a) Small intestine (A).

(b) Bile (B) is a alkaline fluid which is stored in the gall bladder (C).

(c) Pancreatic juice contains three digestive enzymes: Pancreatic amylase (D), Trypsin (E) and Lipase (F).

(d) The inner wall of small intestine (A) has millions of finger-like projections called Villi (G).

(e) (i) The undigested food passes from the small intestine (A) into a wide tube called Large intestine (H).

(ii) The last part of large intestine is Rectum (I).

(iii) The opening by which undigested food is passed out is Anus (J).

(iv) The process by which undigested food is thrown out from the body is Egestion (K).

(a) Amoeba (P) is a unicellular animal which has no mouth for ingestion of food.

(b) (i) Amoeba (P) engulfs the food particles by forming finger-like projections called pseudopodia (Q).

(ii) The food is engulfed with little water to form a food vacuole (R).

(c) (i) Enzymes (S) breaks down food into small soluble molecules.

(ii) The digested food is absorbed directly into the cytoplasm by diffusion (T).

(d) (i) The undigested food is thrown out of the body by rupturing the cell membrane (U) (ii) Egestion (V) is the process of throwing the undigested food out of the body.

(a) (i) B is omnivore. (ii) D is herbivore (iii) A is carnivore.

(b) C is autotroph because it can make its food.

(c) A, B and D are heterotrophs because they cannot make their food.

(d) Organism C can be a producer because it can make own food.

(e) A, B and D are consumers because they cannot make their own food and depend on other organisms for their food.

(f) (i) Tiger (ii) Human beings (iii) Green Plants (iv) Goat

(a)

(i) The mode of nutrition of organism A is parasitic nutrition.

(ii) The mode of nutrition of organism B is holozoic nutrition.

(iii) The mode of nutrition of organism C is saprophytic nutrition

(b) The organism D is called host of organism A.

(c) The process by which undigested food is thrown out of the body is known as egestion (E).

(d) (i) Plasmodium (ii) Amoeba (iii) Fungi

(e) Heterotrophic nutrition

(a)

(i) Green plant (A) cannot move from one place to another.

(ii) Green plant makes food glucose (B).

(iii) Glucose (B) gets converted into a complex food, starch (H).

(b) Plant can make own food from the simple substances carbon dioxide (C) and water (D).

(c) Green pigment called chlorophyll (E) present in the leaves of the plant.

(d) The process by which green plants make their own food is called photosynthesis (G).

(a) Carnivores

(b) Herbivores

(c) Animal (Y) has a longer small intestine. Y is an herbivorous animal which eats grass. Grass contains cellulose which is a carbohydrate and gets digested with difficulty. A longer small intestine facilitates complete digestion of cellulose.

(d) Lion

(e) Cow

No, all cells do not use oxygen to produce energy.

Ethanol is the substance that is produced in anaerobic respiration by an organism but not in aerobic respiration.

Yeast is an organism which doesn’t utilize oxygen.

Aerobic respiration produces more energy than anaerobic respiration.

Lactic acid slowly poison our muscles and cause muscular cramps.

Root hairs takeup oxygen from the soil and thus get involved in the exchange of respiratory gases.

The process by which plant parts like roots, stems, and leaves get oxygen required for respiration is called as diffusion.

Stomata present on the surface of the leaves exchange gases for respiration.

Lenticels present on the stem of a plant exchange gases for respiration.

The extensions of the epidermal cells of a root which help in respiration is known as Root Hair.

(a) Respiration is the process through which plants breathe and it happens all the time.

(b) Photosynthesis happens only during the day time as it requires sunlight.

The organs with which fish breathe is known as Gills.

Earthworm is the animal which exchanges gases i.e. oxygen through its moist skin.

The animal which depends on simple diffusion of gases for breathing is the single-celled Amoeba.

Two animals which breathe through gills are Prawns and Mussels.

The two tubes at the lower end of trachea are known as Bronchi.

Alveoli of lungs is the place where gaseous exchange take place and blood absorb oxygen in the body.

Haemoglobin is a dark red respiratory pigment that carries oxygen in blood.

Oxygen and Carbon Dioxide are the gases which are exchanged inside the lungs.

Alveoli of lungs is the place where exchange of gases takes place.

The tiny air-sacs at the end of the smallest bronchioles are known as Alveoli.

Wind-pipe is also known as Trachea.

On each of the bronchi, lungs are attached.

(a) Inside the lungs, oxygen is taken into the blood.

(b) In the lungs, Carbon Dioxide is taken out from the body.

(a) False. (b) True. (c) False.

(a) Lungs.

(b) Alveoli.

(c) Alveoli.

(d) Anaerobic, aerobic.

(e) Fish.

Land plants die if their roots remain waterlogged for a long time because excess of water, in the soils, expels all the air that is present in between the soil particles. Because of the absence of air, oxygen is not available to the roots and they respire anaerobically leading to generation of alcohol which kills the plants.

Some organisms that use anaerobic mode of respiration are Yeast and some bacteria.

(a) Anaerobic respiration in plants like yeast produces ethanol and carbon dioxide.

(b) Anaerobic respiration in animal tissues like muscles produces lactic acid.

During vigorous physical exercise, anaerobic respiration takes place in human muscles because oxygen is used faster in the muscles compared to its supply by the blood.

(a) Anaerobic respiration in yeast produces C₂H₅0H (ethanol) and C0₂(carbon dioxide)

(b) Aerobic respirations in human beings produces C0₂(carbon dioxide) and H₂0 (water).

(c) Anaerobic respiration in animal muscles produces lactic acid.

Breathing is the process by which organisms takes oxygen from the air and releases carbon dioxide.

Glucose is oxidized, to provide energy in various organisms, in two ways –

i. Aerobic respiration – this respiration process takes place using oxygen. For example, plants and animals oxidize glucose and break it down into carbon dioxide and water to release energy.

ii. Anaerobic respiration – This respiration process takes place in the absence of oxygen. For example, yeast and some bacteria oxidize glucose into ethanol and carbon dioxide.

During the breathing process when air is taken in and let out, some of the air remains inside the lungs to provide sufficient time for oxygen absorption into the blood and release of carbon dioxide from the blood.

Carbon monoxide binds itself strongly with haemoglobin in the blood and prevents it from carrying oxygen to the different parts of the body including brain. Due to this, the person cannot breathe and may even die. Hence, it is dangerous to inhale air containing carbon monoxide.

Respiration happens in amoeba through simple diffusion of gases. It lives in water which contains dissolved oxygen. The diffusion of gases takes place through its cell membrane. Through its thin cell membrane this oxygen diffuses into the body of amoeba and spreads into the whole body. This oxygen is used for respiration inside the Amoeba cell. The process of respiration produces carbon dioxide which diffuses out again through its thin cell membrane.

Figure to show the process of breathing (gaseous exchange) in Amoeba

It is an aerobic respiration.

The three common features of all respiratory organs like skin, gills and lungs are as follows:

i) They have a large surface area to absorb sufficient amount of oxygen.

ii) They have thin walls which makes diffusion and exchange of gases easier.

iii) All respiratory organs like skin, gills and lungs have a rich blood supply for the transportation of respiratory gases.

The respiratory organ in a fish is called as gills which is covered by gill covers. The fish has gills on both sides of its head. Fish live in water containing dissolved oxygen. During the process of respiration, fish takes in the water through its mouth and passes it over the gills. The gills extract the oxygen, dissolved in the water, and send it to all the parts of the fish through blood. The carbon dioxide produced during respiration is carried by the blood to the gills where it is expelled into the surrounding water.

Figure to show the process of breathing in fish

The haemoglobin present in the blood is responsible for carrying oxygen in the blood. Thus the deficiency of haemoglobin will reduce the oxygen carrying capacity of the blood resulting in tiredness, breathing problems and lack of energy.

(a) The epidermal cells of a root have extensions which are known as root hairs. These root hairs are in contact with the soil and the air present in between the soil particles diffuses through these root hairs to reach all other cells of the root for respiration. Carbon dioxide produced by the cells during the respiration reaches the root hairs and moves out through the process of diffusion. Hence, respiration in roots happens by diffusion of respiratory gases through root hairs.

(b) The stems of herbaceous plants have stomata through which oxygen diffuses into the stem and reaches all the cells for respiration. The carbon dioxide produced during respiration diffuses out the stomata. In woody stems, respiration happens through lenticels present in the bark.

(c) Leaves of a plant have tiny pores called stomata. Oxygen, present in the air, diffuses through these stomata and reaches other cells for respiration. Carbon dioxide produced in the cells during respiration also diffuses out through these stomata.

The animals which live in water are aquatic animals and animals which live on land are terrestrial animals.

Aquatic animals utilize the oxygen present in the water for respiration while terrestrial animals take oxygen from the air.

Fishes do not have lungs which can take oxygen from air. Hence, they die when taken out of water. They have gills which can only take oxygen dissolved in water.

The oxygen content of water is much less than the oxygen content of air and hence rate of breathing is aquatic organisms is faster than in terrestrial organisms.

The energy currency in the living organisms is called as “ATP”. During anaerobic respiration in lower organisms, it is produced in cytoplasm while in higher organisms, which respire aerobically, it is produced in mitochondria.

Plants have low energy needs as compared to animals because they do not move. Moreover, in a large plants there are many dead cells like sclerenchyma because of which they also need less energy.

If humans also had gills, deep sea divers could remain under the sea for a longer time without using oxygen cylinders as gills would extract the oxygen, dissolved in water, for breathing.

The primary function of respiratory system is to inhale oxygen, which is then used to digest food and produce energy, and exhale carbon dioxide.

The major organs of respiratory system in humans are: Nose, Nasal Passage, Trachea (wind pipe), Bronchi, Lungs and diaphragm.

Human Respiratory System:

The inner lining of nostril is lined by nasal hair and remains wet due to mucus secretion. When air passes through the nasal passage, the nasal hair and mucus trap the dust particles and other impurities present in the inhaled air. Thus, clean air goes into the lungs.

The walls of trachea do not collapse when there is no air in it because they are supported by rings of cartilage.

When we breath in, the air sacs or alveoli get filled with air containing oxygen. The alveoli are surrounded by thin blood vessels called capillaries carrying blood in them. So, the oxygen of air diffuses out from the alveoli into the blood. Blood carries this oxygen to all the parts of the body. When it passes through the tissues, the oxygen in the blood diffuses into the cells and mixes with the digested food to release energy. Carbon dioxide produced during respiration in the cells diffuses into the blood which is carried to the lungs. Inside the lungs, the carbon dioxide diffuses into the alveoli.

To maximize the exchange of gases, lungs have millions of alveoli which provides a larger surface area for the exchange of gases.

(i) During the daytime, plants carry out both photosynthesis and respiration. During photosynthesis, oxygen is produced some of which is used by the plant leaves and rest is released into the air. During respiration, carbon dioxide is produced which is entirely utilized by leaves for photosynthesis. Leaves even absorb more carbon dioxide from the air for photosynthesis. Thus during the day time, the exchange of gases looks like : Oxygen diffuses out and carbon dioxide diffuses in.

(ii) During the night, photosynthesis doesn’t take place and hence only respiration process occurs in plants. Because of the absence of photosynthesis, oxygen is not produced. For respiration, leaves take in oxygen from the air and release carbon dioxide into the air. Thus during the night time, the exchange of gases looks like : Oxygen diffuses in and carbon dioxide diffuses out.

In the exhaled air, carbon dioxide content is always more than inhaled air because during the respiration process, oxygen breaks down the glucose and generates carbon dioxide which passes out of the body in the exhaled air.

Respiration is a vital function of the body as it provides energy for carrying out biological functions which are essential for survival and maintenance of an organism.

In yeast- Anaerobic respiration

In humans-Aerobic respiration

Large multicellular organisms like humans cannot depend on diffusion to meet the oxygen requirements as the volume is too big and oxygen cannot diffuse into all the cells quickly. Moreover, in order to reach each and every cell of the human body, oxygen will have to travel a large distance.

Large organisms have oxygen carrying pigments, called haemoglobin, in the blood, which carries the oxygen from the lungs to different parts of the body.

The advantage that terrestrial animals have over an aquatic animal is that terrestrial animals live in an oxygen rich environment from where they can take as much oxygen as they want.

During anaerobic respiration, the unicellular fungus (yeast) breaks down the glucose into ethanol (C₂H₅0H) and carbon dioxide (C0₂), and release energy in the form of ATP.

The respiration which takes place without oxygen is called anaerobic respiration. Some micro-organisms like yeast and bacteria obtain energy by anaerobic respiration.

The tiny air-sacs at the end of the smallest bronchioles are known as Alveoli. Alveoli is the place where gaseous exchange take place.

Aquatic animals like electric eel have gills as respiratory organs which extract oxygen dissolved in the water and carbon dioxide from the body.

The end product of anaerobic respiration may be ethanol and carbon dioxide (in yeast) or lactic acid (in animal muscles). Anaerobic respiration produces much less energy which gets stored in the ATP molecules.

Due to the lack of oxygen, muscles do anaerobic respiration and produce lactic acid.

Internal respiration is the exchange of gases between body cells and blood to oxidize food substances to release energy.

When air is blown from mouth into a test-tube containing lime water, the lime water turns milky due to the presence of carbon dioxide.

The correct sequence of air passage during inhalation is :

nostrils pharynx larynx trachea alveoli

Due to the lack of oxygen, anaerobic respiration takes place in the human muscles

In the absence of oxygen, pyruvic acid is converted into lactic acid in the cytoplasm of the cell.

Fermentation is a form of anaerobic respiration. Pyruvate can be converted into ethanol and carbon dioxide by yeast during fermentation.

The tiny air-sacs at the end of the smallest bronchioles are known as Alveoli. Alveoli provides a large surface area for the exchange of gases.

The energy currency in the living organisms is called as “ATP”. During anaerobic respiration, it is produced in cytoplasm while in higher organisms, which respire aerobically, it is produced in mitochondria.

The animals like earthworm which live in soil use their skin to absorb oxygen from the air and remove carbon dioxide in the atmosphere.

In insects like grasshopper, mosquito and cockroach has the tiny holes called spiracles on the sides of their body and the air tube called tracheae as respiratory organs.

Photosynthesis is the process by which green plants make their own food by using simple substances like CO₂ and water in the presence of sunlight. During the day time, if plant is releasing CO_2, it means photosynthesis is not taking place in a plant and only respiration is happening.

In woody stem, breathing and respiration takes place through lenticels.

Prawn is a multicellular organism. So it is not dependent on simple diffusion of gases for breathing and respiration.

During vigorous physical exercise, anaerobic respiration takes place in human muscles because oxygen is used faster in the muscles compared to its supply by the blood. Thus, sudden buildup of lactic acid poison our muscles and cause muscular cramps.

A cockroach has small openings on the sides of the body called spiracles. Air enters the body though these external openings.

The oxygen content of water is much less than the oxygen content of air and hence rate of breathing is aquatic organisms like fish is faster than in terrestrial organisms like dog, man and sparrow.

(a) Organism B

(b) Organism A

(c) Organism A can convert glucose into alcohol by anaerobic respiration.

(d) Yeast behaves like organism A

(e) Man, fish behave like organism B

(a) Organisms (i) Yeast (ii) Amoeba (iii) Mosquito

(b) (i) Ethanol (C₂H₅OH) (ii) Cell membrane (iii) Spiracles and (iv) Tracheae

(c) Organism B (Amoeba) and organism C (mosquito) undergo aerobic respiration.

(d) Organism A (yeast) undergoes anaerobic respiration and produce ethanol and carbon dioxide.

(a) Animal T could be Amoeba because it lives in water and breathes through its cell membrane.

(b) Animal Q could be frog because it can stay in water as well as on land and can breathe both, through moist skin and lungs.

(c) Animal P could be fish because it lives in water and has gills for breathing.

(d) Animal S could be grasshopper because lives on land and breathes through spiracles and tracheae.

(e) Animal R could be earthworm because it lives in soil and breathes only through its skin.

(a) (i) Yeast (ii) Ethanol (iii) Carbon dioxide

(b) Fermentation is the process by which sugar converts into ethanol by the action of Yeast.

(c) Fermentation is an example of anaerobic respiration which is done by yeast (X) in the above experiment.

(a) Yeast.

(b) Human beings

(c) Such kind of respiration occurs in animal’s muscles, when the animal needs more energy for doing heavy physical exercises.

(d) Chemical reaction (ii) represents the aerobic respiration.

(e) Chemical reactions (i) and (iii) represent the anaerobic respiration.

(f) Chemical reaction (ii) represents the aerobic respiration. In aerobic respiration, maximum amount of energy is produced.

A = Nose; B =Nostrils; C =Trachea (Windpipe); D =Bronchi; E =Lungs; F =Bronchioles; G =Alveoli

(a) Organism X could be man. Man (X) have the lungs (A) as breathing organ.

(b) Organism Y could be Fish. Fish has the gills (B) as breathing organ.

(c) Organism Z could be frog. Frog has lungs (C) and skin (D) as breathing organs.

(d) (i) Organism Z (ii) Organism Y (iii) Organism X

(a) Phloem is a plant tissue which transport food from the leaves to other parts of the plant.

(b) Xylem is a plant tissue which transport water and minerals from the soil to the various parts of the plant body.

(a) Xylem vessels and tracheids are two elements of xylem tissue which help in the transportation of water.

(b) The cells of phloem are called sieve tubes. Sieve tubes are conducting element of phloem which is responsible for transportation of food.

Heart is a muscular organ which act as a pumping organ in the circulatory system.

(a) Arteries carry blood from the heart to different organs.

(b) Veins carry blood from different organs to the heart.

The exchange of various materials like carbon dioxide, oxygen, etc., between the blood and the body cells takes place through capillaries.

The valves present in the heart prevent the blood flowing backward through the heart.

(i) The aorta is the largest blood (artery) vessel in the body.

(iii) The vena cava is the largest vein in the body.

The main waste products of plants are carbon dioxide, oxygen and water vapour.

The dirty blood in our body is filtered in glomerulus present in the kidney.

Dialysis is the artificial process which is used in artificial kidney to get rid of waste and unwanted water from the blood.

Blood is a fluid connective tissue which is composed of plasma, platelets, RBC and WBC.

There are two components of the transport system in plants namely xylem and phloem

(a) Phloem carries food from leaves in both the directions, upwards as well as downwards, depending on the requirement of the plant.

(b) Xylem carries water and dissolved minerals only in upward direction from roots to the leaves of plant.

Blood and lymph are two liquid of human circulatory system which help in the transportation of substances in the human body.

The main vain carries deoxygenated blood from all the parts of the body to heart. It is also known as Vena cava.

Phloem is a conducting tissue of plant which is made of two elements i.e. sieve tube and companion cells.

(a) Phloem is a conducting tissue of a plant which is made up of sieve tubes. Sieve tubes are living cells which contain cytoplasm.

(b) Xylem is made up of xylem vessels and tracheids which are non-living cells.

The transport of food from leaves to other parts of the plant is called translocation

The transport of food in a plant is accomplished by utilizing energy from ATP.

There are two types of transport systems in the human beings:

(i) Blood circulatory system

(ii) Lymphatic system

(a) Plants excrete oxygen as waste product by the process of photosynthesis only during the day time.

(b) Plant release carbon dioxide as waste product by the process of respiration during the night time.

The single circulation of blood is found in only fishes whereas the double circulation of blood is found in human beings.

(a) True

(b) False

Plant releases its gaseous waste products into the air through stomata, present in the leaves, and lenticels, present in the stems.

When glucose passes through the nephron tubule along with the glomerular filtrate, it gets collected in the Bowman's capsule.

Carbon dioxide and urea are two waste products which are produced in the body cells of human beings.

Glomerulus, in the kidney, helps in the filtration of blood and resulting in urine formation.

High blood pressure is also known as hypertension.

(a) Waste.

(b) Nephron.

(c) Kidneys.

(d) Lymph.

(e) White, red.

Xylem is a conducting tissue of plants which carry water and minerals from the soils to the various of the plant body. Xylem is made up of xylem vessels and tracheids which are non-living cells.

Phloem is a vascular tissue which transports food from leaves to the other parts of the plant. Phloem is made up of many cells joined end to end to form long tube. Phloem contains two type of cells which are associated with each other. These cells are sieve tubes and companion cell. Both cells are living.

The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.

The transport of food from leaves to other parts of the plant is called translocation.

Phloem is a vascular tissue which transports food from leaves to the other parts of the plant.

(a) (i) and (ii)

Differences between the transport of materials in xylem and phloem

(i) c Explanation:
Heart is a pumping organ, its function is to pump blood from different parts of the body.

(ii) a Explanation:
Arteries and Veins transport blood to different parts of the body.

(iii) d Explanation:
Xylem vessels responsible for transport water in plant body.
(iv) e Explanation:
RBC(Red blood cells) found in blood is use to transport oxygen to different part of the body.

(v) b Explanation:
Platelets is responsible for Clotting of blood.

The biological process of removable of harmful metabolic wastes from the body of a living organism is called excretion.

The excretory unit of a kidney is called nephrons.

The kidneys are bean-shaped organs which filter the wastes from the blood by forming a yellowish liquid called urine.

Kidneys excrete urea from the body.

Each kidney enters a long tube called ureter which connects kidney to urinary bladder.

Urinary bladder is a large muscular bag-like structure which stores the urine temporarily till it is excrete out.

Some people need to use a dialysis machine because one or both of their kidneys fail to work. Dialysis machine cleans the blood of a person by removing the nitrogenous wastes from the blood.

The liquid part of the blood is called plasma. The main function of platelets is to prevent bleeding. Platelets helps in the coagulation of blood (clotting of blood) in a cut or wound.

There are three types of blood vessels are found in human body. These are arteries, veins and capillaries.

Heart needs valves to prevent back flow of blood. Valves allow flow of blood in only one direction.

(i) The tubes of dialysis machine are made up of semipermeable membrane (cellulose).

(ii) Dialysing solution contain water, glucose and salt.

(iii) The main waste is urea which passes into the dialysing solution.

Artery

(i) Thick-walled blood vessel

(ii) Blood flows from the heart to different parts of the body

(iii) Blood flows with high pressure with a high speed

(iv) Valves are absent

Vein

• Thin walled blood vessel.

• Brings blood from the different parts of the body to the heart.

• Blood flows with low pressure and with a low speed.

• Contains valves which permit blood flow only towards the heart.

Capillary

• Thin walled and extremely narrow blood vessel.

• Capillary forms an extensive network throughout all living cells in the body.

• Capillaries connect arteries and veins.

• Valves are absent

The upper part of the heart is called atria.

The lower part of the heart is called ventricles.

Capillaries are thin-walled blood vessels which connect arteries to veins.

(i) Right side of the heart pumps blood into the lungs.

(ii) Left side of the heart pumps blood into the entire body except the lungs.

There are various methods that are used by the plants to get rid of their waste products:

(i) Gaseous waste products are thrown out through the stomata, present on leaves and lenticels, present on stem of the plants.

(ii) Solid and liquid wastes are thrown out by shedding off leaves, peeling of bark and falling of fruits.

(iii) Plants excrete some waste products into the soil around them.

(iv) By secreting gums and resins.

Amoeba is a unicellular organism which removes carbon dioxide from the body through its cell membrane by diffusion whereas it removes nitrogenous waste and water from the body by contractile vacuole.

Lymph is a colorless or slightly yellowish fluid. It is a medium of circulation in human body which flows only in one direction - from body tissues to the heart.

The functions of lymph are:

(i) Lymph helps in removing the waste products.

(ii) Lymph carries digested fat from the small intestine to the entire body.

(iii) Lymph nodes contain lymphocytes which kill the germs or foreign bodies.

The blood pressure of a person is 120/80 which means that the systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg.

High blood pressure is also called hypertension. Hypertension is caused by the constriction of arterioles (small arteries), resulting in increased resistance to blood flow. Very high pressure can cause internal bleeding and rupturing of artery.

Blood is a red colour liquid which circulates in our body. The main components of blood are:

•Plasma

•RBC (Red blood cells)

•WBC (White blood cells), and

•Platelets

Functions:

•Plasma-It is liquid part of the blood. It contains about 90 percent water. Plasma carries dissolved substances like proteins, digested food, waste products, etc. one part of the body to the other parts.

•RBC : It carries oxygen from the lungs to all the cells of the body.

•WBC : Which blood cells (WBC) protect us from diseases. WBC make a chemical, antibodies which help to fight against infection.

•Platelets : The main function of platelets is to prevent bleeding. Platelets helps in the coagulation of blood (clotting of blood) in a cut or wound.

(i) Vena cava is associated with human circulatory system.

(ii) Glomerulus is associated with human excretory system.

(iii) Alveoli is associated with human respiratory system.

(iv) Villi is associated with human digestive system.

Systolic pressure: The pressure of blood inside the artery during ventricular systole (contraction) is called systolic pressure.

Diastolic pressure: The pressure of blood inside the artery during ventricular diastole (relaxation) is called diastolic pressure.

The normal value of systolic pressure is about 120 mm of Hg and the value of diastolic pressure is 80 mm of Hg.

One heart beat includes one complete contraction (systole) and relaxation (diastole) of heart. The normal heart beat rate at rest is 72 times /minute.

(b) When a person runs for a while, his heart beat becomes faster because he needs more energy to run.

When a person runs for a while, his heart beat becomes faster because he needs more energy to run.

Blood is a red coloured fluid which circulates throughout the body. It consists of 55% plasma and 45% blood cells. Blood is red in colour because it contains a pigment called haemoglobin in its red cells (RBC).

The functions of blood:

(i) Transport oxygen from the lungs to different parts of the body.

(ii) Transport CO₂ from the body tissues to the lungs.

(iii) Transport digested food i.e., glucose, amino acids, etc. from alimentary canal to various parts of the body for energy, growth and repair.

(iv) Transport excretory waste product called urea from the liver to the kidneys for removal as urine.

(v) Plasma regulates water balance in the body.

(vi) Regulates the body temperature.

Lymph is a circulatory fluid in the human body other than blood.

The organ system which is responsible for the transport of materials inside the human body is called human circulatory system. Heart is the main organ of the human circulatory system. The other organs of the human circulatory system include arteries, veins and capillaries.

In the case of single circulation, blood passes through the heart only once in one complete cycle of the body whereas in double circulation, blood passes through the heart twice in one complete cycle of the body.

Following steps are included in the functioning of human circulatory system:

(i) The pulmonary vein brings the oxygenated blood from the lungs in the left atrium of the heart.

(ii) Left atrium contracts and pumps blood into the left ventricle through valve.

(iii) When the left ventricle contracts, the oxygenated blood enters the main artery called aorta. The blood travels from the main artery to larger and smaller arteries into the capillary network.

(iv) The aorta transports the blood to all the organs of the body except the lungs. The oxygenated blood releases oxygen, nutrients and other substances and takes on carbon dioxide and waste substances. The deoxygenated blood enters the vena cava which carry it to the right atrium of the heart.

(v) Right atrium pumps deoxygenated blood into the right ventricle through the valve.

(vi) When the right ventricle contracts, the deoxygenated blood enters the lungs through pulmonary artery and releases carbon dioxide and absorbs fresh oxygen from air. The blood becomes oxygenated again and is sent to the left atrium of heart by pulmonary vein for circulation in the body. This whole process is repeated continuously.

Haemoglobin is a respiratory pigment, found in the red blood cells which carries oxygen in the blood.

Mammals and birds are warm-blooded animals. They require more energy to maintain their body temperature, so they require more oxygen to produce energy. Thus, it is necessary that their oxygenated blood get separated with deoxygenated blood.

(i) Thee chamber heart is found in amphibians.

(ii) Four chambered heart is found in mammals.

(iii) Two chambered heart is found in fishes.

Fish has a two-chambered heart-one atrium and one ventricle. In fish, heart pumps blood to the gills where oxygenation of blood takes place. The gills send the oxygenated blood to all the parts of the fish where oxygen is utilized and carbon dioxide enters into it making it deoxygenated. The deoxygenated blood is transported to the heart where it is pumped into the gills.

Lymphatic system is a system of tiny tubes called lymph vessels (lymphatics) and lymph nodes (lymph glands) in the human body which transports the liquid called lymph from the body tissues to the blood circulatory system.

The functions of lymphatic system are:

(i) It helps in removing the waste products.

(ii) It carries digested fat from the small intestine to the entire body.

(iii) Lymph nodes contain lymphocytes which kill the germs or foreign bodies.

The pressure of blood which is exerted on the walls of blood vessels is called blood pressure. This pressure is much greater in the arteries than in the veins. The blood pressure of a person is always expressed by two factors - systolic pressure and diastolic pressure.

The main nitrogenous waste in the human blood is urea. It is removed from the blood by the kidney in the form of urine.

The excretory system of human beings consists: two kidneys, two ureters, a urinary bladder and a urethra.

The primary function of excretory system, in humans, is to remove the nitrogenous wastes such as urea from the body and maintain mineral balance in the blood.

Urine formation: Urine is formed inside the kidney in the nephron. Nephron is a functional unit of kidney. The blood containing waste like urea enters the glomerulus which filters the blood. Water, urea, and other salts like glucose are filtered out in renal tubule. The filtered fluid is called glomerular fluid. When the filtrate containing useful substances as well as the waste substances passes through the tubule, the useful substances like glucose, amino acids, most salts and water are reabsorbed into the blood through blood capillaries surrounding the tubule. Certain substances which are harmful and not needed by the body like urea, remain behind in the tubule. This yellowish liquid is called urine.

Ureters carry urine from kidneys to bladder.

Urethra is a muscular tube through which the urine collected in the urinary bladder is passed out from the body.

Dialysis is a procedure by which blood of a person is cleaned by separating the urea from it. The patients with kidney failure are put on dialysis.

In the process of dialysis, the blood from an artery in the patient’s arm is taken and is made to flow into the dialyser of a dialysis machine. The dialyser is made of long tubes of selective permeable membrane (like cellulose) which are coiled in a tank containing dialysing solution. The dialysing solution is a mixture of water, glucose and salts present in same concentrations as those of normal blood. As the blood passes through the dialysing solution most of the wastes like urea present in it pass through the selectively permeable cellulose tubes into the dialyzing solution. The purified blood is then pumped back into a vein of the patient’s arm.

All living organisms (plant and animals) need water, food and oxygen for their survival and to perform various activities. They need to transport all these materials to various parts of their body.

Plant and animals needs special tissue and organs for the transport of substances because essential substances like water, food and oxygen are made (or absorbed) in one part of the body and carried to other parts of the body.

Xylem tissue transports water and minerals in plants from the soil to leaves. Xylem vessels and tracheids are elements of xylem tissues. They are interconnected in roots, stem and leaves and form a continuous system of water-conducting channels reaching all parts of the plant. Plants take in water from the soil through the roots. The roots have root hairs to absorb water and minerals from the soil by diffusion. Each root hair is single-celled structure. The absorbed water and minerals passes from cell to cell by osmosis through epidermis, root cortex, endodermis and then reach the root xylem. The water enters the root xylem into the stem xylem and then reaches the leaves from the petioles.

The food is manufactured in the leaves by photosynthesis and carried out from the leaves to the other parts of the plant. The transport of food from the leaves to other parts of the plant is called translocation. It is done through a vascular tissue called phloem. The translocation of food takes place in the living cells called sieve tubes with the help of the adjacent companion cells. The translocation of food in phloem takes place by utilizing energy. The food, prepare in the leaves, is loaded into the sieve tubes of the phloem tissue using energy ATP. The water now enters the sieve tube having sugar which causes high pressure and pushes the food to all the parts of the plant having low pressure. This allows the phloem to transport food according to the plant’s needs.

Red blood cell red in colour because of the presence of a pigment called haemoglobin. It does not have a nucleus.

Which blood cells (WBC), a component of blood, protect us from diseases. WBC make a chemical, antibodies which help to fight against infection.

Fish has gills to oxygenated its blood. The oxygenated blood is supplied from the gills to the body.

Phloem is a vascular tissue which transports food substances from the leaves to the other parts of the plant body. It transports in both the directions upward as well as downward.

The blood is made up of plasma and blood cells (RBC, WBC and platelets). Sieve plate is a part of plant vascular system.

Some people need to use a dialysis machine because one or both of their kidneys fail to work. Dialysis machine cleans the blood of a person by removing the nitrogenous wastes from the blood.

When we place a plant place under the fan, the speed of air flow is very high. Transpiration will take place in the presence of high air flow through the stomata. The rate of transpiration increases during windy condition.

Vein is a thin-walled blood vessels which carries blood back to the heart.

In human, heart has two ventricles-right ventricle and left ventricle. The function of ventricles is to pump blood from the heart to the entire body.

The blood leaving the tissues becomes richer in carbon dioxide. When the oxygenated blood passes through the capillaries of the tissue, it gives oxygen to the body cells and takes carbon dioxide, produced during respiration. Thus, it becomes richer in carbon dioxide.

Valves prevent the backflow of blood inside the heart during contraction. They allow the flow of blood in only one direction.

Urine formation takes place inside the kidney. Ureter carries urine from kidneys to bladder. Bladder stores the urine temporarily. Then the urine is discharged out of the body through urethra.

In only pisces (fish) heart does not pump oxygenated blood to different parts of the body. The oxygenated blood is supplied from the gills to the body by dorsal aorta. Thus, in fish, heart receives only deoxygenated blood.

Pulmonary vein brings oxygenated blood from the lungs into the heart.

Pulmonary vein does not carry any carbon dioxide. It brings oxygenated blood from the lungs into the heart.

At higher altitudes, the atmospheric pressure is low and hence body doesn’t get enough oxygen. This leads to many symptoms. More the number of RBC, more is the amount of oxygen that circulates in the body. Thus, to increase amount of oxygen, at low pressure, more RBC is required in the blood.

Phloem is a vascular tissue which transports food materials from leaves to the other parts of the plant.

Cold blooded animals like amphibians and reptiles have three chambered heart.

Kidneys excrete the nitrogenous waste like urea from the body in the form of urine.

The cells of phloem are called sieve tubes. These are living cells which contain cytoplasm but no nucleus.

The process by which phloem carries food from the leaves to other parts of a plant is called translocation.

Tracheids are non-living cells which are present in all the plants but they are only water conducting tissue in non-flowering plants.

Transpiration helps in the upward movement of water and dissolved minerals from the roots to the leaves through the stem

Capillaries are thin walled and extremely narrow blood vessels which do not have valves.

The translocation of food in the phloem takes place by utilizing the energy stored in ATP.

The main function of platelets is to prevent bleeding. Platelets helps in the coagulation of blood (clotting of blood) in a cut or wound.

Pulmonary vein carries oxygenated blood from the lungs to the heart.

The blood pressure is measured with an instrument called sphygmomanometer.

The functional unit of human excretory system is nephrons. Urine formation takes place in nephrons of kidneys.

As the glomerular filtrate passes through the tubular part of the nephron, the useful substances such as glucose, amino acids, salts and water are reabsorbed by the blood capillaries surrounding the nephron and only the waste substances such as urea and excess water remain behind in the tubule.

Dialysis is the procedure of cleaning the blood of a person by using a kidney machine.

In earthworm, excretory organs are nephridia.

Which blood cells (WBC), a component of blood, protect us from diseases. WBC make a chemical, antibodies which help to fight against infection.

Pulse is a wave of expansion of an artery when blood is forced into it.

Xylem is a vascular tissue in plants which carries water and minerals from the roots to the various of the plant.

Cold blooded animals like amphibians and reptiles have three chambered heart.

(a) (i) Phloem (X)

(ii) Sieve tube (A) (iii) Companion cell (B)

(b) (i) Xylem (Y) (ii) Xylem Vessel (C) (iii)Tracheids (D)

(a) (i) Diffusion (A) (ii) Xylem (B) (iii)Transpiration (C)

(iv) Photosynthesis (D)

(v) Phloem (E)

(vi) Translocation (F)

(b) E (c) E (d) B

(a) (i) Blood (A) (ii) Haemoglobin (B) (iii)Red (C)

(b) (i) White blood cells (D) (ii) Platelets (E) (iii)Plasma (F) (iv) Red Blood Cells (G)

(c) Digested Food

(d) E (Platelets) and G (Red Blood Cells)

(e) Amoeba and Grasshopper

(a) Heart (A)

(b) (i) Pulmonary Vein (B) (ii) Aorta (E) (iii) Vena cava (F)

(iv)Pulmonary artery (I)

(c) (i) Left atrium (C) (ii) Left ventricle (D)

(d) (i) Right atrium (G) (ii) Right ventricle (H)

(a) (i) Lymph (X) (ii) Light yellow (Y)

(b) Lymphocytes (Z)

(c) Plasma (C)

(d) Lymph (X) does not contain red blood cells having the red pigment called haemoglobin.

(a) (i) Kidneys (P) (ii) Urea (Q)

(b) (i) Renal artery (R) (ii) Renal vein (T)

(c) Nephrons (S)

(d) (i) Urine (U) (ii) Bladder (V) (iii) Ureters (W) (iv)Urethra (X)

(a) Organs A is Kidney.

(b) Waste substance (B) is urea.

(c) (i) Cellulose (E)

(ii) Dialysing solution (F)

(d) Water (G), Glucose (H) and Salts (I)

(e) Dialysis