Nutrition And Respiration

Size of small intestine depends on the type of food animals eat. As meat can be easily digested so carnivores have shorter small intestine whereas grass or plants takes time to digest so herbivores have longest small intestine.

Amoeba is a unicellular organism. It obtains its food through its cells that is by the process of phagocytosis which means cell feeding. Amoeba ingests its food with the help of pseudopodia (false feet) and lysosomes engulf its food and throw them in food vacuole. Then the process of digestion, assimilation, absorption and egestion occurs inside the vacuole. And then by rupturing its membrane it throws the undigested or waste food out of the body.

In parasitic mode of nutrition one organism depends on other organism for their nutrition. These organisms which depend on ‘host’ organism to obtain their food are known as parasites. Plasmodium is the type of parasite which depends on blood cells of host organism to obtain its nutrition.

In saprotrophic mode of nutrition organisms feeds on dead and decaying matters to get their nutrition. Fungi have saprotrophic mode of nutrition and mushroom is a fungus so, it has saprotrophic mode of nutrition.

Small intestine is the longest part of the human digestive tract whose length is 6.5m in an adult.

Food is first put in our mouth, which is a cavity which contains teeth, tongue, and salivary glands. There with the help of teeth and tongue food is chewed. Then salivary gland secretes enzymes called amylase, which starts acting on the starch and converts them into maltose. Hence the digestion process starts.

In humans small intestine is the site where carbohydrates, proteins and fats are completely digested. Bile, intestinal juices and pancreatic enzymes are responsible for the complete digestion of food in small intestine. After digestion, absorption of food starts in small intestine.

Bile is greenish yellow liquid which is secreted by liver in small intestine. It is stored in gall bladder. Bile is alkaline and makes the acidic food alkaline, so that pancreatic enzymes can work over it.

In autotrophic mode of nutrition organisms prepare their own food in the presence of carbon dioxide, water, chlorophyll and sunlight. This process is known as photosynthesis e.g. green plants, euglena, volvox etc.

Stomach has three glands which secrets gastric juices which has hydrochloric acid, enzyme pepsinogen and mucus. Enzyme pepsinogen digests the proteins in acidic medium which is present in stomach. Pancreas secretes pancreatic juices which has enzymes like amylase, trypsin and lipase. Trypsin enzyme digests proteins in small intestine.

Yeast can respire without oxygen. This type of respiration is known as anaerobic respiration.

Trachea travels down the neck and divides into 2 bronchi which are further divided into bronchioles. Each bronchiole terminates into alveoli where exchange of gases takes place.

Electric ray is type of fish which has gills as respiratory organ whereas in leech and earthworm exchange of gases takes place through skin and in amoeba cell membrane is responsible for exchange of gases.

Autotrophic (Auto means self and trophic means nutrition) organisms make their food on their own. To make their food they require two inorganic substances carbon dioxide and water. Along with these two inorganic substances they require sunlight and chlorophyll to carry out the process of photosynthesis. A result of this process is carbohydrates (which is used by plants) and oxygen (which is given out in air).

Saprophytic mode of nutrition is seen in fungi. In saprophytic mode of nutrition organisms feed on dead and decaying matters to obtain their nutrition. They absorb their nutrition through their body wall. E.g. bacteria and fungi.

Saprophytic nutrition: - In saprophytic mode of nutrition organisms feed on dead and decaying matters to obtain their nutrition. They absorb their nutrition through their body wall. E.g. bacteria and fungi.

Parasitic nutrition: - In parasitic mode of nutrition one organism depends on the other organism often known as host, to get their nutrition. In this host body is not benefited but is harmed by the parasitic organism. Example plants like cuscuta and animals like tapeworm, ascaris etc.

Holozoic nutrition: - In this type of nutrition parts of organism takes in food which is then digested by different digestive enzymes by converting complex substances into simpler form. And then undigested food is thrown out of the body. Example amoeba.

Plants have autotrophic mode nutrition that is they make their own food by the process known as photosynthesis. To carry out this process they require carbon dioxide, water, sunlight and chlorophyll. Steps involved in photosynthesis are:

i. Absorption of light by chlorophyll

ii. Conversion of light into chemical energy

iii. Reducing carbon dioxide into carbohydrates.

In addition to carbon dioxide and water, chlorophyll and sunlight are required for the process of photosynthesis. After the completion of process oxygen and carbohydrates are released as end products.

Chlorophyll is green colored pigment which can absorb solar energy which is used for the process of photosynthesis.

Leafs contain green organelles known as chloroplast which contains the chlorophyll.

Digestive enzymes in food vacuole break down the engulfed food. Pseudopodia are the finger like projections which along with lysosomes ingests that is takes in the food particles to the food vacuole. After ingestion digestive enzymes acts on the food and breaks it down.

After the food is digested, absorbed, and assimilated, the undigested food is egested by rupturing its cell membrane.

Yeast is an organism which can live without oxygen. It undergoes anaerobic respiration (respiration in the absence of oxygen).

Aerobic respiration that is respiration which takes place in the presence of oxygen, releases more energy. 38 ATP molecules are released during aerobic respiration whereas only 2ATP molecules are released in anaerobic respiration.

Epidermal extensions of root are known as root hairs. These root hairs are in contact with air which is present in the soil. So, all the exchange of respiratory exchange of gases takes place through root hairs.

Gills are the respiratory organ of fish. All the exchange of gases takes place through gills.

A.

Autotrophic nutrition: - Auto means self and trophic means nutrition that is it means self-nutrition. It is the mode of nutrition in which organism prepares their food by themselves and they do not have to depend on others to get their nutrition. Example green plants, euglena, volvox etc.

Heterotrophic nutrition: - In this type of nutrition organisms depends on other organism and different materials to get their nutrition. They cannot prepare their food on their own. There are different type of heterotrophic nutrition like some organisms depends on dead and decaying materials to get their nutrition this type of nutrition is known as saprophytic nutrition (example fungi).

B. Carbon dioxide, water, chlorophyll and sunlight are the necessary conditions for autotrophic nutrition. Without these components process of photosynthesis cannot be completed.

A. In heterotrophic nutrition organisms depends on other organism and different materials to get their nutrition. They cannot prepare their food on their own. There are different type of heterotrophic nutrition like some organisms depends on dead and decaying materials to get their nutrition this type of nutrition is known as saprophytic nutrition (example fungi).

B.

A. The process of taking nutrients from organisms or preparing the food on their own in order to get energy to do work is known as nutrition. Carbohydrates, proteins, fats, minerals and vitamins are important nutrients present in food.

B. In heterotrophic mode of nutrition organisms obtain their food from other organisms. There are 3 types of heterotrophic nutrition:

i. Saprophytic nutrition: - In saprophytic mode of nutrition organisms feed on dead and decaying matters to obtain their nutrition. They absorb their nutrition through their body wall. E.g. bacteria and fungi.

ii. Parasitic nutrition: - In parasitic mode of nutrition one organism depends on the other organism often known as host, to get their nutrition. In this host body is not benefited but is harmed by the parasitic organism. Example plants like cuscuta and animals like tapeworm, ascaris etc.

iii. Holozoic nutrition: - In this type of nutrition parts of organism takes in food which is then digested by different digestive enzymes by converting complex substances into simpler form. And then undigested food is thrown out of the body. Example amoeba.

(i) Saprophyte: Saprophytes are the organisms whose mode of nutrition is saprophytic that is they obtain their nutrition from dead and decaying materials. Example fungi and bacteria.

(ii) Parasite: Parasites are the organisms whose mode of nutrition is parasitic that is they depend on the host body to get their nutrition and in return harm the host body. Example plants- cuscuta and animals- ascaris and tapeworm.

A. Hydrochloric acid kills the bacteria which enters the stomach and also makes the acidic medium in the stomach in which enzyme pepsin digests the proteins present in the food.

B. Different enzymes plays different roles in human digestive tract but their main function is to convert complex substances into simpler form for easy digestion of food. Like pepsin and trypsin digests the proteins, salivary amylase and amylase present in pancreatic juices digests starch and lipase digests the fats.

A. Root: Exchange of gases between soil and roots takes place by the process of diffusion. Root hairs are the epidermal extensions of the roots which take up the air molecules present in soil, so oxygen diffuses into root hairs and then reaches all the cells of the plant. And carbon dioxide produced in the same manner through root hairs by the process of diffusion is moves out.

B. Stem: Stems of herbs have stomata through which by the process of diffusion oxygen is taken in to the cells of the plant and by the process of diffusion carbon dioxide is given out in the air. In case of hard and woody stems, they have lenticels to carry the process of respiration.

C. Leaves: Leaves also have stomata which are the small openings through which gases are exchanged by the process of diffusion.

A. Heterotrophic or Holozoic mode of nutrition is seen in amoeba. Amoeba is a unicellular organism. It obtains its food through its cells that is by the process of phagocytosis which means cell feeding. Amoeba ingests its food with the help of pseudopodia (false feet) and lysosomes engulf its food and throw them in food vacuole. After ingestion, digestion of the food starts by secreting digestive enzymes which acts on the food and digests it. After digestion, absorption of food takes place directly by diffusion of food by cytoplasm. After absorption, assimilation of food takes place. Food which is absorbed is used to get energy and rest is used by amoeba. Last step is egestion. In egestion the undigested food is thrown out of the by rupturing its cell membranes.

•Mouth: Mouth is the first step in Digestion Process. Mouth is the cavity which contains tongue, teeth and salivary glands. Salivary gland, secret saliva and enzyme known as salivary amylase. Teeth chew and grind the food and tongue mixes the food with saliva so as to making the food easy to swallow. Salivary amylase digests the starch and converts it into maltose but this digestion of starch is left incomplete because of short duration of time.

•Esophagus: Food is carried from mouth to stomach through esophagus.

•Stomach: Stomach is a J-shaped organ present on the left-side of the abdomen. In stomach tubular glands are present which secretes gastric juice. Gastric juice contains hydrochloric acid, mucus and enzyme pepsin. HCl acid in stomach kills the bacteria which enters the stomach and also provides the proper medium in which enzyme pepsin can work. Mucus protects the lining of the stomach from the acid and pepsin. Pepsin in acidic medium acts on proteins and digest the proteins present in the food.

•Partially digested food is passed on to small intestine which is regulated by the sphincter.

•Small Intestine: Small intestine is about 6.5m long and is the largest part of the alimentary canal. Complete digestion of food takes place in small intestine. Small intestine receives secretions from liver and pancreas. Liver secretes bile which is responsible for converting the acidic food into alkaline so that pancreatic enzymes can work on it. Also the bile salts coverts the large fat globules into small globules so that it can be easily digested. Pancreas secretes pancreatic juice which contains lipase which digests fats, trypsin which digests proteins and amylase which digest starch. Small intestine secretes intestinal juices which have different type of enzymes which digests the carbohydrates and converts them into glucose, proteins and converts them into amino acids and fats and converts them into fatty acids and glycerol.

After the digestion of food absorption of food takes place in small intestine with the help of small finger-like projects known as villi.

•Large intestine: After absorption of food the undigested food is sent to large intestine. Here water is absorbed from the undigested food and it is again converted into solid, which is then thrown out of the body through anus in the form of waste material known as faeces.

A.

B. In leafs exchange of gases takes place through small pores know as stomata. In day carbon dioxide is taken up and oxygen is given out and in night oxygen is taken up and carbon dioxide is given out.

C. In yeast anaerobic respiration takes place that is respiration in the absence of oxygen. Whereas, in humans, aerobic respiration takes place that is respiration in the presence of oxygen.