The processes which are essential to sustain life are called life processes.

Nutrition is the process of intake of nutrients for energy and its utilization by an organism.

The mode of nutrition in which organisms prepare their own food using simple in organic substance is called autotrophic nutrition.

Example- All green plants and some forms of bacteria

The mode of nutrition in which organism derive their food from other organisms is called heterotrophic nutrition.

Example- All animals and non-green plants.

The mode of nutrition in which organisms decompose dead and decaying organic matter to obtain nutrients is called Saprophytic nutrition.

Example-fungi, mushrooms and bacteria

The mode of nutrition in which organisms live on or inside other organisms (host) and obtain food from the body of the host is called parasitic nutrition.

Example- Cucuta

The mode of nutrition in which organisms feed on complex organic substance by ingestion and digest it with the help of enzymes is called holozoic nutrition.

Example- human beings, dog, fish etc.

All green plants are autotrophs.They synthesise food by the process of photosynthesis.Photosynthesis is the process by which green plants

synthesis their food from atmospheric carbon dioxide and water using the energy of light.

6CO2+12H2O C6H12O6+6H2O+6O2

Plants obtain carbon dioxide through tiny pores present on their leaves.

Sunlight

Chlorophyll

The following events occur during this process-

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 carbohydretes.

Amoebea takes in food using temperory fingur-like extensions of the cell surface called pseudopodia (falsefeet).Pseudopodia fuse over the food particle forming a food-vacuole.Inside the food –vacuole, complex substances are broken into simpler ones which then diffuse into cytoplasm.The remaining undigested material is moved to the surface of cell and thrown out.

Human digestive systemThe Human digestive

system comprises of the alimentary canal and associated digested glands.

The alimentary canal starts from mouth and extend upto anus it is 9 to 10 meters long.

Food is taken in the oral cavity

through mouth .Here salivary glands secrets saliva which moisten the food and an enzyme salivary amylase which present in saliva digest starch. Food is also chewed here by teeth.

No digestion take place in oesophagus.

Rhythmic contraction and expansion happens to push the food forward called peristaltic movements.

Stomach has gastric glands which secrets gastric juice.

Gastric juice contains pepsin, hydrochloric acid and mucus

Pepsin digest protein with the help of hydrochloric acid

Hydrochloric acid kill the germs of food and provide acidic medium to pepsin .

Mucus protects the inner lining of stomach from acid.

Complete digestion does not take place in stomach.

Intestinal glands present here.

These glands secrets carbohydrase, Lipase and protease.

Digested food is absorbed by blood here.

It reabsorbs water and minerals.

Rectum is the last part of large intestine and stores digestive waste and finally the waste expelled out through anus.

It is the largest gland of our body.

It secrets bile juice which emulsify fat.

Bile juice make medium alkaline which helps trypsin to digest protines

It stores bile juice.

Pancreas secretes pancreatic juice.

Pancreatic juice contain Trypsin, pancreatic amylase and lipase.