Life Processes

The word life processes means the processes take place in the

human body which are needed for the existence of life on Earth.

For example – Digestion, respiration, excretion,

reproduction, etc.

Nutrition• Autotrophic

nutrition

• Heterotrophic nutrition

Autotrophic Nutrition

• Synthesis of food by photosynthesis• Photosynthesis equation- 6CO2+6H2O

(sunlight and chlorophyll)C6H12O6 + 6O2

• Two phases of photosynthesis- light and dark reactions

• Light reaction- light energy absorbed, H2O split into H2 and O2, ATP and NADPH2 synthesized

• Dark reaction- CO2 reduced to carbohydrates

Heterotrophic Nutrition

• Generally derive energy from plants and animal sources

• Mainly of three types— holozoic (Obtaining

nourishment as animals do by ingesting complex organic matter), parasitic (having the nature or habits of a parasite or leech), and saprophytic (feeding on dead or decaying organic matter)

• Digestion- mechanical and chemical reduction of ingested nutrients

Photosynthesis

• Meaning – the process of the synthesis of carbohydrates or food in presence of carbon dioxide and light is called photosynthesis

• The ways: 1. Absorption of light energy by chlorophyll. 2. Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen 3. Reduction of carbon dioxide to carbohydrates.

Stomata

• Meaning - A minute epidermal pore in a leaf or stem through which gases and water vapor can pass

• The opening and closing of stomata is controlled by guard cells

• When the guard cells absorb water the stoma open and when guard cells don’t have water, the stoma close.

Nutrition in Amoeba• Amoeba takes in food using temporary

finger like extensions of cell surface which fuse over food particle forming food vacuole .

• Inside the food vacuole, complex substances are broken down into simpler ones which then diffuse into the cytoplasm.

• The remaining undigested food is moves to the surface of the cell and thrown out.

Nutrition in Human Beings• The nutrition in human beings takes

place in the human alimentary canal.• The food in taken in through mouth

which is mixed with the saliva and passed to oesophagus. Saliva contains salivary amylase that breaks down starch which is a complex molecule to give sugar.

• The food then goes to the stomach where the digestion process starts.

• The food is then passed to the small and then large intestine where it is reabsorbed and then is thrown out through Anus.

Respiration

• Respiration involves the exchange of gases and oxidation of food in the presence of air to release energy.

• Inhalation and exhalation of air occur due to change in air pressure in lungs

• Diffusion helps in exchange of gases in lungs and tissues.

Transportation in humans

• Blood is a fluid connective tissue that circulates through heart and blood vessels.

• Blood consists of plasma with RBCs, WBCs and platelets. Arteries transport blood from heart to the tissues.

• Blood pressure is the force that blood exerts against the wall of a vessel. Lymphatic system circulates Lymph or tissue fluid.

Circulatory system in humans

• Human heart is a 4 chambered muscular pump located in our chest cavity.

• In humans the blood flows through 2 loops -Pulmonary and systemic circulation.

• The heartbeat is initiated and regulated by cardiac muscles.

• The fish and amphibians have 2 and 3 chambered heart respectively.

Transportation in plants

• The transport system in plants works with the help of conducting tubes known as xylem and phloem.

• The rise of water and dissolved minerals in the xylem vessels against the force of gravity is known as Ascent of sap.

• Transpiration is the process by which water vapor escapes from the stomata in the leaves of living plants.

Excretion • Biological process of eliminating metabolic

waste substances is called excretion.

• Human excretory system consists of pair of kidney and ureter, a Urinary bladder and a urethra.

• Nephrons are structural and functional units of kidney. Ultra filtration, Tubular reabsorption, and Tubular secretion are the steps of Urine formation inside a nephron.

Structure of NEPHRON

• Each kidney has numerous filtration units called Nephrons.

• These Nephrons consist of Glomerulus, Bowman’s capsule, Renal artery, renal vein, collecting duct, etc.

• The blood is filtered in these units, then collected in the collecting tubule/duct.

• This collection is then passed to an organ called urinary bladder where it is stored until thrown out of the body.

Excretion in Plants• The plants also give out some toxic

wastes.

• Plants don’t have any excretory system as human beings have.

• So how do they throw out the toxic waste?

• They throw this waste through many ways such as transpiration, throwing of wilted leaves, giving out it as resins and gums, the toxic salts are first stored in the leaves then these leaves are thrown out, etc.

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Made By : Tarun Gupta