Life Processes

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.

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 NutritionGenerally derive energy from

plants and animal sources.• Mainly of three types :- 1). Holozoic

(Obtaining nourishment as animals do by ingesting complex organic matter), 2). Parasitic (having the nature or habits of a parasite or leech), and 3). Saprophytic (feeding on dead or decaying organic matter)

• Digestion - mechanical and chemical reduction of ingested nutrients.

Photosynthesis•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•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 stomata gets open and when guard cells don’t have water, the stomata gets 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 and mixed with the saliva and passed to oesophagus. Saliva contains salivary amylase that breaks down starch.

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

• The food is then passed to the small and large intestine 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 RBC, WBC 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.

•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.