CBSE Class 10 Science Life Processes Notes Set D

All living things perform certain life processes like growth, excretion, respiration, circulation etc.
All the processes like respiration, digestion, which together keep the living organisms alive and perform the job of body maintenance are called life processes.

Examples : 

Autotrophic Nutrition :
The organisms which carry out autotrophic nutrition are called autotrophs (green plants) 

Autotrophic nutrition is fulfilled by the process bywhich autotrophs take in CO₂ and H₂O and convert these into carlohydrates in the presence of chlorophyll, sunlight is called PHOTOSYNTHESIS
Equation : 

Raw Materials for Photosynthesis :

♦ Sunlight
♦ Chlorophyl → Sunlight absorbed by chlorophyll
♦ CO₂ → enters through Stomata, and Oxygen (O₂) is released as by product through stomata on leaf.
♦ Water → water + dissolved minerals like Nitrogen phosphorous etc are taken up by the roots from the soil.
Site of Photosynthesis :
Chloroplast in the leaf. Chloroplast contain chlorophyll. (green pigment)

Main Events of Photosynthesis :

♦ Absorption of light energy by chlorophy"
♦ Conversion of light energy into chemical energy + splitting (breaking) of water into hydrogen and oxygen.
♦ Reduction of CO₂ to carbohydrates.
STOMATA : Tiny pores present on the surface of the leaves
FUNCTIONS :
(i) Exchange of gases O₂/CO₂
(ii) Loses large amount of water [water vapour] during transpiration. 

How do organisms obtain their food

Unicellular / single celled organism : food is taken up through entire surface.
Example : (i) Amoeba. (ii) Paramaecium 

NUTRITION IN HUMAN BEINGS

The human digestive system comprises of alimentary canal and associated disgestive glands.

Respiration

Respiration involves
(i) Gaseous exchange : Intake of oxygen from the atmosphere and release of CO₂ → Breathing
(ii) Breakdown of simple food in order to release energy inside the cell → Cellular Respiration

Breakdown of Glucose by various pathways 

Human Respiratory System 
Passage of air through the respiratory system.

Terrestial Organism – use atmospheric oxygen for respiration
Aquatic Organisms – used dissolved oxygen for respiration
Respiration in Plants :
Respiration in plants is simpler than the respiration in animals. Gaseous exchange occur through
1. Stomata in leaves
2. Lenticels in stems
3. General surface of the roots.

Life Process (II)

Transporation and Excretion
– Human beings like other multicellular organism need regular supply of food, oxygen etc., This function is performed by circulatory system or Transport system.
– The circulatory system in human beings consists of : 

- Lymph - a yellowish fluids escapes from the blood capillaries into the intercellular spaces contain less proteins than blood. Lymph flows from the tissues to the heart assisting in transportation and destroying germs. 

– Transpiration is the process of loss of water as vapour from aerial parts of the plant.
Function :
1. Absorption and upward movement of water and minerals by creating PULL.
2. helps in temperature regulation in Plant.
– Transport of food from leaves (food factory) to different part of the plant is called Translocation.

EXCRETION

– The process of the removal of the harmful metabolic wastes from the body.
– Excretory system of human beings includes :
1) A pair of kidneys
ii) A Urinary Bladder
iii) A pair of Ureter
iv) A Urethera 

– Urine produced in the kidneys passes through the ureters into the urinary bladder where it is stored until it is released through the urethera.
– The purpose of making urine is to filter out waste product from the blood ie, urea which is produced in the liver.
– Each kidney has large numbers of filtration units called nephrons.
– The Urine formation involves three steps
1. Glomerular Filtration : Nitrogenous wastes, glucose water, amino acid filter from the blood into Bowman Capsule of the nephron.
2. Tubular reabsorption : Now, useful substances from the filtrate are reabsorbed back by capillaries surrounding the nephron.
3. Secretion Extra, water, salts are secreted into the tubule which open up into the collecting duct & then into the ureter.
– Haemodialysis : The process of purifying blood by an artificial kidney. it is meant for Kidney failure patient.

Excretion in Plants 

– Other wastes may be stored in leaves, bark etc. which fall off from the plant.
– Plants excrete some waste into the soil around them.
– Gums, Resin In old Xylem
– Some metabolic wastes in the form of crystals of Calcium oxalates in the leaves of colocasia and stem of Zamikand.

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