LIFE PROCESSES CBSE Class X Important Notes

Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, 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

 Criteria of life- (i) Growth (ii) Movement


 Nutrition- The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body.

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

Nutrition in human beings
 Alimentary canal-
Mouth → Oesophagus → Stomach → Small intestine → Large intestine

 

 Peristaltic movements- Rhythmic contraction of muscles of the lining of Alimentary canal to push the food forward.

 Sphincter muscle- Helps in the exit of food from the stomach.

 Villi- Small finger like projections on the walls of-
(vi) Small intestine- To increase the surface area for the absorption of food.
(vii) Large intestine- For absorption of water.

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

 Some common features of Respiratory organs- (i) Large surface area- for greater rate of diffusion of respiratory gases. (ii) Thin permeable walls – to ensure easy diffusion & exchange of gases. (iii) Extensive blood supply- Respiratory organs are richly supplied with blood vessels for quick transport of gases.

Human Respiratory system- External nostrils → Nasal cavity → Trachea→ Bronchi → Bronchioles →Alveoli  Rings of cartilage present in the throat ensure that the trachea (air passage) does not collapse when there is less air in it.  Lungs – (i) Present in the thoracic cavity. (ii) They are spongy, elastic bags consisting of Bronchi, Bronchioles and Alveoli

Respiration occurs in two phases-
o (i) External-Breathing, which is a mechanical process. (ii) Internal - Cellular respiration
o Mechanism of breathing – It includes : (i)Inhalation (ii) Exhalation
o Exchange of gases-
 Unicellular organisms- By Diffusion
 Animals- (i) As the body size is large, diffusion alone is not enough.
(ii) Respiratory pigments also required.
(iii) Respiratory pigment in human beings is Haemoglobin,
which is present in red blood corpuscles.
(iv) It has very high affinity for Oxygen.
(iv) Carbon dioxide is more soluble in water thanOxygen, so it
Gets dissolves in blood and is thus transported.

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.

 

Transportation in plants-
 Plants need less energy needs- because they do not move and therefore have a slow transport system
 Transport of water-
(i) Takes place by xylem tissue present in roots, stem, leaves and is therefore interconnected.
(ii) Root cells take up ions from the soil, which creates a concentration difference between root and soil. Column of water therefore rises upwards.
 In very tall plants- transpiration creates a suction pressure, which pulls the water upwards.
 Importance of transpiration-
(i) Helps in upward movement of water in plants.
(ii) It regulates the temperature in plants.
 Transport of food-
(i) Takes place by phloem tissue.
(ii) Movement of prepared food in plants is called translocation

 

Kidneys-
(i) Two in number
(ii) Bean shaped
(iii) Present in abdomen on either side of the backbone
(iv) Basic unit is nephron.
a. Glomerulus- Group of capillaries (cluster) present in Bowman‘s capsule to receive blood from renal artery and filters it.
b. Bowman‘s capsule- Cup shaped structure, which contains glomerulus.
c. Convoluted tubule-is long and reabsorbs vital nutrients like glucose, amino acids, salts, urea and water.
Note-Vital functions of kidneys- (a) Filtration & removal of Nitrogenous wastes (Urea ,Uric acid)
(b) Reabsorption of vital nutrients
 Ureters- Transport the urine formed in the kidneys to the urinary bladder.
 Urinary bladder- Muscular bag like structure to store urine.
 Urethra- Helps in removal of urine when the Urinary bladder is full.