Class 10 | Science 2 | Easy notes on chapter 2 Life processes in living organisms part -1

Class 10 | Easy notes on chapter 2. Life processes in living organisms part -1 

Points to Remember :

i) Living organisms and life processes: Various organ-systems are continuously performing their functions in human body. Along with the various systems like digestive, respiratory, circulatory, excretory and control systems, different external and internal organs are performing their functions independently but through a complete co-ordination.

ii) Living organisms and energy production : In living organisms , respiration occurs at two levels as body and cellular level.

Oxygen and Carbon dioxide are exchanged between body and surrounding in case of respiration occuring at body level.

iii) Cellular respiration occurs among the living organisms by two methods:

a) aerobic respiration (oxygen is involved).

b) anaerobic respiration(oxygen is not involved).

In aerobic respiration, glucose is oxidized in three steps:

1. Glycolysis

2. Tricarboxylic acid cycle

3. Electron transfer chain reaction

ATP - Adenosine triphosphate is an energy rich molecule and energy is stored in the bonds by which phosphate groups are attached to each other.

iv) Fatty acids and amino acids are converted into acetyl-CoA and energy is obtained through complete oxidation of acetyl-CoA by the process of Kreb's cycle in mitochondria.

v) Energy Production in micro-organisms is through anaerobic respiration.

vi) Bacteria perform anaerobic

respiration for energy production.

vii) Some higher plants, animals and aerobic micro-organisms also perform anaerobic respiration instead of aerobic respiration if there is depletion in oxygen level in the surroundings.

viii) Glycolysis and fermentation are two steps of anaerobic respiration.

1. Seeds perform anaerobic respiration if the soil is submerged under water during germination.

2. Our muscle cells perform anaerobic respiration while performing exercise.

Energy from different food components :

i. We get 4 kcal energy per gram of carbohydrates.

ii. We get 4 kcal of energy per gram of proteins.

iii. We get 9 kcal energy per gram of lipids.

Vitamins : 

Vitamins are a group of heterogeneous compounds of which, each is essential for proper operation of various processes in the body.

Water :

Water is an essential nutrient.

Functioning of cells and thereby whole body disturbs even if there is a little loss of water from the body.

Fibres :

Fibres help in the digestion of other substances and egestion of undigested substances. Fibre is also an essential nutrient.