CBSE Class 10 Science Important Questions Chapter 6 Life Processes Part 5 (For CBSE, ICSE, IAS, NET, NRA 2022)

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5 Marks Questions

1. What is ‘clotting of blood’ ? Write a flow chart showing major events taking place in clotting of blood?

Ans. Formation of clot at the site of injury to stop bleeding is known as ‘clotting of blood’ . Steps for clotting of blood –

Formation of Clot

2. With the help of a labelled diagram of human excretory system, Mention its important part and explain them.

Ans. 1) Kidney – It is the functional unit of excretory system. Each kidney is made up of about million microscopic coiled channels called nephrons. Nephrons are the basic filtration unit in the kidneys. It consists of – Glomerulus՚s, Bowman՚s capsule, convoluted tubule.

Human Excretory System

2) Ureter – Wastes comes out of the kidney into the ureter.

3) Urinary bladder – Ureter pours its contents into a muscular sac called the urinary bladder.

4) Urethra – Urine flows from bladder to the outside through the urethra.

3. (i) Draw a well labeled diagram of human digestive system

(ii) Describe the role of following in digestion.

a) Bile

b) Salivary amylase

c) HCl

Ans. (i)

Human Digestive System

a) Bile – emulsification of fats

b) Salivary amylase – digest starch in mouth

c) HCl – Activate pepsinogen by making medium acidic in stomata.

4. With the help of labeled diagram, discuss the mechanism of respiration in human beings.

Ans. Mechanism of Respiration – It occurs in following steps

Mechanism of Respiration

a) Breathing – Taking in oxygen and expelling carbon – dioxide out is called breathing. It involves following steps –

(i) Inhalation – It is taking in oxygen. It occurs due to contraction of muscles attached to ribs. This lifts ribs and flatter diaphragm, which increase the volume of thoracic cavity. Hence the pressure inside the thoracic cavity decreases and air rushes inside of the lungs.

(ii) Exhalation – It is expelling of carbon – dioxide. It occurs due to relaxation of muscles attached to ribs and diaphragm is done shaped. This decreases the volume of thoracic cavity and decreases air pressure and expels out of the lung.

b) Exchange of gases – It takes place between the alveoli of lungs and surrounding blood capillaries.

c) Transport of gases in blood – Hemoglobin present in the blood transport. in blood. Oxygen is transport from the lungs to the body cells in the form of any hemoglobin.

d) Oxidation of food – Break down of glucose molecules which produce energy. It occurs is into chondria.

5. Describe an experiment to prove that carbon – dioxide is essential for the process of photosynthesis.

Ans. Experiment showing is essential for photosynthesis.

1) Take a potted plant with elongated leaves

2) Take an empty bottle and put a little amount of potassium hydroxide (KOH) in it.

3) Now cut the cork of the bottle into two parts and place it on one of the leaves of the potted plant in between the two parts of the cork.

4) Now put the bottle in the presence of sunlight 72 – 96 hours.

5) Now test the leaf for the presence of starch.

6. Describe the structure and functioning of nephron.

Ans. Each nephron is a cluster of very thin-walled blood capillaries. Each capillary cluster in the kidney called glomerulus is associated with the cup shaped Bowman՚s capsule that collects the filtered urine. Nephron filters the blood in order to remove nitrogenous waste. They also absorb some useful substance such as glucose, amino acids, minerals and major amount of water from filtrate.

Structure and Functioning of Nephron

7. Describe double circulation in human beings. Why is it necessary?

Ans. In mammals and birds the blood goes through the heart twice during each cycle. This is known as double circulation.

Deoxygenated blood which enters right auricle and then it enters the right ventricle from where it is pumped to lungs for oxygenation. From lungs after oxygenation it comes to left auricle and then enters left ventricle from where it is pumped to various parts of body.

Such system of circulation does not allow mixing of oxygenated and deoxygenated blood which allows efficient supply of oxygen to the body.