Class 10 - Biology - Life Processes

Question 1.

The kidneys in human beings are a part of the system for

  • nutrition

(b) respiration

(c) excretion

(d) transpiration

Answer.

Kidneys are a part of excretory system of our body, they are responsible for blood filtration and removes waste products.

Hence, the answer is (c) excretion.

 

 

Question 2.

The xylem in plants are responsible for

  • transport of water

(b) transport of food

(c) transport of amino acids

(d) transport of oxygen

Answer.

The xylem is responsible for transport of water in plants. Hence, the answer is (a) transport of water.

 

 

 

 

 

 

Question3.

The autotrophic mode of nutrition requires

(a) carbon dioxide and water

(b) chlorophyll

(c) sunlight

(d) all of the above

Answer.

The autotrophic mode of nutrition occurs in green plants which synthesize their own food.

They capture carbon dioxide from  air, roots absorb water and green plants have chlorophyll that helps in capturing light energy from sun.

Hence, (d) autotrophic mode of nutrition requires carbon dioxide, water, sunlight and chlorophyll.

 

 

Question 4.

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

  • Cytoplasm
  • Mitochondria
  • Chloroplast
  • Nucleus

Answer.

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in mitochondria.

Hence, the answer is (b) mitochondria.

Question  5.

How are fats digested in our bodies? Where does this process takes place?

Answer.

Fats are present in form of large globules in small intestine.

Small intestine receives secretions form liver and pancreas as bile juice and pancreatic juice respectively.

Bile salts break down large globules into smaller globules which makes it easier for pancreatic juice to act on them.

This is called emulsification of fats. This process takes place in small intestine.

Question 6.

What is the role of saliva in food digestion?

Answer.

Saliva is secreted by salivary glands present under the tongue. It contains enzyme salivary amylase. It has following two functions:

  • It moistens the food for easy swallowing.
  • Enzyme salivary amylase breaks down the starch present in food to sugars.

 

 

Question 7.

What are the necessary conditions for autotrophic nutrition and what are its by-products?

Answer.

Carbon dioxide (air), water (soil), chlorophyll (green pigment) and sunlight are the necessary conditions for autotrophic nutrition.

Photosynthesis is the process by which autotrophic nutrition takes place. Carbohydrates and oxygen are the by-products of this process.

 

 

Question 8.

What is the difference between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Answer.

 

Aerobic Respiration

 

Anaerobic Respiration

Requirement of Oxygen

Occurs in the presence of oxygen.

1

Occurs in the absence of oxygen.

End Products

End products are carbon dioxide and water.

2

End products are ethanol and carbon dioxide.

Energy Release

More energy is released as compared to anaerobic respiration.

3

Less energy is released as compared to aerobic respiration.

Site of Occurance

This type of respiration takes place in cytoplasm and mitochondria.

4

This type of respiration takes place only in cytoplasm.

Oxidation

Glucose is completely oxidized.

5

Glucose is not completely oxidized.

Exchange of gases

Involves exchange of gases between organism and environment.

6

There is no exchange of gases.

 

Anaerobic respiration occurs in roots of waterlogged plants, muscles of animals, organism such as yeast and bacteria.

 

 

Question 9.

How are the alveoli designed to maximize the exchange of gases?

Answer.

Alveoli are tiny sacs at the end of bronchioles in the lungs.

Alveoli is the place where there is exchange of gases (carbon dioxide is given out and oxygen is taken in).

Alveoli increase the surface area for the exchange of gases and are richly supplied with blood vessels.

 

 

Question 10.

What would be the consequences of a deficiency of haemoglobin in our bodies?

Answer.

Haemoglobin is the respiratory pigment present in our blood which helps in transport of oxygen for cellular respiration.

Deficiency of haemoglobin in blood affects the oxygen carrying capacity of the blood.

This can lead to deficiency of oxygen in the body cells. Deficiency of haemoglobin leads to anaemia.

 

 

Question 11.

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

Answer.

Human heart is divided into four chambers- two atrium and two ventricles. The circulation of blood in human body occurs as follows:

  • Oxygenated blood from lungs is transported into left atrium via pulmonary vein.
  • Then the left atrium contracts and passes this oxygenated blood into left ventricle through auriculo-ventricular aperture.
  • Then blood passes to all the body organs (except lungs) through aorta.
  • Oxygen is used up by the body parts and deoxygenated blood containing carbon dioxide is sent to right atrium through vena cava.
  • Then right atrium contracts and passes the deoxygenated blood to the right ventricle, through auriculo-ventricular aperture.
  • Then right ventricle contracts and passes the deoxygenated blood into lungs through pulmonary artery where carbon dioxide is given out and blood again takes up oxygen and becomes oxygenated blood. Then blood is again passed to left atrium for circulation via pulmonary vein.

Since, in one complete cycle blood is passed twice through the heart so it is called as double circulation.

Importance of double circulation:

The separation of oxygenated and deoxygenated blood allows efficient supply of oxygen to the body cells. 

This also helps to maintain constant body temperature in human beings.

 

 

Question 12.

What are the differences between the transport of materials in xylem and phloem?

Answer.

 

XYLEM

PHLOEM

1

It helps in transport of water and minerals.

It helps in transport of food.

2

Water is transported upwards from roots to all other parts of plants.

Food is transported in both upward and downward directions.

3

Transport in xylem occurs with the help of simple physical forces such as transpiration pull.

Transport of food in phloem requires energy in the form of ATP.

 

 

Question 13.

Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Answer.

 

Alveoli in lungs

Nephrons in Kidneys

1

These are the tiny sac like structures in the lungs.

These are tubular structures present inside the kidneys.

2

These have thin walls and large surface area which are richly supplied with blood vessels.

They are made up of glomerulus, bowman’s capsule and a long renal tube.

3

They help in exchange of gases (oxygen and carbon dioxide).

Blood enters through renal artery and nitrogenous wastes are collected in the form of urine.

4

Alveoli are site for gaseous exchange.

They are the basic filtration unit.

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