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NCERT Solutions for
Class 10 Science Chapter 6 Life Processes
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1. The kidneys in human beings are a part of the system for
(a) nutrition.
(b) respiration.
(c) excretion.
(d) transportation.
► (c) excretion.
2. The xylem
in plants are responsible for
(a) transport of water.
(b) transport of food.
(c) transport of amino acids.
(d) transport of oxygen.
► (a) transport of water.
3. The
autotrophic mode of nutrition requires
(a) carbon dioxide and water.
(b) chlorophyll.
(c) sunlight.
(d) all of the above.
► (d) all of the above.
4. The
breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.
► (b) mitochondria.
5. How are
fats digested in our bodies? Where does this process take place?
Answer
Fats are present in the form of large globules
in the small intestine. The small intestine receives the secretions from the
liver and the pancreas. The bile salts (from the liver) break down the large
fat globules into smaller globules so that the pancreatic enzyme lipase can easily
act on them. This is referred to as the emulsification of fats. This process takes
place in the small intestine.
6. What is the role of saliva in the digestion of
food?
Answer
The role of saliva in the digestion of food:
→ It moistens the food for easy swallowing.
→ It contains a digestive enzyme called salivary
amylase, which breaks down starch into sugar.
7. What are the necessary conditions for
autotrophic nutrition and what are its by-products?
Answer
Autotrophic nutrition takes place through the
process of photosynthesis. Carbon dioxide, water, chlorophyll pigment, and
sunlight are the necessary conditions required for autotrophic nutrition.
Carbohydrates (food) and O2 are the
by-products of photosynthesis.
8. What are
the differences between aerobic and anaerobic respiration? Name some organisms
that use the anaerobic mode of respiration.
Answer
|
Aerobic
respiration |
Anaerobic
respiration |
|
It occurs in the presence of O2. |
It occurs in the absence of O2. |
|
It involves the exchange of gases between the organism and the outside environment. |
The exchange of gases is absent. |
|
It occurs in cytoplasm and
mitochondria. |
It occurs only in the cytoplasm. |
|
It always releases CO2 and
H2O. |
End products vary. |
The
organisms that use an anaerobic mode of respiration include some bacteria and
microorganisms such as yeast.
9. How are the
alveoli designed to maximise the exchange of gases?
Answer
Alveoli provide a surface for the exchange of
gases. An extensive network of blood vessels is present in the wall of the
alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity
becomes spacious. Air is sucked into the lungs and alveoli. The oxygen
from the breath diffuses into the blood and CO2 from the blood brought from the body, diffuses out into
the air.
10. What would
be the consequences of a deficiency of haemoglobin in our bodies?
Answer
Haemoglobin is the respiratory pigment that
transports oxygen to the body cells for cellular respiration. Therefore,
deficiency of haemoglobin in blood can affect the oxygen supplying capacity of
blood. This can lead to deficiency of oxygen in the body cells. It can also
lead to a disease called anaemia.
11. Describe double circulation in human beings.
Why is it necessary?
Answer
During a single cycle, blood goes twice in the
heart which is known as double circulation. It is necessary for a human beings to
separate oxygenated and de-oxygenated blood because this makes their circulatory system is more efficient and helps in maintaining constant body
temperature.
12. What are the differences between the
transport of materials in xylem and phloem?
Answer
|
Xylem |
Phloem |
|
Xylem tissue helps in the
transport of water and minerals. |
Phloem tissue helps in the transport of food. |
|
Water is transported upwards from roots to all other plant parts. |
Food is transported in both upward
and downward directions. |
|
Transport in the 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. |
13. Compare
the functioning of alveoli in the lungs and nephrons in the kidneys with
respect to their structure and functioning.
Answer
|
Alveoli |
Nephrons |
|
Structure |
Structure |
|
Alveoli are tiny balloon-like
structures present inside the lungs. |
Nephrons are tubular structures
present inside the kidneys. |
|
The walls of the alveoli are one cell thick and it contains an extensive network of blood capillaries. |
Nephrons are made of glomerulus,
bowman’s capsule, and a long renal tube. |
|
Function |
Function |
|
The exchange of O2 and CO2 takes place between the blood of the capillaries that surround the alveoli and the
gases present in the alveoli. |
The blood enters the kidneys through the renal artery. The blood is entered here and the nitrogenous waste
in the form of urine is collected by collecting duct. |
|
Alveoli are the site of gaseous exchange. |
Nephrons are the basic filtration
unit. |
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