ICSE Class 10 Biology Competency Focused Practice Questions Solution-Short Answer Questions

ICSE Class 10 Biology Competency Focused Practice Questions Solution:

Short Answer Questions (2 marks each)

Question 31
Haemorrhage frequently happens in viral dengue fever. Compare this condition with haemophilia.

Answer:

In Dengue fever, the platelet count drops sharply. This leads to coagulation of blood slowly, which can lead to haemorrhage. On other hand, haemophilia is a genetic disorder in which the body’s blood clotting process is impaired due to the absence of clotting factors.

Question 32
Differentiate in the rate of photosynthesis for the increase in temperature.

(a) 20°C to 30°C
(b) 40°C to 50°C

Answer:

(a) The rate of photosynthesis gets doubled. Rate of photosynthesis increases with increase in temperature up to the optimum temperature of 35°C.

(b) Photosynthesis stops at 40°C.

Question 33
Name the nitrogenous base with which Guanine pairs up in the helical structure of DNA and through how many hydrogen bonds?

Answer:

Cytosine pairs with Guanine through 3 Hydrogen-bonds.

Question 34
When an irritant enters the nose, a sneezing reflex happens. Identify the stimulus and the response.

Answer:

The stimulus – irritant

The response – sneezing.

Question 35
An atomic explosion in 1945 in Japan led to a large number of persisting deformities in the bodies of plants and animals. What might have happened?

Answer:

Atomic explosion leads to radiation exposure. This radiation exposure leads to change in DNA i.e. mutation. The mutation alters the hereditary material of an organism’s cells.

Question 36
Why is a bicuspid valve in the human heart named so?

Answer:

The bicuspid valve in the human heart is named so because it has two flaps.

Question 37
Under which condition does a leaf take carbon dioxide from the atmosphere?

Answer:

A leaf takes carbon dioxide from the atmosphere when the concentration of CO₂ is higher outside the leaf than inside.

Question 38
A pregnant lady is suffering from viral fever. Will the foetus be infected?

Answer:

No, the foetus will not be infected because the placenta does not allow the passage of germs from the mother to the foetus.

Question 39
Why the blood flows through the glomerulus under great pressure?

Answer:

The efferent (incoming) arteriole is narrower than the afferent (outgoing) arteriole entering the glomerulus. So, the pressure of blood in glomerulus is increased.

Question 40
Differentiate between genotype and phenotype.

Answer:

Genotype	Phenotype
Set of genes present in any organism is known as its genotype.	Characters expressed or physical appearance of characters is called phenotype.

Question 41
The number of asthma patients increases during winters in metropolitan cities like Delhi. Why is it so? How can it be reduced?

Answer:

During winters in metropolitan cities like Delhi, the fog and smoke together form smog. Inhalation of smog causes rise in patients of asthma.

It can be reduced by – (i) Installation of tall chimneys in factories with filters.
(ii) Electrostatic precipitators.

Question 42
In our country, the infant mortality rate is high, but the population is still increasing in India. Explain.

Answer:

In our country, the infant mortality rate is high, but the population is still increasing in India because people from the economically weaker sections think if safer to produce more children
so that at least some may survive.

Question 43
Justify the statement – “Vermiform appendix is a vestigial organ in humans.”

Answer:

The vermiform appendix projects from the blind end of the caecum. It is a vstigial (functionless) organ in humans.

Question 44
What is Adrenal Virilism?

Answer:

Adrenal virilism is a condition that results from overgrowth of the adrenal cortex in a mature woman. It results in the development of a beard, moustache and deep voice.

Question 45
Explain the function of corpus luteum when:

(a) ovum is fertilised.

(b) ovum is not fertilised.

Answer:

(a) Corpus luteum releases progesterone and keeps the uterus in a state suitable for implantation.

(b) The Corpus luteum stops producing progesterone.

Question 46
Shruti’s mother gave birth to two male babies. Both the babies had a strong resemblance to each other. The doctor said that they have been formed from a single ovum.

(a) What kind of twins are they?

(b) Why are they of the same gender?

Answer:

(a) They are identical twins.

(b) Identical twins are of the same gender because they develop from a single ovum. The gender of the twins is determined at the time of fertilisation.

Question 47
State the effect of Adrenaline on:

(a) Pupils of eyes

(b) Heartbeat

Answer:

(a) Adrenaline causes dilation of pupil of eyes.

(b) Adrenaline increases heartbeat in order to increase blood circulation.

Question 48
When is albumin passed out in urine? Name this condition.

Answer:

Albumin may be passed out in urine under following conditions:

(i) due to high blood pressure
(ii) due to increased permeability of the bowman’s capsule membrane on account of bacterial infection
This condition is known as Albuminuria.

Question 49
Mention the significance of the Testes being located inside the scrotum.

Answer:

To maintain a temperature of 2-3°C less than body temperature for sperms to mature.
Protect testes from injuries

Testes are responsible for the production of male gametes i.e., sperms. To mature, sperms need lower temperature than the normal body temperature. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.

Question 50
Give two examples of natural resources which cannot keep pace with the rising population.

Answer:

Two examples of natural resources which cannot keep pace with the rising population are:

Food and Water

Question 51
Keshav enters a dark room from a brightly lit area. He experiences difficulty in viewing objects, but gradually his vision improves.

Answer:

Rhodopsin is the pigment which is responsible for vision in dim lights. It gets bleached in bright light. It takes a few seconds for it to regenerate in dim light. Then, the vision improves. Iodopsin responsible for vision in bright light does not function in dim light.

Question 52
On a winter night, a group of workers slept in a closed room, having a burning furnace to keep themselves warm. Most of them died in their sleep. What is the reason for their fatality?

Answer:

Due to deficiency of oxygen in the room, the burning furnace will emit carbon monoxide. This carbon monoxide when inhaled, combines with oxygen to form a stable compound, Carboxyhaemoglobin, which cuts off the supply of oxygen to tissues, leading to death due to asphyxiation.

Competency Focused Questions – Multiple Choice Questions

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Competency Focused Questions- Short Answer Questions

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