Question 1

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

Accepted 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 2

Question 32Differentiate in the rate of photosynthesis for the increase in temperature.20°C to 30°C40°C to 50°C

Accepted Answer

(a) The rate of photosynthesis gets doubled since it increases with increase in temperature up to the optimum temperature of 35°C.(b) Photosynthesis stops at 40°C.

Question 3

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

Accepted Answer

Cytosine pairs with Guanine through 3 Hydrogen-bonds.

Question 4

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

Accepted Answer

The stimulus is irritant and the response is sneezing.

Question 5

Question 35An 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?

Accepted Answer

Atomic explosion leads to radiation exposure. This radiation exposure leads to change in DNA i.e. mutation. Such mutations are responsible for a large number of persisting deformities in the bodies of plants and animals.

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

No, the foetus will not be infected because the placenta does not allow the passage of germs from the mother to the foetus. There is no mixing of blood between mother and foetus.

Question 9

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

Accepted Answer

The afferent arteriole entering the glomerulus is thicker but the efferent arteriole is thinner. This increases the pressure of blood in glomerulus.

Question 10

Question 40Differentiate between genotype and phenotype.

Accepted Answer

GenotypePhenotypeSet of genes present in any organism is known as its genotype.Characters expressed or physical appearance of characters is called phenotype.Can be determined by genotyping method.Can be determined by observation.It is formed by expressed and unexpressed genes.It consists of only expressed genes.

Question 11

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

Accepted 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:Installation of tall chimneys in factories with filters.Electrostatic precipitators.

Question 12

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

Accepted Answer

In our country, the infant mortality rate is high specially in rural areas or weaker section but the population keeps on rising because people of weaker section think it safer to produce more children so that at least some may survive.

Question 13

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

Accepted Answer

The vermiform appendix projects from the blind end of the caecum in humans. It is called a vestigial organ because it no longer has a vital function for us. It might have been useful to our ancestors for digesting tough plant materials, but now it serves little purpose.

Question 14

Question 44What is Adrenal Virilism?

Accepted Answer

Adrenal virilism is a condition that results from excessive production of androgens (male hormones) by the adrenal glands. It leads to the development of male physical characteristics in females like the development of a beard, moustache and deep voice. It is caused by overgrowth of the adrenal cortex in a mature woman.

Question 15

Question 45Explain the function of corpus luteum when:(a) ovum is fertilised.(b) ovum is not fertilised.

Accepted Answer

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

Question 16

Question 46Shruti’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?

Accepted Answer

(a) They are identical twins.(b) Identical twins (monozygotic twins), are always of the same gender because they originate from a single fertilized egg (zygote). Their gender is decided at the time of fertilization.

Question 17

Question 47State the effect of Adrenaline on:(a) Pupils of eyes(b) Heartbeat

Accepted Answer

(a) Adrenaline cause dilation of pupil of eyes.(b) Adrenaline increase heartbeat in order to increase blood circulation.

Question 18

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

Accepted Answer

Albumin may be passed out in urine under following conditions:due to high blood pressuredue to increased permeability of the bowman’s capsule membrane on account of bacterial infectionThis condition is known as Albuminuria.

Question 19

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

Accepted Answer

Testes are responsible for the production of male gametes i.e., sperms. The normal body temperature does not allow the maturation of the sperms. 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 20

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

Accepted Answer

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

Short Answer Questions