Biology (Part-IV) (UPSC)

Total Questions: 66

31. Consider the following minerals: [2013-11]

1. Calcium

2. Iron

3. Sodium

Which of the minerals given above is/are required by human body for the contraction of muscles?

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (d) 1, 2 and 3

Solution:Calcium is the most common and abundant mineral in the body. It is important for healthy bones and teeth, helps muscle relax and contract, important in nerve functioning, blood clotting etc. Sodium is needed for proper fluid balance, nerve transmission and muscle contraction.

Sodium and potassium play essential roles in muscle contraction because of their importance in nerve function. Calcium and magnesium work together to control muscle contraction. Both minerals interact with the proteins actin and myosin structural proteins that shorten with each muscle contraction, then lengthen to relax your muscles.

32. Consider the following animals: [2013-1]

1. Sea cow

2. Sea horse

3. Sea lion

Which of the above is/are mammal/mammals?

(a) 1 only
(b) 1 and 3 only
(a) 1 only
(d) 1, 2 and 3

Correct Answer: (b) 1 and 3 only

Solution:Sea cow is a mammal. It is a herbivore and it grows up to 9 meters. It looks like a large seal. Sea horse is a fish not a mammal. Sea lion is a mammal. It is a carnivore. It is also known as eared seal.

33. Which of the following statements is/are correct? [2013-1]

1. Viruses lack enzymes necessary for the generation of energy.

2. Viruses can be cultured in any synthetic medium.

3. Viruses are transmitted from one organism to another by biological vectors only.

Select the correct answer using the codes given below.

(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (a) 1 only

Solution:Viruses have no metabolic enzymes and cannot generate their own energy. Viruses require a growth medium containing living cell therefore cannot be cultured in any synthetic medium. Viruses are transmitted from one organism to another not only by biological vectors but also by mechanical vectors. Mechanical vector like an arthropod vector which transmit an infective organism from one host to another but it is not essential to the life of cycle of the parasite.

Class 11, Biology, Chapter 2, Biological Classification-Page number-25-28

34. Among the following organisms, which one does not belong to the class of other three? [2014-1]

(a) Crab
(b) Mite
(c) Scorpion
(d) Spider

Correct Answer: (a) Crab

Solution:Mite, Spider and Scorpion belong to the category of Arachnids, while Crabs belong to the category of crustaceans.

35. Consider the following diseases: [2014-1]

1. Diphtheria

2. Chickenpox

3. Smallpox

Which of the above diseases has/have been eradicated in India?

(a) 1 and 2 only
(b) 3 only
(c) 1, 2 and 3
(d) None

Correct Answer: (b) 3 only

Solution:Smallpox is the only disease eradicated from India.

India accounts for a substantial proportion of global burden of diphtheria and many outbreaks have been reported in recent years.

36. Consider the following pairs: [2014-1]

1. Vitamin C : Scurvy

2. Vitamin D : Rickets

3. Vitamin E : Night blindness

Which of the pairs given above is/are correctly matched?

(a) 1 and 2 only
(b) 3 only
(c) 1, 2 and 3
(d) None

Correct Answer: (a) 1 and 2 only

Solution:Deficiency of vitamin C causes Scurvy, disease of gums. Deficiency of vitamin D causes Rickets (disease of bones) and Deficiency of Vitamin A causes night blindness, disease of eyes.

37. Consider the following: [2014-1]

1. Bats, 2. Bears, 3. Rodents

The phenomenon of hibernation can be observed in which of the above kinds of animals?

(a) 1 and 2 only
(b) 2 only
(c) 1, 2 and 3
(d) Hibernation cannot be observed in any of the above

Correct Answer: (c) 1, 2 and 3

Solution:Hibernation is a state of inactivity and metabolic depression in endothermsis characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. It is found in Bat, bear and rodents etc.

38. H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases? [2015-1]

(a) AIDS
(b) Bird flu
(c) Dengue
(d) Swine flu

Correct Answer: (d) Swine flu

Solution:H1N1 flu is also known as swine flu. The cause of swine flu is an influenza A virus type designated as HINI.

39. Which of the following statements is/are correct? [2016-1]

Viruses can infect -

1. bacteria

2. fungi

3. plants

Select the correct answer using the code given below.

(a) 1 and 2 only
(b) 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Correct Answer: (d) 1, 2 and 3

Solution:(i) A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and fungi.

(ii) According to the type of the host they infect, viruses are classified

mainly into the following four types:

(a) Plant viruses including algal viruses-RNA/DNA

(b) Animal viruses including human viruses-DNA/RNA

(d) Bacterial viruses (Bacteriophages) including cyanophages-
DN

Hence answer "(d)".

40. Consider the following statements: [2018-1]

1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue.

2. Sexual transmission of Zika virus disease is possible.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer: (c) Both 1 and 2

Solution:Dengue, Zika and chikungunya are spread through a common vector, the Aedes aegypti mosquito. So first statement is right. Although Zika virus is primarily transmitted through mosquitoes, it can also be sexually transmitted as well. So second statement is also right.

Female mosquitoes normally lay their eggs above the water line in water-holding containers. Tires, buckets, birdbaths, water storage jars, and flower pots are examples of these containers. Mosquito larvae hatch from the eggs as the containers overflow with water, which occurs often during rain.

The larvae are marine, which means they live in water and eat microorganisms that live there. Larvae go through three stages of growth during which they moult (or lose their skin). The first and fourth instars are the larval stages.

When a larva reaches the fourth instar stage, it undergoes metamorphosis into a new phase known as a pupa, which is the mosquito's "cocoon" stage. This is also an underwater period in the mosquito's cycle.

The completely formed adult mosquito forms and splits through the pupa's skin after two days. The adult mosquito can fly and is no longer an underwater creature. It lives in a terrestrial climate.

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