Biology (Part-IV) (UPSC)

Total Questions: 66

61. Consider the following statements: [2022-1]

1. Other than those made by humans, nanoparticles do not exist in nature.

2. Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.

3. Nanoparticles of some commercial products which enter the environment are unsafe for humans.

Which of the statements given above is/are correct?

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

Correct Answer: (d) 2 and 3

Solution:Statement 2 and 3 are correct: The nanoparticle are used in production of some cosmetics and they may be unsafe for human. Therefore answer is (d).

62. Consider the following statements: [2022-1]

DNA Barcoding can be a tool to:

1. assess the age of a plant or animal.

2. distinguish among species that look alike.

3. identify undesirable animal or plant materials in processed foods.

Which of the statements given above is/are correct?

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

Correct Answer: (d) 2 and 3

Solution:Statement I is wrong: age of the plants and animals are measured using radio active isotopes. So (a) and (c) eliminated. Statements 2 and 3 are correct: DNA Barcoding can be used to distinguish among species that look alike and identify undesirable animal or plant materials in processed foods. Therefore Answer is (d).

63. 'Wolbachia method' is sometimes talked about with reference to which one of the following? [2023-1]

(a) Controlling the viral diseases spread by mosquitoes
(b) Converting crop residues into packing material
(c) Producing biodegradable plastics
(d) Producing biochar from thermochemical conversion of biomass

Correct Answer: (a) Controlling the viral diseases spread by mosquitoes

Solution:The correct answer is (a). Wolbachia is a common bacteria that occurs naturally in 60% of insect species, including some mosquitoes, fruit flies, moths, dragonflies and butterflies. It is not, however, found in dengue carrying Aedes a egypti mosquitoes. Researchers are trying to breed dengue mosquitoes with mosquitoes carrying Wolbachia. This will produce Wolbachia mosquitoes. So, even if they bite people, it won't cause dengue.

64. Which one of the following is synthesised in human body that dilates blood vessels and increases blood flow? [2024-1]

(a) Nitric oxide
(b) Nitrous oxide
(c) Nitrogen dioxide
(d) Nitrogen pentoxide

Correct Answer: (a) Nitric oxide

Solution:Nitric oxide (NO) is synthesized from L-arginine by nitric oxide synthase (NOS) primarily in the endothelium of blood vessels. It acts as a potent vasodilator, relaxing arterial smooth muscles to enhance blood flow and support cardiovascular health.

NO also functions as a neurotransmitter, influencing neuronal activity and contributing to processes like learning.

Hence the correct answer is (a).

65. Consider the following: [2024-1]

1. Carabid beetles

2. Centipedes

3. Flies

4. Termites

5. Wasps

Parasitoid species are found in how many of the above kind of organisms?

(a) Only two
(b) Only three
(c) Only four
(d) All five

Correct Answer: (b) Only three

Solution:Option 1, 3 and 5 are correct.

A parasitoid is an organism whose offspring develop either on or inside a host organism, ultimately leading to the host's death. Parasitoids share traits with both predators and parasites.

Examples of parasitoids are various species of wasps, tachinid flies, carabid beetles, and Gordian worms.

While some centipedes are predators, they do not function as parasitoids.

Notably, termites are unique among most insects in that they have no known parasitoids.

66. The organisms "Cicada, Froghopper and Pond skater" are: [2024-1]

(a) Birds
(b) Fish
(c) Insects
(d) Reptiles

Correct Answer: (c) Insects

Solution:Cicadas, froghoppers, and pond skaters are all types of insects. Cicadas belong to a super family within the order Hemiptera (true bugs).

Froghoppers, also known as the super family Cercopoidea, are a group of hemipteran insects in the suborder Auchenorrhyncha. Pond skaters are a family of insects within the order Hemiptera. Hence, Option (c) is the correct answer.

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