Previous Year Questions : Biology Section UPSC 2013 GS paper 1

Previous Year Questions : Biology Section UPSC 2013 GS paper 1

Previous Year Questions : Biology Section UPSC 2013 GS paper 1

Previous Year Questions : Biology Section UPSC 2013 GS paper 1

Previous Year Questions : Biology Section UPSC 2013 GS paper 1

We have started a series in which Previous Year Questions UPSC IAS questions related to General Studies will be analysed, solved and provided inputs. We will brainstorm on 2013 , 2014 and 2015 Previous Year Questions question papers. Video presentation will be there for each section.

We have started from Biology Section Previous Year Questions and UPSC 2013 GS paper 1 have been taken for solution and analysis. Below the questions , answer/solution and video lectures are given.

This will help you to make strategy what kind of questions are being asked and how you can prepare accordingly.

UPSC 2013 General Studies Paper 1 : Prelims : Total 11 questions were asked from Biology Portion. Which were these 11 questions. Let us discuss.

Previous Year Questions : Video Lectures 

Previous Year Questions : Part 1

Previous Year Questions : Part 2

Q1. Which of the following diseases can be transmitted from one person to another through tattooing?

  1. Chikungunya
  2. Hepatitis B

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

Hepatitis B : How it spreads

By blood products (unclean needles or unscreened blood).

By mother to baby by pregnancy, labor, or nursing.

By having unprotected vaginal, anal, or oral sex.

Hepatitis B : A serious liver infection caused by the hepatitis B virus that’s easily preventable by a vaccine.

Chikungunya is a viral disease transmitted to humans by infected mosquitoes. It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.

Humans and other primates are the natural hosts for the chikungunyavirus. The virus is spread to humans by the bite of an infected female Aedes species mosquito – Aedes aegypti or Aedes albopictus. These are the same tropical and sub-tropical mosquitoes that carry the dengue virus.

Q2. Consider the following minerals

  1. Calcium
  2. Iron
  3. SodiumPrevious Year Questions : Biology Section UPSC 2013 GS paper 1

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

Myoglobin (symbol Mb or MB) is an iron– and oxygen-binding protein found in the muscle tissue

Sodium and Potassium

Sodium and potassium play essential roles in muscle contraction because of their importance in nerve function. Your nervous system communicates with your muscles through structures called neuromuscular junctions, and the activation of a nerve triggers muscle contraction. Sodium and potassium help your nerve cells send electrical signals, called action potentials, that signal for your muscles to contract. A loss of either mineral prevents your nerves from communicating properly with your muscle fibers, leading to muscle weakness or twitching.

Calcium and Magnesium

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. Actin and myosin rely on calcium to shorten and contract your muscles, then rely on magnesium to relax after a contraction. While low calcium levels primarily affect your bones — causing bone loss and putting you at risk for osteoporosis — magnesium deficiency affects your muscles, causing abnormal muscle contraction.


Iron also helps your muscles contract. Each muscle contraction uses up energy as well as oxygen. Iron helps support continued muscle function by supporting energy production in your muscle cells, so that your muscle fibers always have the energy they need to contract properly. Iron also helps your muscles store oxygen to fuel muscle contractions, and promotes healthy circulation so that your muscles can get additional oxygen from your bloodstream.

Q3. Which of the following statements is / are correct?

  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 3Previous Year Questions : Biology Section UPSC 2013 GS paper 1

Most viruses have either RNA or DNA as their genetic material. The nucleic acid may be single- or double-stranded. The entire infectious virus particle, called a virion, consists of the nucleic acid and an outer shell of protein. The simplest viruses contain only enough RNA or DNA to encode four proteins.

Q4. Recombinant DNA technology (Genetic Engineering) allows genes to be transferred

(a)  across different species of plants

(b ) from animals to plants

(c ) from microorganisms to higher organisms

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

Q5. Improper handling and storage of cereal grains and oilseeds result in the production of toxins known as aflatoxins which are not generally destroyed by normal cooking process. Aflatoxins are produced by

(a) bacteria

(b) protozoa

(c) moulds

(d) viruses

Aflatoxin is a potent human carcinogen. It is a naturally occurring toxic metabolite produced by certain fungi (Aspergillus flavis), a mold found on food products such as corn and peanuts, peanut butter. It acts as a potent liver carcinogen in rodents (and, presumably, humans)

Q6. Fruits stored in a cold chamber exhibit longer storage life because

(a) exposure to sunlight is prevented

(b) Concentration of carbon dioxide in the environment is increased

(c ) rate of respiration is decreased

(d ) there is an increase in humidity

During respiration oxygen is consumed and carbon dioxide , water and energy is released. Slower respiration lesser energy , means slow metabolic activities or chemical reactions. In storage principle of slow respiration is followed.

Q7. Many transplanted seedlings do not grow because

(a) the new soil does not contain favorable minerals

(b) most of the root hairs grip the new soil too hard

(c ) most of the root hairs are lost during transplantation

(d) leaves get damaged during transplantation

Root hairs are delicate. When seedlings are transplanted root hairs may damage. Root hairs are useful in respiration, absorption and water /miner transport. Damage in root hairs can stop respiration.

Q8. Which of the following leaf modification occurs/occur in desert areas to inhibit water loss?

  1. Hard and waxy leaves
  2. Tiny leaves or no leaves
  3. Thorns instead of leaves

Select the correct answer using the codes given below:

(a) 1 and 2 only

(b) 2 only

(c) 1 and 3 only

(d) 1, 2 and 3

Hard and waxy leaves slow transpiration. Tiny leaves surface area less so less transpiration, thorns are also modified leaves to reduce level of transpiration.


Q9. Consider the following animals:

  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

( c) 2 and 3 only

(d) 1, 2 and 3

Mammals give birth and feed milk to their offspring.  Sea Cow is a big aquatic mammal and similarly Sea lion. While Sea Horse comes under the category of Pisces.

Q10. Consider the following organisms

  1. Agaricus
  2. Nostoc
  3. Spirogyra

Which of the above is / are used as biofertilizer / biofertilizers

(a) 1 and 2

(b) 2 only

(c) 2 and 3

(d) 3 only

Blue green algae constitute an important group of micro organism capable of fixing atmospheric nitrogen. Nostoc is a type of Blue green algae.


It is a non living nitrogen fixing algae. Its inoculations severs as organic biomass for the growing rice plants.

Furthur, the mucilaginous sheath of the filaments of spirogyra is an abode of many micro organisms some of which may fix nitrogen.

Q11. Which of the following adds / add nitrogen to the soil?

  1. Excretion of urea by animals
  2. Burning of coal by man
  3. Death of vegetation

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

-Excretion of urea by animals : Converted in to ammonia and then nitrates. Burning of coal emits oxide of nitrogen. In atmosphere adds nitrogen which comes on the earth and is used as nitrates. Death of vegetation decompose and result into nitrogen compound.

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