11. Who among the following analysed the DNA for the first time ?
[A] Watson and Krick
[B] Karl von Frisch
[C] M. W. Nirenberg
[D] Hargobind Khurana
Show Answer
Correct Answer: A [Watson and Krick]
Notes:
The discovery in 1953 of the double helix, the twisted-ladder structure of deoxyribonucleic acid (DNA), by James Watson and Francis Crick marked a milestone in the history of science and gave rise to modern molecular biology, which is largely concerned with understanding how genes control the chemical processes.
12. Which of the following crops helps in nitrogen fixation?
[A] Rice
[B] Wheat
[C] Maize
[D] Beans
Show Answer
Correct Answer: D [Beans]
Notes:
Any legume plants will help in nitrogen fixation. Beans contain symbiotic bacteria called Rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants and this helps to fertilize the soil.
13. Which organ is associated with the production of insulin in the human body?
[A] Pancreas
[B] Liver
[C] Kidney
[D] Heart
Show Answer
Correct Answer: A [Pancreas]
Notes:
Insulin is a hormone made by an organ located behind the stomach called the pancreas. It allows body to use sugar from carbohydrates in the food. Insulin helps keep blood sugar level from getting too high (hyperglycemia) or too low (hypoglycemia).
14. Ticks and mites belongs to which of the following classes? (UPSC Prelims 2002)
[A] Arachnids
[B] Crustaceans
[C] Insects
[D] Myriapods
Show Answer
Correct Answer: A [Arachnids]
Notes:
The order Acarina (class Arachnida) includes mites and ticks. Members of this order differ from other arachnids in that the body is not segmented, and the cephalothorax and abdomen are combined into one body region. Larval mites and ticks have three pairs of legs, whereas nymphs and adults have four pairs.
15. Which among the following organs secrete bile juice?
[A] Liver
[B] Pancreas
[C] Stomach
[D] Large intestine
Show Answer
Correct Answer: A [Liver]
Notes:
Bile is a digestive juice secreted by the liver and it aids in the digestion of food. Many waste products are eliminated from the body through bile.
16. Which branch of biology is known for the study of internal body structure?
[A] Anatomy
[B] Biometrics
[C] Pathology
[D] None of these
Show Answer
Correct Answer: A [Anatomy]
Notes:
Anatomy is the branch of biology that studies the structure and parts of organisms. Anatomy is a branch of natural science that deals with the structural organization of living things.
17. The name of Theodor Schwann is associated with the discovery of which of the following?
[A] enzyme pepsin
[B] glial cells in nerves
[C] microorganisms play in alcohol fermentation
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Schwann discovered the enzyme pepsin and discovered glial cells in nerves – these are now known as Schwann cells. He also identified the role of microorganisms in alcohol fermentation.
18. What are cryptogamous plants?
[A] Flowerless plant
[B] Seedless Plant
[C] Reproduce by spores
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Cryptogamic plants include Algae, mosses, liverworts, lichens, ferns and fungi and they reproduce by spores and not producing flowers or seed.
19. Which of the following is not a characteristic of Bryophyta?
[A] Motile sperms
[B] Presence of archegonium
[C] Presence of archegonium
[D] Photosynthetically independent sporophyte
Show Answer
Correct Answer: D [Photosynthetically independent sporophyte]
Notes:
Motile sperms, the Presence of archegonium, and the Presence of archegonium are characteristics of Bryophyta.
20. What is the role of indole acetic acid in plant growth?
[A] cell division and elongation
[B] tissue differentiation
[C] apical dominance
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Indole acetic acid is the main auxin in plants that regulates growth and development processes such as cell division and elongation, tissue differentiation, apical dominance, and responses to light, gravity, and pathogens.
