11. Which one of the following plants can fix nitrogen from air? (UPSC Prelims 1992)
[A] Rice
[B] Wheat
[C] Pea
[D] Maize
Show Answer
Correct Answer: C [Pea]
Notes:
Nitrogen fixing plants don’t pull nitrogen from the air on their own. They actually need help from a common bacteria called Rhizobium. The bacteria infect legume plants such as peas and beans and use the plant to help it draw nitrogen from the air.
12. Which of the following define the hormone insulin? (UPSC Prelims 2004)
[A] Glycolipid
[B] Fatty acid
[C] Peptide
[D] Stero
Show Answer
Correct Answer: C [Peptide]
Notes:
Insulin is a protein chain or peptide hormone. There are 51 amino acids in an insulin molecule. It has a molecular weight of 5808 Da. Insulin is produced in the islets of Langerhans in the pancreas.
13. Which among the following is an autotroph?
[A] Honey bee
[B] Algae
[C] Grasshopper
[D] Butterfly
Show Answer
Correct Answer: B [Algae]
Notes:
Autotrophs are the organisms which are able to prepare their own food without depending on other organism. Auto means self and prophs means food. All the organisms which are capable of carrying photosynthesis are examples of autotrophs.
14. What is the pH range of blood?
[A] 6.55-6.85
[B] 1.55-3.55
[C] 10.5-12
[D] 7.35-7.45
Show Answer
Correct Answer: D [7.35-7.45]
Notes:
Blood has a pH range of 7.35-7.45 which indicates that blood is slightly basic/alkaline. pH scale from 0 to 7 indicates acidic nature, 7 to 14 indicates basic nature of the solution.
15. Which tissue of plant is used to transport food to various parts?
[A] Xylem
[B] Parenchyma
[C] Sclerenchyma
[D] Phloem
Show Answer
Correct Answer: D [Phloem]
Notes:
Phloem, also called bast, are tissues in plants that conduct foods made in the leaves to all other parts of the plant. This transport process is called translocation. Phloem is composed of various specialized cells called sieve tubes, companion cells, phloem fibres, and phloem parenchyma cells.
16. Which of the following is a reducing sugar?
[A] β-methyl galactosidase
[B] Sucrose
[C] Gluconic acid
[D] Galactose
Show Answer
Correct Answer: D [Galactose]
Notes:
The dietary monosaccharides galactose, glucose and fructose are all reducing sugars.
17. What are the inclusion bodies of the measles virus?
[A] intracytoplasmic
[B] intranuclear
[C] both (a) and (b)
[D] none of these
Show Answer
Correct Answer: C [both (a) and (b)]
Notes:
The inclusion bodies of the measles virus are intracytoplasmic and intranuclear.
18. Which of the following structures is responsible for the motility of bacteria?
[A] pilli
[B] flagella
[C] sheath
[D] capsules
Show Answer
Correct Answer: B [flagella]
Notes:
Flagella is responsible for the motility of bacteria. The flagellum is primarily a motility organ. This enables movement and chemotaxis.
19. Which of the following are the roots of gymnosperms?
[A] Tap root
[B] Adventitious roots
[C] Rhizoid
[D] Rhizophores
Show Answer
Correct Answer: A [Tap root]
Notes:
The root system present in gymnosperms is the taproot system. Tap roots somewhat dilute the root of the upright plant and grow vertically downwards.
20. When did gymnosperms originate?
[A] Palaeozoic
[B] PreCambrian
[C] Cenozoic
[D] Mesozoic
Show Answer
Correct Answer: A [Palaeozoic]
Notes:
Gymnosperms were the first seed plants to evolve. The earliest seed-like bodies are found in the rocks of the Upper Devonian chain. They appeared in the Paleozoic period and were the dominant plants during the Mesozoic.
