11. Which of the following forms of Nitrogen is taken up by Higher Plants? (UPSC Prelims 1979).
[A] Nitrites only
[B] Nitrates only
[C] Nitrates and Ammonium
[D] Urea
Show Answer
Correct Answer: C [Nitrates and Ammonium]
Notes:
Plants absorb ammonium and nitrate during the nitrogen assimilation process, after which they are converted into nitrogen-containing organic molecules, such as amino acids and DNA. Animals cannot absorb nitrates directly. They receive their nutrient supplies by consuming plants or plant-consuming animals.
12. Corpus luteum is a mass of cells found in which organ? (UPSC Prelims 1997)
[A] brain
[B] ovary
[C] pancreas
[D] spleen
Show Answer
Correct Answer: B [ovary]
Notes:
The corpus luteum is a hormone-secreting structure that forms in the ovary after an egg has been released during ovulation. It is made up of cells that were part of the follicle that contained the egg, and it produces the hormones progesterone and estrogen, which help to support pregnancy. The corpus luteum is important for maintaining the lining of the uterus and preparing the body for pregnancy. If pregnancy does not occur, the corpus luteum will break down and be absorbed by the body.
13. In the context of the organic evolution, the loss of limbs of snakes is explained by which of the following phenomenon? (UPSC Prelims 2002)
[A] Use and disuse of organs
[B] adaptation to living in burrows
[C] natural selection
[D] inheritance of acquired characters
Show Answer
Correct Answer: A [Use and disuse of organs]
Notes:
In organic evolution, Lamarck believed that any particular part of the body that is put into more frequent use has tendency to develop stronger and better while that part of body which is put into less or no use has tendency to gradually disappear. So, loss of limbs in snake is an example of use and disuse of organs.
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 vitamin is also called as ascorbic acid?
[A] Vitamin A
[B] Vitamin C
[C] Vitamin D
[D] Vitamin K
Show Answer
Correct Answer: B [Vitamin C]
Notes:
Vitamin C is also called as ascorbic acid. Deficiency in vitamin C leads to scurvy. Chemical formula of vitamin C is C6H8O6.
16. Who among the following is considered to be the father of taxonomy?
[A] Engler
[B] Karl Landsteiner
[C] Linnaeus
[D] RH Whittaker
Show Answer
Correct Answer: C [Linnaeus
]
Notes:
The Father of Taxonomy is Carolus Linnaeus. He classified organisms into five parts.
17. Which of the following is a type of Monera Kingdom?
[A] Bacteria
[B] Mushroom
[C] Euglena
[D] Mucor
Show Answer
Correct Answer: A [Bacteria]
Notes:
Bacteria comes under Monera kingdom, Mushroom and Mucor are part of Fungi.
18. Which sugar is present in RNA?
[A] Hexose
[B] Ribose
[C] Fructose
[D] Glucose
Glucose
Show Answer
Correct Answer: B [Ribose]
Notes:
Ribose is a simple sugar present in RNA. The chemical formula of ribose is C5H10O5, Hexose (C6H1206), Glucose (C6H12O6).
19. What is the most popular indirect method of counting virus particles?
[A] hemagglutination assay
[B] plaque-assay
[C] counting plaque-forming units
[D] colony counting
Show Answer
Correct Answer: A [hemagglutination assay]
Notes:
The hemagglutination assay (HA) is a tool used to detect hemagglutinating agents in cell culture isolates or amnioallantoic fluids.
20. Which plant tissue is the only tissue with the highest refractive index due to the presence of pectin?
[A] Sclerenchyma
[B] Collenchyma
[C] Parenchyma
[D] Laticiferous
Show Answer
Correct Answer: B [Collenchyma]
Notes:
Collenchyma tissue is the only tissue with the highest refractive index due to the presence of pectin.
