11. When one gene controls two or more different characters simultaneously, the phenomenon is known by which of the following names? (UPSC Prelims 2002)
[A] Apomixis
[B] Pleiotropy
[C] Polyploidy
[D] Polyteny
Show Answer
Correct Answer: B [Pleiotropy]
Notes:
• Polyploidy occurs in cells and organisms when there are more than two paired (homologous) set of chromosome founds which controls more than one characters simultaneously.
• Apomixis is the process of asexual reproduction in which the embryo grows from egg cells without being fertilized.
• Pleiotropy occurs when a single gene influences multiple phenotypic traits.
• Polytene is a giant chromosome found in some two-winged flies.
12. Which among the following is responsible for the red colour of blood?
[A] Haemoglobin
[B] Platelets
[C] Plasma
[D] None of the above
Show Answer
Correct Answer: A [Haemoglobin]
Notes:
Haemoglogin pigment is responsible for the red colour of the blood. Haemoglobin is responsible for carrying oxygen from lungs to the tissues of the body.
13. Who were the first scientists successfully isolated insulin in 1921?
[A] Frederick Banting and Charles Herbert Best
[B] Robert Hooke and Gregor Mendel
[C] Charles Darwin and Antonie van Leeuwenhoek
[D] Rachel Carson and Theodor Schwann
Show Answer
Correct Answer: A [Frederick Banting and Charles Herbert Best]
Notes:
Insulin was the first peptide hormone discovered. Canadians Frederick Banting and Charles Herbert Best were the first scientists successfully isolated insulin from the dog pancreas in 1921. They achieved this tremendous feat while working in Canada’s University of Toronto J.J.R. Macleod Laboratory.
14. Which of the following are blue-green algae?
[A] Prokaryotes
[B] Eukaryotes
[C] Both 1 and 2
[D] Neither 1 nor 2
Show Answer
Correct Answer: A [Prokaryotes]
Notes:
Blue-green algae or cyanobacteria are prokaryotes. They lack membrane bound organelles and a nucleus.
15. In which part of the body cholesterol is synthesized?
[A] Pancreas
[B] Liver
[C] Spleen
[D] Stomach
Show Answer
Correct Answer: B [Liver]
Notes:
Cholesterol is a type of Lipid or the fat present in blood. The majority of the cholesterol consumed by the human body on a daily basis is synthesised by Liver.
16. Which plant tissue can be classified into sclerenchyma, collenchyma and parenchyma?
[A] Complex Permanent Tissue
[B] Simple Permanent Tissue
[C] Intercalary meristem
[D] Epidermis
Show Answer
Correct Answer: B [Simple Permanent Tissue]
Notes:
Simple Permanent Tissue can be classified into sclerenchyma, collenchyma, and parenchyma.
17. Name the plant tissue which helps in the transport of food.
[A] Xylem
[B] Aerenchyma
[C] Phloem
[D] Chlorenchyma
Show Answer
Correct Answer: C [Phloem]
Notes:
Phloem tissue helps in the transport of food throughout the plant. The diverse elements of phloem include phloem fibers, sieve tubes, phloem parenchyma, and companion cells.
18. When did the effect of cytokinin first appear?
[A] adding the liquid endosperm of papaya
[B] adding the liquid endosperm of coconuts
[C] adding the liquid endosperm of mango
[D] adding the liquid endosperm of grapes
Show Answer
Correct Answer: B [adding the liquid endosperm of coconuts]
Notes:
The effect of cytokinin was first observed when the addition of liquid endosperm of coconut to developing plant embryos in culture promoted their growth.
19. What does it mean for pea grains to be coiled around any support?
[A] Seismonasty
[B] Thigmotaxis
[C] Gravitropism
[D] Thigmotrophism
Show Answer
Correct Answer: D [Thigmotrophism]
Notes:
An example of tropism is thigmotropism, which is a plant’s response to moving toward or away from environmental stimuli.
20. Which plant material is called an embryo?
[A] Seed
[B] Fruit
[C] Flower
[D] Root
Show Answer
Correct Answer: A [Seed]
Notes:
The seed contains plant material, it can develop into another plant. This plant material is called the embryo.
