11. The messages received by and transmitted from the brain to the various parts of the body take the form of which of the following impulses? (UPSC Prelims 1983)
[A] Nervous impulses
[B] Chemical impulses
[C] Mechanical impulses
[D] Automatic impulses
Show Answer
Correct Answer: A [Nervous impulses]
Notes:
The message to the brain form any body part takes the form of nervous impulses. Nerve impulses are mostly electrical signals along the dendrites to produce a nerve impulse or action potential. The action potential is the result of ions moving in and out of the cell.
12. The highest fat content is found in the milk of which of the following animals? (UPSC Prelims 1991)
[A] Buffalo
[B] Cow
[C] Camel
[D] Reindeer
Show Answer
Correct Answer: A [Buffalo]
Notes:
Buffalo milk has the highest fat content, which is on average twice as high as that of cow milk. The fat-to-protein ratio in buffalo milk is about 2:1.
13. Match List I and List II and select the correct answer by using the codes given below the lists:
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List I
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List II
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I. Malaria
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(A) Bone marrow
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II. Filaria
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(B) Brain
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III. Encephalitis
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(C) Muscle
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IV. Leukaemia
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(D) Lymph node
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(E) Blood cells
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Codes: (UPSC Prelims 1997)
[A] I-E, II-C, III-B, IV-A
[B] I-E, II-D, III-B, IV-A
[C] I-D, II-C, III-E, IV-A
[D] I-E, II-D, III-A, IV-B
Show Answer
Correct Answer: B [I-E, II-D, III-B, IV-A]
Notes:
• Invasion by the malaria parasite, Plasmodium falciparum, brings about extensive changes in the host red cells. Numerous proteins secreted by the internalized parasite and interacting with red cell membrane proteins are responsible for the changes occurring to the host cell.
• Lymphatic filariasis is caused by the worms Wuchereria bancrofti, Brugia malayi, and Brugia timori. These worms occupy the lymphatic system, including the lymph nodes; in chronic cases these worms lead to the syndrome of elephantiasis. These worms occupy the subcutaneous layer of the skin, in the fat layer.
• Encephalitis is an acute inflammation of the brain usually resulting from either a viral infection or due to the body’s own immune system mistakenly attacking brain tissue.
• Leukaemia is a cancer that starts in blood-forming tissue, usually the bone marrow. It leads to the over-production of abnormal white blood cells, the part of the immune system which defends the body against infection.
14. Branch of science dealing with the medicinal plants is known as__?
[A] Pharmacognosy
[B] Pharmacology
[C] Phenology
[D] None of these
Show Answer
Correct Answer: A [Pharmacognosy]
Notes:
Pharmacognosy is the study of drugs or raw drugs produced from natural sources such as plants, microbes, and animals. It involves the analysis of their biological, chemical, biochemical and physical properties.
15. What is a common feature of archaebacteria?
[A] Structure of cell membrane
[B] Structure of cell wall
[C] Has fatty acid synthetase
[D] Structure of flagellin protein
Show Answer
Correct Answer: C [Has fatty acid synthetase]
Notes:
Archaebacteria are primitive bacteria that have a cell wall consisting of branched lipids that help them to endure adverse conditions.
16. Which of the following is not a part of the sexual cycle of fungi?
[A] Meiosis
[B] Karyogamy
[C] Mitosis
[D] Plasmogamy
Show Answer
Correct Answer: C [Mitosis]
Notes:
Mitosis is a process where a single cell divides into two identical daughter cells.
17. 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.
18. 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.
19. The region where the leaves arise is__.
[A] internodes
[B] buds
[C] nodes
[D] stomata
Show Answer
Correct Answer: C [nodes]
Notes:
The region where the leaves arise is nodes and the region between the nodes is known as the internode.
20. Which of the following is not a stem modification?
[A] Corm of Colocasia
[B] Rhizome of Ginger
[C] Tuber of Potato
[D] Pitcher of Nepenthes
Show Answer
Correct Answer: D [Pitcher of Nepenthes]
Notes:
The corm of Colocasia, Rhizome of Ginger, and Tuber of Potato are stem modifications. Pitcher of Nepenthes is a leaf modification.
