11. What does the term “Zoophyte”, in biological context, refer to?
[A] A plant that visually resembles an animal
[B] An animal that visually resembles a plant
[C] A plant that grows on an animal
[D] An animal that grows on a plant
Show Answer
Correct Answer: B [An animal that visually resembles a plant]
Notes:
In biology, Zoophytes are organisms that exhibit characteristics of both animals and plants, although they are animals. They have plant-like appearance and perform photosynthesis, but belong to the animal kingdom. The term is commonly used to describe certain types of marine life, such as sea anemones and corals. These organisms are often static and have similar systems of feeding and growth as certain plant species. Zoophytes display an extraordinary demonstration of nature’s capacity for variation and adaptation.
12. Golden rice is a variety of rice produced through genetic engineering to biosynthesize beta-carotene. This genetically engineered (GE) rice variety, can help to alleviate deficiency of _?
[A] Vitamin A
[B] Vitamin B
[C] Vitamin C
[D] Vitamin D
Show Answer
Correct Answer: A [Vitamin A]
Notes:
Golden Rice is a genetically engineered (GE) rice variety that has been developed by the biotech industry to produce pro-vitamin A. Vitamin A deficiency can be caused by infections that reduce appetite or the body’s ability to absorb vitamin A or may cause night blindness. Golden Rice has the potential to complement existing efforts that seek to reduce blindness and other VAD induced diseases.
13. What is the main product of photosynthesis?
[A] Chlorophyll
[B] Carbon dioxide
[C] Oxygen
[D] Glucose
Show Answer
Correct Answer: D [Glucose]
Notes:
The main product of photosynthesis is glucose, which is the molecule that produces energy to run the processes of the cell. Oxygen is mainly a byproduct of the process of photosynthesis. Six molecules of carbon dioxide and six molecules of water are needed to produce one molecule of glucose.
14. At which of the following stages the sex of the offspring is determined?
[A] The conception takes place
[B] The sperm fertilises the ovum
[C] The embryo is partially developed
[D] The end of gestation period is near
Show Answer
Correct Answer: A [The conception takes place]
Notes:
Biological sex is determined by a pair of sex chromosomes: XY in males and XX in females. Genes on the X chromosome are said to be X-linked. X-linked genes have distinctive inheritance patterns because they are present in different numbers in females (XX) and males (XY).Thus usually occurs as soon as conception takes place.
15. Due to which of the following reasons the scratching eases itching? (UPSC Prelims 1993)
[A] it removes the outer dust in the skin
[B] it kills the germs
[C] it stimulates certain nerves which direct the brain to increase the production of antihistaminic chemicals
[D] it suppresses the production of enzymes which cause itching
Show Answer
Correct Answer: C [it stimulates certain nerves which direct the brain to increase the production of antihistaminic chemicals]
Notes:
Scratching helps to relieve an itch because it reduces the sensations of pain sent to the brain, a new study has found. Scientists found that skin cells in that part of the body tended to respond more to itchy substances than those in other areas.
16. With reference to the blood in a normal person, which one of the following statements is correct? (UPSC Prelims 2002)
[A] Compared to arteries, veins are less numerous and hold less of the body’s blood at any given time
[B] Blood cells constitute about 70 per cent of the total volume of the blood
[C] White Blood Cells (WBC) are made by lymph nodes only
[D] The blood has more platelets than WBC
Show Answer
Correct Answer: D [The blood has more platelets than WBC]
Notes:
Blood has more platelets than corpuscles. A microlitre of blood contains 5,000-10,000 of White blood cells (WBC) and 150,000-500,000 platelets.
17. Consider the following conditions of sick human body
1. Swollen lymph nodes
2. Sweating at night
3. Loss of memory
4. Loss of weight
Which of these are the symptoms of AIDS? (UPSC Prelims 2003)
[A] 1 and 2
[B] 2, 3 and 4
[C] 1, 2 and 3
[D] 1, 2, 3 and 4
Show Answer
Correct Answer: D [1, 2, 3 and 4]
Notes:
AIDS is a viral disease. In this disease the immune system weakens and the body becomes prone to different type of infection by pathogens. Sweating at night, swollen lymph nodes, loss of memory and loss of weight are also symptoms of AIDS.
18. Which among the following are female sex harmones?
[A] Estrogen
[B] Progesterone
[C] Testosterone
[D] Both a and b
Show Answer
Correct Answer: D [Both a and b]
Notes:
Estrogen and progesterone are the female sex harmones. Estrogen is responsible for the development of secondary sexual characteristics. Progesterone supports during pregnancy and controls the menstrual cycles in women.
19. Which modern concept was pioneered by Rudolf Virchow?
[A] pathological processes
[B] process of fermentation
[C] isotopes as tracers to study chemical and biological processes
[D] None of these
Show Answer
Correct Answer: A [pathological processes]
Notes:
Rudolf Virchow was a German pathologist and politician who pioneered the modern concept of disease processes by his application of cell theory to explain the effects of disease in body organs and tissues.
20. How do small molecules pass through the outer membrane of mitochondria?
[A] Carrier protein
[B] Channels
[C] Porins
[D] ATP pump
Show Answer
Correct Answer: C [Porins]
Notes:
The outer membrane is a relatively simple phospholipid bilayer made up of protein structures called porins. This makes it permeable to molecules of about 10 kilodaltons or less.
