11. Which of the following cells are closely associated and interacting with guard cells?
[A] Transfusion tissue
[B] Complementary cells
[C] Subsidiary cells
[D] Hypodermal cells
Show Answer
Correct Answer: C [Subsidiary cells]
Notes:
Subsidiary cells are the accessory cells to guard cells in the epidermis of plants. Two or four subsidiary cells are found surrounding the pair of guard cells. Subsidiary cells do not consist of chloroplasts. They provide support for the functioning of guard cells in the epidermis.
12. BCG vaccination is to be given to a new born child after what time?
[A] Immediately after birth
[B] Within 48 hours
[C] Within seven days
[D] Within six months
Show Answer
Correct Answer: A [Immediately after birth]
Notes:
Bacillus Calmette Guérin or BCG is usually given around birth to prevent severe TB in infants. The neonatal immune system is immature. Delaying BCG vaccination from birth to 10 weeks of age would enhance the vaccine-induced immune response. The BCG vaccine is an injection given to children who have a higher risk of catching TB. The BCG vaccine helps your child’s immune system fight the germs that cause TB and helps stop them from getting serious TB disease.
13. Which of the following define Biofilms? (UPSC Prelims 1993)
[A] Colour films used by biologists to photograph living organisms
[B] photomicrographs of microorganisms from various habitats
[C] accumulations of microorganisms at surfaces such as those of a rock, a tooth or an oil droplet
[D] photographic films made through fermentation processes of certain industrial microorganisms
Show Answer
Correct Answer: C [accumulations of microorganisms at surfaces such as those of a rock, a tooth or an oil droplet]
Notes:
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances. Microorganisms that form biofilms include bacteria, fungi and protists. One common example of a biofilm dental plaque, a slimy buildup of bacteria that forms on the surfaces of teeth.
14. Which of the following is the major component of honey? (UPSC Prelims 1997)
[A] Glucose
[B] sucrose
[C] maltose
[D] fructose
Show Answer
Correct Answer: D [fructose]
Notes:
Fructose comprises the major portion of honey – about 82%. The carbohydrates present are the monosaccharides fructose (38.2%) and glucose (31%); and disaccharides (~9%) sucrose, maltose, isomaltose, maltulose, turanose and kojibiose.
15. Among living organisms, which one of the following is the most responsible factor for bringing about the origin of a new species? (UPSC Prelims 2002)
[A] Isolation
[B] Mutation
[C] Natural Selection
[D] Sexual Reproduction
Show Answer
Correct Answer: A [Isolation]
Notes:
Origin of new species depends on isolation of gene flow between new species and develops significant genetic divergence.
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. Which among the following is an optimum temperature for wheat seed germination?
[A] 11-15 deg celsius
[B] 15-25 deg celsius
[C] 10-12 deg celsius
[D] 20-22 deg celsius
Show Answer
Correct Answer: C [10-12 deg celsius]
Notes:
10-12 deg celsius is the optimum temperature for wheat germination. 25-30 deg celsius is the optimum temperature for crop growth.
18. Which is the world’s smallest bird?
[A] Red-cheeked Cordon-Bleu
[B] Costa’s Hummingbird
[C] Bee Hummingbird
[D] Goldcrest
Show Answer
Correct Answer: C [Bee Hummingbird]
Notes:
Bee Hummingbird is the smallest bird in the world. It is only 2 to 2.4 inches long and weighs 0.056 to 0.071 ounces. This bird is also known as zunzuncito or Helena Hummingbird. This bird is native to Cuba. It is endemic to the entire Cuban archipelago. It is “Nearly Threatened” bird species according to IUCN Red List of Threatened Species.
19. Which of the following cell organelles contain RNA?
[A] Plastids
[B] Mitochondria
[C] Ribosomes
[D] Lysosomes
Show Answer
Correct Answer: C [Ribosomes]
Notes:
Ribosomes are small organelles that contain RNA and specific proteins within the cytoplasm.
20. Who discovered nucleus of cell wall?
[A] Theodor Boveri
[B] Robert Brown
[C] Albert von Kolliker
[D] Robert Hooke
Show Answer
Correct Answer: B [Robert Brown]
Notes:
Robert Brown discovered the nucleus in the cell in 1831. The nucleus is a protoplasmic body in eukaryotic cells. It is covered by a double membrane that contains the hereditary details.
