11. The right portion of human heart receives which type of blood?
[A] mixed
[B] impure
[C] Pure
[D] None of these
Show Answer
Correct Answer: B [impure]
Notes:
The right portion receives blood (which is impure) from the body and pumps the same to the lungs for purification (oxygenation). The impure blood enters the heart from two large veins called the superior and inferior vena cava.
12. Why honey bees are called social insects? (UPSC Prelims 1982)
[A] They visit all flowers to collect nectar
[B] They live in large family groups
[C] They depend for their food upon other insects
[D] They move socially with other insects
Show Answer
Correct Answer: B [They live in large family groups]
Notes:
Social insects are highly evolved insects that engage in a variety of complex tasks not practiced by the multitude of solitary insects. Honey bees are social insects because they live together in large, well-organized family groups. A single honeybee cannot grow or survive by itself. The three distinct kinds of honeybees in a colony are queen, worker, and drone.
13. Which of the following microorganisms causes Ring worm? (UPSC Prelims 1990)
[A] Bacterium
[B] Fungus
[C] Virus
[D] Worm
Show Answer
Correct Answer: B [Fungus]
Notes:
Ringworm isn’t a worm. It’s a skin infection that’s caused by moldlike fungi that live on the dead tissues of your skin, hair, and nails. It can occur at any place and on your scalp. When one gets it between the toes, it’s what people call athlete’s foot.
14. The sequencing of the entire genome (the totality of all genes) of an organism was completed in 1996. Which one of the following was that organism? (UPSC Prelims 1997)
[A] Albino mouse
[B] yeast
[C] human being
[D] Plasmodium vivax
Show Answer
Correct Answer: D [Plasmodium vivax]
Notes:
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria.
15. Which part of the human body is affected by Alziemer’s disease?
[A] Brain
[B] Lungs
[C] Heart
[D] Kidneys
Show Answer
Correct Answer: A [Brain]
Notes:
Alziemer’s is a disease which attacks the neural system, It results in continuous decline in the number brain cells which leads to loss of memory.
16. The scientific study of organisms as affected by seasonal climates e.g. of bird migration, the opening of flowers, etc is called __?
[A] Phenology
[B] Phylogeny
[C] Phrenology
[D] Phycology
Show Answer
Correct Answer: A [Phenology]
Notes:
The scientific study of organisms as affected by seasonal climates e.g. of bird migration, the opening of flowers etc is called Phenology.
17. The theory of DNA structure and nature was propounded by __?
[A] Oswald Avery
[B] James Black
[C] Watson and Crick
[D] John Eccles
Show Answer
Correct Answer: C [Watson and Crick]
Notes:
Watson and Crick realized that DNA was made up of two chains of nucleotide pairs that encode the genetic information for all living things.
18. Which of the following vitamins was discovered by Sir Edward Mellanby?
[A] Vitamin C
[B] Vitamin D
[C] Vitamin K
[D] Vitamin E
Show Answer
Correct Answer: B [Vitamin D]
Notes:
Vitamin D was discovered by Sir Edward Mellanby.
19. What is the translucent fluid part of the cytoplasm called?
[A] Cell protein
[B] Cytosol
[C] Matrix
[D] Organelles
Show Answer
Correct Answer: B [Cytosol]
Notes:
Cytosol is the liquid found inside cells. It is a water-based solution that floats organelles, proteins, and other cell structures.
20. A segment of DNA consists of 120 adenine and 120 cytosine bases. What is the total number of nucleotides present in the segment?
[A] 120
[B] 240
[C] 345
[D] 480
Show Answer
Correct Answer: D [480]
Notes:
According to Chargaff’s laws, the amount of adenine is always equal to that of thymine, and the amount of guanine is always equal to that of cytosine, i.e. A = T(120) and G = C (120), hence, the total no. The number of nucleotides would be 120 x 4 = 480.
