11. Which one of the following genetic diseases is sex-linked? (UPSC Prelims 1999)
[A] Royal haemophilia
[B] Tay-Sachs disease
[C] Cystic fibrosis
[D] Hypertension
Show Answer
Correct Answer: A [Royal haemophilia]
Notes:
Royal haemophilia is sex- linked disease. Clotting of blood is abnormally delayed even small cut will result in non stop bleeding in the affected individual. Queen Victoria was a carrier of this disease and produce haemophilic descendents, so haemophilia is a royal disease.
12. Phototropism Theory is related to which of the following scientist?
[A] Jane Goodall
[B] Charles Darwin
[C] Francis Galton
[D] None of these
Show Answer
Correct Answer: B [Charles Darwin]
Notes:
Plant physiologists have investigated phototropism for over 100 years. The best known early research on phototropism was by Charles Darwin.
13. 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.
14. Which of the following comprise plant decomposers?
[A] Monera and fungi
[B] Plantae and fungi
[C] Monera and Animalia
[D] Animalia and Protista
Show Answer
Correct Answer: A [Monera and fungi]
Notes:
Decomposers are a type of bacteria and fungi that break down dead and decaying organic matter into simpler things like carbon dioxide, water, simple sugars and mineral salts, and return nutrients to the soil.
15. rRNA is synthesized by which of the following?
[A] Nucleus
[B] Nucleolus
[C] Golgi body
[D] Cytoplasm
Show Answer
Correct Answer: B [Nucleolus]
Notes:
Molecules of rRNA are synthesized by the nucleolus in a specialized region of the cell nucleus, which appears as a dense region within the nucleus and contains genes encoding rRNA.
16. Which cell organelle controls the entry and exit of molecules into and out of the cell?
[A] Golgi bodies
[B] Cell membrane
[C] Lysosomes
[D] Mitochondria
Show Answer
Correct Answer: B [Cell membrane]
Notes:
A plasma membrane is made up of lipids and proteins. The composition can fluctuate depending on the fluidity in the plasma membrane, the external environment, and the different stages of cell development.
17. Which one of the following is an example of a phospholipid?
[A] Steroid
[B] Cholesterol
[C] Lecithin
[D] Sterol
Show Answer
Correct Answer: C [Lecithin]
Notes:
Lecithin is a mixture of brown and yellow colored phospholipids that contain glycerol. It also acts as an emulsifier in many types of food.
18. What is involved in the release of pollen grains?
[A] Pectin and cellulose
[B] Lignocellulose
[C] Pollenkit
[D] Sporopollenin
Show Answer
Correct Answer: D [Sporopollenin]
Notes:
Sporopollenin is the most chemically inert organic polymer. It is a major component of the tough outer (outer) walls of plant spores and pollen grains.
19. Which of the following is wrong for bryophytes?
[A] Vascular tissue lacking clear
[B] Independent sporophyte absent clear
[C] Gametophyte reduced and dependent done
[D] Asexual reproduction by zoospores absent
Show Answer
Correct Answer: C [Gametophyte reduced and dependent done]
Notes:
The main plant of Bryophyta is the gametophyte. The gametophytic stage is independent.
20. Fruits are not found in gymnosperm plants because__?
[A] They are seedless plants
[B] They are not pollinated
[C] They have no ovary
[D] Process of fertilization does not take place in them
Show Answer
Correct Answer: C [They have no ovary]
Notes:
Fruits are not found in gymnosperm plants because they have no ovaries. Gymnosperms belong to the Kingdom Plantae and the sub-kingdom Embryophyta.
