11. Who among the following carries the Haemophilia, a hereditary disease? (UPSC Prelims 1993)
[A] females and expressed by females
[B] females and expressed by males
[C] males and expressed by females
[D] males and expressed by males
Show Answer
Correct Answer: B [females and expressed by males]
Notes:
If he inherits his mother’s other X chromosome, he will have normal blood clotting. So a carrier’s son has a 50% chance of having hemophilia. A baby girl will inherit an X chromosome with a dominant gene for normal blood clotting from her father. So the daughter will not have hemophilia.
12. Which one of the following statements is correct? (UPSC Prelims 2002)
[A] Prions are the smallest free-living cells
[B] The cell wall of Mycoplasmas is made up of amino sugars
[C] Viroids consist of a single-stranded RNA molecule
[D] Rickettsias lack cell wall
Show Answer
Correct Answer: C [Viroids consist of a single-stranded RNA molecule]
Notes:
Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating. All known viroids are inhabitants of higher plants, in which most cause diseases, ranging in economic importance.
13. Which of the following branch of biology deals with the study of mycoplasma?
[A] Mycoplasmology
[B] Limnology
[C] Ethnobotony
[D] None of these
Show Answer
Correct Answer: A [Mycoplasmology]
Notes:
Mycoplasma is a genus of bacteria that do not have a cell wall surrounding the cell membrane.
14. Empedocles is related to which of the following theory of biology?
[A] theory of cell
[B] theory of natural selection
[C] theory of mutation
[D] theory of disease
Show Answer
Correct Answer: B [theory of natural selection]
Notes:
Empedocles formulated a theory of natural selection. He proposed that everything in existence is composed of different combinations of four elements: air, fire, water and earth.
15. Which of the following are non-motile, highly thickened asexual spores called?
[A] Hypnospores
[B] Aplanospores
[C] Macrozoospores
[D] Microzoospores
Show Answer
Correct Answer: A [Hypnospores]
Notes:
Hypnospores are thick-walled structures that form under unfavorable conditions. Under prolonged unfavorable conditions, the protoplasm of hypnospores divides to form cysts. Cysts are capable of forming new thallus.
16. Which of the following is called Calyx?
[A] the outermost whorl of a flower
[B] consists of many numbers of petals
[C] four-lobed sac-like structure responsible for pollen formation
[D] thread-like structures are attached to the anther
Show Answer
Correct Answer: A [the outermost whorl of a flower]
Notes:
The calyx is the outermost circle of a flower. It includes units called sepals.
17. Phylum Porifera is classified based on__.
[A] Branching
[B] Symmetry
[C] Spicules
[D] Reproduction
Show Answer
Correct Answer: C [Spicules]
Notes:
Phylum Porifera is classified based on Spicules. Porifera are a phylum composed of sponges, they lack true tissues, have no body symmetry, and are sessile.
18. Into how many parts are amphibians divided?
[A] Two
[B] Three
[C] Four
[D] Five
Show Answer
Correct Answer: B [Three]
Notes:
The Amphibians are divided into three orders – Apoda, Urodela, and Anura.
19. Which of the following were lizard-like reptiles?
[A] Ichthyopterygia
[B] Lepidosauria
[C] Archosauria
[D] Synapsida
Show Answer
Correct Answer: B [Lepidosauria]
Notes:
Lepidosauria were lizard-like reptiles and there were two temporary voids in his skull. Youngina is an example of Lepidosauria.
20. The number of cervical vertebrae in reptiles is __
[A] 4
[B] 6
[C] 7
[D] 8
Show Answer
Correct Answer: C [7]
Notes:
Most reptiles have seven cervical vertebrae, including a three-part atlas and axis.
