11. 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.
12. Which vitamin is also called as ascorbic acid?
[A] Vitamin A
[B] Vitamin C
[C] Vitamin D
[D] Vitamin K
Show Answer
Correct Answer: B [Vitamin C]
Notes:
Vitamin C is also called as ascorbic acid. Deficiency in vitamin C leads to scurvy. Chemical formula of vitamin C is C6H8O6.
13. Who among the following is considered as the father of microbiology?
[A] Stephen Hales
[B] Antonie Van Leeuwenhoek
[C] Edwin John Butler
[D] Pier Antonio Micheli
Show Answer
Correct Answer: B [Antonie Van Leeuwenhoek]
Notes:
Antoine van Leeuwenhoek used the single-lens microscope he built to make the first observations of bacteria and protozoa. Leeuwenhoek is universally acknowledged as the father of microbiology.
14. What is the term known as a giant growth of algae?
[A] Panic boom
[B] Algal boom
[C] Herbal boom
[D] Patkai boom
Show Answer
Correct Answer: B [Algal boom
]
Notes:
A massive growth or rapid increase in the population of algae in water is known as algal boom.
15. Which is the largest phylum of Animalia?
[A] Arthropoda
[B] Annelida
[C] Moluska
[D] Aves
Show Answer
Correct Answer: A [Arthropoda]
Notes:
Arthropoda is the largest phylum of animals. In Arthropoda we study in detail about insects.
16. What is the approximate number of specific cells in the human body?
[A] 200 types
[B] 300 types
[C] 250 types
[D] 150 types
Show Answer
Correct Answer: A [200 types]
Notes:
Scientists estimate that the human body contains around 37 trillion cells and 200 different cell types. This includes 50 billion fat cells and 2 billion heart muscle cells. The number of bacterial cells inside a human body is around 38 trillion. This is much closer to the estimated 30 trillion human cells in the body.
Scientists used data reported by others about individual organs and some mathematical modeling to obtain their results.
17. Who among the following discovered the cytoplasm?
[A] Rudolf von Kölliker
[B] Camillo Golgi
[C] Christian de Duve
[D] Walther Flemming
Show Answer
Correct Answer: A [Rudolf von Kölliker]
Notes:
The term was introduced by Rudolf von Kölliker in 1863. It was originally synonymous with protoplasm, but later changed to mean cell matter and organelles outside the nucleus.
18. Which of the following plant group requires both land and water to complete its life cycle?
[A] Tracheophyta
[B] Pteridophyta
[C] Thallophyta
[D] Bryophyta
Show Answer
Correct Answer: D [Bryophyta]
Notes:
Bryophyta plant group requires both land and water to complete its life cycle. Bryophytes are an informal division consisting of 3 groups of non-vascular plants, namely mosses, liverworts and hornworts.
19. The cell wall of which of the following is made up of pectin and cellulose?
[A] Sclerenchyma
[B] Parenchyma
[C] Collenchyma
[D] All of the above
Show Answer
Correct Answer: C [Collenchyma]
Notes:
Collenchyma’s cell walls are made up of pectin and cellulose. They are stretched out, living cells with minute intercellular gaps.
20. Which of the following tissue provides strength to the plant?
[A] Intercalary
[B] Parenchyma
[C] Sclerenchyma
[D] Collenchyma
Show Answer
Correct Answer: C [Sclerenchyma]
Notes:
Sclerenchyma provides strength to the plant. It is found in the covering of seeds and nuts, around the vascular tissues in stems and the veins of leaves.
