assertion reason Biology test

assertion reason Biology test
objective type multiple choice assertion-reason type questions from Biology
Biology Assertion & Reason for Competitive Examinations
Directions: The following items consist of two statements are labelled the ‘Assertion A’ and the other labelled the ‘Reason R’. You are to examine these two statements carefully and decide if the Assertion A and the Reason. R are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answer to these items using the codes given below and mark your answer sheet accordingly.
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but l. is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
1. Assertion (A): The degeneration of tadpole tail occurs during metamorphosis.
Reason (R): This degeneration is brought about by hydrolytic enzymes.
Ans. (a)

2. Assertion (A): Geological evidence indicates that free oxygen began accumulating in the atmosphere about two billion year ago.
Reason (R): The free oxygen in the atmosphere is produced by cyanobacteria like forms.
Ans. (d)

3. Assertion (A): Thalassaemia is a dreaded disease of blood caused by structural variations in or globin chains.
Reason (R): Structural variations in globin chains are due to amino acid replacements.
Ans. (a)

4. Assertion (A): Prokaryote cells prolife-rate at a much more rapid rate than eukaryotes.
Reason (R): In prokaryotes there is no condensation of the chromosomes, no spindle apparatus and they follow a simple duplication and separation of DNA pattern.
Ans. (a)

5. Assertion (A): Each gene can exist in a variety of different forms called alleles.
Reason (R): Different alleles of the same gene arise by heritable changes (mutations) in the gene itself.
Ans. (a)

6. Assertion (A): Pila produces two types of sperm, namely eupyrene and oligopyrene.
Reason (R): Eupyrene sperm has XX chromosomes and can produce only female while oligopyrene sperm has XV chromosomes and can produce only male.
Ans. (c)

7. Assertion (A): Echinodermata and Hemichordata are both deuterostomes.
Reason (R): During early development of these ‘phyla, the blastopore becomes the mouth opening.
Ans. (c)

8. Assertion (A): Bryozoa is now divided into two separate phylaendoprocta and Ectoprocta
Reason (R): Though Endoprocta has some superficial similarities with Ectoprocta, the former is acoelomate and the latter acoelomate.
Ans. (c)

9. Assertion (A): The ‘killer’ stains of Paramecium aurelia produce a toxic substance (paramecin) which kills the ‘sensitive’ ones.
Reason (R): Such ‘killer’ stains lack the Kappa particles.
Ans. (c)

10. Assertion (A): The adults of echinoderms generally exhibit pentamerous radial symmetry.
Reason (R): A unique ambulacral system is typically present in echinoderms.
Ans. (b)

11. Assertion (A): Balanoglossus is not a chordate.
Reason (R): The so-called notochord of Balanoglossus is only pre-oral extension of the gut.
Ans. (a)

12. Assertion (A): In birds, the synsacrum is fused with the pelvic girdle.
Reason (R): The synsacrum provides a rigid framework for perching.
Ans. (c)

13. Assertion (A): The accidental leak of methyl isocyanate from a storage tank of a factory in Bhopal in 1980 killed more than 25, 000 people.
Reason (R): In the factory, the safety scrubber chimneys, filled with the detoxifying solution failed to function.
Ans. (c)

14. Assertion (A): After removal of parathyroids in lizards the blood calcium level rises rapidly.
Reason (R): Parathyroids regulate the level of calcium in blood.
Ans. (d)

15. Assertion (A): Linoleic acid and linolenic acid are essential polyunsaturated fatty acids.
Reason (R): Linoleic acid and linolenic acid are biosynthesized in human beings.
Ans. (c)

16. Assertion (A): As a fuel, coal releases two-thirds more carbon dioxide per unit of energy than floes gasoline.
Reason (R): Coal is largely carbon, whereas gaso-line contains more hydrogen.
Ans. (a)

17. Assertion (A): In pearl oyster, it is the necre, which forms the pearl.
Reason (R): Necre is secreted continuously by the edge of the mantle.
Ans. (b)

18. Assertion (A): Queen bee after mating produces both fertilized and unfertilized eggs.
Reason (R): Fertilized eggs produce queen and drones (males), whereas unfertilized eggs are eaten up. by the workers.
Ans. (c)

19. Assertion (A): Puffs in the polytene chromosomes are the sites of gene transcription.
Reason (R): DNA unfolds into open loop to facilitate RNA synthesis in the puff.
Ans. (a)

20. Assertion (A): Enlargement of spleen in a malarial patient is due to hemorrhage of arteries.
Reason (R): Infective states of Plasmodium are responsible for causing excessive proliferation of erythrocytes.
Ans. (d)

21. Assertion (A): Miracidium larva of Fasciola is endowed with cilia, penetration gland and apical gland.
Reason (R): The structure of miracidium is best adapted to penetrate into the liver and gall-bladder of sheep.
Ans. (c)

22. Assertion (A): A cell placed in an isotonic solution shows no change in size or volume.
Reason (R): Isotonic solutions have the same chemical composition as the cell cytoplasm.
Ans. (c)

23. Assertion (A): Cardiac muscle cells contain much large amounts of RNA than pancreatic cells.
Reason (R): High-protein-producing cells contain larger amount of RNA in comparison to low protein producing cells.
Ans. (d)

24. Assertion (A): Responses mediated by peptide hormones such as insulin are relatively slow.
Reason (R): The polypeptide hormones are rapidly removed from the blood by hydrolytic enzymes.
Ans. (c)

25. Assertion (A): Myoglobin bears an iron-containing haem group capable of combining reversibly with oxygen.
Reason (R): Myoglobin is made up of a monomeric polypeptide chain without a tertiary structure.
Ans. (c)

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