CSIR NET JRF: Zoology MCQs (Practice-Test 20 of 112)

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1. If a mutation occurs in a gamete it would influence

   1. only the particular sex of the progeny, whose gamete had undergone mutation

   2. only a single individual

   3. all successive generation of the parents

   4. sterility in the progeny

2. An analysis of chromosomes in a big city revealed the presence of four types of rather rare human beings, whose sex chromosome compositions are mentioned in the List I They are phenotypically either male (M) or female (F) as recorded in List II. Match List I with List II and select the correct answer:

   List-I (Chromosome composition)	List-II (Sex)
   XO XXXY XYY XXY	Male (M) Female (F) N/A N/A

   • A
   • B
   • C
   • D
   1. • 1
      • 2
      • 1
      • 2
   2. • 2
      • 1
      • 1
      • 2
   3. • 1
      • 1
      • 2
      • 1
   4. • 2
      • 1
      • 1
      • 1

3. A certain human abnormal individual showing 2 Barr bodies in the somatic cells, would be

   1. Only a male with one X chromosome

   2. Only a female with two K chromosomes

   3. Only a male having two Y chromosomes

   4. Either a male or a female having three X chromosomes

4. Okazaki is famouse for his studies on

   1. DNA replication

   2. somatic mutations

   3. gene expression

   4. somatic hybridization

5. The cross-over percentage between linked genes J and M is 20%, J and L is 35%, J and N is 70%, L and K is 15%, M and N is 50%, and M and L is 15%. Thus the sequence of genes on the chromosome is

   1. J, N, M, L, K

   2. J, M, L, N, K

   3. J, M, L, K, N

   4. M, J, L, K, N

6. Which one of the following is correctly matched explaining the particular stage of meiotic prophase and the event occurring in it?

   1. • Diplotene
      • Bivalent chromosomes split longitudinally
   2. • Leptotene
      • Homologous chromosomes get associated as bivalents
   3. • Pachytene
      • Homologous chromosomes come in pairs
   4. • Zygotene
      • Chromatin begins to get compacted showing fine threads

7. If a certain couple shows the probability of having only half of the sons hemophilic and only half of the daughters hemophilic, the parents are likely to be

   1. hemophilic carrier mother and hemophilic father

   2. hemophilia carrier mother and normal father

   3. normal mother and hemophilic father

   4. hemophilic mother and normal father

8. Which of the following modifications are necessary for most eukaryotic RNA processing?

   1. Addition of modified nucleotide at the 5' terminal

   2. Cleavage of long precursor RNA into smaller one

   3. Formylation of bases at 3' poly (A) tail

   4. Alteration of incorrect bases through proof reading

   Select the correct answer using the codes given below:

   1. 1 and 2

   2. 2 and 3

   3. 1 and 4

   4. 2 and 4

9. Initiation of polypeptide chain formation is always brought about at the site of a codon coding for an amino acid called

   1. Isoleucine

   2. cystein

   3. phenylalanine

   4. methionine

10. In case of lac operon when disaccharide enters the cell

    1. it binds to the bound-repressor-to-theoperator and the structural genes are transcribed because the RNA polymerase can recognise and bind, the transcription initiation site

    2. it binds to the repressor and structural genes are transcribed because the repressor has an altered conformation, is inactivated and does not bind the operator

    3. the membrane protein interacts with the operator and the RNA polymerase can recognise the transcription initiation site

    4. the membrane protein has an altered conformation and does not interact with the operator, thus leading to the transcription of the structural genes

11. The earliest known jawless fossil vertebrates with heavy armour or dermal plates are collectively called the

    1. Placoderms

    2. Ostracoderms

    3. Acanthodii

    4. Arthrodira

12. Which of the following animals are included under Enteropneusta?

    1. Ptychodera

    2. Cephalodiscus

    3. Rhabdopleura

    4. Balanoglossus

    Select the correct answer using the codes given below:

    1. 1 and 2

    2. 2 and 3

    3. 3 and 4

    4. 1 and 4

13. Which one of the following orders of mammals possesses homodont dentition?

    1. Monotremata

    2. Marsupialia

    3. Chiroptera

    4. Cetacea

14. Ganoid scales are present in

    1. Labeo

    2. Anguilla

    3. Amia

    4. Lepidosteus

15. Which one of the following crustaceans is an example of the subclass Branchiura?

    1. Argulug

    2. Balanus

    3. Cyclops

    4. Daphnia