Biology

1. In prokaryotes, the lagging primers are removed by …

DNA ligase

DNA polymerase II

DNA polymerase I

3’ to 5’ exonuclease

Question 1 of 20

2. A solution contains DNA polymerase, I, Mg²⁺ salts of dATP, dGTP, dCTP, and dTTP, and an appropriate buffer. Which of the following DNA molecules would serve as a template for DNA synthesis when added to this solution.

A single-stranded closed circle

A single-stranded closed circle base-paired to a shorter linear strand with a 3’- terminal phosphate

A single-stranded closed circle base-paired to a shorter linear strand with 3’- terminal hydroxyl

A double-stranded closed circle

Question 2 of 20

3. Approximately how many Okazaki fragments are synthesized during one round of the E. coli genome?

2500 to 5000

5000 to 10000

4 x 10⁶

Question 3 of 20

4. Which of the following statements about DNA polumerase I is correct?

It joins together Okazaki fragments to complete the lagging strand during DNA replication

It requires a template and a primer to polymerize deoxyribonucleoside triphosphates

It functions as a DNA repair enzyme but is not involved in the DNA replication process

It produces Okazaki fragments linked to RNA primer chains

Question 4 of 20

5. Which of the sequences listed below best describe the order in which the following enzymes participate in the replication of DNA in bacteria?

1) DNA polymerase I

2) 5’→3’ Exonuclease

3) DNA polymerase III

4) DNA ligase

5) Primase

3, 2, 1, 5, 4

5, 3, 2, 1, 4

5, 3, 4, 2, 1

5, 3, 1, 2, 4

Question 5 of 20

6. Which of the following features of transcription is similar to that of replication?

RNA synthesis requires DNA topoisomerase action

Polymerization does not have proof reading activity

No primer is required for polymerization

Newly synthesized strand starts falling off the template before complete RNA is synthesized

Question 6 of 20

7. Okazaki fragments are used to elongate:

The lagging strand towards the replication fork

The leading strand away from the replication fork

The leading strand towards the replication fork

The lagging strand away from the replication fork

Question 7 of 20

8. The fact that DNA polymerase I from E. coli has a 5’-3’ exonuclease activity’

Implies that DNA polymerase I can use both DNA and RNA as primers

Implies that the enzyme has multiple subunits

Makes the enzyme able to detect thymine dimmers in double-stranded DNA

Enables the enzyme to play an important role in DNA replication

Question 8 of 20

9. Which of the following activities is typical of histones during replication of eukaryotic DNA?

They are both conserved and associated with the leading daughter strand and newly synthesized and and associated with the lagging daughter strand

They remain bound to the DNA throughout replication

They are not synthesized for cell division but are retained from generation to generation

They undergo proteolysis and are replaced by newly synthesized protein on each daughter strand

Question 9 of 20

10. During DNA replication, the synthesis of the leading strand occurs in the 5’→ 3’; direction along with the movement of the replication fork. Which one of the following statements is true about the synthesis of the lagging strand?

DNA polymerase I is utilized, which can carry out DNA synthesis in the absence of any primer

Synthesis of the lagging strand occurs in the small fragments by DNA polymerase in 5’→3’ direction using a de novo synthesized DNA primer

DNA polymerase II, which has an additional activity of polymerization in 3’→ 5’ direction, is utilized.

Synthesis of the lagging strand occurs in small fragments in 5’→3’ direction utilizing RNA primers

Question 10 of 20

11. Which enzyme removes the RNA primer and fills in deoxyribonucleorides in prokaryotic replicons?

Exonuclease MFI

DNA polymerase III

DNA polymerase I

DNA polymerase II

Question 11 of 20

12. The essential initiator protein at the E. coli origin of replication is …

DnaC

DnaA

DnaE

DnaB

Question 12 of 20

13. Prokaryotic plasm ids can replicate in yeast cells if they contain a cloned yeast …

ARS

ORC

CDK

RNA

Question 13 of 20

14. DNA replication under going in an E. coli cell resulted into two circular DNAs interlocked with each other; this may be due to a defective gene encoding:

DNA polymerase

Primase

DNA topoisomerase I

DNA topoisomerase II

Question 14 of 20

15. Correct statements describing DNA polymerase I include which of the following?

It can act as a 5’ to 3’ – exonuclease

It can act as an endonuclease in DNA repair

It can add deoxyribonucleoside triphosphates to the 3’- hydroxyl end of a DNA primer chain

It is the major polymerizing enzyme in the replication process

Question 15 of 20

16. Characteristic unique in DNA is:

Denaturation and renaturation

Polymer complex

Replication

Resistance to temperature change

Question 16 of 20

17. DNA ligase of E.coli requires which of the following cofactors?

Nicotinamide-adenine dinucleotide (NAD+) to form an active adenyl enzyme

Flavin-adenine dinucleotide as an electron acceptor

NAD+ as an electron acceptor

Nicotinamide-adenine dinucleotide phosphate as a phosphate donor

Question 17 of 20

18. A bacterial culture growing in a medium containing ¹⁵NH₄CI is switched to a medium containing ¹⁴NH₄CI for three generations (resulting into eight fold increased in its population), what is the molar ratio of hybrid DNA (¹⁵N-¹⁴N) to light DNA (¹⁴N-¹⁴N) at this point?

4/4 or 1.00

1/7 or 0.14

3/5 or 0.60

2/6 or 0.33

Question 18 of 20

19. Which phase would a cell enter if it was starved of mitogens before the R point?

Question 19 of 20

20. E.coli cells that had been cultured in a light medium containing ¹⁴N-ammonium chloride as the sole nitrogen source were transferred to a heavy medium containing ¹⁵N-ammonium chloride. After three generations of growth in the heavy medium, what will be the proportion of dual light strands (LL), dual heavy strands (HH) and hybrid light-plus-heavy strands (LH) in the DNA duplexes?

3 HH to 1 LH

33 LH to 1 HH

3 HH to 1 LH/4 LL

15 LL to 1 LH

Question 20 of 20

Test Name	DNA Genetic Material Test
Subject	Biology
Test Type	Mcqs
Total Question	20
Total Marks	40
Total Time	20
Test Help For	Biology Everyday Science General Knowledge Competitive Exams All Entrance Test

Test By Subject	Science
Test By Topics	Biology Subject

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