The enzyme that removes RNA primers and replaces them with DNA during replication is: MCQ with Answer and Explanation

The enzyme that removes RNA primers and replaces them with DNA during replication is:
A. DNA polymerase III
B. Helicase
C. Ligase
D. DNA polymerase I
Answer: Option D
Solution (By JKSSB Mock Tests)
In prokaryotes, DNA polymerase I has 5'→3' exonuclease activity that removes the RNA primer and fills the gap with DNA. DNA polymerase III adds nucleotides to the growing strand. Ligase seals the nicks. Helicase unwinds DNA. In eukaryotes, RNase H removes primers and DNA polymerase δ fills the gap.

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Practice More Biology Questions

Question #1
The organ that produces clotting factors and albumin is the:
A. Spleen
B. Pancreas
C. Kidney
D. Liver

Correct Answer: Option D


Explanation:
The liver synthesizes most plasma proteins, including albumin (osmotic pressure) and clotting factors (I, II, VII, IX, X). The kidneys produce erythropoietin and active vitamin D, pancreas digestive enzymes, spleen filters.

This question belongs to: Science Biology
Question #2
Consider statements about evolution: 1. The theory of use and disuse was given by Lamarck. 2. The theory of natural selection was given by Darwin. 3. The theory of mutation was given by Hugo de Vries. Which are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1, 2 and 3
D. 1 and 3 only

Correct Answer: Option C


Explanation:
Jean-Baptiste Lamarck proposed the theory of inheritance of acquired characters, based on the use and disuse of organs. Charles Darwin proposed the theory of evolution by natural selection, emphasizing survival of the fittest. Hugo de Vries, a Dutch botanist, proposed the mutation theory of evolution after working on evening primrose, stating that evolution occurs via sudden, large mutations (saltations). All statements are correct.

This question belongs to: Science Biology
Question #3
Which of the following is a defining feature of all chordates at some stage of their life?
A. Notochord
B. Scales
C. Gills
D. Vertebral column

Correct Answer: Option A


Explanation:
All chordates possess a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail at some stage of development. The notochord may be replaced by the vertebral column in vertebrates. Gills and scales are not universal (e.g., mammals lack both). The notochord provides skeletal support and is the defining feature of the phylum Chordata.

This question belongs to: Science Biology