Q.45 Match List I with List II
LIST I
Enzymes |
LIST II
Functions |
| A. |
DNA polymerase α (alpha) |
I. |
Base-excision DNA repair |
| B. |
DNA polymerase β (beta) |
II. |
RNA/DNA primary initiation of DNA synthesis |
| C. |
DNA polymerase γ (gamma) |
III. |
Mitochondrial DNA replication and repair |
| D. |
DNA polymerase κ (kappa) |
IV. |
Translesion DNA synthesis |
Choose the correct answer from the options given below:
- A-I, B-II, C-IV, D-III
- A-II, B-I, C-III, D-IV
- A-II, B-III, C-IV, D-I
- A-IV, B-II, C-III, D-I
DNA polymerase α initiates synthesis, β does base-excision repair, γ handles mitochondrial DNA, and κ performs translesion synthesis.
The correct matching is A-II, B-I, C-III, D-IV (option 2), standard eukaryotic polymerase classification.
Question Breakdown
-
A. DNA polymerase α: Primase-associated, RNA/DNA primer synthesis for replication initiation
-
B. DNA polymerase β: Base-excision repair (BER), short-patch repair of oxidized bases
-
C. DNA polymerase γ: Exclusive mitochondrial replication/repair enzyme
-
D. DNA polymerase κ: Y-family TLS polymerase bypasses UV adducts
Option Analysis
-
A-I, B-II, C-IV, D-III: Wrong (α ≠ BER)
-
A-II, B-I, C-III, D-IV: Correct (perfect textbook matching)
-
A-II, B-III, C-IV, D-I: Wrong (β ≠ mito, κ ≠ BER)
-
A-IV, B-II, C-III, D-I: Wrong (α ≠ TLS)
Correct Answer
A-II, B-I, C-III, D-IV (option 2)
Eukaryotic DNA Polymerase Families
DNA polymerase α (alpha) forms complex with primase, synthesizes RNA/DNA primary initiation primers (10nt RNA + 20nt DNA) for Okazaki fragments. DNA polymerase β (beta) executes base-excision DNA repair via dRP lyase activity in BER pathway. DNA polymerase γ (gamma) exclusively replicates mitochondrial DNA. DNA polymerase κ (kappa) enables translesion DNA synthesis past benzo[a]pyrene adducts.
Correct Matching Table
| Enzyme |
Function |
| A. DNA pol α |
II. RNA/DNA primary initiation (primase partner) |
| B. DNA pol β |
I. Base-excision DNA repair (BER short patch) |
| C. DNA pol γ |
III. Mitochondrial DNA replication/repair |
| D. DNA pol κ |
IV. Translesion DNA synthesis (Y-family TLS) |
Function Summary
-
α (B-family): Low processivity, primer synthesis only
-
β (X-family): Nuclear repair, no 3’→5′ exo
-
γ (A-family): Mitochondrial replicase + repair
-
κ (Y-family): Error-prone TLS, low fidelity
Exam Strategy
NEET/GATE mnemonic: “α-Start, β-Fix bases, γ-Mito, κ-TLS”. Option 2 = gold standard. Distractors swap repair roles (β vs κ) or locations (nuclear vs mito).
Essential molecular biology question for your biochemistry exam prep.
