Category: CSIR NET Life Science PYQs and Solutions Eukaryotic Transcription

CSIR NET Life Science Previous Year Questions and Solution Eukaryotic Transcription

Introduction

Eukaryotic Transcription is a vital topic under the “Fundamental Processes” unit of CSIR NET Life Sciences. It includes the transcription machinery, RNA polymerases, transcription factors, enhancers, and gene regulation in eukaryotic cells. Questions from this area test both memory and analytical understanding.

In this article, we cover previous year CSIR NET questions on eukaryotic transcription, with concept-based detailed solutions to help you understand the logic behind the correct answers.

Key Concepts in Eukaryotic Transcription

Before solving PYQs, revise these important subtopics:

RNA polymerases I, II, III: functions and promoters
General transcription factors (GTFs) like TFIID, TFIIB, etc.
Role of TBP and TATA box
Enhancers, silencers, mediator complex
Chromatin remodeling and epigenetic regulation
Transcription elongation and termination
mRNA processing: capping, splicing, polyadenylation

CSIR NET Previous Year Questions on Eukaryotic Transcription

Question 1: (CSIR NET Dec 2017)

Which of the following statements is true about RNA polymerase II transcription initiation?

A. TBP binds to the enhancer sequence
B. TFIIB binds after TFIIH
C. Mediator complex interacts with activators and RNA polymerase II
D. RNA polymerase II binds directly to the TATA box

Correct Answer: C
Explanation: The mediator complex acts as a bridge between gene-specific transcription factors bound to enhancers and the general transcription machinery. TBP binds to the TATA box (not enhancers), and RNA pol II does not bind directly to DNA.

Question 2: (CSIR NET June 2016)

Which RNA polymerase is responsible for synthesizing 5S rRNA in eukaryotes?

A. RNA Pol I
B. RNA Pol II
C. RNA Pol III
D. All of the above

Correct Answer: C
Explanation: RNA polymerase III transcribes tRNAs and 5S rRNA. RNA Pol I synthesizes large rRNA precursors, and RNA Pol II synthesizes mRNAs.

Question 3: (CSIR NET Dec 2018)

The TFIID complex involved in RNA Pol II transcription initiation contains:

A. Only TBP
B. Only TAFs
C. TBP and several TAFs
D. RNA Pol I

Correct Answer: C
Explanation: TFIID is a multi-subunit complex containing TBP (TATA-binding protein) and TAFs (TBP-associated factors) which help in recognizing promoter elements.

Question 4: (CSIR NET June 2019)

Which of the following is not required for RNA Pol II promoter clearance?

A. TFIIH helicase activity
B. Phosphorylation of CTD of RNA Pol II
C. TBP binding to DNA
D. TAF-mediated histone acetylation

Correct Answer: D
Explanation: TAF-mediated histone acetylation is associated with chromatin remodeling and transcription initiation, but not directly with promoter clearance.

Question 5: (CSIR NET Dec 2021)

Which subunit of TFIIH is involved in DNA helicase activity?

A. XPB
B. TFIIB
C. TAF1
D. TBP

Correct Answer: A
Explanation: XPB and XPD subunits of TFIIH possess helicase activity required for DNA unwinding at the transcription start site.

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