Question

Which of the following component of RNA polymerase facilitates the recognition of promoter sequences?
A. a subunit
B. b subunit
C. s subunit
D. c subunit

Answer 1

Answer:

The recognition of promoter sequences is made easier by this RNA polymerase ς subunit.

Explanation:

• The ς subunit is only loosely attached to the rest of the enzyme (the core polymerase, E); it is responsible for RNA polymerase's recognition of specific promoters, but it is released during the initiation phase.

• Aided diffusion is thought to be how RNA polymerases (or associated general transcription factors) get to promoter sequences (FD). In FD, a protein attaches to nontarget DNA first, then uses a 1D sliding search to reach the target.

• The holoenzyme form of bacterial RNA polymerase binds promoters, with the specificity subunit being principally responsible for promoter recognition.

• An extra -subunit is required for specific transcription initiation at promoter locations. The holoenzyme formed by the union of core and is capable of finding promoter sequences, opening DNA to generate a transcription bubble, and commencing RNA synthesis.

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Answer 2

Answer:

The correct option is the d. c subunit

Explanation:

• The polymerization of ribonucleotides into a sequence complementary to the template DNA is carried out by DNA-directed RNA polymerases (also known as DNA-dependent RNA polymerases).
• RNA polymerases are enzymes composed of several subunits:-

1. The core assembly is initiated and activated by a-subunit, forming a platform on which the beta subunits can interact.
2. The b-subunit is engaged in template-dependent chain initiation and polynucleotide production catalysis.
3. The s-subunit aids in the assembly of RNA polymerase (RNAP) and stabilizes the finished product.
4. The c-subunit/factor is a protein that is solely required for the initiation of RNA synthesis. It's a bacterial transcription initiation factor that allows RNA polymerase to bind to gene promoters in a specific way.

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