Question

If a cell lacks RNA polymerase III, then it cannot synthesize
A.tRNA
B.28S rRNA
C.5S rRNA
D.Both (1) and (3)

Answer 1

A RNA polymerase (RNAP), or polymer polymerase, maybe a multisubunit enzyme that catalyzes the method of transcription where an RNA polymer is synthesized from a DNA template. The sequence of the RNA polymer is complementary to it of the template DNA and is synthesized in an exceedingly 5’→ 3′ orientation. This RNA strand is termed the primary transcript.

Complete step by step answer: Eukaryotic RNA polymerase:
1.There are 5 known types of RNA polymerases, each for the synthesis of specific subtypes of RNA. These include RNA polymerase I that synthesizes a pre-rRNA 45S (35S in yeast), which matures and forms the main RNA sections of the ribosome.
2.RNA polymerase II synthesizes precursors of mRNAs and most snRNA and microRNAs.
3.RNA polymerase III synthesizes tRNAs, rRNA 5S, and other small RNAs found within the nucleus and cytosol.
4.RNA polymerase IV and V found in plants don't seem to be well understood, however, they create siRNA. The plant chloroplast encodes the ssRNAPs and uses bacteria-like RNA Polymerase.
5.Each of the nuclear RNA polymerases could be a large molecule with about 8 to 14 subunits and therefore the mass is approximately 500,000 for every.

Each of those polymerases features a different function:
a.RNA polymerase I:
This enzyme is found within the nucleolus of the cell.
It could be a specialized nuclear substructure where the ribosomal RNA (rRNA) is synthesized by transcription and assembled into ribosomes.
The rRNA are component elements of the ribosomes and are important within the process of translation.
Therefore, RNA polymerase I synthesize most rRNAs except 5S rRNA. In yeast, the enzyme incorporates a mass of 600kDa and 13 subunits.
b.RNA polymerase II:
This enzyme is found within the nucleus.
Most organisms that possess RNA polymerase II have a 12-subunit RNAP II. It is structurally made of holoenzyme and mediators, with General Transcriptional factors (GTFs).
They contain transcription factors and transcriptional regulators.
It functions by synthesizing all proteins that code for the nuclear pre-mRNAs in eukaryotic cells (mRNAs in prokaryotic cells).
It is accountable for transcribing most of the eukaryotic genes and particularly found in human genes.
c.RNA polymerase III:
It is found within the nucleus.
The RNA polymerase III has 14 or more distinct subunits with a mass of roughly 700 kDa.
Its function is to transcribe RNA (tRNA), ribosomal RNA (rRNA), and other small RNAs.
Some of its target points are important for the traditional functioning of the cell.
RNA polymerase III- a complex multisubunit enzyme that transcribes genes for little stable untranslated RNAs (tRNAs, 5S rRNA, Alu RNA, U6 snRNA) and a few other genes.
Therefore, the correct option 4, both (1) & (3).

Note: The genes transcribed by RNA Pol III fall within the category of "housekeeping" genes whose expression is required all told cell types and most environmental conditions. Therefore, the regulation of Pol III transcription is primarily tied to the regulation of cell growth and cell cycle, thus requiring fewer regulatory proteins than RNA polymerase II.