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2021-05-15

What is the goal of transcription in biology?

What is the goal of transcription in biology?

The goal of transcription is to make a RNA copy of a gene’s DNA sequence. For a protein-coding gene, the RNA copy, or transcript, carries the information needed to build a polypeptide (protein or protein subunit). Eukaryotic transcripts need to go through some processing steps before translation into proteins.

What is the goal of transcription and where does it happen?

Where does transcription occur in eukaryotes?

eukaryotic nucleus

Does transcription occur in eukaryotic cells?

Transcription occurs in the nucleus of a eukaryotic cell.

Why can translation begin before transcription is complete in prokaryotes but not in eukaryotes?

Why can translation begin before transcription is complete in prokaryotes but not in eukaryotes? Because mRNA is produced in the cytoplasm in prokaryotes, the start codons of an mRNA being transcribed are available to ribosomes before the entire mRNA molecule is even made.

Why is transcription and translation coupled in prokaryotes but not in eukaryotes?

(b) Transcription and translation occur in the same compartment cytosol, as there is no well defined nuclear membrane. There for it can be coupled. Since RNA is synthesised inside the nucleus and translation occurs in the cytoplasm, coupling of transcription and translation is not possible.

Why can’t transcription and translation happen at the same time in eukaryotes?

Prokaryotic transcription and translation can occur simultaneously. This is impossible in eukaryotes, where transcription occurs in a membrane-bound nucleus while translation occurs outside the nucleus in the cytoplasm. Many of these transcription factors are homodimers containing helix-turn-helix DNA-binding motifs.

What is similar between transcription and translation?

Transcription is the synthesis of RNA from a DNA template where the code in the DNA is converted into a complementary RNA code. Translation is the synthesis of a protein from an mRNA template where the code in the mRNA is converted into an amino acid sequence in a protein.

What happens to a primary transcript in eukaryotic cells before translation can occur?

Overview of pre-mRNA processing in eukaryotes This transcript must undergo processing (splicing and addition of 5′ cap and poly-A tail) while it is still in the nucleus in order to become a mature mRNA. In bacteria, RNA transcripts are ready to act as messenger RNAs and get translated into proteins right away.

Is there a sigma factor in eukaryotic transcription?

The eukaryotic transcription factors may indeed act as sigma factors to allow the eukaryoitic RNA polymerase to recognize the promoter. Some of the factors may be specific to certain promoters so groups of factors like these would be expected to exist.

Why is RNA polymerase not bound to the promoter?

The RNA polymerase can not attach at any random site on DNA; for this special promoter site is present just before the gene. Between promoter and gene another site is present called operator site. Hence transcription of gene can not take place when repressor molecule is attached to operator site of DNA.

Why do eukaryotes have 3 RNA polymerases?

Eukaryotic cells contain three distinct nuclear RNA polymerases that transcribe different classes of genes (Table 6.1). RNA polymerase III transcribes the genes for tRNAs and for the smallest species of ribosomal RNA (5S rRNA).