5 Transcription and RNA Processing Free Online FlashCards

What defines a gene?

A gene is a stretch of DNA whose transcription produces a functional RNA.

What does a promoter do?

The promoter is where transcription machinery assembles; it helps determine where transcription begins and which DNA strand is used.

What is the transcription start site?

The transcription start site is the first DNA position copied into RNA. It is not necessarily the start of the protein-coding sequence.

Are all parts of an exon protein-coding?

Exons remain in mature RNA, but may include untranslated regions and are not always entirely protein-coding.

In which directions does RNA polymerase read and synthesize?

RNA polymerase reads the template strand 3′ to 5′ and synthesizes RNA 5′ to 3′.

How does RNA compare with the coding DNA strand?

The RNA sequence matches the nontemplate (coding) DNA strand, except RNA uses uracil (U) instead of thymine (T).

What are the three broad stages of transcription?

The three broad stages are initiation, elongation, and termination.

Are RNA cleavage and transcription termination identical events?

In eukaryotic protein-coding genes, RNA cleavage and transcription termination are linked but are not always the same event.

Where does transcription occur in eukaryotes and bacteria?

Eukaryotic transcription occurs in the nucleus. Bacteria lack a nucleus, so transcription occurs in the cytoplasm and can overlap with translation.

What is the 5′ cap, and what does it help with?

A modified guanine nucleotide is added to the pre-mRNA 5′ end. The cap helps protect RNA from breakdown and supports nuclear export and translation machinery recognition.

What does the spliceosome do?

The spliceosome, a complex of proteins and small nuclear RNAs, removes introns and joins neighboring exons.

What can alternative splicing produce?

Alternative splicing joins different combinations of exons, allowing one gene to produce multiple mature RNA forms.