Module 33 Terms - Transcription and RNA Processing

Question 1

Template strand

Answer 1

The strand of DNA used as the model for synthesis of an RNA transcript. Also called the noncoding strand, antisense strand, or minus strand

Question 2

RNA polymerase

Answer 2

The enzyme that synthesizes RNA. Reads the template strand in the 3’ to 5’ direction, and builds the RNA from the 5’ to 3’ direction

Question 3

Nontemplate strand

Answer 3

The other strand of DNA that is not used as the template for transcription. Also called the coding strand, sense strand, or plus strand

Question 4

Promoters

Answer 4

Regions on DNA to which RNA polymerase and associated proteins bind and initiate transcription

Question 5

Primary transcript

Answer 5

The RNA transcript that comes fresh off the template DNA strand (only in eukaryotes, not prokaryotes)

Question 6

Messenger RNA (mRNA)

Answer 6

The RNA molecule that combines with the ribosome to direct protein synthesis.

In prokaryotes, all completed RNA is mRNA, but in eukaryotes, RNA must go through RNA processing to become mRNA

Question 7

RNA processing

Answer 7

When the primary transcript undergoes a series of chemical modifications that convert the primary transcript into mRNA

Question 8

GTP cap (5’ cap)

Answer 8

A modified nucleotide becomes attached to the 5’ end of the primary transcript during RNA processing. Allows ribosomes to recognize mRNA

Question 9

Poly(A) tail

Answer 9

A long string of consecutive adenine nucleotides at the 3’ end of the primary transcript. Helps stabilize the RNA

Question 10

Exons

Answer 10

Regions in eukaryote transcripts that are expressed as proteins

Question 11

Introns

Answer 11

Regions in eukaryote transcripts that are interspersed with exons and not expressed as proteins. These regions are removed from the primary transcript

Question 12

RNA splicing

Answer 12

The process by which exons are stitched together and introns are removed

Question 13

Alternative splicing

Answer 13

A process in which primary transcripts from the same gene can be spliced in different ways to yield different mRNAs and therefore different protein products

Question 14

Ribosomal RNA (rRNA)

Answer 14

A noncoding RNA that makes up the majority of ribosomes and is essential in translation

Question 15

Transfer RNA (tRNA)

Answer 15

A noncoding RNA that carries individual amino acids for use in translation