Transcription and Translation

Question 1

Function of mRNA

Answer 1

Messenger RNAs, code for proteins

Question 2

Function of rRNAs

Answer 2

Ribosomal RNAs,

Form the basic structure of the ribosome, and catalyse protein synthesis

Question 3

Function of tRNAs

Answer 3

Transfer RNAs

Central to protein synthesis as adaptors between mRNA and amino acids

Question 4

Function of snRNAs

Answer 4

Small nuclear RNAs

Function in a variety of nuclear processes including the splicing of pre-mRNA

Question 5

Function of snoRNAs

Answer 5

Small nucleolar RNAs

Help process and chemically modify rRNAs

Question 6

Function of miRNAs

Answer 6

MicroRNAs

Regulate gene expression by blocking translation of specific mRNAs and cause their degradation

Question 7

Function of siRNAs

Answer 7

Small interfering RNAs
Turn off gene expression by directing the degradation of selective mRNAs and the establishment of compact chromatin structures

Question 8

Function of piRNAs

Answer 8

Piwi-interacting RNAs

Bind to piwi proteins and protect the germ line from transposable elements

Question 9

Function of lncRNAs

Answer 9

Long noncoding RNAs

Scaffold: regulation of cell processes including X-chromosome inactivation

Question 10

Genes transcribed by RNA polymerase I

Answer 10

rRNA genes

Question 11

Genes transcribed by RNA polymerase II

Answer 11

All protein-coding genes
snoRNA
miRNA
siRNA
lncRNA
snRNA

Question 12

Genes transcribed by RNA polymerase III

Answer 12

tRNA
snRNA
Other small RNAs

Question 13

What is the significance of polyadenylation and capping?

Answer 13

Allow the cell to assess whether the mRNA is intact before it is exported to the cytosol

Question 14

What 4 types of proteins does RNA polymerase II require to transcribe?

Answer 14

General transcription factors
Activator
Mediator
Chromatin-modifying proteins

Question 15

Explain ‘capping’

Answer 15

Addition of a modified guanosine nucleotide to the 5’ end of a pre-mRNA

Question 16

Polyadenylation

Answer 16

The addition of a poly-A tail to the 3’ end of pre-mRNA

Question 17

Spliceosome

Answer 17

Large assembly of RNA and protein molecules - performs splicing of pre-mRNA

Question 18

Chaperone

Answer 18

Molecule that helps proteins fold correctly. Helps mend incorrectly folded proteins

Question 19

Transcription is carried out by…

Answer 19

RNA polymerase

Question 20

Role of general transcription factors

Answer 20

Help position eukaryotic RNA polymerase correctly at promotor
Aid in pulling apart DNA strands
Release RNA polymerase from promotor into elongation mode