Ch.17: Non-coding RNAs

Question 1

In most cells…

Answer 1

ncRNAs are more abundant than mRNAs and perform a diverse set of functions and can act as ribozymes, blockers or decoys

Question 2

Ribozyme

Answer 2

RNA molecules with catalytic function

Question 3

Blocker

Answer 3

A ncRNA physically prevents or blocks a cellular process from happening

Question 4

Decoy

Answer 4

A ncRNA recognizes another ncRNA and sequesters it

Question 5

What is the idea of the “RNA World”?

Answer 5

the subsequent discovery that hat RNA can act as enzymes by themselves and a RNA ribozyme catalyzes the peptide bond during
protein synthesis

Question 6

What is a con of the “RNA World” theory?

Answer 6

that proteins were always available and were part
of the evolutionary process

Question 7

What does dsRNA contain and do?

Answer 7

contains both antisense RNA and sense RNA is even more effective at inhibiting
mRNA translation than either antisense RNA or sense RNA alone

Question 8

What is RNA interference mediated by?

Answer 8

microRNAs (miRNAs) or small-interfering RNAs (siRNAs)

Question 9

Summarizes the mechanism of RNA interference

Answer 9

DS pre-miRNA from the cell or DS pre-siRNA from a viral infection associates with
proteins to form a RNA-induced silencing complex (RISC) that silences mRNA

Question 10

What do small nucleolar RNAs do?

Answer 10

direct covalent modifications to ribosomal RNAs

Question 11

What does the Crispr gene contain?

Answer 11

a series of repeats that are interspersed with short,
unique sequences, called spacers that are derived form invading bacteriophage

Question 12

What does the Crispr gene produce?

Answer 12

a ncRNA called pre-crRNA, which
contains the unique spacer sequences from bacteriophages
and the repeat sequence; A region of the tracrRNA is complementary to the repeat
sequences of the pre-crRNA

Question 13

What do PIWI-interacting RNAs do?

Answer 13

Silence transposable elements