Question

1.Phase variation controls protein levels by
a. altering the DNA sequence.
b. changing the rate of mRNA translation.
c. changing the rate of mRNA stability.
d. changing the rate of protein stability

2.Chlamydomonas spp. can survive at freezing temperatures in their natural Antarctic environment. They have 39 different RNA helicase genes, and it has been hypothesized some of these are activated at freezing temperatures. What technique would be used to test this?

	a.	ChIP-seq
	b.	CRISR-Cas9
	c.	RT-PCR
	d.	DNA protection analysis

Answer 1

1. Phase variation controls protein levels by a. altering the DNA sequence.

Changing the number of repeats in the open reading frame can affect the codon sequence by adding a premature stop codon or by changing the sequence of the protein.

2. c. RT-PCR would be used to test this.

RT-PCR combines reverse transcription of RNA into DNA and amplification of specific DNA targets using PCR. It measures the amount of RNA, which is done by monitoring the amplification reaction using fluorescence through Real Time PCR or qPCR. Combined RT-PCR and qPCR are used for analysis of gene expression.