Regulation of Gene Expression

Question 1

Transcription general steps

Answer 1

(1) RNA polymerase binds to DNA at a promoter along with general transcription factors (Bind)
(2) DNA is unwound by various proteins (helicase, chromatin modifying enzymes, etc.) (Unwind)
(3) One strand acts as a template for synthesis of RNA (Template and Copy)
(4) Many RNA copies can be made at the same time
(5) Termination occurs at termination signal

Question 2

Transcription factors help _____ and activate ______.

Answer 2

Transcription factors help initiate transcription and active RNA polymerase.

Question 3

General transcription factors are required for

Answer 3

mRNA transcription

Question 4

What is a pre-initiation complex and what is it necessary for?

Answer 4

Combination of general trx factors, RNA polymerase II, and promoter. Necessary for basal level trx.

Question 5

Upstream transcription factors do what?

Where do they bind and how do they interact with promoter?

Two domain types and what they do.

Answer 5

They increase or decrease trx initiation by the pre-initiation complex.

They bind thousands of nucleotides away from promoter but can interact with it due to DNA looping.

Activation domains: turn on gene by accelerating rate of trx initiation, attracting GTFs to promoter, and modifying DNA to make it more accessible.

Repressor domains: turn off gene by modifying DNA to make it less accessible or interfering with GTFs.

Question 6

What are inducible trx factors

Answer 6

Upstream trx factors that need to be activated of inhibited in order to influence the rate of trx. Environmental cues can alter gene expression patterns.

Question 7

What are cis regulatory elements? Where are they? Examples

Answer 7

DNA elements in the major groove that regulate trx. Promotor, regulatory sequence, insulator

Question 8

What are trans regulatory elements? Where are they usually? Examples

Answer 8

Protein factors that regulate trx. They’re usually bound to cis elements in the major groove. GTFs, regulatory proteins, mediator.

Question 9

Regulatory proteins recognize specific DNA sequences through ____ in ____. Notable example of (1) and what it allows for?

Answer 9

Regulatory proteins recognize specific DNA sequences at through DNA binding motifs in DNA binding domains. Leucine zippers motifs allow for combinatorial control of trx because it can exist as a homodimer or heterodimer.

Question 10

Posttrx modification of RNA does what?

Answer 10

Used to stabilize mRNA, facilitate exist from nucleus, and allow for translation

Question 11

Splicing is? Done by? Improper splicing arises from? Alternative splicing allows for?

Answer 11

Splicing is removal of introns to form mature mRNA. It is done by a spliceosome. Improper splicing arises from mutations at splice sites. Alternative splicing allows for 200 million proteins to be made from 20K genes.

Question 12

The genetic code is ____ and ____.

Answer 12

Degenerate and specific

Question 13

What is used to add amino acids to protein?

Answer 13

tRNA

Question 14

tRNA is synthesized by?

Answer 14

RNA Pol III

Question 15

tRNA base pairing characteristics

Answer 15

tRNA can base pair with more than one codon due to a wobble on the third base pair

Question 16

Correct addition of amino acid requires

Answer 16

aminoacyl-tRNA synthetase

Question 17

RNA message is decoded in ____ and amino acids are added to the ____.

Answer 17

RNA message is decoded in ribosomes and amino acids are added to the C-terminal end.

Question 18

Ribosomes are made of ____.

Answer 18

2/3 RNA and 1/3 protein

Question 19

rRNA used in ribosomes are assembled with ___ in ____. r

Answer 19

rRNA used in ribosomes are assembled with ribosomal proteins in the nucleolus

Question 20

Ribosomes initiate translation at ___ and terminate at ____.

Answer 20

Ribosomes initiate translation at an AUG site and terminate at a stop codon (TAG, TAA, or TGA)