Week 7 - Regulation Of Gene Expression

Question 1

What is gene expression?

Answer 1

Control at multiple steps

Question 2

Define an operon.

Answer 2

A functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter

Question 3

What is the function of the E. coli lac operon?

Answer 3

Control of gene expression for efficient substrate use

Question 4

What induces the synthesis of enzymes for lactose metabolism in E. coli?

Answer 4

Presence of lactose

Question 5

How is the lac operon expression inhibited?

Answer 5

By a repressor protein

Question 6

What is the role of allolactose in the lac operon?

Answer 6

Binds to repressor protein and blocks its action

Question 7

What type of expression system is the lac operon an example of?

Answer 7

Inducible expression system

Question 8

What is the function of the trp operon?

Answer 8

Codes for genes responsible for synthesis of amino acid tryptophan

Question 9

What happens to the trp operon when tryptophan levels are low?

Answer 9

Repressor is inactive, operon expressed, tryptophan synthesized

Question 10

What happens to the trp operon when tryptophan levels are high?

Answer 10

Tryptophan binds to repressor, operon expression inhibited

Question 11

What are regulatory transcription factors (TFs)?

Answer 11

Proteins that activate or inhibit transcription

Question 12

What is the difference between transcriptional activators and repressors?

Answer 12

Activators promote transcription, repressors inhibit transcription

Question 13

What is chromatin remodeling?

Answer 13

Alteration of chromatin structure to regulate transcriptional activity

Question 14

What is euchromatin?

Answer 14

Open chromatin structure that is transcriptionally active

Question 15

What is heterochromatin?

Answer 15

Condensed chromatin that is normally transcriptionally silent

Question 16

What role do histone modifying enzymes play?

Answer 16

Catalyze histone modifications that affect chromatin structure

Question 17

How does acetylation affect transcriptional activity?

Answer 17

Tends to increase transcriptional activity

Question 18

What is DNA methylation?

Answer 18

Addition of methyl groups to DNA, typically resulting in transcriptional silencing

Question 19

What is alternative splicing?

Answer 19

Process by which genes can encode more than one protein through different mRNA transcripts

Question 20

What is the role of translation initiation factors?

Answer 20

Mediates the process of translation initiation

Question 21

What is the function of micro RNAs (miRNAs)?

Answer 21

Regulate gene expression by binding to target mRNAs and inhibiting translation

Question 22

What happens to translation initiation in low iron levels?

Answer 22

IRP binds to IRE, interferes with translation initiation

Question 23

What is the action of eIF2 in translation regulation?

Answer 23

Active eIF2-GTP escorts initiator Met-tRNA to ribosome

Question 24

What occurs when growth factors stimulate 4E-BPs?

Answer 24

Phosphorylation of 4E-BPs dissociates them from eIF4E, allowing translation to proceed

Question 25

What initiates mRNA degradation in eukaryotes?

Answer 25

Deadenylation of the poly-A tail followed by exonuclease digestion

Question 26

What are AU-rich elements (AREs)?

Answer 26

Sequences in mRNA that serve as binding sites for RNA-binding proteins (RBPs)

Question 27

In prokaryotes, what is the typical half-life of mRNA?

Answer 27

Minutes

Question 28

What is the primary role of RNA-binding proteins (RBPs)?

Answer 28

Influence mRNA fate by binding to regulatory sequences

Question 29

What is the key outcome of transcriptional control in eukaryotes?

Answer 29

Gene expression is chiefly controlled by transcription factors and chromatin remodeling

Question 30

What is the title of the book authored by Alberts et al. in its 6th edition?

Answer 30

Molecular Biology of the Cell ## Footnote Published by Garland Science in 2015

Question 31

What is the URL for the online resource provided by the DNA Learning Centre?

Answer 31

http://www.dnalc.org/ ## Footnote This is a Cold Spring Harbor online DNA learning resource

Question 32

What is the focus of the 'DNA from the Beginning' resource?

Answer 32

An animated primer of 75 experiments that made modern genetics ## Footnote This resource helps in understanding fundamental concepts in genetics

Question 33

What type of content does Bozeman Science provide?

Answer 33

Basic video tutorial on Transcription and translation ## Footnote Includes educational resources for molecular biology

Question 34

Fill in the blank: The 6th edition of 'Molecular Biology of the Cell' was published by _______.

Answer 34

Garland Science

Question 35

True or False: The DNA Learning Centre is a resource for learning about RNA synthesis.

Answer 35

False ## Footnote The DNA Learning Centre focuses on DNA and genetics, not specifically on RNA synthesis.

Question 36

List the online resources mentioned for molecular biology education.

Answer 36

* DNA Learning Centre * DNA from the Beginning * Bozeman Science