Chapter 19: Control of Gene Expression in Eukaryotes

Question 1

Interact with the TATA box, other proteins, and RNA polymerase to form transcription initiation complex

Answer 1

General transcription factors

Question 2

Different cell types express different subsets fo genes

Answer 2

Differential gene expression

Question 3

Far away from the promoter (can be upstream, downstream, or in an intron)

Answer 3

Enhancers

Question 4

What do HDACs (histone deacetylases) do?

Answer 4

Takes acetyl groups off

Question 5

Strongly increase or decrease transcription rate

Answer 5

Specific transcription factors

Question 6

How can histones be modified?

Answer 6

The addition or removal of specific chemical groups to histone tails

Question 7

Loosens DNA coiling with HATs and HDACs

Answer 7

Acetylation (-COCH3)

Question 8

Most eukaryotic genes have associated segments of noncoding DNA that serve as binding sites for proteins to start transcription

Answer 8

Regulatory sequences

Question 9

Study of changes in gene expression not due to change in DNA sequence

Answer 9

Epigenetics

Question 10

What percentage of protein coding genes are expressed by cells in humans?

Answer 10

About 20%

Question 11

What are the types of regulatory sequences?

Answer 11

Promoter-proximal elements and enhancers

Question 12

What do transcription factors do?

Answer 12

Bring everything together to form transcription initiation complex

Question 13

Can recruit proteins for chromatin remodeling

Answer 13

Specific transcription factors

Question 14

Have a low rate of transcription

Answer 14

General transcription factors

Question 15

What do different cell types have for gene expression?

Answer 15

Different activators and repressors

Question 16

What does acetylation of histones do to DNA?

Answer 16

Promotes loose chromatin structure that permits transcription

Question 17

What can epigenetics explain?

Answer 17

The differences seen in identical twins and why one expresses traits and the other doesn’t or why one develops a disease and the other doesn’t

Question 18

What do chromatin modifications do and not do?

Answer 18

Do not change the DNA sequence but may be passed on to future generations

Question 19

What do genes with related functions that need to be expressed coordinately share?

Answer 19

A specific combo of control elements

Question 20

What do all cells express?

Answer 20

Different genes from each other depending on their function

Question 21

What does regulation of gene expression depend on?

Answer 21

The combination of control elements

Question 22

What happens in DNA methylation?

Answer 22

Adds methyl groups (-CH3) to cytosine (C) residues that trigger chromatin to condense

Question 23

What can influence methylation?

Answer 23

Environmental factors

Question 24

What do HATs (histone acetyltansferases) do?

Answer 24

Transfer acetyl groups to histones

Question 25

What do errors in remodeling after histone modification lead to?

Answer 25

Many different diseases including cancer

Question 26

Two types of specific transcription factors that strongly increase or decrease transcription rate

Answer 26

Activators and repressors

Question 27

What can methylated genes cause?

Answer 27

Play a role in cancer development

Question 28

Regulatory sequences which can inhibit transcription

Answer 28

Silencers

Question 29

What does condensed chromatin cause?

Answer 29

Genes to not be expressed bc transcription cant occur bc the DNA is too tightly wound

Question 30

How is gene expression controlled in eukaryotes?

Answer 30

At many levels in different ways. The farther along you get, the more energy and resources the cell has to use

Question 31

Bind to regulatory sequences

Answer 31

Specific transcription factors

Question 32

What must happen for a gene to be expressed (transcribed)?

Answer 32

The cellular machinery must be able to access it

Question 33

What is DNA wrapped around?

Answer 33

Histones

Question 34

What do methyl groups added to histones cause?

Answer 34

DNA that is more tightly packed together

Question 35

Loosens DNA coiling

Answer 35

Phosphorylation (PO4)

Question 36

Tightens DNA coiling

Answer 36

Methylation (CH3)

Question 37

What do activators do?

Answer 37

Appropriate activators bind to the control elements regardless of where the gene is in the genome

Question 38

What usually happens when a gene is methylated?

Answer 38

It usually remains that way through successive rounds of division and can occur throughout life due to environmental factors

Question 39

Essential for the transcription of all protein coding genes

Answer 39

General transcription factors