Chapter 11

Question 1

What are the 4 differences between eukaryote and prokaryote transcription?

Answer 1

1.) More genes that are far apart
2.) 3 RNA polymerase types
3.) Transcription happens in the nucleus
4.) DNA is packaged into chromatin

Question 2

What do general transcription factors do?

Answer 2

They bind sequences in the promoter.

Question 3

What is the preinitiation complex?

Answer 3

Complex RNA pol II and general transcription factors.

Question 4

What is mRNA capping?

Answer 4

Adding methylated guanine on the 5’ end of the mRNA to protect decay from exonuclease.

Question 5

What is mRNA polyadenylation?

Answer 5

Conserved sequences in the 3’ UTR signal for cleavage of RNA from RNA pol II and additional of the poly-A taile protects from decay.

Question 6

How are different proteins encoded by splicing?

Answer 6

Cutting introns out or leaving them in certain areas of the genes therefore the proteins made are varied.

Question 7

What is the difference between transcription factors and coregulators?

Answer 7

Coregulators cannot bind to DNA directly but transcription factors can.

Question 8

Transcription factors and coregulators can either be?

Answer 8

Repressors or activators

Question 9

What is the core promoter?

Answer 9

A region surrounding the transcription start site where the transcription factor binds.

Question 10

What are coregulators?

Answer 10

These are factors that can bridge the interaction between transcription factors and RNA pol II.

Question 11

What are the 2 required elements for transcription?

Answer 11

1.) DNA binding domain
2.) Activation/repression domain

Question 12

What are the 2 optional elements for transcription?

Answer 12

1.) Dimerization domain
2.) Ligand binding domain

Question 13

In the absence of glucose other than lactose what carbon source can be used as energy?

Answer 13

Galactose

Question 14

Which enzymes are used to import and metabolize galactose?

Answer 14

Gal2
Gal1
Gal7
Gal10

Question 15

What are the regulatory proteins that can regulate transcription of the enzyme enoding genes?

Answer 15

Gal4
Gal3
Gal80

Question 16

What happens when galactose is absent?

Answer 16

The following are not expressed:
Gal2
Gal1
Gal7
Gal10

Question 17

What happens when galactose is present?

Answer 17

The following are expressed:
Gal2
Gal1
Gal7
Gal10

Question 18

Which of the following Gal are always expressed?

Answer 18

Gal4
Gal3
Gal80

Question 19

What is the relationship between Gal4 and Gal80?

Answer 19

Gal80 is the repressor for Gal4.

Question 20

What happens to Gal3 when galactose is present?

Answer 20

It undergoes conformational changes.

Question 21

What are nucleosomes?

Answer 21

These are basic units of chromosomes that include histone proteins and DNA is wound around it because DNA is negatively charged and histones are positively charged.

Question 22

What do histone octomers consist of?

Answer 22

H2A
H2B
H3
H4
(2 of each)

Question 23

What do the histone tails do?

Answer 23

These tails are flexible and they interact with adjacent nucleosomes and proteins.

Question 24

What is heterochromatin?

Answer 24

This is when the histones and the DNA are tightly compacted with one another.

Question 25

What is constituitive heterochromatin?

Answer 25

This is when the chromatin is always tightly compacted.

Question 26

What is facultative heterochromatin?

Answer 26

This is when the chromatin switches between very compacted to not.

Question 27

What is euchromatin?

Answer 27

This is when the histone proteins loosen their compaction.

Question 28

What is acetylation?

Answer 28

The addition of an acetyl group to the tails and it leads to reduce chromatin compaction and creates a protein binding domain called bromodomain for transcriptional co-activators that cannot bind to DNA directly.

Question 29

What is HAT?

Answer 29

Histone acetyltransferase which adds the acetyl groups and makes the compaction euchromatin.

Question 30

What is HDAC?

Answer 30

Histone deactylase which removes the acetyl groups and makes then more compacted heterochromatin.

Question 31

What are the CPG islands in expressed genes?

Answer 31

Unmethylated

Question 32

What are the CPG islands in unexpressed genes?

Answer 32

Methylated

Question 33

What are CPG Islands?

Answer 33

These are regions that found in most gene promoters.

Question 34

What do unmethylated CPG islands do?

Answer 34

Open chromatin and activate transcription.

Question 35

What do methylated CPG islands do?

Answer 35

Close the chromatin and repress transcription.

Question 36

What is the epigenetic mechanism?

Answer 36

Identical genes will be either active or inactive depending on the inheritance pattern from the mother or the father.