Genome organization

Question 1

Define synteny

Answer 1

Refers to two genes that are on the same chromosome

Question 2

What percentage of the genome codes for protein

Answer 2

1.5%

Question 3

What is the average length of an exon

Answer 3

100-200

Question 4

What percentage of a gene is repetitive DNA?

Answer 4

50%

Question 5

What is the average size of a gene?

Answer 5

27k

Question 6

What are the four levels of DNA compaction?

Answer 6

1. Nucleosome: beads on a string
2. 30nm fibers
3. Interphase chromosomes
4. M-phase mitosis model

Question 7

What is the diameter of a nucleosome?

Answer 7

10 nm

Question 8

What are the four different proteins that make up the histone?

Answer 8

H2A, H2B, H3, H4

Question 9

How many bp wrap around the histone?

Answer 9

146-147

Question 10

In a complete nucleosome, how many bp?

Answer 10

200

Question 11

What is an example of a function of the chromatin remodeling complex?

Answer 11

Spacing between histones

Question 12

Name four covalent modifications to histone tails

Answer 12

1. Lysine acetylation
2. Lysine methylation
3. Serine phosphorylation
4. Ubiquitination

Question 13

What enzyme carries out histone acetylation

Answer 13

histone acetyl-transferase

Question 14

What protein is involved in modifying DNA trajectory upon leaving the nucleosome and forming 30nm fiber sturcture

Answer 14

Histone H1

Question 15

The highly condensed form of chromatin

Answer 15

heterochromatin

Question 16

The less condensed form of chromatin

Answer 16

euchromatin

Question 17

Define constitutive heterochromatin

Answer 17

heterochromatin is tightly packed all the time

Question 18

Define facultative heterochromatin

Answer 18

Applies to a region of the genome that is hetero- in some cell types, and not in others

Question 19

Positional effect

Answer 19

The need for a gene to be in the right part of the genome in order to be expressed

Question 20

What is able to block heterochromatin movement, and what is an example of this?`

Answer 20

Isolators: HS4 sequence

Question 21

What is a “reader writer” complex?

Answer 21

A group of proteins that gather more more proteins which work together to compact DNA and create heterochromatin

Question 22

What are tandemly repeated short sequences in the centromere called?

Answer 22

alpha satellite DNA

Question 23

What is different about nucleosomes in the centromere?

Answer 23

They have a histone H3 variant named CENP-A

Question 24

How many nucleotide pairs in an alpha satellite DNA monomer

Answer 24

171

Question 25

What are two examples of interphase chromosome compaction

Answer 25

1. lampbrush chromosomes (amphibian oocytes)

2. polytene chromosomes (drosophila salivary glands)

Question 26

What is the highest level of chromatin compaction?

Answer 26

mitotic chromosomes

Question 27

What are two roles of mitotic chromosome compaction?

Answer 27

1. it untangles sister chromatids

2. protects DNA molecules while being pulled to daughter cells

Question 28

What group of proteins are used to compact interphase chromosomes?

Answer 28

condensins