Trigger 8: Structure of nucleosomes

Question 1

role of DNA methylation

Answer 1

• silencing genes
• silences repetitive elements
• plays a role in X chromosome inactivation
• establishment and maintenance of imprinted genes
• in carcinogenesis

Question 2

DNA methylation occurs at

Answer 2

CpG dinucleotides

Question 3

DNA methylation silences genes by

Answer 3

displacing TFs

- attracts methyl-bidnign proteins

Question 4

how many m of DNA in every cell

Answer 4

2m

Question 5

diameter of DNA within cells

Answer 5

5-10um

Question 6

chromatin not only packages

Answer 6

DNA, but also regulated DNA accessibility through modification in chromatin structure

Question 7

chromatin is made up of

Answer 7

DNA and proteins and RNA

Question 8

which proteins make up chromatin

Answer 8

histones

Question 9

DNA wraps around histone how many times

Answer 9

1.65

Question 10

nucleosome consist of

Answer 10

8 histone proteins around which DNA warps 1.65 times

Question 11

what influences activity of DAN transcirptions

Answer 11

chromatin compaction

Question 12

chromatin is found in how many forms

Answer 12

2

Question 13

name the two forms of chromatin

Answer 13

euchromatin and heterochromatin

Question 14

heterochromatin DNA

Answer 14

compact- not transcriptionally active

Question 15

euchromatin

Answer 15

less compact- transcriptionally active

Question 16

nucleosomes are the

Answer 16

basic units of DNA condensation (fundamental repeating unit of chromatin)

Question 17

histones cosnituttue the

Answer 17

largest portion component of chromatin

Question 18

histones are

Answer 18

highly conserved a

Question 19

histones assemble into an

Answer 19

octameric complex (nucleosomes)

Question 20

nucleosome are made of

Answer 20

DNA wound around a histone core

Question 21

nucleosome structure

Answer 21

1) DNA wound around a histone core- makes nucleosome core particle
2) linker DNA- between nucleosomes

Question 22

how many base paris in linker DNA

Answer 22

54bp (between nucleosomes)

Question 23

how big are nculeosomes

Answer 23

10nm diameter

Question 24

each hsitoen octamer is composed of

Answer 24

two copies of the four histones (H2A, H2B, H3 and H4)

Question 25

how may bp of DNA wrap around histone octamer

Answer 25

147

Question 26

adjacent ncuelosome are linked via

Answer 26

linker DNA (45-60bp)

Question 27

Histone H1 sits ar

Answer 27

the base of the nucleosome near DNA- bdininf to the linker region of DNA

Question 28

distance between nucleosomes

Answer 28

14nm

Question 29

function of nucleosome

Answer 29

acts a signalling hub by providing a scaffold for the bidding of chromatin enzymes

Question 30

nucleosomes display

Answer 30

a combinatorial array of post translation modifications (PTMs)

Question 31

PTMs regulate

Answer 31

recruitment of chromatin enzyme, nucleosome stability and higher-order compaction of chromatin