11.2: The Organization of Chromatin

Question 1

Individual chromosomes occupy () within the nucleus

Answer 1

distinct territories

Question 2

chromosomes are organized in such a way that the transcriptional activity of a gene is related to its ()

Answer 2

position

Question 3

() proposed that each chromosome occupies a distinct territory, with centromeres and telomeres attached to opposite sides of the nuclear envelope

Answer 3

Carl Rabl

Question 4

Carl Rabl proposed that each chromosome occupies a distinct territory, with centromeres and telomeres attached to

Answer 4

opposite sides of the nuclear envelope

Question 5

the 2 ways in which the organizations of chromosomes within the nucleus has been studied

Answer 5

1. fluorescence in situ hybridization (FISH)
2. chromosome conformation capture (3C)

Question 6

this method uses probes that specifically detect repeated sequences on individual chromosomes, thus it has been used to visualize the location of chromosomes within a nucleus

Answer 6

fluorescence in situ hybridization (FISH)

Question 7

this method identifies the sites of association between chromosomal regions, thus it has been used to analyze the interactions between different regions of chromosomes in living cells

Answer 7

chromosome conformation capture (3C)

Question 8

how does 3C detect sites of association between chromosomal regions

Answer 8

sites of association are detected by cross-linking adjacent DNA sequences, which can then be amplified and identified by high-throughput sequencing

Question 9

() divide each chromosome into distinct domains, so that the two arms of each chromosome don’t interact with one another

Answer 9

centromeres

Question 10

highly condensed and transcriptionally inactive chromatin in interphase cells

Answer 10

heterochromatin

Question 11

heterochromatin is usually associated with:

Answer 11

the nuclear envelop or the periphery of the nucleolus

Question 12

decondensed and transcriptionally active chromatin in interphase cells

Answer 12

euchromatin

Question 13

euchromatin is preferentially localized to

Answer 13

the interior of the nucleus or next to nuclear pore complexes

Question 14

Chromatin within the nucleus is divided into (), restricting the interaction of chromosomal regions

Answer 14

looped domains

Question 15

chromatin is organized in looped domains such that

Answer 15

regions within a domain interact frequently with one another, but only rarely interact with regions from other domains

Question 16

the boundaries of these chromosomal domains contain binding sites for (1) and (2), the latter of which is thought to act as an architectural protein that regulates the organization of the genome

Answer 16

1. cohesin
2. CTCF

Question 17

Heterochromatin is localized to the nuclear lamin by binding to

Answer 17

lamins and the lamin B receptor

Question 18

chromatin domains associated with the nuclear lamina are called (); these cover about 40% of the human genome

Answer 18

lamina-associated domains or LADs

Question 19

the binding of the lamin B receptor to () mediates the association of heterochromatin with the nuclear lamina

Answer 19

HP1

Question 20

HP1 binds to methylated histone (), which are characteristic of transcriptionally inactive chromatin

Answer 20

H3 lysin 9 residues

Question 21

chromatin domains associated with the nucleolus’ periphery are called

Answer 21

nucleolus-associated domains or NADs

Question 22

genes found in LADs or NADs are generally

Answer 22

transcriptionally repressed

Question 23

Chromosomes are divided into domains corresponding to (1) and (2)

Answer 23

1. transcriptional units
2. regions of chromatin modification

Question 24

Replication and transcription take place within

Answer 24

clustered regions

Question 25

DNA replication occurs within discrete regions called

Answer 25

replication factories

Question 26

replication factories were initially defined by visualizing newly synthesized DNA by labeling cells with

Answer 26

bromodeoxyuridine

Question 27

clustered sites of newly synthesized DNA also represent concentrated sites of the () involved in DNA replication

Answer 27

proteins

Question 28

transcription also occurs at clustered sites called

Answer 28

transcription factories

Question 29

transcription factories may also facilitate the () of related genes

Answer 29

coordinated regulation