Lecture 7 (Ch 11)

Question 1

T/F: Bacteria chromosome organized into chromatin

Answer 1

F- eukaryotic

Question 2

Chromatin state is important for gene expression– ___ is expressed and ___ isn’t

Answer 2

euchromatin vs. heterochromatin

Question 3

Chromatin is ___

Answer 3

DNA + proein

Question 4

Protein of chromatin control ___ and ___

Answer 4

structure and function

Question 5

DNA compaction is achieved via 2 fold steps:

Answer 5

1. 10 nm fiber

2. 30 nm fiber

Question 6

Nucleosome = __ + __

Answer 6

Histone + DNA wrapped around it x2

Question 7

10 nm fiber: Nucleosome has 8 subunits called ___; the individual name of them are ___

Answer 7

histones; H2A, H2B, H3, and H4 (x2)

Question 8

10 nm fiber: in nucleosome, ___ and ___ form dimers; ___ and ___ form dimers

Answer 8

H2A + H2B

H3 + H4

Question 9

10 nm fiber: nucleosome’s dimensions are:

Answer 9

11 nm diameter, 5.7 nm thickenss

Question 10

10 nm fiber: has 3 parts. Which is conserved and which is variable?

Answer 10

nucleosome, core DNA, linker DNA;

former 2 conserved, latter 1 variable

Question 11

10 nm fiber: core DNA has ___ bp

Answer 11

146

Question 12

10 nm fiber: linker DNA has ___ bp

Answer 12

50-100 bp

Question 13

T/F: H1 dimerizes with H2A

Answer 13

F. H1 not part of 10 nm fiber

Question 14

30 nm fiber: 10 nm fiber coil into ___

Answer 14

solenoids

Question 15

30 nm fiber: solenoids contain ___ per turn

Answer 15

6-8 nucleosome

Question 16

30 nm fiber: H1 histone’s funciton is to ___

Answer 16

stabilize the solenoid for an additional level of condensation.

Question 17

30 nm fiber: H1 histone is believed to wrap around ___

Answer 17

linker DNA

Question 18

Metaphse Chromosome is additionally condensed via ___ that form ___ that form ___ that form ___

Answer 18

non-histone scaffolding proteins to form chromatin loops; they form rosettes that form bundles.

Question 19

Max level of condensation is achieved in ___, achieved with the help of ___

Answer 19

mitotic chromosome;

condensin

Question 20

DNA Replication: nucleosome ___ during passage of replication fork

Answer 20

diassemble transiently

Question 21

DNA Replication: T/F: the daughter and the mother nucleosome will reassemble semiconservatively across daughter and mother strand

Answer 21

F. Histone dimers disassemble and reassemble at random

Question 22

Histones: T/F they are considered small at 100 kbp

Answer 22

F. they are considered small, but at 11-14 kbp

Question 23

Histones: are rich in ___ AA, which makes them ___.

Answer 23

lys; basic (:N)

Question 24

Gene Expression: If promotor is at the core DNA, _____ conformation of transcription. If promotor is at the linker DNA, _____ conformation of transcription

Answer 24

closed; open

Question 25

Gene Expression: two ways nucleosome can effect expression

Answer 25

1. chromatin remodeling

2. epigenetic/covalent modification

Question 26

Gene Expression: relate histone code and chromatin remodeling

Answer 26

histone code determiens which genes are open/closed (revealed/hidden); chromatin remodeling must be done to move nucleosome to expose/hide promotors and other regulatory sequences

Question 27

Gene Expression: covalent modification modifies ___

Answer 27

N-terminus of H3/H4

Question 28

Gene Expression: epigenetic modification indicates that

Answer 28

DNA isn’t changed, but this modification will be trasmitted during cell division and reproduction

Question 29

FISH: stands for…

Answer 29

Flourescent in situ Hybridization

Question 30

FISH: T/F: cell lysis is the first step

Answer 30

F. in situ - live cells can be used

Question 31

FISH: 2 steps are

Answer 31

1. synthesize DNA sequence of choice linked covalently with dye PNA as a probe
2. denature cellular DNA and hybidize it

Question 32

FISH: can be used to __ or ___

Answer 32

id chromosomes or location of gene within the chromosome

Question 33

FISH: in human cell, gene for hair color is marked with FISH-blue. How many signals do you expect?

Answer 33

2, beause diploid organism– 1 paternal and 1 maternal

Question 34

FISH: How is it used to diagnose lyphobia/leukemia?

Answer 34

these diseases are caused by chimeric gene/chromosomal translocation. Target 2 genes expected to be on 2 different chromosomes– if the are on the same chromosome, you know that translocation occured

Question 35

FISH: T/F: Philadelphia chromosome is the chimeric chromosome that is the result of 9/22 translocation

Answer 35

F. It’s the leftover 22 chromosome that is shortened due to translocation.

Question 36

Centromere: is ___ in ___. It facilitates ___ and ___.

Answer 36

repetitive DNA sequence in centromere;

facilitate kineticore protein and spindle microtubule

Question 37

Centromere: T/F Kineticore protein is conserved

Answer 37

T

Question 38

Centromere: T/F Centromere size is conserved

Answer 38

F. Yeast ~100s kb. Other euk sev 100s kb.

Question 39

PEN: Stands for

Answer 39

position effect vairiegation

Question 40

PEN: Muller’s experience focused on the location of ___ gene, which coded for ___. Its mutated form gave phenotype of ___.

Answer 40

w+; red eye color;

white eye color

Question 41

PEN: What happened to the w+ gene after exposure with radiation? Why?

Answer 41

w+ moved to nearby heterochromatins.
x2 stranded breaks led to some heterochromatin (methylated H3/H4) “invading” w+ gene and silencing it, causing white color eyes.

Question 42

PEN: What mechanism underlies the regulation of heterochromatin and euchromatin boundaries?

Answer 42

Unknown.