Molecular Biology (2) Flashcards

1
Q

How many chromosome pairs are in the human genome?

A

23

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the packing ratio of DNA?

A

(Length of B-form DNA)/(Actual length)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which type of chromatin is loosely packed and has a light colour with a stain?

A

Euchromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which type of chromatin is densely packed and has a dark colour with a stain?

A

Heterochromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is chromatin?

A

Double stranded helical DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many histone molecules make a histone core?

A

Eight (histone octamer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a nucleosome?

A

Chromatin complexed with histone cores

Basic repeating unit of chromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the subtypes of core histones?

A

H2A, H2B, H3, H4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the net charge on a core histone and why?

A

Positive

Many lysine and arginine residues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many times does dsDNA wrap around each histone core?

A

Twice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How long are the linker sequences between nucleosomes?

A

20-60bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of histone H1?

A

Fastens DNA to nucleosome core

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What part of the histone molecules can be modified?

A

Tails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What us the effect of histone modifications?

A

Change condensation of nucleosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which features of DNA affect its stability and how?

A

Hydrogen bonding - specificity and stability
Stacking - induced dipole interactions between aromatic bases
Cations - counteract electrostatic repulsion of anionic phosphates
Hydrophobic effects - hydrophobic bases inside double helix - stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Tm?

A

Melting temperature of DNA

17
Q

What is the value of Tm for natural DNA and why?

A

Between poly(AT) and poly(CG) melting temperatures - contains A-T and C-G bonds

18
Q

What does alkaline phosphatase do?

A

Removes 5’ phosphate

19
Q

How does ethidium bromide work?

A

Binds to minor groove of B-DNA