Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cell Biology > Lecture 5 Slides > Flashcards

Lecture 5 Slides Flashcards

0
Q

Where is nuclear lamina? What binds to it?

A

On inside of inner nuclear membrane. Peripheral heterochromatin binds to it.

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

Nuclear envelope made up of

A

Outer and inner nuclear membranes

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

What is a continuation of the outer nuclear membrane

A

Endoplasmic reticulum

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

What is a chromosome. What does it do?

A 
A single DNA molecule.
Function:
Maintain genetic info
Replicate genetic info
Segregate genetic info
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is chromatin made of

A

DNA
Histones
Non-histone proteins

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

How many histones in nucleosome

A

Eight

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

What links Nucleosomes? What is length between them?

A

Linker DNA.

200 nucleotide pairs of FNA

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

What does nuclease do

A

Digest linker DNA

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

What is the diameter of a nucleosome

A

11 nm

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

How many times does DNA wrap around nucleosome core

A

1.67 times

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

How is DNA coiled in Nucleosomes

A

Negatively

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

How big are histones? How are thy structured?

A

102-133 aa

Histone fold at C terminus

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

What is the charge of histones

A

Positive

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

What are histones enriched in? What is their PI?

A

Enriched in arginine and lysine. pIs range from 9.8 to 10.25

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

How foes histone bind to DNA

A

Via various noncovalent bonds

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

What extends from nucleosome. What does it have?

A

Amino-terminal tails. Have numerous covalent modifications.

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

What encodes histones

A

Multigene families expressed during DNA replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Are histones found in bacteria

A

No, but in archaea yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Are histones present in all eukaryotes

A

All but dinoflagellates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do archaea histone-like proteins assemble

A

Tetramers that protect ~60bp of DNA from nuclease digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is chromatin remodeled

A

ATP-dependent DNA translocate a anchor on histone October and move DNA around the nucleosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of chromatin remodeling complexes

A
  • work with histone chaperones to remove and replace histones
  • assemble Nucleosomes on newly-replicates DNA
  • assist in DNA repair
  • condense chromatin to form heterochromatin
  • regulate gene expression by altering chromatin structure at promoters
  • modify transcription elongation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Isotonic buffer

A

Has same ionic conditions as inside cell

23
Q

How is 30nm fiber extracted from cells

A

Using isotonic buffers

24
How are Nucleosomes stacked
In 30 nm fibers
25
What are 30 nm fibers formed by
Interaction of histone tails | Linker histone H1 (1 per nucleosome)
26
Qualities of epigenetic inheritance
Phenotypes not based on changes in DNA sequence Genes may lie within different chromatin structures: -euchromatic or heterochromatin
27
Euchromatin
Less condensed, active in gene expression
28
Heterochromatin
Highly condensed, gene expression repressed
29
What happens to gene expression if structural gene is not barred from heterochromatin
Structural gene may be inactivated
30
Result of chromosome rearrangement
Allows heterochromatin to spread into structural gene
31
Result of acetylation of lysine on N terminal (histone) tails
Loosens chromatin structure
32
What does acetyl group do to lysine
Removes its positive charge and reduced the affinity of the tails for adjacent Nucleosomes
33
Histone acetyl transferase
Adds acetyl group to lysine
34
Histone deacetylase
Removes acetyl group from lysine
35
Lysine methyl transferase and demethylase
Add and remove methyl groups to lysine, respectively
36
Arginine methyl transferase
Adds methyl group to arginine
37
What does serine phosphorylation do to a histone
Gives it a negative charge
38
Types of histone modifications
Code "writer" Code "eraser" Code "reader or effector"
39
Code "writer"
Enzyme that adds a modification
40
Code "eraser"
Enzyme that removes a modification
41
Code "reader or effector"
Enzyme that recognizes the modification and translates it into a specific outcome
42
Which trimethylations are associated with transcriptional repression
H3K9, H3K27, and H4K20. Enriched in heterochromatin.
43
Which methylations are associated with transcriptional activation
H3K4, H3K36, H3K79. Enriched in euchromatic
44
MLL
Histone methyl transferase. h3K4Me. Over expression resulting from gene fusions in hematopoietic stem cells are associated with leukemia
45
Trans effect
Invites other molecules to come and bind? Positive feedback loop and self propagating. Changes both chromosomes.
46
Cis effect
Affects only one chromosomal copy. Depends on transcription regulators synthesized in cytosol.
47
To loosen chromatin, you need an acetyl group. To tighten then you need
A methyl group or more
48
How does histone deacetylase propagate heterochromatin?
Removes acetyl group from H3 tail lysine 9 so that histone methyl transferase can methyl H3K9
49
How does HP1 chromo domain work
It is a reader. It reads the histone code. Binds H3K9Me3
50
What does Chromatin remodeling complex do to promote heterochromatin
It is ATP dependent. Uses ATP to shift DNA on Nucleosomes
51
How is heterochromatin structure stabilized
Oligomerization of HP1
52
What is loss of HP1 associated with
Several cancers
53
Chromatin immunoprecipitation
To identify DNA sequence to which a modified histone or regulatory protein will bind
54
Antibodies can be used to identify DNA bound by 3
Gene regulatory protein Modified histone Chromatin-associated protein

Cell Biology (35 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions