Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SL12003 Genetics > Chromosomes and cytogenetics > Flashcards

Chromosomes and cytogenetics Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

How is DNA compacted?

A

By forming complexes with histone proteins

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

What are the core histone proteins?

A

H2A, H2B, H3 and H4

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

How many times does DNA wrap around the histone proteins?

A

Twice

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

What is a nucleosome?

A

A section of DNA wrapped around histone proteins

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

What are histones packed into?

A

A 30nm fibre

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

What is the 30nm fibre wrapped around?

A

A protein scaffold

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

What is chromatin?

A

The DNA-histone subunit

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

What type of chromatin is most of the genome in?

A

Euchromatin

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

Difference of compaction between euchromatin and heterochromatin?

A

Heterochromatin is more permanently compacted

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

What is H1?

A

A linker histone

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

What is the effect of H1 dissociating?

A

The chromatin becomes less compact

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

What is the effect of chromatin becoming less compact?

A

Transcription factors and RNA polymerase can access the DNA more easily

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

What is the effect of chromatin becoming more compact?

A

Transcription factors and RNA polymerase can less easily access the DNA

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

What is the association and dissociation of chromatin used to do?

A

Regulate gene expression

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

What is the split in terms of how much of the genome is made up of euchromatin and heterochromatin?

A

More euchromatin

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

How does heterochromatin form?

A

Recruitment of condenser proteins

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

Example of a condenser protein?

A

HP1

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

What do condenser proteins do?

A

Indure permanent condensation of heterochromatin

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

What does heterochromatin have a tendency to do?

A

Spread

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

Why is heterochromatin spreading an issue?

A

It could cause genes to permanently shut off as it would condense them

21
Q

What is position effect variegation?

A

Genes “turning off” due to them being condensed by heterochromatin

22
Q

What is structural heterochromatin?

A

Heterochromatin that is found in structural elements

23
Q

What structural elements is structural heterochromatin found in?

A

Centromeres and telomeres

24
Q

Where are telomeres found?

A

At the end of each chromosome

25
Q

What is one role of telomeres (cancer one)?

A

prevent chromosomal fusion

26
Q

What is a problem with chromosomal fusion?

A

Chromosomes will separate incorrectly during mitosis, leads to cell abnormalities

27
Q

What kind of repetitive DNA does structural heterochromatin contain?

A

Satellite DNA

28
Q

What is small satellite DNA called?

A

Microsatellites

29
Q

How long are telomeric DNA sequences?

A

10-15 kilobases

30
Q

What are the two strands of the telomere called?

A

G rich strand and C rich strand

31
Q

Why is the G rich strand called the G rich strand?

A

Has a high guanine content

32
Q

Why is the C rich strand called the C rich strand?

A

Has a high cytosine content

33
Q

Which telomere strand is longer?

A

G rich strand

34
Q

How much longer is the G rich strand?

A

30 repeats longer

35
Q

How is a T loop formed?

A

The g tail loops over and disrupts some of the upstream double stranded portion

36
Q

What promotes and stabilises the formation of the T loop?

A

A telosome/shelterin complex

37
Q

What is cytogenetics?

A

The study of chromosomes

38
Q

What are cells treated with before making a karyogram?

A

Colcemid

39
Q

What is the effect of colcemid?

A

It disrupts the mitotic spindle, and causes the cell cycle to arrest

40
Q

When does the cell cycle arrest after the addition of colcemid?

A

metaphase

41
Q

Why are the cells collected in metaphase?

A

They are highly condensed

42
Q

What is done after treating the cells with colcemid (when making a karyogram)?

A

They are placed in a hypertonic solution

43
Q

Why are cells placed in a hypertonic solution (when making a karyogram)?

A

To cause them to swell

44
Q

What are the two arms of the chromosome?

A

P arm and Q arm

45
Q

Short chromosome arm name?

A

P arm

46
Q

Long chromosome arm name?

A

Q arm

47
Q

How many levels is the p arm divided up into?

A

3–> the sub regions, the sub sub regions and the sub sub sub regions

48
Q

How many levels is the q arm divided up into?

A

2–> the sub regions and the sub sub regions

49
Q
A

SL12003 Genetics (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions