Brainscape's Knowledge GenomeTM

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


See full index

PoD topics > Chromosomes and Cell Division > Flashcards

Chromosomes and Cell Division Flashcards

1
Q

describe function of a telomere on a chromosome

A

protects the ends of the chromosomes to make sure they aren’t eroded

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

where is the centromere found?

A

typically in the centre of the chromosome (holds two chromatids together)

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

what is heterochromatin?

A

non-functional units

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

what is euchromatin?

A

functional units

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

why is DNA replication not symmetrical?

A

DNA polymerase can only synthesise from 5’ to 3’ direction, adding free nucleotides to the 3’ end of the strand

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

what happens over many generations to chromosomes?

A

they will get shorter

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

what can telomerase do?

A

enzyme which can add a DNA sequence using an RNA template to a DNA which has been eroded

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

what repeats does telomerase add to the ends of existing elongated chromosomes?

A

5’-TTAGGG-3’ repeats (hundreds of copies)

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

Most cells in humans don’t express telomerase, but which cells do?

A
  • fetal tissues
  • adult germ cells
  • tumour cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what occurs at G1 phase of cell cycle?

A

cellular components are duplicated, prepared for cell division

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

what occurs at S phase of the cell cycle?

A

DNA synthesis

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

what occurs at G2 phase of the cell cycle?

A

cell double checks chromosomes for error and makes any repairs

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

what occurs at prophase?

A
  • chromosomes condense and become visible/compact
  • nuclear membrane disappears
  • spindle fibres form from the centriole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what occurs at metaphase?

A
  • chromosomes align at the equator of the cell
  • chromosomes attached by fibre by each centriole
  • max. condensation of chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what occurs at anaphase?

A
  • sister chromatids separate at centromere by spindle fibres
  • separate longitudinally
  • move to opposite poles of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what occurs at telophase?

A
  • new nuclear membrane forms

- each cell now contains 46 chromosomes (diploid)

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

what occurs at cytokinesis?

A
  • cytoplasm separates

- two new daughter cells formed

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

what do centromeres do?

A

hold two sister chromatids together

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

what can happen if centromere doesn’t work properly?

A

Irregular separation occurs leading to cellular problems

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

what forms centromeres?

A

satellite DNA (non-coding) forms heterochromatin

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

what is a kinetochore?

A

protein complex assembled on the centromere which binds to spindle fibres (microtubules)

22
Q

how many genes does the human body approx. have?

A

20-30,000

23
Q

in what two places is satellite DNA found?

A
  • cenromeres

- telomeres

24
Q

what 2 components are DNA sequences in our genome made of?

A
  1. SINEs ( short interspread nuclear elements)

2. LINEs (long interspread nuclear elements)

25
Q

is majority of DNAm SINEs or LINEs?

A

LINEs

26
Q

what structures make up chromatin?

A

histones

27
Q

histone +DNA =

A

nucleosome

28
Q

what charge is DNA and histone?

A

DNA: -ve
histone: +ve

29
Q

how many nucleosomes per turn are there in wrapping?

A

6 nucleosomes

30
Q

what structure is formed by compact DNA by a factor of 40?

A

solenoid structure

31
Q

what are the 4 levels of packaging DNA to form a chromosome?

A
  1. nucleosome
  2. chromatin fibre
  3. fibre-scaffold complex (lots of heterochromatin)
  4. chromosome
32
Q

what is the purpose of packaging DNA?

A
  • negative DNA neutralised by positive histones
  • DNA takes up less space
  • inactive DNA can be folded into inaccessible locations until required
33
Q

what is the short arm of the chromosome called?

A

p arm

34
Q

what is the long arm of the chromosome called?

A

q arm

35
Q

what is a submetacentric chromosome?

A

centromere is not quite at the centre of the chromosome

36
Q

what is a metacentric chromosome?

A

centremere is at the centre of a chromosome

37
Q

what does chromosome analysis by karyotyping require beforehand?

A

blood sample

38
Q

what is a colchicine?

A

microtubule inhibitor, no mitosis occurs but chromosomes align (become visible)

39
Q

what does karyotyping allow us to do?

A

look at individual chromosomes

40
Q

what does FISH allow us to do?

A

used to look at sequence content of chromosomes (as karyotyping doesn’t let us do it)

41
Q

how does FISH work?

A
  • fragment of desired DNA sequence is isolated
  • DNA sequence is labelled with fluorescent dye
  • cytogenic technique that uses fluorescent probes bind only to the part of the chromosome with a high degree of sequence complementarity
  • specific regions on the chromosomes can be looked at
42
Q

what are the 4 different FISH probes?

A
  1. unique sequence probes
  2. centromeric probes
    - for determining chromosome number
  3. telomeric probes
    - present in children with retardation diagnosis
    - detect subtelometic rearrangements
  4. whole chromosome probes
    - detects translocations and rearrangements
43
Q

what is meiosis?

A
  • cell division in germ cells
  • diploid cells divide to to form haploid cells
  • recombination or rearrangment of genes creates diversity
  • 4 haploid cells formed
44
Q

what is oogenesis?

A

process of egg formation

45
Q

what is speratogenesis?

A

process of sperm formation

46
Q

do sperm go through more cell divisions than eggs?

A

Yes- therefore higher chance of mutations

47
Q

what is fertilisation?

A

two haploid cells (sperm and egg) fuse to form a diploid cell (zygote)

48
Q

who does the embryo get their mitochondria (and its DNA) from?

A

the mother (maternal inheritance)

49
Q

why is X inactivation necessary in females?

A
  • so only characteristics of one X chromosome are expressed (no double characteristics)
  • deactivation is RANDOM
50
Q

when does X deactivation happen?

A

in embryonic stage

PoD topics (34 decks)

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