cell division Flashcards

1
Q

where are the chromosomes found in a eukaryotic cell?

A

in the nucleus

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

describe the chromosomes found in a human

A

23 pairs

each pair consists of one paternal and one maternal

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

what is the diploid number of chromosomes?

A

the total number of chromosomes in a normal body cell

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

what is the diploid number in humans ?

A

46

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

give the definition of a chromosome

A

long, linear structures consisting of DNA and histone proteins. they are made of units called genes

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

give the definition of chromatid

A

one of the two threads of a chromosome, formed after DNA replication. Each chromatid in a chromosome is and exact replica of the other (known as sister chromatids )

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

give the description of a homologous chromosome

A

a pair of chromosomes containing the same genes in the same position (loci), each derived originally from a different parents gamete at fertilisation

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

what are chromatids held together by ?

A

centromere

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

name the two types of cell division

A

meiosis and mitosis

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

what are produced from mitosis?

A

two new daughter cells

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

what is the DNA like in the daughter cells after mitosos?

A

an exact replica of the parent cells, genetically identical

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

what is the only way that variation can arise when a cell divides by mitosis?

A

mutation

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

give the main uses of mitosis

A
  • increase the number of cells during growth
  • replaces tissue during repair, replacing the gut
  • it allows asexual production which produces offspring that are gentically identical to the parent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

why is asexual reproduction useful?

A

ideal for when organisms are rapidly establishing a population and variation would be a disadvantage

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

what happens to the chromosomes during prophase?

A

condense/shorten due to the coiling up of DNA and become visible

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

what is the function of the centromere?

A

holds 2 chromatids together

17
Q

what happens to the nuclear membrane at the end of prophase?

A

breaks down

18
Q

what happens to DNA during inerphase?

A

replicates

19
Q

what other events occur during interphase?

A
  • protein syntheisis
  • increase number of organelles
  • ATP production (repiration)
  • cell increases in size
20
Q

are the chromosomes visible during interphase?

A

no

21
Q

describe interphase

A

cell is actively synthesising proteins. the chromosomes are no visible prior to mitosis. the DNA has replicated

22
Q

describe prophase

A

the nuclear membrane breaks down . the nucleolus disappears. The DNA is free in the cytoplasm. chromosomes condense and become shorter. chromosomes become visible. Centrioles divide and move to the poles of the cell. spindle fibres form across the cell

23
Q

describe metaphase

A

chromosomes move to the equator of the cell. chromosomes attach to the spindle at their centromere

24
Q

what happens to the chromosomes during metaphase?

A

line up along the equator of the cell and attach to spindle fibres by their centromeres

25
Q

describe anaphase

A

spindle fibres contract, the centomeres holding a pair of chromatids together divide. sister chromatids are pulled apart, 1 sister chromatid form each chromosomes moves to opposite poles of the cell

26
Q

describe telophase

A

nuclear membranes form around each c=group of chromosomes - the cell has 2 nucleui briefly. the nucleolus reforms, the chromosomes unwind and become diffuse (decondense) and are no longer visible.

27
Q

what happens to the chromosomes during anaphase?

A

centromere divides, spindle fibres contact pulling apart the chromatids of each chromosome. sister chromatids go to opposite polls

28
Q

what happens to the chromosomes during telophase?

A

uncoil and become threadlike again and no loner visible

29
Q

what forms around eash set of daughter chromosomes?

A

new nuclear membrane/ envelope

30
Q

what marks the end of mitosis?

A

two new nuclei formed