Brainscape's Knowledge GenomeTM

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


See full index

Human Physiology > C2 - Cell Division > Flashcards

C2 - Cell Division Flashcards

1
Q

MITOSIS

What are the stages of the cell cycle?

A

Interphase (G1, S, G2)

Mitosis (PMAT)

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

What does PMAT in mitosis stand for?

A

Prophase

Metaphase

Anaphase

Telophase

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

What is G1 of the interphase during the cell cycle?

A

Growth phase

i.e mitochondria + chloroplasts replicate as they have their own DNA to copy

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

What is S of the interphase during the cell cycle?

A
  • DNA réplication.

- Duplicates the centrosomes which help separate DNA during mitosis.

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

What is G2 of the interphase during the cell cycle?

A

2nd growth phase.

Synthesis of proteins and organelles

Begins to reorganize its contents in preparation for mitosis.

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

In what type of cells does mitosis occur?

A

Somatic (body cells)

NOT gamete cells

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

What is mitosis important for?

A

Growth

Asexual reproduction

Repair damaged tissue

Replace worn out cells

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

MITOSIS

What happens to chromatin during interphase

A

It duplicates itself

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

MITOSIS

What happens to chromatin during prophase

A

Coils up into chromosomes

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

What happens in mitosis

A

Nuclear division producing 2 g. identical daughter cells.

Each containing the same no. of chromosomes as parent nucleus.

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

MITOSIS

Describe what happens in prophase (longest of the 4 stages of mitosis)

A

(DNA already been replicated)

Chromosomes condense = visible as pairs of chromatids.

Centrioles move to opposite poles of nucleus + develop spindle apparatus.

Nucleolus + nuclear membrane break down + disappears.

== Pairs of chromatids are free in cytoplasm.

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

MITOSIS

Describe the chromosomes produced in prophase

A

1 chromosome has 2 g. identical chromatids held together by a centromere.

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

MITOSIS

Describe what happens in metaphase

A

(Nuclear membrane has disappeared)

Microtubules attach to centromeres = chromosomes align on equator of spindle.

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

MITOSIS

Describe what happens in anaphase

A

Attached microtubules (spindle fibres) contract = splitting centromeres in 2.

This pulls chromatids to opp. poles of cell, centromere 1st.

Chromatids now called DAUGHTER CHROMOSOMES.

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

MITOSIS

Describe what happens in telophase

A

Daughter chromosomes reach poles, uncoil + lengthen

Spindle fibres break down

Nucleolus + nuclear envelope re-form

Animal cells = cytokinesis

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

How do you calculate the mitotic index?

A

No. of cells in mitosis / Total no. of cells X 100

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

MITOSIS

What is the chromosome appearance + location for the interphase

A

DNA replicates

Chromatin

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

MITOSIS

What is the chromosome appearance + location for the prophase

A

Chromosomes coil up

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

MITOSIS

What is the chromosome appearance + location for the metaphase

A

Chromosomes line up along equator

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

MITOSIS

What is the chromosome appearance + location for the telophase

A

Chromosomes uncoil back into chromatin

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

MITOSIS

What is the chromosome appearance + location for cytokinesis

A

Chromatin

22
Q

Cancer

A

Uncontrolled mitosis

Cancerous cells divide repeatedly w/ formation of a tumour

Thought to be initiated by gene mutations in oncogenes or tumour suppressor genes

23
Q

What does meiosis do

A

Produces cells w/ 1 set of chromosomes (1 from each homologous pair) from 2 stages of cell division:

Meiosis I and II.

24
Q

When does meiosis occur

A

During sexual reproduction:

1 Diploid cell divides to produce 4 haploid cells (gametes).

25
Q

What is the purpose of meiosis?

A

To keep the chromosome no. constant from 1 generation to the next.

G. variation in gametes + the zygotes they produce. There are 2 ways this can happen:

  1. Crossing over during prophase 1.
  2. Independent assortment at metaphase 1 so daughter cells contain diff. comb. of maternal + paternal chromosomes OR at metaphase II so daughter cells have diff. combination of chromatids.
26
Q

Describe the interphase of meiosis

A

Can’t see chromosomes.

DNA replicates

Chromosomes made of 2 identical molecules of DNA

More organelles are synthesised

Mit. + Chlo. replicate

High rate of ATP + protein synthesis

Can still see nuclear envelope + nucleolus

27
Q

When does crossing over take place

A

In prophase 1 in meiosis.

Between non-sister chromatids in bivalent.

== Each chromatid may break + reconnect to another chromatid.

=== Recomb. of maternal + paternal gen. info.

28
Q

Describe what happens in prophase 1 of meiosis

A

Chromosomes condense, coil + thicken = visible as 2 chromatids.

Centrioles move to opp. poles of cell.

SYNAPSIS + crossing over occurs. (Be able to explain these)

29
Q

Describe what happens in metaphase 1 of meiosis

A

Spindle fibres attach to centromere + move whole chromosome to middle/equator of cell.

Homologous chromosomes aren’t found opposite each other so are arranged randomly either side of the cells equator. = G.VARIATION

Bivalents (pairs of chromosomes) arrange at equator of spindle. REMEMBER the pairs aren’t identical.

30
Q

Describe what happens in anaphase 1 of meiosis

A

Spindle fibres shorten to pull centromeres to opp. poles of cell.

Whole chromosomes are pulled but still made of 2 chromatids.

31
Q

Describe what happens in telophase 1 of meiosis

A

2 new nuclear envelopes reform.

Each nucleus contains 1/2 of original no. of chromosomes but still made of 2 chromatids.

= Chromoses g. diff. from those in original cell.

CYTOKINESIS occurs

32
Q

What is each chromosome made up of?

A

A pair of chromatids

33
Q

What does meiosis 2 do?

A

Separates the 2 chromatids.

34
Q

Describe what happens in prophase 2 of meiosis

A

Chromatin condenses + chromosome becomes visible.

Centrioles replicate.

New spindle fibres form at 90o to 1st.

Nuclear envelope + nucleolus disappear.

35
Q

Describe what happens in metaphase 2 of meiosis

A

Spindle fibres align chromosomes randomly on equator of spindle.

Again, intro. g. variation due to random assortment of chromatids at equator.

36
Q

Describe what happens in anaphase 2 of meiosis

A

Microtubules contract + centromeres divide.

Chromatids are pulled to opp. poles of cell by attaches spindle fibres.

When separated produce chromosomes.

37
Q

Describe what happens in telophase 2 of meiosis

A

Chromosomes ucoil = each new chromosome may be g. diff. from original one.

Nucelar envelope + nucleolus reappear.

Cytokinesis begins

== 4 HAPLOID CELLS

38
Q

Define an oncogene

A

A gene w/ the pot. to cause cancer

39
Q

In simple terms, what is the result fo meiosis I?

A

Homologous pairs of chromosomes have separated w/ 1 chromosome of each pair going into either of the 2 daughter cells.

Each daughter cell has only 1 of each homologous pair, so they contain 1/2 the no. of chromosomes of the parent nucleus

40
Q

In simple terms, what is the result fo meiosis II?

A

Chromatids separate + 2 new haploid nuclei divide again == 4 haploid nuclei are formed from parent nucleus each containing 1/2 the no. of chromosomes.

Every gamete is genetically unique.

41
Q

What’s the difference in prophase between meiosis 1 + meiosis 2

A

Follows DNA replication = M1 yes / M2 no

Cross over = M1 yes / M2 no

42
Q

What’s the difference in metaphase between meiosis 1 + meiosis 2

A

M1 = Homologous pairs align either side of the equator

M2 = Chromosomes align on the equator

43
Q

What’s the difference in anaphase between meiosis 1 + meiosis 2

A

M1 = Chromosomes separate

2 daughter cells

M2 = Chromatids separate

4 daughter cells

44
Q

Compare mitosis + meiosis

A

MITOSIS vs. MEIOSIS

No. of divisions = 1 vs. 2

No. of daughter cells = 2 vs. 4

No. of chromosomes in daughter cells = Same as parent vs. 1/2 of parent

Chiasmata = Absent vs. Present

G. Cross over = None vs. In prophase 1

Independent assortment = None vs. In metaphase 1 + 2

Genetic composition = G. identical w/ parent cell + each other vs. G. different

45
Q

Why is it not possible for an organism to have a diploid number lower than 2?

A

Diploid means a pair of each chromosome.

So meiosis wouldn’t be able to take place.

Also because haploid can’t be less than 1.

46
Q

“Push down hard on the cover slip, but don’t push the cover slip sideways”.

Explain this instruction

A

Push hard = spread/squash tissue

Don’t push sideways = avoid breaking chromosomes.

47
Q

Why did the biologist choose to do the experiment on 200 cells

A

To ensure a representative sample

48
Q

State the name given to the exchange of segments of chromatids by breaking and rejoining

A

Crossing over

49
Q

Genetic difference between sister + non-sister chromatids

A

Sister = 2 identical copies of a chromatid w/ same genes + alleles

Non-sister = 1 strand is from mother + the 1 from father.

50
Q

Explain how a doctor would recognise which cells are in interphase when looking at tissue samples

A

Able to see nucleus as nuclear membrane wouldn’t have been broken down.

+

No chromosomes would be visible.

Human Physiology (16 decks)

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