Brainscape's Knowledge GenomeTM

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


See full index

utas anatomy and physiology > 1.11 cell division > Flashcards

1.11 cell division Flashcards

1
Q

what’s the word for chromosomes that aren’t sex chromosomes?

A

somatic chromosomes

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

Ploidy

A

The number of sets of chromosomes in a cell or an organism.

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

The cell cycle refers to

A

the sequence of events that a cell experiences between successive cell divisions.

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

The cell cycle can be divided into two main parts:

A

interphase and mitosis

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

describe the phases of the cell cycle with abbreviations of them.

A

G1- growth-> S- DNA synthesis-> G2- growth and preparation for mitosis-> M- mitosis (cell division

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

Explain what happens in the G1 phase.

A
  • (Gap 1) of the cycle
  • is when the cell functions normally
  • is the major period of cell growth
  • requires protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain what happens in the S phase.

A
  • is when DNA is synthesised (“replicated”)
  • is when chromosomes are duplicated (DNA + histones)
  • is only a minor period of cell growth
  • also requires protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain what happens in the G2 phase.

A
  • gap 2
  • rapid cell growth & protein synthesis
  • preparing for M phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain what happens in the M phase.

A
  • mitosis
  • is when cell is dividing
  • NO DNA synthesis (chromosomes already duplicated)
  • No protein synthesis
  • No gene expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where are the checkpoints in the cell cycle and what are checked there?

A

G1 checkpoint: Has the cell received a signal to divide? Is the extracellular environment favourable? Is there any
DNA damage?

G2 checkpoint: Is DNA replication
complete? Is the DNA damaged?

M checkpoint: halts mitosis until
chromosomes are aligned properly

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

checkpoints diagram

A

photos

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

What is the point of having a checkpoint?

A

Makes sure all is going well, if not, causes cell death (apoptosis) and will not cause damage to person

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

definition of apoptosis

A

programmed cell death

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

what is apoptosis essential for?

A
  • normal tissue development
  • homeostasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the process of apoptosis

A
  1. Cell shrinks, chromatin condenses
  2. membrane starts blebbing (forming protrusions), organelles disintegrate
  3. nucleus and organelles collapse, membrane continues to bleb
  4. apoptotic bodies form (cell in pieces)
  5. macrophages phagocytose apoptotic bodies
  6. No inflammation!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe how the activation of signals/genes are used for the function of apoptosis.

A

Involves activation of genes that:
* Code for proteins that breakdown the cell’s DNA
(DNases)
* Cause cell-blebbing
* Breakdown cell components

  • cells undergoing apoptosis sends out distress signal detected by immune cells to remove the leftover debris
17
Q

What happens when apoptosis does not function properly?

A

cancer

18
Q

what happens when apoptosis functions too much?

A

can lead to neurodegenerative diseases like
- parkinsons
- motor degenerative disease (MND)
- etc

19
Q

Explain in simple words what is mitosis.

A

Cell division of somatic cells

20
Q

In what phase of the cell cycle does a chromosome duplicate?

A

S phase-> synthesis

21
Q

separating cell birds eye view diagram fill in

A

photos

22
Q

what do centrioles do in mitosis?

A

they duplicate and promote assembly of the mitotic spindle microtubules (on each side)

23
Q

explain function of centrioles in a few words

A

microtubule organising centre

24
Q

What do aster microtubules do in mitosis?

A

anchors the spindle pole (region of the cell where the centrosome is located and toward which the chromosomes will move)

25
Q

What do kinetochore microtubules do in mitosis?

A

anchor on centromere and pulls apart chromatids

26
Q

What do interpolar microtubules do in mitosis?

A

regulate width between chromosomes and cells as division occur
- drives assembly of spindle

27
Q

What are the 4 phases of mitosis?

A

Prophase - individual chromosomes become visible as chromatin condenses

Metaphase - chromosomes line up in the middle of cell

Anaphase -chromosomes/chromatids separate and move toward
poles

Telophase – chromosomes/chromatids decondense and become
chromatin again

28
Q

Describe in depth what happens in prophase.

A

early prophase:
- Chromosomes condense and become visible (become individual instead of the clumps in heterochromatin and euchromatins)
- centrioles starting to produce microtubules
late prophase:
- Nucleolus disappears and nuclear envelope breaks down completely
- chromosomes begin to move towards the middle
- centrioles move towards poles
- Mitotic spindle assembles between the centrosomes

29
Q

Describe in depth what happens in metaphase.

A
  • Nuclear envelope has fragmented
    and chromosomes align at
    equator (metaphase plate)
  • ‘Paired kinetochore’ microtubules attach to opposite spindles in a way that is twinded in (the more it’s pulled the tighter it gets, helping to separate chromatids)
30
Q

Describe in depth what happens in anaphase.

A
  • Sister chromatids separate
  • Kinetochore microtubules shorten and spindle poles move further apart, both contributing to segregation of chromosomes
31
Q

Describe in depth what happens in telophase.

A
  • Cytoplasm constricts and contractile ring starts to form at the metaphase plate
  • Nuclear envelopes reform
  • Chromosomes uncoil and return to their typical chromatin state
    (*reverse of prophase)
  • cleavage furrow form due to actin
  • no gene expression at all as all chromosomes are busy in cell division
32
Q

What happens in cytokinesis?

A
  • Cytoplasm is divided by contraction of the actin
    ring (contractile ring of microfilaments) at the
    metaphase plate
  • Occurs after mitosis (nuclear division) is completed
  • actin ring continues to constrict, once complete, creates two daughter cells
  • cytoplasm and cell membrane separates
33
Q

Explain the process of meiosis.

A

Meiosis I:

Prophase I:
- Chromosomes condense and become visible.
- Homologous chromosomes pair up and undergo synapsis, forming tetrads.
- Crossing over occurs, where segments of nonsister chromatids are exchanged, leading to genetic recombination.
- The nuclear envelope breaks down, and spindle fibers begin to form.

Metaphase I:
- Tetrads align along the metaphase plate, with one homologous chromosome pair on each side.
- Spindle fibers from opposite poles attach to the kinetochores of each homologous chromosome.

Anaphase I:
- Homologous chromosomes are pulled apart toward opposite poles of the cell, guided by spindle fibers.
- Sister chromatids remain attached at their centromeres.

Telophase I:
- Chromosomes arrive at the poles of the cell.
- The nuclear envelope reforms around each set of chromosomes, and the cell undergoes cytokinesis, resulting in two haploid daughter cells, each with half the number of chromosomes as the original cell.

Meiosis II:

  1. Prophase II:
    - Chromosomes condense again if they had decondensed in telophase I.
    - The nuclear envelope breaks down, and spindle fibers begin to form.

Metaphase II:
- Chromosomes line up individually along the metaphase plate of each haploid daughter cell.

Anaphase II:
- Sister chromatids are pulled apart toward opposite poles of the cell by spindle fibers.

Telophase II:
- Chromosomes arrive at the poles of the cells.
- Nuclear envelopes form around each set of chromosomes.
- Cytokinesis occurs, resulting in a total of four haploid daughter cells, each genetically distinct from the others due to crossing over and independent assortment during meiosis I.

34
Q

Roughly describe what happens in meiosis I and II.

A

Meiosis I
Replicated chromosomes exchange DNA & divide
– Homologous recombination occurs via crossing over
– Homologous chromosomes separated (chromosomes 1-23
in each cell – random assortment)
- one chromosome goes into one while the other goes into another cell
- sister chromatid type

Meiosis II
Similar to mitosis (note: no “S” phase occurring prior cuz already occurred)
except with 23 double chromatid chromosomes (not 46)
– Sister chromatids separated
– End product= 4 genetically distinct haploid cells

35
Q

synapsis

A

The tight pairing of the homologous chromosomes after homologous pair finds each other

36
Q

compare metaphase of mitosis and meiosis.

A
  • While sister chromatids align at the
    metaphase plate and are separated into
    daughter cells during mitosis; in Meiosis I
    homologous chromosomes align at the
    metaphase plate to be separated into
    daughter cells
37
Q

Describe what happens at metaphase I.

A
  • pairs of homologous chromosomes move to the equator of the cell
    Microtubules attaches to the centromere with kinetochore, located at the metaphase plate
38
Q

How many variations of chromosome sets are there?

A

more than 8.5 million variations

39
Q

How does inbreeding impact genetic variation?

A

reduces random assortment

utas anatomy and physiology (9 decks)

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