Cell DIvision Flashcards

1
Q

A cell has what three possible destinys

A
  • live and function without dividing
  • grow and divid
  • die
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2
Q

What is the cell theory

A

States that all organisms are made of cells and all cells come from pre-existing cells

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3
Q

In somatic cell division, how do cells divide

A

Mitosis: diploid (2n) to diploid (2n)

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4
Q

In reproductive cell division, how do cells divide

A

Through meiosis - diploid (2n) to haploid (1n)

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5
Q

Why do somatic cells divide

A
  • growth and development
  • tissue renewal
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6
Q

in regards to cells

What do somatic cells result in

A

2 daughter cells that are genetically and functionally identical to the parent cell

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7
Q

Do all somatic cells divide

A

Many, but not all, some more than others

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8
Q

What are somatic cells doing most of the time?

A

Going about their functions, within interphase

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9
Q

What is happening in the G1: Growth or Gap phase 1 (interphase)

A

Most cellular activities are occuring here.

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10
Q

What is happening in the S: Synthesis of DNA phase (interphase)

A

DNA replication occurs where strands are separated at the H bonds holding the nucleotides together.
New strand of DNA is synthesied opposite each of the old strands.

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11
Q

What is happening in the G2: Growth or Gap Phase 2 (interphase)

A

Checks for correct DNA synthesis as it preapres for the mitotic phase (synthesis of the proteins and enzymes are required, gathering of reactants).
Replication of centrosomes is completed.

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12
Q

What are the three phases involved in Interphase of the eukaryotic cell cycle

A

G1 (growth or gap phase 1), S (syntheis of DNA), G2 (growth or gap phase 2)

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13
Q

How long does the G1 phase take

A

8-10 hours

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14
Q

How long does the G2 phase take

A

4-6 hours

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15
Q

How long does the S phase take

A

8 hours

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16
Q

What are the 4 parts of the mitotic phase

A
  1. prophase
  2. metaphase
  3. anaphase
  4. telophase and cytokinesis
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17
Q

in terms of chromosomes

What does a human diploid have

A

46 chromosomes, 23 from each parent

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18
Q

During interphase, DNA ___

A

Replicates

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19
Q

During prophase, DNA __

A

Condenses
and there are two identical chromatids per chromosome called sister chromatids

20
Q

What are sister chromatid

A

Two identical chromatids per chromosome

21
Q

During metaphase, chromosomes __

A

“line up”

22
Q

What happens during anaphase

A

Sister chromatids separate before the nuclear envelope reforms in the telophase

23
Q

Daughter cells are __ to the parent cell

A

Identical

24
Q

What does the cell cycle result as an end product

A

Two daughter cells that are genetically identically to the parent cell

25
Q

What do the G1 checkpoints in the cell cycle check fore

A
  • Is the DNA undamaged
  • is cell size and nutrition okay
  • are appropriate cell signals present
26
Q

What happens if the G1 checkpoint is not satisfied

A

Exit to G0

27
Q

What do the M checkpoints check for

A
  • Are all chromosomes attatched to spindles
28
Q

What happens when there is without full chromosome attatchment during the M signal

A

Stop signal received

29
Q

Where does meiosis occur

A

Occurs in the gonads (ovaries and testes

30
Q

What is the purpose of meiosis

A
  • produces gametes which are haploid (single set of 23 chromosomes)
  • fertilisation then restores the diploid number of chromosomes (2n)
  • produces cells that are genetically different from the parent cell
31
Q

How many stages of meiosis are there

A

2

32
Q

What is Meiosis 1

A

Separates homologous chromosomes

33
Q

What happens in Prophase 1

A

Synapsis: when two sister chromatids of each pair of homologous chromosomes pair up. The four chromatids are called a tetrad

34
Q

What happens in Metaphase 1

A
35
Q

What happens in Anaphase 1

A

Sister chromatids remain attatched and homologous chromosomes separate

36
Q

What happens in Telophase 1 and Cytokinesis

A

Cleavage furrow

37
Q

How is Meiosis ll different to Meiosis l

A

Very similar but meiosis ll is not preceded by DNA replication

38
Q

For mitosis, DNA replication occurs in ____ but in meiosis it occurs in ___.

A
  1. both diploid and haploid cells
  2. diploid cells only
39
Q

For DNA replication in mitosis, it occurs during ____ but for meiosis, it occurs during ______.

A
  1. interphase before mitosis begins
  2. interphase before meiosis l but not meiosis ll
40
Q

What is the number of divisions for mitosis compared to meiosis

A

For meiosis, there is 1 (including prophase, prometaphase, metaphase, anaphase and telophase)
For mitosis, there is 2 (including prophase, metaphase, anaphase and telophase

41
Q

For the synapsis of homologous chromosomes, does it occur in meiosis and mitosis (and if so when)

A

Does not occur for mitosis
For meiosis: occurs during prophase 1 along with crossing over between non-sister chromatids; resulting chiasmata holds pairs together due to sister chromatid cohesion

42
Q

What is the number of daughter cells and genetic composition in mitosis and meiosis

A

Mitosis: two
Meiosis: Four

43
Q

For mitosis, what is the number of daughter cells and genetic composition

A

Two, each genetically identical to the parent cell, with the same number of chromosomes

44
Q

For meiosis, what is the number of daughter cells and genetic composition

A

Four, each haploid (n); genetically different from the parent cell and from each other

45
Q

Three sources

What are the sources of variation as a result of meiosis

A
  • Independent assortment at metaphase 1
  • crossing over at prophase 1
  • Fusion between two gametes