Mitosis and Meiosis Flashcards

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1
Q

What are the 4 phases of cell cycle?

A

G1, S, G2, M

G1, S, and G2 are the interphase

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2
Q

How much time does a cell spend in the interphase?

A

90%

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3
Q

What is a chromosome?

A

A molecule of DNA and the associated proteins

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4
Q

What is a chromatid? What are sister chromatids?

A

One of the duplicated copies of DNA. Sister chromatids are identical to each other

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5
Q

How many chromosomes are in a pair of sister chromatids?

A

1

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6
Q

What is a centromere?

A

Region of DNA where sister chromatids are attached

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7
Q

What is the kinetochore?

A

The proteins attached to the centromere

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8
Q

What is a karyotype? What distinguishes chromosomes?

A

An image of chromosomes during metaphase. Size, centromere position, secondary constriction, and banding patterns

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9
Q

What are the 3 centromere positions?

A

Metacentric: in the middle
Acrocentric: not in the middle, one arm is shorter than the other
Telocentric: at the telomere

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10
Q

What is a secondary constriction?

A

Places where transcription is occurring, but RNA and proteins aren’t on the karyotype

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11
Q

What is mitosis?

A

An equational division that gives two daughter cells with the same ploidy as the original cell

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12
Q

What are the phases of mitosis?

A

Prophase, metaphase, anaphase, telophase, cytokinesis

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13
Q

What happens in prophase of mitosis?

A

Sister chromatids condense, mitotic spindle begins to form, the mass of chromatin becomes distinguishable chromosomes

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14
Q

What occurs in prometaphase of mitosis?

A

The nuclear envelope breaks apart, sister chromatids finish condensing, mitotic spindle finishes, microtubules attach to the kinetochores

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15
Q

What occurs in metaphase of mitosis?

A

Chromosomes line up along the metaphase plate in the middle of the cell

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16
Q

What occurs in anaphase of mitosis?

A

Sister chromatids separate, the microtubules attached to the kinetochores pull each sister chromatid to opposite ends of the cell

17
Q

What occurs in telophase of mitosis?

A

Nuclear envelope reforms around each set of chromosomes, chromosomes decondense, mitotic spindle is disassembled

18
Q

What occurs in cytokinesis of mitosis?

A

The cell membrane pinches inward at the cleavage furrow and the cytoplasm divides

19
Q

What is the ploidy, chromosome number (in human cells), and DNA content in each phase of of the cell cycle of a diploid cell?

A

G1: 2n, 46, 2c
S: 2n, 46, 4c
G2: 2n, 46, 4c
M: 2n, 46, 2c

20
Q

What is the ploidy, chromosome number (where n=8), and DNA content in each phase of the cell cycle of a haploid cell?

A

G1: n, 8, c
S: n, 8, 2c
G2: n, 8, 2c
M: n, 8, c

21
Q

What is meiosis?

A

Two successive rounds of nuclear division, with the first being reductional and second equational

22
Q

Where does meiosis occur? What are the products?

A

In specialized meiocytes in diploid organisms. Results in 4 gametes or spores that are genetically different from the parent cell

23
Q

What is the difference between meiosis 1 and meiosis 2?

A

Meiosis 1 is a reductional division, meiosis 2 is an equational division

24
Q

What is a dyad?

A

A pair of sister chromatids

25
Q

What are phases of meiosis 1?

A

Prophase 1, metaphase 1, anaphase 1, telophase 1

26
Q

What occurs in prophase 1 of meiosis?

A

Chromosomes become highly condensed, homologous chromosomes synapse and form a bivalent. Crossing over can occur

27
Q

What are chiasmata?

A

The visual manifestation of the place where the chromatids cross over

28
Q

What is synapsis?

A

A very tight association between non-sister chromatids of homologous chromosomes

29
Q

What occurs in metaphase 1 of meiosis?

A

Bivalents align along the metaphase plate independently of each other and in a random orientation

30
Q

What occurs in anaphase 1 of meiosis ?

A

Ploidy is reduced, spindle fibres pull apart the bivalent and pull one pair of sister chromatids to each end of the cell

31
Q

What occurs in telophase 1 of meiosis?

A

Nucleus reforms at each pole, chromosomes decondense. Each new cell has one of the homologous chromosomes

32
Q

How does meiosis 2 proceed? What kind of division occurs?

A

Proceeds like mitosis. Is an equational division

33
Q

What occurs in prophase 2 of meiosis?

A

Chromosomes recondense

34
Q

What occurs in metaphase 2 of meiosis?

A

Chromosomes align along metaphase plate, individually this time

35
Q

What occurs in anaphase 2 of meiosis?

A

Sister chromatids are pulled apart by the mitotic spindle

36
Q

What occurs in telophase 2 of meiosis?

A

Chromosomes decondense, nucleus reforms around each set of chromosomes, cytokinesis occurs

37
Q

What is the ploidy, chromosome number (in a 2n=8 cell), and DNA content in each phase of meiosis 1 and 2?

A
Prophase 1: 2n, 8, 4c
Metaphase 1: 2n, 8, 4c
Anaphase 1: n, 4, 2c
Telomere 1: n, 4, 2c
Prophase 2: n, 4, 2c
Metaphase 2: n, 4, 2c
Anaphase 2: n, 4, c
Telophase 2: n, 4, c