Start Meiosis -- Lecture 8 Flashcards

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1
Q

cytokinesis (what is it)

A

process of dividing 1 cell into 2

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2
Q

cytokinesis in animal cells:

animal cells use a ___

A

contractile ring

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3
Q

cytokinesis in animal cells:

___ use a contractile ring

A

animal cells

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4
Q

cytokinesis in animal cells:

contractile ring is composed of

A

actin microfilaments

myosin motor proteins

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5
Q

cytokinesis in animal cells:

in the contractile ring, ___ and ___ contract rapidly to pinch cell in 2, forming a cleavage furrow

A

actin microfilaments

myosin motor proteins

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6
Q

cytokinesis in animal cells:

in the ___, actin microfilaments and myosin motor proteins contract rapidly to pinch cell in 2, forming a cleavage furrow

A

contractile ring

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7
Q

cytokinesis in animal cells:

in the contractile ring, actin microfilaments and myosin motor proteins contract rapidly to pinch cell in 2, forming a ___

A

cleavage furrow

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8
Q

cytokinesis in plants:

vesicles (definition)

A

membrane-bound delivery vehicles

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9
Q

cytokinesis in plants (steps)

A

1) vesicles accumulate in middle of cell
2) vesicles bring the necessary material to form a temporary structure called a cell plate
3) cell plate goes thru a series of biochemical changes and becomes the cell wall

vesicles in middle –> cell plate –> cell wall

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10
Q

chromosome terminology:

In human cells: in G1: there are 46 one-chromatid ___

A

chromosomes

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11
Q

chromosome terminology:

In human cells: in G1: there are ___ one-chromatid chromosomes

A

46

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12
Q

chromosome terminology:

In human cells: in G1: there are 46 ___-chromatid chromosomes

A

one

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13
Q

chromosome terminology:

In ___ cells: in G1: there are 46 one-chromatid chromosomes

A

human

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14
Q

chromosome terminology:

the chromosomes are in ___: 1 from Mom, 1 from Dad

A

pairs

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15
Q

chromosome terminology:

each pair chromosomes are referred to as ___ or ___

A

homologs

homologous chromosomes

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16
Q

chromosome terminology:

homologous chromosomes are very similar but ___

A

slightly different

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17
Q

chromosomes revisited:

homologous chromosomes contain same ___ but have slightly different ___

A

genes

DNA sequences

18
Q

chromosomes revisited:

before DNA replication, each homolog has ___ chromatid

A

1 chromatid

19
Q

chromosomes revisited:

after DNA replication, each homolog has ___

A

2 chromatids

20
Q

ploidy (definition)

A

of homologs of each chromosome in a cell

21
Q

diploid (definition)

A

has 2 homologs of each chromosome – 1 from each parent

2n

22
Q

haploid (definition)

A

have 1 homolog of each chromosome

n or 1n

23
Q

polyploid (definition)

A

have 3 or more homologs of each chromosome

24
Q

diploid cells (2n):

46 one-chromatid chromosomes

how many homologous pairs?

A

23

25
Q

haploid cells (n):

23 one-chromatid chromosomes

how many homologous pairs?

A

none

26
Q

mitosis vs. meiosis:

mitosis (definition)

A

a eukaryotic cell divides and makes a clone of itself

each new cell has the same # of chromosomes as the original cell

27
Q

mitosis vs. meiosis:

meiosis (definition)

A

a eukaryotic cell divides

each new cell has 1/2 the # of chromosomes as the original cell

28
Q

mitosis vs. meiosis:

why would a eukaryote go thru meiosis?

A

reproduction

29
Q

meiosis enables reproduction

A

each parent is diploid (46 one-chromatid chromosome)

thru meiosis, their gametes are haploid (23 one-chromatid chromosomes)

gametes fuze into zygote, a 1-celled embryo, which is diploid (46 one-chromatid chromosomes)

30
Q

gametogenesis (definition)

A

making sperm and egg cells

31
Q

spermatogenesis results in…

A

results in 4 viable haploid sperm cells

32
Q

spermatogenesis (process)

A

1, primary spermatocyte (diploid)

thru meiosis becomes…

4, mature sperm cells (haploid)

33
Q

oogenesis results in…

A

results in 1 viable egg cell and 3 nonviable egg cells called polar bodies (all haploid)

34
Q

polar bodies

A

3 of the 4 egg cells produced in oogenesis which are nonviable

35
Q

oogenesis (process)

A

1, primary oocyte (diploid)

thru meiosis becomes…

4 egg cells (haploid)
1 viable egg cell and 3 polar bodies (nonviable egg cells)

36
Q

meiosis overview (meiosis I):

beginning of the process

A

cell in G1:
- 4 one-chromatid chromosomes –> 1 diploid cell

S-phase:
- 4 two-chromatid chromosomes –> 1 diploid cell

Meiosis I (first of 2 cell divisions):
- homologous pairs segregate into different cells --> 2 haploid cells
37
Q

meiosis overview (meiosis I):

after meiosis I

A

there are 2 haploid cells, each w/ 2 two-chromatid chromosomes

38
Q

meiosis overview (meiosis I):

which meiosis is called reduction division?

A

meiosis I

39
Q

meiosis overview (meiosis I):

why is meiosis I called reduction division?

A

because the chromosome # is less

40
Q

meiosis overview (meiosis II):

meiosis II (the 2nd of 2 cell divisions) – what happens?

A

chromatids separate and segregate into different cells

41
Q

meiosis overview (meiosis II):

after meiosis II

A

4 cells each w/ 2 one-chromatid chromosomes –> haploid