MEIOSIS Flashcards

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1
Q

The form of cell division by which gametes, with half the number of chromosomes, are produced.

A

Meiosis

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2
Q

_______ is sexual reproduction.

A

Meiosis

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3
Q

The fusion of a sperm and egg to form a _____?

A

zygote

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4
Q

A zygote is a____?

A

fertilized egg

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5
Q

n=___egg

A

23

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6
Q

2n=____zygote

A

46

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7
Q

Sex cells divide to produce ?

A

gametes (sperm or egg)

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8
Q

Occurs only in gonads (testes or ovaries).

A

Meiosis

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9
Q

for male

A

spermatogenesis

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10
Q

for female

A

oogenesis

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11
Q

Each duplicated chromosome consist of two identical sister chromatids attached at their centromeres.

A

Interphase I

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12
Q

Centriole pairs also replicate.

A

Interphase I

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13
Q

Nucleus and nucleolus visible.

A

Interphase I

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14
Q

how many phases does meiosis I have?

A

four phases

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15
Q

Meiosis I (four phases)

A

a. prophase I
b. metaphase I
c. anaphase I
d. telophase I

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16
Q

Cell division reduces the chromosome number by one-half.

A

Meiosis I

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17
Q

Longest and most complex phase (90%).

A

Prophase I

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18
Q

Chromosomes condense.

A

Prophase I

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19
Q

Synapsis occurs: homologous chromosomes come together to form a tetrad.

A

Prophase I

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20
Q

is two chromosomes or four chromatids (sister and nonsister chromatids).

A

Tetrad

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21
Q

Pair of chromosomes (maternal and paternal) that are similar in shape and size.

A

Homologous Chromosomes

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22
Q

carry genes controlling the same inherited traits.

A

Homologous pairs (tetrads)

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23
Q

Each _____ (position of a gene) is in the same position on homologues.

A

locus

24
Q

Humans have ___ pairs of homologous chromosomes.

A

23

25
Q

22 pairs of ?

A

autosomes

26
Q

01 pair of ?

A

sex chromosomes

27
Q

A method of organizing the chromosomes of a cell in relation to number, size, and type.

A

Karyotype

28
Q

21 trisomy

A

Downs Syndrome

29
Q

If the offspring has two “X” chromosomes it will be a ?

A

female

30
Q

If the offspring has one “X” chromosome and one “Y” chromosome it will be a ?

A

male

31
Q

In Humans the “Sex Chromosomes” are the __rd set

A

23rd

32
Q

may occur between nonsister chromatids at the chiasmata.

A

Crossing over (variation)

33
Q

segments of nonsister chromatids break and reattach to the other chromatid.

A

Crossing over

34
Q

are the sites of crossing over.

A

Chiasmata (chiasma)

35
Q

Shortest phase

A

Metaphase I

36
Q

align on the metaphase plate.

A

Tetrads

37
Q

In terms of Independent Assortment -how many different combinations of sperm could a human male produce?

A

Formula: 2n
Human chromosomes: 2n = 46 n = 23

223 = ~8 million combinations

38
Q

Homologous chromosomes separate and move towards the poles.

A

Anaphase I

39
Q

Sister chromatids remain attached at their centromeres.

A

Anaphase I

40
Q

Each pole now has haploid set of chromosomes.

A

Telophase I

41
Q

Cytokinesis occurs and two haploid daughter cells are formed.

A

Telophase I

42
Q

No interphase II
(or very short - no more DNA replication)

A

Meiosis II

43
Q

same as prophase in mitosis

A

Prophase II

44
Q

same as metaphase in mitosis

A

Metaphase II

45
Q

same as anaphase in mitosis

A

Anaphase II

46
Q

sister chromatids separate

A

Anaphase II

47
Q

Same as telophase in mitosis.

A

Telophase II

48
Q

Nuclei form.

A

Telophase II

49
Q

Cytokinesis occurs.

A

Telophase II

50
Q

four haploid daughter cells produced.

A

Telophase II

51
Q

gametes =

A

sperm or egg

52
Q

Important to population as the raw material for natural selection.

A

Variation

53
Q

What are the three sexual sources of genetic variation?

A
  1. crossing over (prophase I)
  2. independent assortment (metaphase I)
  3. random fertilization
54
Q

In Humans the “Autosomes” are sets ?

A

1-22

55
Q

Tetrads align on the metaphase plate

A

metaphase I

56
Q

Four hapliod daugther cells produced

A

telophase II