Chapter 8-Sexual Reproduction and Meiosis Flashcards

1
Q

What is asexual reproduction?

A

reproduction without a mate.

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2
Q

What is a conjugation?

A

form of gene transfer in some microorganisms

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3
Q

Asexual reproduction can be successful when?

A

in a stable environment

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4
Q

When will sexual reproduction be more desired?

A

in a changing environment

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5
Q

Diploid cells contain…

A

2 sets of homologous chromosomes (one from each parent)

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6
Q

What do X & Y chromosomes determine in humans?

A

gender

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7
Q

What does not determine human’s sex?

A

the 22 homologous pairs of autosomes.

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8
Q

What do homologous chromosomes share?

A

same size, same banding patterns, same centrosome location

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9
Q

How do homologous chromosomes differ?

A

they carry different alleles

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10
Q

Gametes are…

A

haploid cells

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11
Q

What does meiosis do?

A

halves the genetic materials to produce haploid cells & scrambles alleles

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12
Q

When does fertilization occur?

A

when gametes fuse (haploid sperm/haploid egg) to form a diploid zygote

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13
Q

What does mitotic cell division produce?

A

the body’s cells during growth and development

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14
Q

What type of cells undergo meiosis?

A

specialized germ cells

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15
Q

What cells do not participate in reproduction?

A

somatic cells

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16
Q

What do diploid germ cells produce?

A

haploid cells

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17
Q

What do the events of meiosis ensure?

A

gametes are haploid & genetically variable

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18
Q

What replicates once in meiosis, what divides twice?

A

DNA, nucleus

19
Q

What happens before meiosis?

A

interphase (DNA replication)

20
Q

Spindle fibers attach to what in meiosis?

A

kinetochores to move chromosomes

21
Q

What do homologous pairs do in meiosis 1?

A

pair up and separate

22
Q

In what phase in meiosis 1, do chromosomes align?

A

prophase 1

23
Q

In what phase in meiosis 1, do chromosomes split?

A

anaphase 1

24
Q

What does meiosis 2 produce?

A

4 haploid cells ( the two products of meiosis II divide, producing 4 cells that each contain half as many chromosomes as a diploid cell)

25
Q

What does crossing over do?

A

shuffles alleles (Produces variability when portions of homologous chromosomes switch places)

26
Q

When does crossing over occur?

A

prophase 1

27
Q

When do chromosomes randomly align?

A

metaphase 1

28
Q

What is the chance for any orientation of homologous chromosomes at metaphase 1?

A

all combinations are equally likely

29
Q

What does fertilization do to the diversity of zygotes?

A

multiplies it, because any sperm can fertilize any egg cell

30
Q

How do identical (monozygotic) twins arise?

A

zygote splits into two embryos (shared placentas)

31
Q

How do fraternal (dizygotic) twins arise?

A

develop from separate zygotes (separate placentas)

32
Q

What division makes identical cell copies and occurs throughout life?

A

Mitotic division

33
Q

What division occurs only in specialized cells and only during some parts of the life cycle?

A

Meiosis

34
Q

What does polyploidy mean?

A

extra chromosome sets

35
Q

Polyploidy cells contain?

A

1 or more sets of chromosomes

36
Q

What is a triploid zygote’s possible gametes?

A

1n, 1n+1, 1n+1, 2n

37
Q

Nondisjunction results in…

A

missing or extra chromosomes.

38
Q

What is nondisjunction?

A

the failure of chromosomes to separate in meiosis

39
Q

A sex chromosome abnormality is typically less severe than…

A

an incorrect number of autosomes

40
Q

What can chromosomal rearrangement do?

A

delete or duplicate genes

41
Q

What does an inversion do?

A

flips gene order

42
Q

What happens in a translocation?

A

two non-homologous exchange parts

43
Q

Inversions and translocations may do what?

A

disrupt vital genes