Chapter 8-Sexual Reproduction and Meiosis Flashcards

(43 cards)

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?

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?

23
Q

In what phase in meiosis 1, do chromosomes split?

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
What does crossing over do?
shuffles alleles (Produces variability when portions of homologous chromosomes switch places)
26
When does crossing over occur?
prophase 1
27
When do chromosomes randomly align?
metaphase 1
28
What is the chance for any orientation of homologous chromosomes at metaphase 1?
all combinations are equally likely
29
What does fertilization do to the diversity of zygotes?
multiplies it, because any sperm can fertilize any egg cell
30
How do identical (monozygotic) twins arise?
zygote splits into two embryos (shared placentas)
31
How do fraternal (dizygotic) twins arise?
develop from separate zygotes (separate placentas)
32
What division makes identical cell copies and occurs throughout life?
Mitotic division
33
What division occurs only in specialized cells and only during some parts of the life cycle?
Meiosis
34
What does polyploidy mean?
extra chromosome sets
35
Polyploidy cells contain?
1 or more sets of chromosomes
36
What is a triploid zygote's possible gametes?
1n, 1n+1, 1n+1, 2n
37
Nondisjunction results in...
missing or extra chromosomes.
38
What is nondisjunction?
the failure of chromosomes to separate in meiosis
39
A sex chromosome abnormality is typically less severe than...
an incorrect number of autosomes
40
What can chromosomal rearrangement do?
delete or duplicate genes
41
What does an inversion do?
flips gene order
42
What happens in a translocation?
two non-homologous exchange parts
43
Inversions and translocations may do what?
disrupt vital genes