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BIOL-L 112 Exam 2 > Meiosis > Flashcards

Meiosis Flashcards

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1
Q

In Asexual Reproduction

A

A single individual passes all of its genes to its offspring without the fusion of gametes

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2
Q

A clone is..

A

a group of genetically identical individuals from the same parent

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3
Q

In sexual reproduction, two parents ..

A

give rise to offspring that have unique combinations of genes inherited from the two parents

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4
Q

How many pairs are in Human Somatic Cells?

A

They have 22/23 pairs (plus XX or XY) of Chromosomes

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5
Q

What is a karyotype?

A

An ordered display of the p airs of chromosomes from a cell

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6
Q

Two chromosomes in each pair are called

A

Homologous Chromosomes, or Homologs

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7
Q

Chromosomes in a homologous pair are..

A

the same length and shape and carry genes controlling the same inherited characters

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8
Q

Each pair of homologous chromosomes include one chromosome from each _____

A

parent

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9
Q

The 46 chromosomes in a human somatic cell are two sets of ____

A

23: one from the mother and one from the father

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10
Q

A diploid cell has how many sets of chromosomes?

A

Two sets

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11
Q

For humans, the diploid number is

A

46 (2n = 46)

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12
Q

For humans, the haploid number is

A

(n) = 23

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13
Q

The sex chromosomes that determine the sex of the individual are called..

A

X and Y

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14
Q

Human females have a homologous pair of

A

X Chromosomes (XX)

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15
Q

Human males have _______ chromosomes

A

one X and one Y

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16
Q

Sex in human is determined by the presence of

A

the Y chromosome

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17
Q

The remaining 22 pairs of chromosomes are called..

A

Autosomes

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18
Q

A gamete (sperm or egg) contains a single set of ____ and is ____

A

Chromosomes, and is haploid (n)

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19
Q

For humans, the haploid number is

A

23 (n = 23)

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20
Q

Each set of 23 in Haploid consist of

A

22 Autosomes and a single sex chromosome

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21
Q

In an unfertilized egg (ovum), the sex chromosome is

A

X

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22
Q

In a sperm cell, the sex chromosome may be either

A

X or Y

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23
Q

What is Fertilization?

A

The union of gametes (the sperm and the egg)

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24
Q

The fertilized egg is called a …

A

Zygote, and has one set of chromosomes from each parent

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25
The zygote produces somatic cells by.
Mitosis and develops into an adult
26
Meiosis reduces the number of chromosome sets from ..
diploid to haploid
27
Like Mitosis, Meiosis is preceded by
the replication of chromosomes
28
Meiosis takes place in two consecutive cell divisions called
Meiosis I and Meiosis II
29
The two cell divisions in Meiosis result in
Four daughter cells, rather than the two daughter cells in Mitosis
30
Each daughter cell in Meiosis has only
half as many chromosomes as the parent cell
31
Chromosomes duplicate during
Interphase
32
The resulting sister chromatids are closely associated
along their lengths
33
Sister chromatids that are closely associated along their lengths are called
Sister Chromatic Cohesion
34
Chromatids are sorted into
four haploid daughter cells
35
Division in Meiosis I occurs in four phases
Prophase I Metaphase I Anaphase I Telophase I and Cytokinesis
36
Division in Meiosis II also ocurs in four phases
Prophase II Metaphase II Anaphase II Telophase II and Cytokinesis
37
Prophase I info
Each chromosome pairs with its homolog and crossing over occurs
38
(Prophase I) What are Chiasmata?
They are X-Shaped regions and are sites of crossing over --> Genetic Variability
39
Prophase I; Gametes are not
like each other and not like their parents
40
Prophase I; After interphase, the sister chromatids are held together by proteins called
Cohesins -- Sister Chromatid Cohesion
41
Prophase I; Non-sister chromatids broken at
precisely corresponding positions
42
Prophase I; what is the Synaptonemal Complex
It is zipper-like structure that holds the homologs together tightly
43
Prophase I; DNA breaks are repaired, joining...
DNA from one non-sister chromatid to the corresponding segment of another
44
Mitosis vs Meiosis: Mitosis
Conserves the number of chromosome sets, producing cells that are genetically identical to the parent cell
45
Mitosis vs Meiosis: Meiosis
Reduces the number of chromosomes sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell
46
Mitosis Property
Occurs in both Diploid and Haploid Cells
47
Meiosis Property
Can occur only in diploid cells
48
Mitosis DNA replication
Occurs during interphase before mitosis begins
49
Meiosis DNA replication
Occurs during interphase before Meiosis I begins
50
Mitosis Number of Divisions
One, including Prophase, Prometaphase, Metaphase, Anaphase, and Telophase
51
Meiosis Number of Divisions
Two, each including Prophase, Metaphase, Anaphase, and Telophase
52
Mitosis Synapsis of Homologous Chromosomes
Does Not Occur
53
Meiosis Synapsis of Homologous Chromosomes
Occurs during Prophase I along with crossing over between nonsister chromatids; resulting Chiasmata hold pairs together due to sister chromatid cohesion
54
Mitosis Number of daughter cells and genetic composition
Two, each genetically identical to the parent cell, with the same number of chromosomes
55
Meiosis number of daughter cells and genetic composition
Four, each haploid (n); Genetically different from the parent cell and from each other
56
Mitosis Role in the animal or plant body
Enables multicellular animal or plant (gametophyte or sporophyte) to arise from a single cell; produces cells fpr growth, repair, and in some species, a sexual reproduction produces gametes in the gametophyte plant
57
Meiosis Role in the animal or plant body
Produces gametes (in animals) or spores (in the sporophyte plant); Reduces number of chromosomes sets by half and introduces genetic variability among the gametes or spores
58
Mutations
Changes in an organism's DNA are the original source of genetic diversity
59
Alleles
Mutations create different versions of genes, these are called alles
60
Genetic Variation
The reshuffling of alleles during sexual reproduction
61
Mechanisms contribute to genetic variation
Independent assortment of chromosomes Crossing Over Random Fertilization Mutation
62
Independent Assortment , each pair of chromosomes
sorts maternal and paternal homologs into daughter cells independently of the other pairs
63
The number of combinations possible when chromosomes assort independently into gametes is
2^n, where n is the haploid number
64
For humans (n=23), there are more than
8 mllion (2^23) possible combinations of chromosomes
65
Crossing over produces
Recombinant Chromosomes, which combine DNA inherited from each parent
66
Crossing over contributes to
Genetic Variation, by combining DNA from two parents into a single chromosome
67
In humans an average number of crossover events per chromosome is
1-3 Crossovers
68
Random fertilization adds to genetic variation because
Any sperm can fuse with any ovum (unfertilized egg)
69
The fusion of two gametes produces
a zygote with any of about 70 trillion diploid combinations
70
Natural selection results in
The accumlation of genetic varations favored by the environment
71
Meiosis --> Nondisjunction
The members of a chromosome pair fail to separate at Anaphase Producing gametes with an incorrect number of chromosomes Can occur in Meiosis I or II
72
Down Syndrome
Occurs because there is an extra chromosome in number 21; Trisomy 21
73
Edwards Syndrome
Occurs in Trisomy 18, due in part because of an extra chromosome. Result sin the back part of skull being prominent, along with clenched hands, and a shield chest.
74
Patau's Syndrome
Extra Chromosome in Trisomy 13. Results in cleft lip or palate, clenched hands, undescended or abnormal testes. Messed up face yo
75
Klinefelter' Syndrome
Result of a XXY male. Male features poor beard growth, breast development, front baldness absent, and female type pubic hair pattern.
76
Triple X Female
XXX Female. Short Stature, Low Hairline. No Menstruation, Redimenary Ovaries
77
XO or Monosomy Turner's Syndrome
No Chromosomes, DNA or Genitalia, but Androgen levels. "She" has a Y chromosome, external female genitalia
78
Cell Death _ Necrosis
Low Oxygen, Toxins, ATP Depletion Random Fragmentation Ingeseted by Phagocytes Inflammation
79
Cell Death - Apoptosis
Programmed Cell Death Chromatin condensation, membrane blebbing, single cell death Ingested by neighboring cells Vitamin D dependent

BIOL-L 112 Exam 2 (5 decks)

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