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BIO 375 - Genetics > Ch 2: Chromosomes and Cellular Reproduction (BIO 375 - Genetics) > Flashcards

Ch 2: Chromosomes and Cellular Reproduction (BIO 375 - Genetics) Flashcards

1
Q

karyotype

A

complete set of an individual’s chromosomes; an image of a set of chromosomes (humans have 46 chromosomes, and 23 homologous pairs)

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2
Q

autosomes

A

any chromosome that is not a sex chromosome

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3
Q

chromosomes

A

thread like structures that carry genetic information

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4
Q

prokaryotes

A

single circular molecule of DNA with no end to chromosome; unicellular organism with simple cell structure; divided into eubacteria or archaea; reproduce through binary fission (chromosome replicates and cell divides)

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5
Q

eukaryotes

A

have multiple linear chromosomes composed of DNA and histone proteins packed like chromatin, where the chromosomes have identifiable ends; compartmentalized cell structure with components bounded by intracellular membranes; can be unicellular or multicellular

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6
Q

diploid

A

carry two sets of genetic information

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7
Q

haploid

A

single set of chromosomes; one copy of each gene

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8
Q

homologous chromosomes

A

alike in structure and size, each carrying genetic information for the same set of hereditary characteristics (except sex chromosomes); one chromosome of the pair is a maternal chromosome and the other is a paternal chromosome

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9
Q

centromere

A

region of chromosome where spindle fibers attach during cell division

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10
Q

telomeres

A

natural ends of a linear chromosome that protect and stabilize the chromosome ends

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11
Q

origins of replication

A

sites where DNA synthesis begins; sister chromatids

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12
Q

cell cycle

A

life cycle of a cell between cell divisions where progression through the cycle is regulated at checkpoints (key transition points)

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13
Q

phases of cell cycle

A
  1. Interphase (G1/G0, G1/S checkpoint, S, G2, G2/M checkpoint)
  2. Mitosis (Prophase, Metaphase, Anaphase, Telephase)
  3. Cytokinesis (cell division)
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14
Q

interphase

A

period between cell divisions (where cell grows, develops, and functions); nuclear membrane is present and chromosomes are relaxed

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15
Q

G1

A

Gap 1: cell growth; unduplicated chromosomes/chromatin

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16
Q

G0

A

Stasis, non-dividing phase

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17
Q

S

A

Synthesis: DNA duplicates/is synthesized

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18
Q

G2

A

Gap 2: mitosis preparation; duplicated chromosomes

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19
Q

prophase

A

chromosomes condense; each chromosome possesses two chromatids; mitotic spindle forms

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20
Q

metaphase

A

chromosomes line up on metaphase plate

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21
Q

anaphase

A

sister chromatids separate and move toward opposite poles

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22
Q

telophase

A

chromosomes arrive at spindle poles; nuclear membrane reforms and chromosomes relax

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23
Q

number of chromosomes per cell

A

equivalent to number of functional centromeres

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24
Q

number of DNA molecules per cell

A

equivalent to twice the number of chromosomes IF sister chromatids are present; if NO sister chromatids are present then equivalent to number of chromosomes

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25
mitosis
asexual reproduction; increase in cell numbers; produces identical daughter cells; occurs in most cells; one division of nucleus
26
meiosis
sexual reproduction; begins in specialized gametic stem cells; produces unique haploid progeny cell; two divisions of nucleus (meiosis I and meiosis II)
27
meiosis I
reductional division; a diploid cell divides and forms two haploid cells (halving chromosomal number); introduces genetic variation
28
prophase I
chromatin condenses into chromosomes; nuclear membrane breaks down; homologous chromosomes pair... occurs in 5 substages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis
29
leptotene
chromosomes condense
30
zygotene
close pairing and association of homologous chromatin; forms a bivalent or tetrad; where synapsis begins
31
pachytene
synaptonemal complex develops between homologues; crossing over occurs
32
crossing over
exchange of genetic information between nonsister chromatids
33
diplotene
centromeres of homologues move apart and homologues remain attached at chiasmata
34
diakinesis
centromeres continue to separate, but chromosomes are still attached at chiasmata
35
metaphase I
homologous pairs of chromosomes line up along metaphase plate; chiasmata are lined up on metaphase plate
36
anaphase I
homologous chromosomes separate and move toward opposite poles
37
telophase I
chromosomes arrive at spindle poles and cytoplasm divides; nuclear membrane reforms; chromosomes decondense to chromatin; two haploid cells are produced; priority on cytokinesis so the "reversal of prophase I" is not as regulated and may vary or not always occur in process
38
meiosis II
equational division (halves amount of genetic material); begins with haploid cells; individual chromosomes line up on equatorial plate -> sister chromatids pull apart and move to opposite poles -> cytokinesis; steps: prophase II, metaphase II, anaphase II, telophase II; gametes remain in G0 upon completion until fertilization or cell death
39
prophase II
chromosomes recondense
40
metaphase II
individual chromosomes line up on equatorial plate
41
anaphase II
sister chromatids separate and move to opposite poles
42
telophase II
chromosomes arrive at spindle poles and cytoplasm divides
43
consequences of meiosis
crossing over and recombination produce nonidentical sister chromatids (rearranges linked loci and produces genetic variation)' independent assortment of chromosomes produces variation
44
recombination
creating new combinations of alleles on a chromatid
45
crossing over shuffles
alleles on same chromosome into new combinations
46
random distribution of maternal/paternal chromosomes shuffles
alleles on different chromosomes into new combinations
47
fertilization
two haploid gametes fuse and restore chromosome number to original diploid value; sperm head enters the secondary oocyte where meiosis II occurs to form a mature ovum... haploid nuclei merge to form a diploid zygote
48
spermatogenesis
begins at puberty; takes appx. 64 days; spermatogonium (gametic stem cells of males) differentiate then undergo meiosis I and II to produce sperm
49
oogenesis
begins 4 months after fertilization; takes 12-50+ years; oogonium (gametic stem cells of females) differentiate then undergo meiosis I and II to produce ovum
50
identification of chromosomes
by size and location of centromere
51
short arm
p arm; the segments of the chromosome above centromere
52
long arm
q arm; segments of chromosome below the centromere
53
number of chromatin
(approximately) number of DNA molecules
54
metaphase to anaphase, metaphase II to anaphase II
number of chromosomes doubles
55
metaphase I to anaphase I
number of chromosomes remains the same
56
middle prophase I
(leptotene) chromosomes condense and spindles form
57
late prophase I
(zygotene, pachytene, diplotene, diakinesis) homologous chromosomes pair; crossing over takes place and nuclear membrane breaks down
58
synaptonemal complex
molecular glue holding chromatin of homologous chromosomes together; reduces chances of unequal crossing over
59
bivalent
2 chromosomes
60
tetrad
4 chromatids
61
unequal crossing over
Misalignment of the two DNA molecules during crossing over, resulting in one DNA molecule with an insertion and the other with a deletion; unequal parts of chromosome exchange during crossing over, resulting in gain or loss of DNA
62
chiasmata
points where chromosomes participated in crossing over and are still "stuck together" / touching one another
63
cytokinesis
when DNA decreases / halves
64
crossing over leads to
recombination
65
linked loci
genes that are physically joined together on same piece of chromosome
66
spermatogenesis produces
4 mature gametes (sperm)
67
oogenesis produces
1 mature gamete (ovum)
68
independent assortment
different combinations of chromosomes depending on how chromosomes (maternal and paternal) align/separate in meiosis I and II
69
gametogenesis
process of making gametes
70
spermatogenesis cycle
occurs in waves for groups of cells
71
oogenesis cycle
all oogenium are converted to primary oocytes until 7 months after fertilization (when they then die)... then the primary oocytes undergo cycle in waves
72
unequal distribution of cytoplasm between ovum and polar body
so the ovum has nutrients for the zygote/developing embryo until it fuses with the uterine lining
73
secondary oocyte
the cell that is ovulated if no sperm is present; product of meiosis I of primary oocyte; are 1n
74
ovum
formed from meiosis II ONLY if there is contact with sperm
75
spermatogonium
starting gametic stem cells of spermatogenesis; are 2n
76
primary spermatocyte
product of differentiation of spermatogonium; produced after mitosis; are 2n
77
secondary spernatocyte
product of meiosis I of primary spermatocytes; are 1n
78
spermatids
product of meiosis II of secondary spermatocytes; are 1n
79
sperm
matured spermatids after G1; are 1n
80
oogonium
starting gametic stem cells of oogenesis; are 2n
81
primary oocyte
product of differentiation of oogonium; produced after mitosis; are 2n
82
first polar body
the other product of meiosis I of primary oocyte; are 1n but with double the chromosomal number
83
ovum
product of meiosis II of secondary oocyte if contact is made with sperm; are 1n
84
second polar body
the other product of meiosis II of secondary oocyte if contact is made with sperm; are 1n but with double chromosomal number
85
(mitosis) G1
2n number of DNA and chromosomes
86
(mitosis) S
4n number of DNA and 2n number of chromosomes
87
(mitosis) G2
4n number of DNA and 2n number of chromosomes
88
(mitosis) P
4n number of DNA and 2n number of chromosomes
89
(mitosis) M
4n number of DNA and 2n number of chromosomes
90
(mitosis) A
4n number of DNA and number of chromosomes
91
(mitosis) T
2n number of DNA and number of chromosomes
92
(meiosis) G1
2n number of DNA and number of chromosomes
93
(meiosis) S
4n number of DNA and 2n number of chromosomes
94
(meiosis) G2
4n number of DNA and 2n number of chromosomes
95
(meiosis) PI
4n number of DNA and 2n number of chromosomes
96
(meiosis) MI
4n number of DNA and 2n number of chromosomes
97
(meiosis) AI
4n number of DNA and 2n number of chromosomes
98
(meiosis) TI
2n number of DNA and n number of chromosomes
99
(meiosis) PII
2n number of DNA and n number of chromosomes
100
(meiosis) MII
2n number of DNA and n number of chromosomes
101
(meiosis) AII
2n number of DNA and 2n number of chromosomes
102
(meiosis) TII
n number of DNA and number of chromosomes
103
(meiosis) after meiosis
n number of DNA and number of chromosomes

BIO 375 - Genetics (8 decks)

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