1.
a diploid organism has:: 2 sets of chromosomes organized as homolgous pairs
2.
acrocentric:: close to end
3.
after G1/S: the cell is commited to dividing
4.
after G2/M: the cell can divide
5.
after S phase and during G2:: each chromosome consists of 2 DNA molecules (2 sister chromatids)
6.
alleles:: alternative forms of a gene found at the same position of homologous chromosomes
7.
anaphase: the chromatids are pulled apart by the mitotic spindle
8.
aneuploid: none of the above
9.
at the end of mitosis and during G1:: each chromosome consists of a single DNA molecule
10.
centromere:: the region of the chromosome where sister chromatids are joined (also present before DNA replication)
11.
checkpoints: progression through the cell division may be halted at checkpoints bc of DNA damage, incomplete DNA replication, insufficient cell size, or incomplete mitotic spindle formation
the cycle is resumed after the problems are fixed
12.
chromatin:: fibers of decondensed DNA chromosomes
occurs during nondivisional phases of the cell cycle
13.
chromosome:: before DNA replication: a single molecule of DNA
following DNA replication in preparation for cell division: chromosomes consist of 2 sister chromatids that contain identical DNA sequences
14.
cri-du-chat syndrome: loss of a small portion of the small arm of chromsome 5
result: partial monosomy (46-5p)
humans with complete autosomal monosomies do not survive
15.
cytokinesis: division of the cytoplasm
16.
diakinesis: the chromosomes pull further apart
further condensation occurs
17.
diploid: 2n cell contains homologous chromosomes in pairs
18.
diploid (2n): 2 copies of genetic material subdivided into chromosomes
19.
diplotene: homologous chromosomes begin to pull apart
the chiasmata become visible: regions in which DNA exchange occurred
20.
DNA replication: dupliaction of the chromosomes -> sister chromatids
21.
Down syndrome: nondisjunction of chromosome 21
result: trisomy 21
trisomy X also exists
22.
G0: cell may exit to G0 in response to outside signals
23.
G1: Gap 1: cell growth
24.
G2: Gap 2: cell growth
25.
haploid: 1n single set of chromosomes (no pairs)
26.
haploid (n):: 1 copy of genetic material subdivided into chromosomes
27.
homologous chromosomes:: chromosomes with identical length and cetromere location
contain the same genes but not necessarily identical DNA sequences (some of their genes may be allelic)
28.
human karyotype: shows all 22 homologous pairs of autosmomal (non sex determining) chromosomes plus the pair of sex chromosomes
29.
humans have:: 23 pairs of chromosomes
30.
if cell damage is too extensive: the cell may be induced to die
31.
if cell division controls are defective: uncontrollable cell proliferation (tumors, cancer)
32.
in G2: the cell prepares for mitosis
33.
Interphase: G1 + S + G2
cell may exit the division cycle at G1 and go into G0 to become a nondividing cell
34.
leptotene: DNA beings to partially condense with the help of histones
35.
M phase: mitosis and cytokinesis take place
36.
M phase: cell division (mitosis + cytokinesis)
37.
meiosis: homologous chromosomes pair to form tetrads during prophase 1
anaphase 1: the tetrads are disjoined and the homologous chromosomes are segregated to daughter cells
anaphase 2: the chromosomes are disjoined and the chromatids are segregated to daighter cells
38.
meiosis: a cell undergoes 2 rounds of cell divisions to generate daughter cells with half the content of the original parent cell
the dividing cell must have an even number of homologous haploid sets
39.
meiosis: special type of cell division cycle that occurs during the generation of gametes (sperm and egg) or spores
2 rounds of cell divisions
outcome: 4 haploid (1n) cells
40.
Meiosis 1: reductional
tetrads are disjoined
outcome: dyads
homologous chromosomes (with 2 chromatids each) are segregated to daughter cells
the # of chromosomes in the daughter cells is half the original
41.
Meiosis 1: reductional 2n -> n
42.
Meiosis 2: equatorial n -> n
43.
Meiosis 2: equatorial
resembles mitosis
the chromosomes are disjoined
the chromatids are segregated to daughter cells
44.
meiotic failures: meiosis fails in organisms that do not contain a chromsome complement consisting of an even number of homolgous haploid sets (multiples of the diploid number) -> produce no gametes
ex. mules and seedless watermelons
45.
Meiotic Prophase 1: leptotene
zygotene
pachytene
diplotene
diakinesis
46.
metacentric:: middle
47.
metaphase: highest level of DNA condensation
48.
mitosis: division of the nucleus
49.
mitosis: homologous chromosomes do not pair
during anaphase, the chromosomes are disjoined and the chromatids are segregated to daughter cells
50.
mitotic cell division: a cell divides to generate 2 daughter cells with the same chromosomal content as the parent cell
the dividing cell may have any chromosomal content
51.
nondisjunction: may occur at the 1st or 2nd meiotic division
chromosomes or chromatids do not separate during anaphases 1 or 2
both chromosomes/chromatids migrate to the same gamete
after fusion with a normal gamete, trisomic and monosomic progenies may occur
52.
oogenesis: unequal cytokinesis
one cell (the egg) recieves all the cytoplasm
rest of the cells become polar bodies
53.
outcome of mitosis in diploid cells: 2 diploid daughter cells (with the same chromosomal content of the original cell)
each chromosome consists of a single DNA molecule
54.
p arm:: petite: short arm of chromosome
55.
pachytene: condensation continues and the sister chromatids of the chromosome are visible
DNA exchange occurs (crossing over)
56.
polyploid: 3n, 4n, 5n etc
57.
prior to cell division:: the chromatin condenses into visible chromosome due to the tightening of interactions between DNA and chromatin proteins (histones)
58.
prometaphase/metaphase: the nuclear envelope disintegrates, the mitoticspindle (microtubules) attach to the centromere of the chromatids, and the chromosomes line up on the metaphase plate
59.
prophase: the chromatin condenses into visible chromosomes (with the help of histones)
60.
q arm:: long arm, always shown below the centromere
61.
S phase: synthesis: DNA replication
produces identical sister chromatids
62.
spermatogenesis: equal cytokinesis
outcome: 4 gametes (sperm)
63.
spindle microtubules during mitosis: attached to centromeres and the sister chromatids are segregated
64.
submetacentric:: between middle and end
65.
telocentric:: at end
66.
telomeres:: stable ends of linear chromosomes
67.
telophase: the chromatids are segregated and their DNA decondenses
the chromatids become the chromsomes of the daughter cells
68.
turner syndrome: complete X chromosome monsomy (XO)
69.
zygotene: homologous chromosomes pair to form tetrads (or bivalents).
synaptonemal complex forms
