LO10 Flashcards
(95 cards)
1
Q
Carry genetic information
A
chromosomes
2
Q
each chromosome contains ______ of genes
A
1000’s
3
Q
definition: a segment of DNA that codes for a protein
A
gene
4
Q
DNA is a ______________ gene
A
protein-coding
5
Q
RNA is a ______________ gene
A
non-coding
6
Q
regulate the expression of protein-coding genes
A
non coding genes
7
Q
has multiple linear chromosomes
A
eukaryotes
8
Q
has single circular chromosomes that is supercoiled in the nucleoid region
A
prokaryotes
9
Q
are highly organized
A
chromosomes
10
Q
DNA double helix would around histone proteins
A
chromatin
11
Q
Definition: prevent the DNA from getting tangled and help regulate gene expression
A
histones
12
Q
basic unit of chromatin structure is the ____________
A
nucleosome
13
Q
nucleosome includes _____ bp of DNA wrapped around ___ histones
A
146; 8
14
Q
nucleosomes are packed together to form compacted _______
A
chromatin
15
Q
most cells ____ when mature
A
divide
16
Q
definition: the longest part of the cell cycle
A
interphase
17
Q
there is not division during this phase of the cell cycle
A
Interphase
18
Q
during interphase a cell is (doing what?)
A
growing and carrying out normal activities while preparing to divide
19
Q
includes mitosis + cytokinesis
A
M phase
20
Q
definition: division of the nucleus in five stages
A
M phase
21
Q
this phase result in two genetically identical daughter nuclei
A
M phase
22
Q
division of the cytoplasm
A
cytokinesis
23
Q
this phase splits the cell and results in two identical daughter cells
A
cytokinesis
24
Q
Interphase includes three parts
A
G1, S, G2
25
the first gap phase and longest part of interphase
G1
26
during G1 the cell does what?
grows and prepares for S phase
27
what happens when some cells don't divide once their mature
they remain in a modified G1 (called G0) permanently
28
what cells remain in G0
animal blood cells, neurons and muscle cells
29
S in interphase is what?
synthesis
30
what happens during the S phase of Interphase
- DNA replication occurs and additional histone proteins are synthesized to help organize the new DNA
- centrioles are duplicated
31
G2 is what in interphase
The second gap phase
32
during G2 what happens
- the cell makes final preparation for M phase
33
what is the first stage of mitosis
prophase
34
how does prophase begin
as chromatin condenses to form mitotic chromosomes
35
definition: a chromosomes that is temporarily attached to an identical during cell division
chromatid
36
during prophase each chromosome temporarily consists of ______________ joined at their ________
two identical sister chromatids; centromeres
37
during prophase the ____ begins to form
mitotic spindle
38
the mitotic spindle is made from
microtubules
39
spindle microtubules eventually do what?
attatch to proteins called kinetochores at the centromere of each sister chromatid
40
in prophase the nuclear envelope begins to what?
fragment and the cytoskeleton is disassembled
41
during _______ spindle microtubules attach to sister chromatids and gradually move chromosomes towards the equator
prometaphase
42
prometaphase begins when?
the nuclear envelope is complete
43
during prometaphase sister chromatids end up attached to spindle microtubules from _______ poles
opposite
44
this phase in M phase occurs when the chromosomes are aligned along the metaphase plate in the middle of the cell
metaphase
45
this phase in M phase begins when the sister chromatids start to separate
anaphase
46
during anaphase what happens to sister chromatids
they are pulled to opposite poles of the cell by shortening microtubules as the cohesin proteins that holding the chromatids together dissociate
47
M Phase: the last phase of mitosis and results in a return to interphase conditions
telophase
48
what happens during telophase
- the nuclear envelope re-forms
- chromosomes decondense
- spindle microtubules are disassembled
49
cytokinesis begins when?
late anaphase or telophase
50
in cytokinesis animal and fungal cells do what?
form a contractile ring or microfilaments and myosin to physically separate the daughter cells
51
in cytokinesis plant cells do what?
form a cell plate along their equator
52
the cell plate plant cells from is made from
membranous vesicles that form plasma membrane between the daughter cells
53
how do prokaryotes divide
by binary fission
54
definition: binary fission
method of asexual reproduction in that it produces daughter cells that are genetically identical to the parent cells
55
steps of binary fission
- begins with a cell's circular chromosome
- duplicated chromosomes move to opposite ends of the cell
- cell divides as the plasma membrane grown inward
- a new cell wall forms between the daughter cells
56
in eukaryotes mitochondria and chloroplast divide how?
by binary fission in interphase
57
definition: ensure tha tthe events of a particular stage are properly completed before the next stage begins
cell-cycle checkpoints
58
what are the checkpoints that eukaryotes have
- G1-S checkpoint
- G2 - M checkpoint
- metaphase - anaphase
59
this checkpoint ensures that the cell has the needed nutrients and enzymes to synthesize DNA
G1-S checkpoint
60
this checkpoint ensure that DNA replication is finished before the ce;l begin mitosis
G2-M checkpoint
61
if a cell is damaged or unreplicated DNA this checkpoint will prevent it from entering M phase
G2-M checkpoint
62
this checkpoint ensures that kinetochores are properly attached to spindle fibers along the metaphase plate
metaphase - anaphase checkpoint
63
if this checkpoint is defective what will happen?
chromosomes may not be properly separated during anaphase
64
definition: individuals have 3 copies of chromosomes 21 because chromosomes were not properly separated
trisomy-21
65
definition: kinases that bind with cyclin proteins to form cyclin-Cdk complexes that regulate the cell cycle by phosphorylating needed enzymes
Cyclin-dependent kinases (Cdk's)
66
in animals somatic cells are _____
diploid 2n
67
definition: contain two copies of each chromosome
diploid
68
homologous pairs are what?
two copies of chromosomes
69
definition: contain the same genes in the same order but they may have dif variant of those genes
homologs
70
somatic cells
non-reproductive cells
71
gametes
reproductive cells
72
definition: typically haploid n
reproductive cells
73
definition: union of two haploid gametes to form a diploid zygote
fertilization
74
sexual reproduction requires what?
a reduction division in the reproductive cells prior to fertilization to offset the combining of chromosomes during fertilization
75
during meiosis a diploid cell undergoes what?
two division meiosis I and II
76
at the end of meiosis what is produced
four haploid cells
77
what is apart of the meiotic cell cycle
interphase + M Phase
78
definition: an abbreviated interphase without an S phase
interkinesis
79
during interphase of meiosis chromosomes are duplicated
during S phase and producing sister chromatids
80
at the beginning of prophase I homologous chromosomes under go what?
synapsis
81
during synapsis what happens?
homologs join to form tetrads of four chromatids
82
homologs are held together by what
synaptonemal complex which facilitates crossing over
83
what happens during crossing over in prophase 1
equivalent segments of DNA are exchanged between nonsister chromatids
- this allows for genetic recombination
84
definition: where crossing over occurs
chiasmata
85
things that happen during prophase I include
- chromatin condenses
- meiotic spindle forms and centrioles duplicated
- nucleus fragments
86
during metaphase 1 where are tetrads?
lined up along the equator
87
during anaphase I what happens?
- homologs are pulled to opposite poles
- sister chromatids remain attached
- each pole receives a random combination of maternal and paternal homolgs
88
During telophase I what happens
- nuclei reform and chromosome decondense
- each nucleus is haploid
89
meiosis 1 cytokinesis produces what?
two genetically different haploid daughter cells
90
in meiosis II each haploid daughter cell
proceed through interkinesis and then enters meiosis II
91
in prophase II there is no crossing over
homologs are in different daughter cells
92
during metaphase II chromosomes line up where?
along the metaphase plate
- sister chromatids are attatched to microtubules from opposite poles
93
during anaphase II sister chromatids are pulled where?
to opposite poles
94
during telophase II there is?
one chromatid from each homolog at each pole
95
