Cell Cycle Flashcards
1
Q
characteristic that best distinguishes living things from non living things
A
ability to produce more of their own kind
2
Q
continuity of life is based on the principle called
A
cell division
3
Q
role of cell division in prokaryotic cells
A
reproducing because it makes new organisms
4
Q
role of cell division in multicellular eukaryotes
A
allows each cell to develop from a single cell
5
Q
important part of the cell cycle
A
cell division
6
Q
cell cycle
A
the life of a cell from the time its formed to its own division into daughter cells
7
Q
in both prokaryotes and eukaryotes, most cell division involves
A
distribution of identical genetic material (DNA) to two daughter cells
8
Q
meiosis can only produce
A
sperm and egg
9
Q
genome
A
all the cell’s DNA (genetic information)
10
Q
how long is eukaryotic DNA
A
2 meters per cell
11
Q
before a cell divides
A
All the DNA must be copied
12
Q
what happens to the copies of DNA before the cell division
A
must be separated so that each daughter cell ends up with a complete genome
13
Q
the replication and distribution of the DNA is possible by
A
the DNA molecules being packaged into chromosomes
14
Q
each chromosome has
A
a very long and linear DNA molecule
15
Q
genes
A
units of information that specifies an organisms inherited traits
16
Q
DNA molecules carry several hundred to thousand
A
genes
17
Q
chromatin
A
entire complex of DNA and proteins that is the building material of chromosomes
18
Q
varies in its degree of condensation during the process of cell division
A
chromatin
19
Q
somatic cells
A
all body cells EXCEPT the reproductive cells
20
Q
have 46 chromosomes
A
somatic cells
21
Q
gametes
A
reproductive cells
22
Q
have half as many chromosomes as somatic cells
A
gamets
23
Q
sperm and eggs are considered
A
gametes
24
Q
what is a chromosome like when the cell isn’t dividing
A
a long, thin chromatin fibre
25
after DNA replication what happens to the chromosome as the cell divides
they condense and become short and thick
26
sister chromatids
joined copies of the original chromosome
27
each sister chromatid has a
centromere
28
centromere
region made up of repetitive sequences in the chromosomal DNA
29
where is the centromere attached closer
the sister chromatid
30
what happens to the sister chromatids later in cell division
will separate and move into two NEW nuclei
31
what are the sister chromatids called once seperated
individual chromosomes
32
sister chromatid cohesion
initially attached all along their lengths by protein complexes
33
arm of the chromatid
portion along either side of the centromere
34
mitosis
division of the genetic material in the nucleus
35
mitosis is followed by
cytokinesis
36
meiosis produces
gametes
37
the daughter cells produced in meiosis have
half the chromosomes of the parent cells
38
where does meiosis take placed
special cells in the ovaries and testes (gonads)
39
what does fertilization do in meiosis
fuses the two games together and the chromosome number returns to 46
40
phases of the cell cycle
1. Mitosis (m) phases
2. Interphase
41
The M phase includes
mitosis and cytokinesis
42
what is the shortest part of the cell cycle
M phase
43
phases in Interphase
G1
S phase
G2
44
G1
cell begins to grow
45
At what time are different cells the most variable in length
G1 phase
46
S phases is also called
synthesis
47
what happens in S phase
duplication of chromosomes and cell continues to grow
48
describe the chromosomes in S phase
cannot be seen individually because they are not condensed
49
G2
cell grows more as it prepares to divide
50
what stage of interphase does the nuclear envelope enclose the nucleus
G2
51
the nucleus contains one or more
nucleoli
52
what stage of interphase do the two centrosomes form
G2
53
function of the centrosomes
organize the microtubules of the spindle
54
what is happening during interphase
intense metabolic growth
55
how does a cell grow
by producing proteins and cytoplasmic organelles
56
6 phases in mitosis
1. prophase
2. prometaphase
3. metaphase
4. anaphase
5. telophase
6. cytokinesis
57
what stage of mitosis does this describe?
chromatin fibres become more tightly coiled and condense into discrete chromosomes
prophase
58
what stage of mitosis does this describe?
nucleoli disappear
prophase
59
what stage of mitosis does this describe?
each duplicated chromosomes appears as sister chromatids joined at their contromeres
prophase
60
what stage of mitosis does this describe?
the mitotic spindle begins to form
prophase
61
what is the mitotic spindle made from
microtubules and the centrosomes
62
what stage of mitosis does this describe?
centrosomes begin to move away from each other by lengthening of the microtubules
prophase
63
what stage of mitosis does this describe?
nuclear envelope fragments
prometaphase
64
what stage of mitosis does this describe?
microtubules can now invade the nuclear area
prometaphase
65
what stage of mitosis does this describe?
chromosomes have become more condensed
prometaphase
66
what stage of mitosis does this describe?
kinetochore has now formed at the centromere of each chromatid
prometaphase
67
what stage of mitosis does this describe?
some microtubules attach to the kinetochores
prometaphase
68
what stage of mitosis does this describe?
the centrosomes are now at opposite ends of the cell
metaphase
69
what stage of mitosis does this describe?
the chromosomes have all arrived at the metaphase plate
metaphase
70
where is the metaphase plate located
equidistant from the spindle at both poles
71
what stage of mitosis does this describe?
each sister chromatid of the chromosome are attached to the kinetochore-microtubule form opposite poles
metaphase
72
what stage of mitosis does this describe?
shortest stage of mitosis
anaphase
73
what stage of mitosis does this describe?
begins with the cohesion proteins cleaved
anaphase
74
what does having the cohesion proteins cleaved do to the sister chromatids
allows them to seperate
75
what stage of mitosis does this describe?
two liberated daughter chromosomes move towards opposites poles
anaphase
76
what stage of mitosis does this describe?
cell elongates as the nokinetochore microtubules length
anaphase
77
what is needed to lengthen the nonkinetochore microtubules
ATP
78
what stage of mitosis does this describe?
the two ends of the cell have equivalent and complete collections of chromosomes
anaphase
79
what stage of mitosis does this describe?
two daughter nuclei form in the cell
telphase
80
what stage of mitosis does this describe?
nuclear envelope arises from the fragments of the parent's cell
telophase
81
what stage of mitosis does this describe?
nucleoli reappears
telophase
82
what stage of mitosis does this describe?
chromosomes become less dense
telophase
83
what stage is the last stage of mitosis
telophase
84
what does the nuclear envelope arise from
fragments of the parent's cell
85
division of the cytoplasm
cytokinesis
86
what pinches the cell in two during cytokinesis in animals
the formation of a cleavage furrow
87
what pinches the cell in two during cytokinesis in plants
formation of a cell plate
88
when does cytokinesis begin
during anaphase or telophase
89
when does the mitotic spindle begin to form
in the cytoplasm during prophase
90
what does the mitotic spindle consist of
1. fibres made from microtubules and proteins
2. the disassembled elements of the cytoskeleton
91
how does the mitotic spindle elongate
incorporating more subunits of the protein tubulin
92
how the does mitotic spindle shorten
losing subunits of tubulin
93
in animal cells, the assembly of the mitotic spindle takes place
at the centrosome
94
what is used to separate the sister chromatids of each chromosome
separase
95
what are NOT needed for mitosis
centrioles
96
where do the two centrosomes stay close during interphase
near the nucleus
97
when do the centrosomes move apart
during prophase and prometaphase
98
aster
radio array of shorten microtubules
99
an aster extends from each
centrosome
100
when is the mitotic spindle structure complete
when the microtubules of the asters have grown and are in contact with the plasma membrane
101
kinetochore
structure made up of proteins that have assembled on a specific section of DNA at each centromere
102
the chromosome's two kinetochores face
in opposite directions
103
acts as a coupling device that allows the motor of the spindle to attach to its cargo
kinetochore
104
two types of movements done by the kinetochore
1. The motor proteins on the kinetochores "walk" the chromosomes along the microtubules
2. Chromosomes can also be reeled in by motor proteins at the spindle poles
105
cytokinesis in animal cells
occurs by a process called leave
106
what causes the cleavage furrow to contract
actin interacts with the myosin
107
the cleavage furrow deepens until the parent cell _____ and produces ____
pinches in two and two seperate cells
108
cytokinesis in plant cells
there is no cleavage furrow
109
what happens during telophase in plant cells
vesicles made from the golgi move along microtubules to the middle of the cell
110
what is produced instead of a cleavage furrow in plants
cell plate
111
what collects inside the cell plate as it grows
cell wall materials carried in the vesicles
112
when does the cell plate enlarge
as the surrounding membrane fuses with the plasma membrane
113
binary fission
the asexual reproduction of single cells eukaryotes
114
what does the prokaryote cell division produce
forms two NEW cells
115
describe the bacteria chromosome and DNA
single bacterial chromosome that is made from a circular DNA molecule
116
during binary fission, each cell inherit
a complete genome
117
who preceded who on Earth
prokaryotes proceeded eukaryotes
118
mitosis could have arisen from
simpler prokaryotic mechanisms of cell reproduction
119
timing and rate of cell division in different parts of the organism is crucial for
normal growth, development and maintenance
120
____ depends on each type of cell
frequency of cell division
121
skin cells divide
a lot
122
liver cells divide
only when needed to
123
never cells divide
NOT AT ALL
124
the cell cycle is driven by
specific signalling molecules present in the cytoplasm
125
cell cycle control system
cyclically operating set of molecules in the cell that triggers and coordinates key events in the cell cycle
126
three important checkpoints are found at
G1
G2
M phase
127
cell cycle clock
The sequential events of the cell cycle are paced by rhythmic fluctuations in the activity of the cell cycle molecules
128
two types of regulatory molecules
1. protein kinase
2. protein cyclins
129
protein kinases
enzymes that activate or inactivate other proteins by phosphorylating them
130
protein kinases are usually present in
constant concentration in the growing cell
131
what form are most protein kinases in
their inactive form
132
protein cyclins
proteins that makes kinases active
133
protein that is named based on its cyclically fluctuating concentration in the cell
cyclins proteins
134
when does the cyclin rise
during S phase and G2 phase
135
when does the cyclin fall
during the M phase
136
MPF triggers what
the cell's passage past the G2 checkpoint and into M phase
137
MPF works directly and indirectly as a
kinase
138
what does MPF do during anaphase
helps switch itself off
139
how does MPF switch itself off during anaphase
initiating a process that leads to the destruction of its own cyclin
140
mitosis is initiated by
cyclins that have accumulated during G2 and associate with cyclin-dependent kinase molecules
141
G1 checkpoint
restriction point
142
what seems to be the most important stop/go checkpoint
G1
143
what happens if the G1 checkpoint receives a go signal
will complete G1, G2, S and M phases then divide
144
what happens if the G1 checkpoint DOESN'T receive a go signal
exits the cycle and switches into a nondividing state
145
the S phase checkpoint
stops cell with DNA damage from proceeding in the cell cycle
146
cells fail to divide if
essential nutrients is lacking in the culture medium
147
growth factor
protein released by certain cells that stimulates other cells to divide
148
density dependent inhibition
crowded cells stop dividing
149
anchorage dependence
to divide, cells must be attached to a substratum
150
cancer cells do not heed what
the normal signals that regulate the cell cycle
151
cancer cells do not
stop dividing when growth factors are depleted
152
when cancer cells stop dividing, they do so
at random points in the cycle
153
if cancer cells have a continuous supply of nutrients
divide endlessly
154
tumour
mass of abnormal cells within normal tissue from cells evading destruction
155
types of tumours
1. benign
2. malignant
156
benign tumours
abnormal cells that remain at the original site
157
what type of tumour is this?
do not cause serious problems
benign
158
malignant tumour
cell whose genetic and cellular changes allows them to spread to new tissue
159
what type of tumour is this?
impairs the function of one or more organs
malignant
160
what type of tumour is this?
considered to be transformed cells
malignant
161
what type of tumour is this?
said to have cancer
malignant
162
with abnormal changes on the cell's surface, cancer cells
lose attachments to the neighbouring cells and can spread throughout the tissues
163
metastasis
the spread of cancer cells to locations distant from their orignal site
164
what can a localized tumour be treated with
high energy radiation which damages the DNA in cancer
165
side effects of chemotherapy come from
the drug's effect on normal cells that divide often
166
What mitotic phase is this?
Prometaphase
167
What mitotic phase is this?
Prophase
168
What mitotic phase is this?
Anaphase
169
What mitotic phase is this?
Metaphase
170
what mitotic phase is this?
Telophase and cytokinesis
171
what happens if a G1 cell fuses with a S phase cell
G1 cell is able to enter into S phase
172
what is suggested by G1 cells entering S phase after fusing together
that S phase cells contain an activator that pushes G1 cells into S phase
173
what happens if a G2 cell and S phase cell fuse
G2 cell is not able to enter S phase
174
what is suggested by G2 cells NOT entering S phase when fused
1. G2 cells do not have the capacity to divide
2. S phase has a signal that prevents the cell from entering mitosis
175
what happens when a G2 cell fuses with a G2 cell
G1 cell will enter S phase while G2 cells will not
176
what is suggested by G1 cells entering S phase while G2 cells don't
G2 cells do not suppress S phase for G1 cells
177
critical spot where signals can regulate the cycle
ceckpoints
178
what acts on G2 checkpoints to trigger mitosis
MPF
179
when does the cyclin level rise
during interphase (G1, S and G2)
180
when does the cyclin level fall
mitosis (M phase)
181
when is there enough cyclin to produce molecules of MPF
by the G2 checkpoint
182
how does MPF promote mitosis
phosphorylation of various proteins and enzymes
183
how will the kinase of Cdk be restored
with the new cyclin that accumulates during interphase
184
internal regulation signal
messages from kinetochores
185
when will anaphase ONLY begin
when all chromosomes are properly attached to the spindle
186
external regulation signal
growth factors
density-dependent inhibition
anchorage dependence
187
PDGF
required for the division of fibroblasts and to heal wounds
188
anchorage dependence
to divide, all cells must be attached to the substratum
189
substratum
extracellular matrix of a tissue
190
metastasis is dependent on
blood being present
