CELL CYCLE Flashcards
(116 cards)
1
Q
is the ability of organisms to produce more of their own kind and best distinguishes living organisms from nonliving things.
A
Cell Division
2
Q
In ________, the division of one cell reproduces the entire organism.
A
unicellular organisms
3
Q
Multicellular eukaryotes depend on cell division for:
A
- Development from a fertilized cell
- Growth
- Repair
4
Q
is an integral part of the cell cycle, the life of a cell from formation to its own division.
A
Cell division
5
Q
a series of events that take place in a cell leading to its division and duplication of its DNA (DNA replication) to produce two daughter cells.
appears to be driven by specific chemical signals present in the cytoplasm
A
Cell Cycle
6
Q
conserves the number of chromosome sets, producing cells that are genetically identical to the parent cell.
A
Mitosis
7
Q
reduces the number of chromosome sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell.
A
Meiosis
8
Q
constitutes all the DNA in the cell. It can consist of a single DNA molecule or a number of DNA molecules.
A
Genome
9
Q
DNA molecules in a cell that is packed.
A
Chromosomes
10
Q
a complex of DNA and protein that condenses during cell division.
A
Chromatin
11
Q
(nonreproductive cells) - have two sets of chromosomes.
A
Somatic Cells
12
Q
(reproductive cells) - have half as many chromosomes as somatic cells.
A
Gametes
13
Q
Each duplicated chromosome has two sister chromatids (joined copies of the original chromosome), attached along their lengths by ____.
A
cohesins
14
Q
is the narrow “Waist” of the duplicated chromosome, where the two chromatids are most closely attached.
A
centromere
15
Q
Eukaryotic cells cell division consists of
A
Mitosis and cytokinesis.
16
Q
is the division of the genetic material in the nucleus.
A
Mitosis
17
Q
is the division of the cytoplasm.
A
Cytokinesis
18
Q
are produced by the variation of cell division called meiosis.
A
Gametes
19
Q
yields non-identical daughter cells that have half as many chromosomes as the parent cell.
A
Meiosis
20
Q
= nucleus + division
A
Karyokinesis
21
Q
= cytoplasm + division
A
Cytokinesis
22
Q
The cell cycle consists of
A
- Mitotic (M) phase (Mitosis and Cytokinesis)
- Interphase (cell growth and copying of chromosomes in preparation for cell division.)
23
Q
Interphase can be divided into subphases:
A
- Gap1 phase (“First Gap”)
- S phase (“Synthesis”)
- Gap2 phase (“Second Gap”)
24
Q
The cell grows during all three phases but the chromosomes are duplicated only during
A
S phase
25
The longest mitotic phase
Prophase
26
The longest phase of the cell cycle
Interphase
27
structure made of microtubules that control chromosome movement during mitosis.
Mitotic Spindle
28
the microtubule organizing center where the assembly of spindle microtubules begins.
Centrosome
29
The centrosome replicates during __________,
interphase
30
forming two centrosomes that migrate to opposite ends of the cell during __________.
prophase and prometaphase
31
(a radial array of short microtubules) extends from each centrosome.
aster
32
During ___, some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes.
prometaphase
33
are protein complexes associated with centromeres.
Kinetochores
34
At ___________, the chromosomes are all lined up at the metaphase plate, a plane midway between the spindle's two poles.
metaphase
35
cohesins are cleaved
Sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell. The microtubules shorten by depolymerizing at their kinetochore ends
anaphase
36
cohesins are cleaved by an enzyme called
separase
37
The eukaryotic cell cycle is regulated by a molecular control system
Cell Cycle Control
38
cells that manage to escape the usual controls on the cell cycle.
Cancer cells
39
The sequential events of the cell cycle are directed by a distinct _____________, which is similar to a clock. The clock has specific checkpoints where the cell cycle stops until a "go-ahead" signal is received.
cell cycle control system
40
most important checkpoint
If a cell receives a go-ahead signal, it will usually complete the S, G2, and M phases and divide
G1 checkpoint
41
If the cell does not receive the go-ahead signal in g1, it will exit the cycle, switching into a nondividing state called the
G0 phase
42
Living organisms are distinguished by their ability to reproduce their own kind
true
43
are the units of heredity and are made up of segments of DNA.
Genes
44
Genes are passed to the next generation via reproductive cells called
gametes (sperm and eggs)
45
Most DNA is packaged into _________.
chromosomes
46
Humans have __chromosomes in their somatic cells, all cells of the body except gametes and their precursors.
46 chromosomes
47
A gene's specific position along a chromosome is called the __.
locus
48
a single individual passes all of its genes to its offspring without the fusion of gametes.
asexual reproduction
49
is a group of genetically identical individuals from the same parent.
clone
50
two parents give rise to offspring that have unique combinations of genes inherited from the two parents.
sexual reproduction
51
Human somatic cells have ___ pairs of chromosomes.
23
52
is an ordered display of the pairs of chromosomes from a cell.
karyotype
53
two chromosomes in each pair in karyotype are called
they are the same length and shape and carry genes controlling the same inherited characters.
homologous chromosomes, or homologs
54
Each pair of homologous chromosomes include one chromosome from each parent.
true
55
The 46 chromosomes in a human somatic cell are two sets of 23: one from the mother and one from the father.
true
56
(2n) has two sets of chromosomes. For humans, the __ number is 46 (2n = 46).
diploid cell
57
contains a single set of chromosomes and is haploid (n).
A gamete (sperm or egg)
58
For humans, the haploid number is _______.
23
59
Each set of 23 consists of 22 autosomes and a single-sex chromosome, for humans
true
60
is the union of gametes (the sperm and the egg).
Fertilization
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The fertilized egg is called a ________ and has one set of chromosomes from each parent.
zygote
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The ________ produces somatic cells by mitosis and develops into an adult.
zygote
63
each chromosome pairs with its homolog, and crossing over occur.
X-shaped regions called chiasmata are the sites for crossover.
prophase 1
64
pairs of homologs line up at the metaphase plate, with one chromosome facing each pole.
Microtubules from one pole are attached to the kinetochore of one of the chromosome of each tetrad.
Microtubules from the other kinetochore of the other chromosome pole are attached.
Metaphase 1
65
pairs of homologous chromosomes separate.
One chromosome of each pair moves toward opposite poles, guided by the spindle apparatus.
Sister chromatids remain attached at the centromere and move as one unit toward the pole.
Anaphase 1
66
each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids.
Telophase 1
67
usually occurs simultaneously, forming two haploid daughter cells. The cell then proceeds to meiosis 2 which is similar to mitosis.
Cytokinesis
68
DNA synthesis
cell cycle
S phase
69
gap for growth
cell cycle
G phase
70
mitosis (nuclear division)
cell cycle
M phase
71
cell performs all of its regular functions and gets ready to divide
Metabolic activity is very high
celll phase
interphase
72
DNA is duplicated
DNA is in the form of chromatin
celll phase
interphase
73
Any cell that is going to divide must enter this phase
This is the period before DNA synthesis begins
refers to the gap between cell division and DNA synthesis
Here the cell makes ER, ribosomes, and cytosol to make 2 functional cells
G1
74
Once all of the organelles have been replicated, the cell enters this phase
For the next 6-8 hours it will replicate its DNA
S PHASE
75
The goal of replication
is to accurately copy the genetic information in the nucleus so that each daughter cell will have an exact copy of the parental DNA
76
Before a cell starts dividing, the chromosomes are duplicated
This process produces sister chromatids
EM of human chromosome that has duplicated
S PHASE
77
are identical pairs of chromosomes.
One inherited from mother and one from father
made up of sister chromatids joined at the centromere
Homologous chromosomes
78
process of dna replication
dna
enzyme unzips into 2 strands
new bases are added in between strands
79
are homologous chromosome just one double stranded dna that doubled in size
true
80
This phase spans the time from the completion of DNA synthesis to the onset of cell division
Following DNA replication, the cell spends about 2-5 hours making proteins prior to entering the M phase
G2 Phase
81
process that separates the duplicated sister chromatids of the parental cell into 2 nuclei
refers specifically to the division of the nucleus of the cell
M PHASE
MITOSIS
82
Mitosis is a continuum but biologists distinguish 4 stages
Prophase
Metaphase
Anaphase
Telophase
83
eukaryotic cell has many more genes than a prokaryotic cell
true
84
are grouped into multiple chromosomes, found in the nucleus
genes
85
The orientation of the
division plane is determined by a band of cytoskeletal elements called the
thickening at the cell membrane
preprophase band
86
nucleus migrates to the middle of the cell and layer of cytoplasm forms in the plane where cell division will occur, to keep nucleus in place
phragmosome
87
nuclear membrane disintegrates nucleolus disappears
chromosomes condense
mitotic spindle begins to form between centrioles
kinetochores begin to mature and attach to spindle
prophase
88
kinetochores attach chromosomes
to mitotic spindle and align them along metaphase plate at equator of cell
Metaphase
89
kinetochore microtubules shorten, separating chromosomes to opposite poles
polar microtubules elongate, preparing cell for cytokinesis
mitosis
Anaphase
90
cell divides, the sister chromatids separate
Two daughter cells are produced
Each has a complete and identical set of chromosomes
mitosis
Anaphase
91
cell plate forms, dividing daughter
CYTOKINESIS
92
chromosomes reach poles of cell kinetochores disappear
polar microtubules continue to elongate, preparing cell for cytokinesis
nuclear membrane re-forms nucleolus reappears
chromosomes decondense
mitosis
Telophase
93
Similar in many ways to mitosis
Several differences
Occurs only in sex cells
Yields gametes (=eggs & sperms) or spores
Involves 2 cell divisions
Results in 4 haploid cells
Leads to genetic variations
Meiosis
94
Synapsis and crossing over occur
Prophase I
95
pairing of homologous chromosomes
Synapsis
96
exchange of segments of homologous chromosomes
Crossing over
97
Alignment of pairs of homologous chromosomes at the metaphase plate
Metaphase I
98
Splitting of the pairs of homologous chromosomes and subsequent movement to opposite poles
Anaphase I
99
Cytokinesis results to two haploid cells (n)
Telophase I
100
Areas of homologous chromosomes connect at areas or crossing over
chiasmata
101
DNA does not double
Stages occur like regular mitosis.
Cytokinesis results to four haploid cells (n)
Meiosis II
102
Proteins called ______proteins monitor
progression through the cell cycle.
checkpoint
103
places of dna damage checkpoint
g2
s
g1
104
places of apoptosis
before mitosis
105
places of spindle checkpoint
anaphase
106
Two types of regulatory proteins are involved in cell cycle control
cyclins and cyclin-dependent kinases (Cdks)
107
proteins produced in synchrony with the cell cycle
regulate passage of the cell through cell cycle checkpoints
cyclins
108
enzymes that drive the cell cycle
activated only when bound by a cyclin
cyclin-dependent kinases (Cdks)
109
The activity of a Cdk rises and falls with changes in concentration of its cyclin partner
true
110
cyclin-Cdk complex that triggers a cell’s passage past the G2 checkpoint into the M phase
MPF (maturation-promoting factor)
111
the signal for anaphase to proceed is transmitted through
activates the proteins that remove the cohesin holding sister chromatids together
anaphase-promoting complex (APC)
112
cells will not begin anaphase until all chromosomes are properly attached to the spindle at the metaphase plate
mechanism assures that daughter cells have the correct number of chromosomes
internal signal
113
But plant cells are anchored in place by the cell walls, so plant cancers never spread far or metastasize to other tissues.
true
114
is the process of genome doubling that gives rise to organisms with multiple sets of chromosomes.
Polyploidy
115
Polyploidy that occurs when organisms have more than two sets of chromosomes from the same species
Autoploidy
116
Polyploidy that Results from hybridization between different species
Allopolyploidy
