Chapter 9 Flashcards
1
Q
2 Phases of Cell Division
A
mitosis
cytokinesis
2
Q
5 Phases of Mitosis
A
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
3
Q
Mitosis is followed by __________ when the cytoplasm splits to form two separate daughter cells
A
cytokinesis
4
Q
The cytoplasm in late _________ contains ___ centrosomes and each may contain a pair of centrioles
A
interphase
two
5
Q
Prophase of Mitosis
A
chromosomes condense and centrosomes move to opposite sides of the nucleus
this initiates the formation of the mitotic spindle
6
Q
Metaphase
A
nucleus dissolves and the cells’ chromosomes condense and move together, aligning in the center of the dividing cell
7
Q
Anaphase
A
sister chromatids separate from each other and are pulled towards opposite ends of the cell
8
Q
Telophase
A
chromosomes arrive at the cell poles, the mitotic spindle disassembles, membrane forms around the two sets of chromosomes
9
Q
Cytokinesis
A
the splitting of the cytoplasm and separating daughter cells
10
Q
What is checked at the G1 checkpoint?
A
Growth of the cell and DNA
11
Q
What happens during the S phase?
A
DNA replicates
12
Q
What is checked at the G2 checkpoint?
A
if DNA was replicated properly and if the cell is growing well enough
13
Q
What is checked at the M checkpoint?
A
checking to see if the chromosomes are lined up properly for mitosis
14
Q
Genes in your body can code for ________ that do various functions and there are specific ________ that regulate the cell cycle
A
proteins
15
Q
Positive Regulators allow
A
moving forward in the cycle
16
Q
Negative Regulators
A
make processes stop
17
Q
Two proteins that are involved in positive regulation
A
cyclin and cdk
18
Q
G0 is the
A
resting phase
19
Q
Examples of cells that stay in G0
A
neurons of the brain and spinal cord
20
Q
a type of cell division that generates new cells for growth and repair
A
Mitosis
21
Q
Eukaryotes use mitosis for both _____ and ______
A
growth
repair/regeneration
22
Q
Prokaryotes use a process called ________________ in which the organism will grow twice its size then split into two genetically identical cells
A
binary fission
23
Q
True or False: both prokaryotic and eukaryotic cells undergo mitosis
A
false
24
Q
Chromosomes in prokaryotes are located in the
A
nucleoid
25
Chromosomes in eukaryotes are located in the
nucleus
26
Prokaryotes have _____ chromosome
one
27
Eukaryotes have __________ chromosomes
multiple
28
Prokaryote chromosome has more of a _______ shape
circular
29
Eukaryote chromosomes have more of a ________ shape
linear
30
Somatic cells are _____ cells
body
31
Examples of somatic cells
skin, liver, brain, blood, etc
32
Gametes are ____ cells
sex cells/ reproductive cells
33
Examples of gametes
sperm/ egg cells
34
Chromatin
complex of DNA and structural proteins
35
Chromosome
condensed chromatin visible under a light microscope
36
When a cell prepares to divide, each chromosome replicates resulting in two identical DNA molecules called
sister chromatids
37
Sister chromatids join at a constriction called
centromere
38
In nondividing cells, each chromosome consists of ___ molecules of DNA
one
39
True or False: the number of chromosomes is the same in all species of eukaryotes
false
40
True or False: the cell spends most of its cycle in the mitotic phase
false
41
True or False: the S phase produces two identical copies of cell's DNA content
true
42
True or False: chromosomes observed during G1 phase are duplicated
false
43
True or False: chromosomes observed during G2 phase are duplicated
true
44
G1 Phase Description
growth, intense metabolic activities
45
S Phase Description
synthesis, or replication of DNA
46
G2 Phase Description
cell grows more, makes proteins and organelles
47
M Phase Description
cell division
48
Animal Cells form a _______________ using a contractile ring of _____________
cleavage furrow
microfilaments
49
Cleavage Furrow
50
Plant cells fuse vesicles with cell wall material to form a ____ ______
cell plate
51
True or False: after mitosis, each daughter cell has twice as much DNA as the parent cell
false
52
Number of Chromosomes in Cell Before Interphase
46
53
Number of DNA Molecules in Cell Before Interphase
46
54
Number of Chromosomes in Cell After Interphase
46
55
Number of DNA Molecules in Cell After Interphase
92
56
Number of Chromosomes in Cell After Mitosis
46
57
Number of DNA Molecules in Cell After Mitosis
4
58
True or False: in the daughter cells produced by mitosis, each chromosome, formerly a sister chromatid, consists of one DNA molecule
true
59
True or False: human nerve and muscle cells are examples of cells that commonly pass the G1 checkpoint and continue on to cell division
false
60
Growth Factor
protein released by certain cells that stimulates other cells to divide
61
Anchorage Dependence
to divide, most tissue cells must be attached to substratum
62
Density- Dependent Inhibition
cells will stop dividing if the cells are too crowded
63
True or False: Healthy cells stop dividing after they create a single layer due to a process known as anchorage dependence
true
64
When the cell cycle fails, cells continuously divide and never differentiate. Resulting cells are abnormal and form a mass called a
tumor
65
Tumors do not exhibit _____________________ and or ______________________
anchorage dependence
density-dependent inhibition
66
process where a normal body cell is converted to a cancerous cell
transformation
67
Benign Tumor
abnormal cells remain at the original site
68
Malignant Tumor
cells invade surrounding tissues and can metastasize
69
True or False: malignant cells have no anchorage dependence and can travel through the blood and lymphatic vessels
true
70
You would be unlikely to see which of the following human cells dividing?
nerve cell
71
Observations of cancer cells in culture support the hypothesis that cancer cells __________.
do not exhibit density-dependent inhibition
72
If a human somatic cell is in metaphase, it has __________ chromatids.
92
73
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle each contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in a daughter cell of one of these cells?
100 units
74
You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.
it had formed a cell plate
75
Sister chromatids are __________.
identical copies of a chromosome
76
Which of the following processes does not occur in dividing bacteria?
Mitosis
76
The person credited with the axiom, “Every cell from a cell” is __________.
Rudolf Virchow
77
The function of mitosis and cytokinesis is to produce daughter cells that __________.
are genetically identical to the parent cell
78
Assume that you are dealing with a species in which the number of chromosomes in each somatic cell is 14. How many sister chromatids are present in the early telophase of mitosis?
0
79
Tissue culture experiments with PDGF demonstrate that without this substance __________.
fibroblasts fail to divide
80
One event occurring during prophase is __________.
the beginning of the formation of a mitotic spindle
81
During binary fission of a bacterium, __________.
origins of replication move apart
82
Which of the following represents a mismatch or incorrect description?
Metaphase: the nuclear envelope disappears
83
In a human skin cell that is going through the cell cycle, when do the centrosomes separate?
Prophase
84
Which of the following does not occur during mitosis?
Duplication of chromosomes
84
Down syndrome is characterized by cells having three copies of chromosome 21. As a somatic cell in an individual with Down syndrome prepares to enter mitosis, how many chromatids would be present in the cell’s nucleus?
94
85
A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled __________.
between the G1 and G2 phases
86
When not engaged in the processes leading to cell division, how many chromosomes from your mother are present in the nucleus of each of your somatic cells?
23
86
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
chromatin
87
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
88
Label The Cell Cycle Diagram
a: G2 phase
b: G1 phase
c: interphase
d: S phase
e: mitotic ( M) phase
f: mitosis
g: cytokinesis
88
The cleavage furrow forms during which stage of mitosis and cell division of an animal cell?
cytokinesis
89
Label the Diagram
a: mitotic spindle forming
b: sister chromatids centered
c: chromosomes separating
d: nuclear envelopes forming
e: interphase
f: prophase
g: metaphase
h: anaphase
i: telophase and cytokenesis
90
True or false: Mitosis takes place during M phase of the cell cycle, which is longer than interphase.
false
90
A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?
24
91
Which of the following checkpoints does not occur late in G1?
A check that chromosome replication has been successfully completed
92
What must happen before a cell can begin mitosis?
The chromosomes must be duplicated.
93
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
prophase
94
The chromosomes line up in the center of the cell during which phase of mitosis?
Metaphase
95
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Anaphase
96
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase
97
. DNA replication produces two identical DNA molecules, called
___________ which separate during mitosis.
sister chromatids
97
After chromosomes condense, the _________
is the region where the identical DNA molecules are most tightly attached to each other.
centromere (s)
98
During mitosis, microtubules attach to chromosomes at the
kinetochore(s)
99
In dividing cells, most of the cell's growth occurs during
interphase
100
The _____________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division
mitotic spindle(s)
101
During interphase, most of the nucleus is filled with a complex of DNA and protein is dispersed form called ________
chromatin
102
In most eukaryotes, division of the nucleus is followed by ___________, when the rest of the cell divides
cytokinesis
103
The ___________ are the organizing centers for microtubules involved in separating chromosomes during mitosis
centrosome(s)
104
Label the Diagram
a: non-dividing cells exit cell cycle
b: at this point, cell commits to go through the cycle
c: DNA replicates
d: two centrosomes have formed
e: mitotic spindle begins to form
f: cell divides, forming two daughter cells
105
Are sister chromatids present in G1 phase?
no
106
Are sister chromatids present in the S phase?
yes
107
Are sister chromatids present in G2 phase?
yes
108
Are sister chromatids present at the beginning of M phase?
yes
109
Are sister chromatids present at the end of M phase?
no
110
Is DNA condensed in G1 phase?
no
111
Is DNA condensed in the S phase?
no
112
Is DNA condensed in the G2 phase?
no
113
Is DNA condensed in the beginning of the M phase?
yes
114
Is DNA condensed at the end of the M phase?
yes
115
Does the cell contain twice as much DNA in the S phase as it did in the G1 phase?
yes
116
Does the cell contain twice as much DNA in the G2 phase as it did in the G1 phase?
yes
117
Does the cell contain twice as much DNA at the beginning of the M phase as it did at the beginning of the G1 phase?
yes
118
Explain the relationship between chromosomes and sister chromatids
Sister chromatids are joined identical copies of a duplicated chromosome
119
When considering all 46 chromosomes, how many sister chromatids are there total in a human cell immediately after interphase?
92
120
The chromosome is composed of?
two double stranded DNA molecules
121
Which statements does NOT accurately describe the initial stage of the cell cycle that would most likely be disrupted if animal cells were treated with specific chemicals?
cytokinesis would be disrupted by a chemical that interferes with the formation of the contractile ring of microtubules that deepen the cleavage furrow
122
One difference between cancer cells and normal cells is that cancer cells
are always in the M phase of the cell cycle
