Cell Growth And Division Flashcards
(119 cards)
1
Q
What are the 3 stages to interphase?
A
G1- growth 1
S- synthesis
G2- growth 2
2
Q
Growth 1
A
Cell grows, metabolism is active, new proteins and RNA are made.
3
Q
S phase
A
- processing (synthesis) of DNA
- DNA content doubles (info is copied)
4
Q
G2 phase
A
- cell now contains twice as much DNA
- cell processes a substance that triggers cell
division to begin mitosis - enzymes released
5
Q
M phase
A
- nucleus reproduces through a series of
events called mitosis - chromosomes become visible (condensed)
- not apart of interphase
6
Q
What are the stages of the cell cycle?
A
- Interphase
- Mitosis
- Cytokinesis
7
Q
How often do most eukaryotic cells divide?
A
Once every 24 hours
8
Q
Chromosome
A
One long strand of DNA that consists of numerous genes along with regulatory info.
9
Q
How many chromosomes are in our bodies?
A
46
10
Q
Chromatin
A
Loose combination of DNA and proteins
11
Q
Histones
A
DNA wraps around it at regular intervals, similar to beads on a string
12
Q
Chromatid
A
1/2 of a duplicated chromosome
13
Q
Sister chromatids
A
Two identical chromatid
14
Q
Centromere
A
A region of the condensed chromosome that looks pinched
15
Q
Telomeres
A
The ends of DNA molecules form structure
16
Q
Spindle
A
Found in centrioles (only in animal cells), determines the direction of the cells during division.
17
Q
What happens when the ratio of surface area to volume is too small?
A
The cell cannot move materials into and out of the cell at a sufficient rate or in sufficient quantities.
18
Q
Does a cells volume increases as a cell grows?
A
Yes, more rapidly than its surface area
19
Q
What are the stages of mitosis?
A
- prophase
- metaphase
- anaphase
- telophase
20
Q
Prophase
A
- mitosis begins
- centrioles (poles) appear and begin to move
to opposite ends of a cell - spindle fibers form between the poles
- chromosomes condense
- nuclear membrane disappears
21
Q
Metaphase
A
- Chromosomes move to the center of the cell
AKA the cell’s equator - chromatids attach to the spindle fibers
22
Q
Interphase
A
- chromosomes are copied
- chromosomes appear as threadlike coils or
chromatin at the start, but each chromosome
and its copy (sister chromosome) change to
sister chromatids at end of this phase
23
Q
Anaphase
A
chromatids separate and begin to move to
opposite ends of the cell
24
Q
Telophase
A
- two new nuclei form
- chromosomes appear as chromatin
- chromosomes gather to opposite poles
- nuclear membrane forms around each group
of chromosomes - each nuclei contains a set of identical
chromosomes - mitosis ends
25
Cytokinesis
- cytoplasm divides into 2 parts
- cells are diploid (2n)
- cell membrane moves inward to create 2
daughter cells
26
What factors regulate cell division?
Internal and external
27
What are external factors?
Physical (cell contact) & chemical signals (growth factors)
28
What are growth factors?
Proteins that simulate cell division
- most mammal cells form a single layer in a
culture dish and stop dividing once they touch
other cells.
29
What are the internal factors?
Kinases & cyclins
30
Kinases
An enzyme (protein) that, when activated, transfers a phosphate group from one molecule to a specific target molecule. This changes the shape of a molecule.
31
Cyclin
A group of proteins that are rapidly made & destroyed at certain points I the cell cycle.
32
What factors trigger internal factors?
External factors
33
Apoptosis
- programmed cell death
- a normal feature of healthy organisms
- caused by a cell's production of self
destructive enzymes
- occurs in development of infants
34
Is cell division uncontrolled by cancer?
Yes
35
Tumors
Cancer cells formed in disorganized clumps
36
Benign tumors
Tumors that remained clustered and can be removed
37
Malignant tumors
Tumor that metastasize or break away and can form more tumors
38
Do cancer cells carry out necessary functions?
No
39
Carcinagers
Substances known to promote cancer (from the environment)
40
Standard cancer treatments
Typically kill both cancerous and healthy cells
41
Where do cancer cells come from?
Normal cells with damage to genes involved in cell cycle regulation
42
Oncogenes
Accelerate the cell cycle
43
What do most cancer cells carry mutations/errors in?
2 types of genes
44
How many chromosomes do daughter cells have compared to the original cell during meiosis?
Half as many
45
What does meiosis produce?
Gametes turn to 2 diploids turn to 4 haploids
46
Gametes
Eggs and sperm
Haploid cell
47
Where does meiosis occur?
Female
- ovaries or oogenesis
Male
- testes or spermatogenesis
In our germ cells that produce gametes
48
How many chromosomes do you start with during meiosis?
46 double stranded chromosomes or 2n
49
How many chromosomes do you have after division I of meiosis?
23 double stranded chromosomes or n
50
How many chromosomes do you have after division II of meiosis?
23 single stranded chromosomes or n
51
Why do we need meiosis?
It is the fundamental basis of sexual reproduction.
52
How are 2 haploid gametes brought together?
Through fertilization
53
What do the 2 haploid gametes produce?
A diploid or 2n zygote
54
Diploid or 2n
A cell that has two sets of chromosomes in its nucleus.
55
Haploid or n
A cell with only one set of chromosomes in. It's nucleus.
56
Meiosis I
First two stages of meiosis
57
Homologous chromosomes
Chromosomes that carry the same genes and are similar in size and shape
58
Homologue
Member of pair of homologous chromosomes
59
Crossing over
The exchange of segments (genes) between chromatids (synapsis). Produces recombination in an offspring.
60
Genetic recombination
The regrouping of genes into new combinations.
61
What must fertilization restore?
The 2n number
62
Prophase I
Early prophase
Late prophase
63
Early prophase
- homologous prophase
| - crossing over occurs
64
Late prophase
- chromosomes condense
- spindle forms
- nuclear envelope fragments
65
What forms during prophase I?
Tetrads
66
Synapsis
Homologous chromosomes with sister chromatids join to form a tetrad during prophase I.
67
What does crossing over multiple?
The huge number of different gamete types
68
What are the huge number of different gamete types produced by?
Independent assortment
69
Metaphase I
Homologous pairs of chromosomes align along the equator of the cell.
70
Anaphase I
- homologous separate and move to opposite poles
| - sister chromatids remain attached to their centromeres
71
Telophase I
- nuclear envelopes reassemble
- spindle disappears
- cytokinesis divides cell into two.
72
How many homolog of each chromosome are present in each cell during meiosis II?
1
73
What do sister chromatids carry during meiosis II?
Identical genetic information
74
Meiosis II
Produces gametes with one copy of each chromosome and thus one copy of each gene
75
Prophase II
- nuclear envelope fragments
| - spindle forms
76
Metaphase II
Chromosomes align along the equators of the cells
77
Anaphase II
- sister chromatids separate and move to opposite poles
78
Telophase II
- nuclear envelope assembles
- chromosomes decondense
- spindle disappears
- cytokinesis divides the cell into two
79
What are the results of meiosis?
- gametes form
- four haploid cells with one copy of each chromosome
- one allele of each gene
- different combinations of alleles for different genes along the chromosome
80
How many divisions are in mitosis?
1
81
How many divisions are in meiosis?
2
82
How many daughter cells are formed in mitosis?
2
83
How many daughter cells are formed during meiosis?
4
84
Are the cells genetically identical during mitosis?
Yes
85
Are the cells genetically identical during meiosis?
No
86
How many parent chromosomes remain after mitosis?
Same
87
How many parent chromosomes remain after meiosis?
Half
88
Where does mitosis take place?
Somatic cells
89
Somatic cells
Body cells
90
When does mitosis occur?
Throughout life
91
When does meiosis occur?
At sexual maturity
92
What role does mitosis play?
Growth and repair
93
What role does meiosis play?
Sexual reproduction
94
Where does the cell spend most of its time?
Interphase
95
How long is mitosis?
About 1 hour
96
What is the diploid number of chromosomes?
2n=46
97
What is the haploid number of chromosomes?
N=23
98
When does crossing over take place?
After prophase 1
99
What is the benefit of crossing over?
Genetic variation goes up
100
Do all cells go through meiosis?
No, only gametes
101
How many daughter cells form after meiosis I?
2
102
How many daughter cells form after meiosis II?
4
103
Why is meiosis I called the reduction division?
Because the chromosomes are reduced by half
104
When does meiosis take place?
After fertilization
105
Male gamete
Haploid sperm
106
Female gamete
Haploid egg
107
What causes uncontrollable cell division?
Cancer
108
Homologous chromosomes
Two chromosomes one inherited from the mother and one from the father. Chromosome 9 always matches up together.
109
Autosomes
Chromosomes 1-22 that contain genes for characteristics not directly related to the sex of an organism (eye, hair, skin color).
110
Sex chromosomes
Chromosome 23 that controls the development of sexual characteristics
111
What kind of sex chromosomes does a female have?
2 X chromosomes
112
What kind of sex chromosomes does a male have?
X and Y chromosome
113
Are autosomes homologous pairs?
Yes
114
Sperm
A male gamete that gives 1/2 the DNA to an embryo.
115
Egg
A female gamete that gives organelles, molecular building blocks, 1/2 the DNA, and materials to begin life to an embryo.
116
Which chromosome carries the fewest number of genes?
Y
117
Metastasize
When cancer cells break away from the tumor and attach to other areas
118
Polar bodies
Cells with little more than DNA that are eventually broken down.
119
Stem cells
A unique type of body cell that has the ability to develop into a variety of specialized cell types.
