Unit B: Cell Division Flashcards
1
Q
What are the two types of cell division?
A
- Mitosis
- Meiosis
2
Q
What cells does mitosis occur in?
A
All cells (somatic cells)
3
Q
What does mitosis produce?
A
2 identical daughter cells (diploid)
4
Q
What do diploid cells have?
A
Full genetic material (2n)
5
Q
Mitosis is used for the ? or ? of cells
A
Growth or replacement
6
Q
What type of reproduction is mitosis used in?
A
Asexual
7
Q
What type of cells does meiosis occur in?
A
Only in sex cells (germ cells)
8
Q
What does meiosis produce?
A
4 non-identical gametes (sex cells) (haploid)
9
Q
What do haploid cells have?
A
Half genetic material (n)
10
Q
What type of reproduction is meiosis used in?
A
Sexual
11
Q
How much time do cells spend dividing?
A
10%
12
Q
How much time do cells spend in interphase (prep)?
A
90%
13
Q
What is the first step/phase of interphase?
A
G1 (gap phase)
14
Q
What happens during G1?
A
The cell manufactures proteins and amino acids needed for both cell processes and cell division, carries out metabolic duties
15
Q
What is the second step/phase of interphase?
A
S phase (synthesis phase)
16
Q
What happens during S phase?
A
DNA replicates
17
Q
Why is S phase the longest stage of the cell cycle?
A
To ensure proper perfect DNA replication for new cell
18
Q
What is the third step/phase of interphase?
A
G2 (gap phase)
19
Q
What happens during G2?
A
- The cell increases the rate of protein synthesis and prepares to divide
- Grows larger by increasing cytoplasm, making organelles, energy
20
Q
How many times can a single cell divide on average?
A
50
21
Q
What do cells do to ensure that cells within a tissue are healthy?
A
Undergo a from of cell suicide called apoptosis
22
Q
Chromatin
A
Complex long threads made of DNA and protein that makes up chromosomes (long, thin, unorganized)
23
Q
Uncondensed Chromosome
A
Long, thin strands not visible with light microscope
24
Q
Condensed Chromosome
A
Short and visible
25
Chromosome vs Chromatid
Chromosomes replicate before division to form 2 matched sister chromatids
26
How many chromosomes do humans have?
- 46 (diploid) (2n)
| - Full set of genetic material
27
How many chromosomes do sex gametes have?
- 23 (haploid) (n)
| - Half set of genetic material
28
What are homologous chromosomes?
Same size and shape and carry the genes for the same traits, but have different details
29
How many homologous chromosomes do humans have?
23 (for a total of 46)
30
Homologous chromosomes in males vs females
Males: 22 pairs (1 pair that is not, XY)
Female: 23 pairs
31
What stage do homologous hormones only occur in?
Meiosis 1
32
What is the basic unit of heredity?
Gene
33
What is a gene?
Sequence of nucleotide bases in DNA
34
A gene codes for a specific?
Protein
35
What are chromosomes that do not influence biological sex?
- Autosomes
| - Humans have 22 pairs
36
What are X and Y chromosomes that determine biological sex in humans?
- Sex chromosomes
| - Humans have 1 pair of these located in the 23rd chromosome pair
37
I-PMAT
- Mitosis
| - Interphase, Prophase, Metaphase, Anaphase, Telophase
38
What is the longest phase of cell division?
Prophase (prepare)
39
What happens during early prophase?
- Chromatin condenses to form chromosomes
| - Centrioles move to poles and attach to spindle fibres
40
What happens during late prophase?
- Spindle fibres attach to centromeres
| - Nuclear membrane dissolves
41
What happens during metaphase (middle)?
Chromosomes line up on the equatorial plate (centre of the nucleus) (single file)
42
What happens during anaphase (aggressive)?
- Spindle fibres contract from the centrioles
- Sister chromatids begin to separate apart
- Immediately chromosomes begin to unravel
43
What happens during telophase?
- Nucleolus re-appears, nuclear membrane reforms, the chromosomes unravel to form a loose mass of chromatin
- Cells undergo cytokinesis (divide cytoplasm)
44
Most scientists always describe mitosis as starting with ? and ending with ?
- Replicating
| - Cytokinesis
45
What are two methods of asexual reproduction?
- Binary Fission
| - Budding
46
What is binary fission?
Equal division of both the organism's cytoplasm and nucleus to for two identical organisms
47
What are some examples of organisms that reproduce through binary fission?
Protist, amoeba, and bacteria
48
What is budding?
One parent dividing its nucleus (genetic material) equally, but cytoplasm unequally
49
What are some examples of organisms that reproduce through budding?
Fungi, and yeast
50
When does meiosis occur?
Sexual reproduction
51
Where does meiosis occur in males?
Spermatogonium (results in 4 sperms)
52
Where does meiosis occur in females?
Oogonium (results in 4 eggs)
53
What are two tasks that meiosis I accomplishes?
- Creates genetic variety
| - Separate replicated homologous chromosomes
54
What happens during prophase I?
Homologous chromosomes undergo synapsis (pair up) and crossing over occurs
55
Similarly to mitosis, what also happens during prophase I?
Chromosomes condense, nuclear membranes disappear, and centrioles move to opposite poles
56
What happens during metaphase I?
Homologous pairs line up along the equatorial plate (not single file), spindles insert into the centromeres
57
What happens during anaphase I?
Homologous chromosomes separate and are pulled to opposite poles (segregation) (entire chromosomes split from each other)
58
What are the two reasons for genetic diversity?
- Prophase 1 (crossing over)
| - Anaphase 1 (separate)
59
What do organisms undergo in anaphase I?
Independent assortment (same as segregation)
60
What happens during telophase I?
- Daughter cells separate (each has one chromosome from each homologous pair)
- Cytokinesis
61
What happens during telophase 1?
- Daughter cells separate (each has one chromosome from each homologous pair)
- Cytokinesis
62
How does meiosis I differ from mitosis?
- Meiosis produces 4 unique daughter cells, while mitosis produces 2 identical daughter cells
- Mitosis occur in all cells, meiosis only occurs in sex cells
- Mitosis produces cells that are diploid, meiosis produces cells that are haploid
- Meiosis produces genetically different cells, while mitosis produces genetically identical cells
63
How does meiosis 1 differ from mitosis?
- Meiosis produces 4 unique daughter cells, while mitosis produces 2 identical daughter cells
64
How does meiosis II differ from meiosis I?
- Like mitosis
| - Very brief (not as long as meiosis I)
65
What happens during prophase II?
Spindles form
66
What happens during metaphase II?
Chromosomes align at the equatorial plate (single file)
67
What happens during anaphase II?
The daughter chromatids separate and move towards separate poles
68
What happens during telophase II?
Spindle fibres disappear, nuclei reform, and cytokinesis takes place (all 4 daughter cells are haploid)
69
What is the very first cell with full genetic material?
Zygote (every cell will be genetically identical to this)
70
What cells are always haploid?
Gametes
71
What is the process of meiosis called within males?
Spermatogenesis (4 sperm)
72
What is the process of meiosis called within females?
Oogenesis (1 egg + 3 polar bodies)
73
During oogenesis, when is meiosis II completed?
Only when egg is fertilized
74
During oogenesis, what receives most if the cytoplasm, thus becoming the egg?
Secondary oocyte
75
During spermatogenesis, what sperm cell receives the most cytoplasm?
All sperm cells produced receive an equal share of cytoplasm
76
What happens to polar bodies during oogenesis?
Have less cytoplasm and degenerate
77
What forms from one of the centrioles during spermatogenesis?
Flagellum (tail)
78
What is produced during oogenesis?
1 egg cell
79
What is produced during spermatogenesis?
4 spermatids
80
What can be used to detect chromosomal abnormalities?
Karyotype chart (number of chromosomes)
81
What is the biological sex of females?
XX
82
What is the biological sex of males?
XY
83
What must be extracted in order to make a karyotype?
Fetal cells
84
How are fetal cells extracted in order to make karyotypes?
- Amniocentesis
| - Chronic villi sampling
85
What two things does successful cell division rely on?
- Accurate replication of the chromosomes (S-phase)
| - Exact separation/distribution of the chromosomes (anaphase I)
86
What is it called when three chromosomes replace a normal pair (47 chromosomes in humans)?
Trisomy
87
What is abnormal meiosis called?
Non-disjunction
88
What happens during non-disjunction?
Occurs when two homologous chromosomes move to the same pole causing the chromosomes to not separate properly
89
What causes non-disjunction?
Improper anaphase I
90
How are fetal cells extracted in order to make karyotypes?
- Amniocentesis
| - Chronic villi sampling
91
What two things does successful cell division rely on?
- Accurate replication of the chromosomes (S-phase)
| - Exact separation/distribution of the chromosomes (anaphase I)
92
What is it called when three chromosomes replace a normal pair (47 chromosomes in humans)?
Trisomy
93
What is abnormal meiosis called?
Non-disjunction
94
What happens during non-disjunction?
Occurs when two homologous chromosomes move to the same pole causing the chromosomes to not separate properly
95
What causes non-disjunction?
Improper anaphase I
96
What does Klinefelter's syndrome (XXY male) result in?
Sterile males with underdeveloped testes, overdeveloped breast tissue, and sub-normal intelligence
97
Down's syndrome is more common in children born to women over the age of what?
40
98
What chromosome does Edward's syndrome affect?
18 (trisomy 18)
99
What does Edward's syndrome result in?
Severe overall defects with a life expectancy of only 10 weeks
100
What chromosome does Patau's syndrome affect?
13 (trisomy 13)
101
What does Patau's syndrome result in?
Non-functioning eyes, severe defects, and limited life expectancy
102
What does Klinefelter's syndrome result in (XXY male)?
Sterile males with underdeveloped testes, overdeveloped breast tissue, and sub-normal intelligence
103
What are characteristics of a metafemale (XXX female)?
No obvious defects however menstrual irregularities and early menopause are common, some have increased aggression
104
What are characteristics of XYY male?
Taller than normal, recurrent acne
105
What is it called when one chromosome replaces a normal pair (45 chromosomes in humans)?
Monosomy
106
What does Turner's syndrome (XO female) result in?
Female's with short stature, broad chest, heart defects, lack of breasts, and absence of sexual maturation and menstruation
107
What does Cir du Chat syndrome result in?
Deletion of a portion of one copy of chromosome number 5, malformed face and head, and a shorter life span
108
After the nucleus is implanted into the egg cell and a zygote is formed, what happens next?
The zygote or blastula is implanted into the mother's uterus
109
Is cloning similar to mitosis or meiosis?
Mitosis
110
What is the quick and easy, yet not so successful way of cloning?
Somatic-cell nuclear transfer
111
What occurs during the first step of somatic-cell nuclear transfer?
An egg cell taken from an adult female and the nucleus is removed (enucleation)
112
What occurs during the second step of somatic-cell nuclear transfer?
The nucleus of the egg cell is replaced with the nucleus from a body cell of the individual to be cloned
113
What must the body cell of the donor be?
Tri-potent or have its identity genes turned off (can use stem cells here)
114
What societal issue deals with right or wrong, beliefs, etc. (religion vs science)?
Ethical
115
What societal issue deals with money, expenses, cost, cost vs time/benefit?
Economical
116
What societal issue deals with class differences?
Socio-economical
117
What societal issue deals with changes to the abiotic or biotic aspects of an ecosystem?
Environmental
118
What societal issue deals with bylaws, rues, and control?
Governmental
119
What is the major problem with cloning?
Ethical issue
120
What seems to happen to artificially cloned organisms?
Age faster
121
Why is cloning not regularly carried out?
- Very time and resource consuming
| - Not guaranteed to work
122
What are the ends of chromosomes called?
Telomeres
123
What happens to telomeres each time a cell divides?
They shorten
124
What happens when a cell becomes critically short?
Cell dies
125
What does totipotent mean?
When cells reach a certain number of divisions, or age, DNA begins to alter
126
What is cancer?
Abnormal, uncontrolled cell division of cells that did not get proper genetic material due to improper S-phase
127
What may cause cancer?
Mutation of genes
128
What do tumour suppressor genes do?
Suppress cell division (mutation turns these off)
129
What do proto-oncogenes do?
Stimulate cell division (mutation turns these on)
130
What happens to telomeres in cancerous cells?
Do not shrink
131
Why are cancer cells bad?
- Cancer cells do not participate in helping the body to function
- Cancer cells require and take away nutrients
- Cancer cells can breaks away (metastasis) from the tumour mass and spread to other parts of the body
