3 - CELL CYCLE Flashcards
1
Q
why do cells divide?
A
- reproduction
- tissue renewal
- growth and development
2
Q
what structures divide during cell division?
A
- DNA
- chromosomes
- nucleus
3
Q
4 stages of interphase
A
g1, s, g2, g0
4
Q
- normal metabolic activity
- number of cell organelles increases to normal levels and the volume of cytoplasm increases too, eventually reaching mature size
- a cell can remain in this phase indefinitely
- doubling of number of cell organelles
- stage of the cycle where cells stay the longest
A
g1 phase
5
Q
- Synthesis phase
- DNA and chromosomes replicate inside the nucleus (92 chromosomes / 46 pairs)
A
s phase
6
Q
- Structures directly involved in mitosis develop
- Preparation phase for cell division
A
g2 phase
7
Q
- Time-out phase
- Can last for years
- Cells may die, proceed to cell division, or remain specialized
A
g0 phase
8
Q
When Do Chromosomes Duplicate?
A
- During the S phase, all the chromosomes duplicate
- When a chromosome duplicates, it produces a replica chromosome referred to as chromatid/sister chromatid
9
Q
where are the sister chromatids joint?
A
centromere (specifically kinetochore)
10
Q
- The mechanism by which somatic eukaryotic cells produce identical daughter cells
- Produces 2 identical diploid daughter cells
- Involved partition of both cytoplasmic
A
mitosis
11
Q
four phases of mitosis
A
- prophase
- metaphase
- anaphase
- telophase
12
Q
- Chromatin condenses into chromosomes by dehydrating and coiling
- 1 chromosome pair = 2 sister chromatids
- Pairing of chromatids happens in this phase
- Nucleolus and nuclear envelope begins to disappear
- Centrosomes divide into 2 centrioles pair, move apart, forms spindle fiber
A
prophase
13
Q
- During ________, the chromosomes align near the center of the cell called equator
- The movement of chromosomes is regulated by the attached spindle fibers
- Motion similar to tug-of-war
- Longest stage of mitosis
A
metaphase
14
Q
- The centromere dissolves and releases each chromatid to be pulled by the spindle fibers via the kinetochore
- At the end, each set of chromosomes has reached an opposite pole of the cell, and the cytoplasm begins to divide.
- Shortest stage of mitosis
A
anaphase
15
Q
- Chromosomes in each of the daughter cells become organized to form two separate nuclei, one in each newly formed daughter cell
- Cleavage furrow forms preparing for complete division
A
telophase
16
Q
After telophase, the mother cell splits into 2 and produces 2 daughter cells by undergoing?
A
cytokinesis
17
Q
mitosis control checkpoints
A
- DNA damage checkpoints
- apoptosis checkpoint
- spindle assembly checkpoint
18
Q
checkpoint that happens during s phase
A
DNA damage checkpoint
19
Q
- Survivins ensure that mitosis continues instead of apoptosis
- As mitosis begins
A
apoptosis checkpoint
20
Q
checkpoint that happens during metaphase
A
Spindle assembly checkpoint
21
Q
uncontrollable cell / continuously dividing cells spread out throughout the body
A
Metastatic spurt
22
Q
- Specialized type of cell division which reduces the chromosome number by half
- This process occurs in all sexually reproducing eukaryotes both single-celled and multicellular including animals, plants, and fungi
A
meiosis
23
Q
end of meiosis 1
A
2 daughter cells with 46 chromosomes each and are no longer identical due to recombinant chromosomes
24
Q
tetrad formation and crossing over
A
Prophase I
25
Each sister chromatid will link with their homologous chromosome
tetrad formation
26
Interchange of genetic material between homologous chromosomes occurring during Prophase I
crossing over
27
- Tetrads line up at the equator
- 1 sister chromatid is pulled to each polar end
metaphase I
28
- Tetrads line up at the equator
- 1 sister chromatid is pulled to each polar end
- Upon separation of each sister chromatid, 1 will result to a unique sister chromatid
anaphase I
29
- Nuclear envelopes partially assemble around chromosomes
- Spindle disappears
- Cytokinesis divides the cell into two
telophase I
30
Interchange of genetic material between homologous chromosomes occurring during Prophase I
crossing over
31
Same as prophase except:
Sister chromatids are now recombinant
prophase II
32
Each sister chromatid lines up at the equator (2)
Metaphase II
33
- Each individual chromosomes are pulled to opposite poles
- Each developing cell will only get 1 copy of each chromosome
Anaphase II & Telophase II
34
Haploid sperm cell and oocyte are derived from
diploid germ cells
35
process of developing haploid cells (N or 23 chromosomes)
meiosis
36
begins with double number of chromosomes and ends up with 2 diploid cells
first meiotic division
37
reduction of chromosome number since each of the cells from the first division divides again = 4 cells
second meiotic division
38
Substances that may produce physical or functional defects in the human embryo or fetus after the pregnant woman is exposed to the substance
teratogens
39
period where the pregnant woman is most vulnerable to teratogens
1st trimester
40
most common teratogens
Tobacco and cannabis
Arsenic and benzene
Caffeine and alcohol
