Cell Cycle Flashcards
a series of events that takes place in a cell as it grows and divides.
Cell Cycle
-a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus.
- Results in diploid cells (2n = 46 chromosomes)
- Takes place throughout an organism’s lifetime
- Involved in asexual reproduction
Mitosis
Produces genetically unique cells
- Results in haploid cells (1n = 23 chromosomes)
(needs maternal and paternal cells to complete the 46
chromosomes)
- Takes place only at a certain time in an organism’s
life cycle
- Involved in sexual reproduction
Meiosis
cells that continuously multiply and divide throughout life.
Labile Cell
Type of cell that is present in skin
Epithelial Cells
Does not constantly proliferate
- After it complete the phase, it will stay under G0
phase
- It would only replicate if there is a stimulus
- Liver. Hepatocytes – meaning it would
regenerate.
- Epithelium of kidney tubules and alveolar of the
lungs
Stable cell
- Cells that would no longer proliferate after it undergoes the
cycle - Skeleton muscle, cardiac muscles and neurons
Permanent/Amitotic Cells
-genes that make sures that there is not abnormal
growth of cells. Disruption of cells could cause
cancer cells.
Tumor Suppressor Genes
90% of the process (of the entire cell cycle)
- Mammalian cells = 12-24 hours to complete
interphase
- Root tip = 12-30 hours to complete interphase
Interphase
- Prepares the cell
- Cell would start making more organelles for it to
be enough to replicate the cell - Cell would start synthesizing proteins and
enzymes - Repair of thymidine dimer. It would scan DNA
to make sure that there are no mistakes to avoid
mutation - it is use to synchronize cell during G1 and S
phase - Last for 8 hours or a year depending on a cell
type
G1 Phase (1st Gap Phase)
- Phase quiescent stage
- Rest phase for cells
G0 Phase
- DNA is being replicated to form 2 sister
chromatids, which is held at centromere. - DNA polymerase would help in replication of
DNA - Enzymes would open a bubble in a DNA
strand. As it opens, it would start replicating
for a new strand of DNA - The diploid cell (2n) would now become 2
diploid cells (4n).
S Phase (Synthesis)
- Found in between G1 and S phase
- Make sures that there’s no issue with the
cells and have enough enzymes - DNA would decide if it would divide or not,
or enter rest phase
G1/S phase checkpoint
The cell growth will continue and continue
increase the cytoplasm
- Make sures that everything is equal
- Increase in synthesizing of ATP or energy that is
needed for cell division
G2 Phase
- Cells make sures to prevent damage cells
(damage DNA) - The cell would either repair or stop to
proliferate
G2-M Checkpoint
a condition of the cell where it could no longer
proliferate, even if there is a strong stimulus
present.
Cellular Senescence
Nuclear envelope would start to dissolve.
- There would be a phosphorylation of the Lamin
and the histone would activate proteases and
dissolve the nuclear envelope
- Nucleus would disappear and leave loose
chromatins that would start to condense
- Microtubules organizing center (MTO)
- Would form centrosomes and move apart to
opposite directions
Prophase
imaginary line within the cell
that is where the chromosomes would start to
line up
Metaphase plate
- Centrosomes are already in opposite poles. It
would also start budding out mitotic spindles
and would start attaching to kinetochore. - Kinetochore is a protein that connect
chromosomes to microtubules of mitotic spindle
Metaphase
- The cell would check if the sister chromatids
are correctly attached to the mitotic spindle - If it’s not, it would pause to give time to the
sister chromatids to attached to the mitotic
spindle
M Checkpoint or Spindle Checkpoint
- Mitotic spindle will start pulling the
chromosomes apart. Motor proteins contain
dynein and kinesin - As they separate, they are now called daughter
chromosome - Cohesin – a type of protein that connects
chromosomes in centromere
Anaphase
Spindle fibers will disappear
- Chromosomes would start to uncoil. It would
go back as loose chromatin
- Nuclear envelope or reappearing, as well as the
nucleus.
- It would start constricting to form the cleavage
(myosin protein).
- By creating cleavage furrow, it would now lead
to cytokinesis
- In Plants
- As vesicles became secretary vesicles from
the Golgi apparatus. It is filled with cell wall
components called cellulose.
- Vesicles (cellulose) would build up and
create a cell plate, to become a cell wall in
that would trigger cell division or
cytokinesis
Telophase
- The diploid cell (a result of mitosis) would start
DNA replication and begins Meiosis I. - Homologues are pulled apart and sister
chromatids would stay together. - It will undergo cell division and create 2 haploid
cells
Meiosis I
- Same with prophase in mitosis
- Disappearance of nucleus and nuclear
envelope - Chromosomes condense
- Crossing over occurs. It is an exchange of
genetic information between 2 sister
chromosomes - Proteins will break both DNA strands of the
2 sister chromatids - The chromosomes have swapped each other
DNA information - Every pair of homologous chromosomes
will cross over at least once - At the end of it, it will have recombinant
chromosomes or recombinant DNA
(carrying genes from 2 chromosome)
Prophase I
- Almost the same with Metaphase in mitosis
- The only difference is they would line up
randomly - Mitotic spindles would attach to the
chromosomes
Metaphase I
- This phase would start to pull apart the sister
chromosomes
Anaphase I
- This phase would produce 2 haploid cells, genetically
unique cells
Telophase I
phase where it would generate
gametes and will create 4 haploid gametes
- Process is the same in Mitosis, the only
difference is the chromosomes have or is a
recombinant chromosome
Meiosis II
Male gamete
- Haploid (1n=23)
- Also called spermatozoa
Sperm
- Contains nucleus
- Contains chromosome
- Autosomes: 22
- Sex chromosomes: 1
PART OF THE SPERM
Head
- Contain the enzyme necessary for
fertilization
PART OF THE SPERM
Acrosome
Contains the Mitochondria
- Produces ATP (adenosine triphosphate) or
energy since sperm cells are motile
PART OF THE SPERM
Midpiece
- Also called flagellum
- Used in order to propel themselves
- Moves in a whip-like motion to propel the sperm
forward
Tail
is the biological process of producing mature sperm cells, and occurs in a sexually reproductive organism’s male gonad. In this process, a series of events develop the undifferentiated male germ cells into spermatozoa.
- Spermatogonia (2n)
- Males are born with a finite number
- Can undergo mitosis
- Approximately 50-500 million sperm are ejaculated
or per-ejaculation
Spermatogenesis
Process that produces the egg cells (produces 4, but only 1 is
used to form an egg cell)
- Primordial Follicles under FSH (follicle-stimulating
hormone) are stimulated (produced from pituitary
gland) - These are under develop cells
- Develops into Graafian follicle
- Pituitary Glands produces Luteinizing Hormone
(LH) is secreted that causes ovulation - Graafian follicle releases ovum
- Occurs on day 14 of cycle
- Graafian follicle becomes corpus luteum under the
influence of FSH and LH - Secretes Progesterone
Oogenesis
Is the site where egg cells are produced
Ovary
-wall that thickens to prevent polyspermy.
is a dense jelly type barrier that
surrounds the ovum. Sperm cells tend to get stuck
here when burrowing
Zona pellucida
Spermatogenesis consists of the following stages: ____________, __________, __________, and __________. Spermatogenesis begins at puberty in humans, and continues throughout life. It can take some 64 days to complete the process.
spermatocytogenesis, spermatogenesis, spermiogenesis, and spermiation
surrounds the oocytes that releases peptide for ovarian hormone synthesis regulation.
Follicle Cells
supply vital proteins to the egg cell
Corona Radiata
-Presence of an abnormal number of chromosomes
-More common in humans
-Nullisomy, monosomy, disomy trisomy and tetrasomy are the different types
-Causes chromosomal disorders; some of them are lethal
Aneuploidy
-Presence of more than two homologous chromosome sets
-Rare in humans
-Triploid, tetraploid, hexaploidy, octaploid, dodecaploic, etc. are the different types
-Triploid and tetraploid situations are lethal
Polyploidy
