Cell Reproduction and Differentiation Flashcards
This is crucial because without it, we would have remained unicellular.
cell reproduction
Creatingmillionsofcellsisnot
enough; we can’t just keep creating. Differentiation is key. We assign them distinct purposes, functions, and roles.
cell differentiation
cell division = reproduction
unicellular organisms
Like us, they undergo cell division, PMAT, and have the ability to reproduce. When they divide to become another cell, it is a form of reproduction. The initial cell, upon giving birth, generates additional cells, leading to an increase in population.
unicellular organisms
cell division = development
multicellular organisms
As we age, our internal structures evolve into increasingly complex forms.
development
Every time our cells divide, it
involves growth, which can manifest in literal size.
★ Fertilized cell -> Baby
growth
Our bodies have the ability to self repair because of cell division.
regeneration
two phases of cell cycle
interphase and mitotic phase
→ Primary period of cell growth
→ The cells are starting to create the organelles
→ “Organelle Factory”
→ Here, we are developing our
mitochondria, chromosomes, nuclear membranes, and many more. The major organelles are created here.
G1phase
- “In between cell division”
- Long growth period between cell
divisions - Long portion of the Cell Cycle
- A lot of people say that everything
here is at rest but that is not correct. It is actually preparing for the main event which is the M Phase.
interphase
→ DNA is duplicated
→ Growth continues slowly
→ Creating the genetic material that could mean DNA and RNA
→ Central Dogma happens here
→ A composition of a cell is simply organelles inside then on the middle is the nucleus and inside that nucleus are the genetic material. So the G1 and S Phase are both equally important phases.
S phase
→ Cell prepares for division
→ Chromatin condenses into
chromosomes
→ Growth continues slowly
→ Preparing for the next step
→ Double checking the organelles
and genetic material because for the preparation for M Phase
→ Everything entering the M Phase needs to be perfect already.
G2 phase
Inside our bodies, there are cells that decode signals to cease reproduction; they become non-dividing. These cells retain the characteristics you have at a certain age until the day you die. If they get damaged, repairing them becomes nearly impossible.
G0
→ are cells that can be found in the bones
→ At some point in our life, our bones stop growing.
osteocytes
→ Permanent
→ At some point in our lifetime, our neurons stop reproducing. This will cause conditions related to memory and impaired brain function.
neurons (nervous system)
→ Temporary
→ These are for boys and this only
activates at a certain period of their life to generate sperm cells.
spermatocytes
→ Temporary
→ These are for girls that are
temporarily G0 and only activate when they experience menstruation.
oocytes
How long does the M phase take?
less than an hour
how long does g1 take?
5-6 hours
how long does s phase take?
10-12 hours
how long does g2 take?
4-6 hours
in human cells, complete cell cycle takes how long?
18-24 hours
- Not all cells divide at the same rate
- Internal surveillance and control
mechanism - Several key checkpoints where “go
ahead” signals must be received in order for the cycle to progress to the next phase - Outside influences can modify cell cycle
- Hormones, growth factors,
presence of other cells - These are for checking, controlling,
and regulating the different
processes - Located in between the phases
cell regulation
it checks the organelles
g1 checkpoint
it checks the genetic material
s checkpoint
it double checks the double checker to ensure that everything is perfect to produce a perfect and healthy cell
g2 checkpoint
the cell examines whether all the sister chromatids are correctly attached to the spindle microtubules
M checkpoint
this is continually being formed from deep layers of cells. the outermost layer of dead cell is constantly being sloughed off
skin cells
___ lining the inner surfaces of body organs such as the digestive tract and the lungs are exposed to frequent damage and must be replaced
epithelial cells
stems cells in the _____ produce red blood cells and white blood cells throughout life. WBC production can be increased as part of the immune response
bone marrow cells
_____ divide to produce sperm throughout life in the adult male. the rate declines with age.
spermatogonia (after puberty)
____ dont normally divide in adulthood but will do if part of the ____ is cut off
liver cells
although there are exceptions, most human ____ apparently do not divide in adulthood
nerve cells
called granulosa cells, they are quiescent for most of adult life. they begin to divide as the follicle matures
epithelial cells surrounding the egg
mature bone cells called ___ become trapped within the hard crystalline matrix of the bone
osteocytes
the commonly held view is that most ____ do not divide in adulthood, or divide very slowly
muscle cells
- Cell Division
- PMAT happens here
- Small portion of the Cell Cycle
- Main Event
mitotic phase / m phase
→ Cytoplasm division
→ two daughter cells are formed
Cytokinesis
Nuclear division, duplicated DNA distributed to daughter cells
mitosis / meiosis
→ Generates haploid cells(1n), one set of chromosomes per cell only
→ Involve and is exclusively sex cells
★ Gametes: sperm, egg, spores
→ Requires two cell division
→ 4 Daughter cells are genetically different from parent cells
→ For producing gametes or spores, first step of reproductive process in sexually reproducing organisms
meiosis
Diploid cell to 2 haploid cells,
crossover
meiosis I
2 haploid cells to 4 haploid cells
Meiosis II
→ Generates new diploid cells (2n), two sets of chromosomes from parent cells
→ Asexual reproduction
→ Nuclear division (mitosis) followed by cytoplasmic decision
(cytokinesis)
→ 2 Daughter cells offspring are generally identical to the parent cell
→ For reproduction : single-celled
organisms - binary fission
→ For cell growth: repair
→ These are somatic cells or our body cells. All body cells go through mitosis except for two: egg cells and sperm cells.
★ Neurons
★ Livercells
★ Cells of the uterus
★ Cellsofthetestis
mitosis
2 strands
Diploid
1 strand
haploid
- Singular but not looking for a
pair - Not moving
chromatin
- Single but becoming closer to
your pair - Not yet connected
- Unattached but had started to
move already
chromatid
Already bound on the middle
chromosome
- Chromatin condenses into visible chromatids
- Nuclear envelope disappears
- Mitotic spindle formed
prophase
sister chromatids join and pair at the
centromere
spindle fibers attach themselves to
kinetochores
____ perform the pulling action, directing some chromosomes to cell 1 and cell 2
spindle fibers
- structures resembling stars
- consist of various components, including centrosomes and microtubules
- serve as a powerful mechanism for the pulling process.
- While spindle fibers act as ropes or pullers, the true power or machinery lies within this
- must travel towards the two opposite poles, ensuring an equal and balanced distribution of genetic material.
asters
true or false: centromeres are only found in animal cells
true
Within the centromere, proteins are present, forming a structure known as the..
kinetochore
→ Nuclear envelope fragments
→ More condensed chromosomes
→ Each chromatid now has
kinetochores
→ The microtubules attach to the kinetochores “kinetochore
microtubules”
→ Non kinetochore microtubules interact with those of the opposite
poles of the
→ This is the continuation of
everything that happened in
prophase.
→ Earlier, the nuclear envelope
began to dissolve, and here, it continues to dissolve. Similarly, asters were traveling towards opposite poles before, and here, they are still traveling. Spindle fibers are still forming.
prometaphase
- Duplicate chromosomes from a single lines at the equator between centriole poles a “metaphase plate”
- Centrosomes are at opposite poles of the cell
- One of the longest phases
- this is the lining up in the middle
metaphase
This phase is the longest because it takes a significant amount of time to form a complete centromere.
metaphase
→ Sister chromatids separate (disjunction)
→ Daughter chromosomes are pulled towards poles by microtubules
→ Cell elongates as nonkinetochore
microtubules lengthen
→ Shortest stage
→ This is known as separation or
disjunction. This is the shortest stage because it is easy to separate, especially considering the fact that there are forces pulling them. Asters are the ones that pull them, and spindle fibers are used for pulling them.
anaphase
indicates that they have been separated for a while or are already in the process of separating.
late anaphase
chromosomes have just separated
early anaphase
→ Reverse of prophase
→ Daughter nuclei forms
■ Nuclear membrane reforms
■ Nucleoli reappear
→ Mitotic spindle disintegrates
→ Chromosomes start to uncoil and
revert to chromatin
→ Cleavage furrow forms
→ The nuclear envelope will reform again. This means that our nucleus will become well-defined. One nucleus for Cell 1 and another for Cell 2. Spindle fibers will disappear because their job is done. Asters will deactivate; they won’t travel anymore, pull, or exert power. They will be at rest.
→ The main goal is for chromosomes to become chromatids and eventually return to the chromatin state.
telophase
Official separating creating two identical daughter cells
cytokinesis
Can be found inside the asters
centrosome
It is the one found in the middle that makes it official. It is in the center; it is the one that binds the two strands together.
Centromere
