Foundation Cell Division and Histology Flashcards
Haploid means
Diploid means
Haploid means one set of chromosomes and diploid means 2
G1 and G2 phase is a phase where the cell monitors _____________ to make sure the conditions are suitable
So, the G1 and G2 phase is a phase where the cell monitors the internal and external environment to endure that conditions are suitable, and preparations are complete before the cell commits itself to the major upheavals of S phase and mitosis.
List the controls of the Cell Cycle
- G1/S-cyclins
- S cyclins
- M cyclins
For CDK to be active. it must be bound to ______
Cyclin
Only when the complex is formed between cyclin and cdk, what happens?
The protein kinase is activated to trigger specific cell cycle events
Without cyclin, cdk is _____
Inactive
G1/S cyclin activates cdks is ________
In late G1 and triggers the progression through start resulting in a commitment to cell cycle entry
S cyclins bind to cdks and helps stimulate _______
Help stimulate chromosome duplication. S cyclin levels remain elevated until mitosis and these cyclins also contribute to control some early mitotic events.
M cyclins activate cdks that stimulate entry into mitosis at the _______ checkpoint
G2/M checkpoint. M cyclins are later destrpyed in the mid mitosis phase.
What regulatory protein acts like cyclin-cdk complex and controls the metaphase to anaphase transition?
APC/C
To summarize the cell cycle, there are ___ checkpoints of which _____ are controlled by cyclins and one by a regulatory protein.
3 checkpoints, of which 3 are controlled by cyclins
What is cell synchronization?
A process by which cells in a culture at different stages are brought to the same phase. YOU’RE TRYNA SYNC THEM UP
Serum or growth factor starvation arrests cells at ______
G0/G1
Replication Inhibitors arrest at _______ and ______
G1/S and S phase
Mitotic inhibitors can arrest at
The M phase
Centrifugal elutriation is what
a technique by which cells are fractionated based on their size
What size cells are G1
small size
What size cells are G2
large size
what size cells are S
intermediate size cells
What happens in prophase of mitosis
- Nucleolus disappears
- Chromatin condenses
- separation of centrosomes
- formation of the mitotic spindle
what happens in prometaphase of mitosis
- nuclear envelope disassembles
- chromosomes attch to spindle microtubles via kinetochores
The plus ends of the microtubules project _____ from centrosomes while the minus ends are anchored at the ________
Plus ends = away from centrosomes
minus ends= anchored at spindle poles
Kinetochore microtubles connect the spindle poles with the _______
kinectochores of sister chromatids
Iinterpolar microtublues from the two poles interdigitate at the ________
spindle equator
Astral microtubules radiate out from the poles into the _________ and usually interact with the _________ helping to position the spindle in the cell
Astral microtubles = radiate into cytoplasm
usually interact with the cell cortex helping to position the spindle in the cell
Motor proteins are involved in _________
spindle assembly and function
Dynein is a motor protein that moves towards the _______
minus end
kinesin-5 is a motor protein that moves towards the
plus end
kinesin-14 is a motor protein moving twards the
minus end
kinesin -4, 10 is a motor protein moving towards the
plus end
Motor proteins helps in
anchoring the microtubule to the chromatids, aligning at the equator
then segregation of the chromatids to the opposite poles.
Explain for kinetochores capture microtubles from opposite spindle pole to convert unipolar to bipolar attachment. Use the following terms
- Prometaphase
- astral microtubule
- lateral attchment
- unipolar attachment, bipolar attachment
Sister kinetochores are constructed in a ________ orientation
Back to back orientation. This reduces the likelihood that both kinetochores can face the same spindle pole.
What are the two theories that explain depolymerization pulling the kinetochore towards the spindle
- Force pulls
- Polar ejection force
What happens in metaphase of mitosis?
- meet in the middle
- chromosomes align at the equator of the spindle
- kinetochore microtubles attches to the sister chromatids
What happens in anaphase in mitosis
- Pulled apart
- chromatids separate to form two daughter chromosomes
- move towards opposite poles kinetochore microtublue gets shorter
Whats the difference between anaphase A and B
A: shortening of kinetochore microtubules, movement of daughter chromosomes to poles, forces generated mainly at kinetochores
B: Sliding force is generated between interpolar microtubules from opposite poles to push poles apart; interpolar microubules also elongate
A pulling force acts directly on the poles to move them apart
What happens in telophase of mitosis
- T for terminal/ the end
- new nuclear envelope forms chromosomes unfold back into chromatin
- nucleoli reappears
- cell continue to elongate
What two things happen in cytokineses
- cytoplasm divides into 2
- daughter cells divide.
What is the gist of meiosis
dont be scared.
its the process by which germ cells divide to produce gametes.
Its a cell division that reduces the number of chromosomes in the parent by half and PRODUCES 4 GAMETE CELLS
Meiosis begins with a parent cell that is ____
Diploid. Has two copies of each chromosome.
What is the result of meiosis
results in 4 daughter cells that are haplois, contain half the number of chromsomes of the diploid parent cell.
*lol dont forget (a)chaar mei
When does crossing over occur?
Prophase I of meiosis 1
What happens in Prophase 1 of meisosis 1
- chromatids match up with their homologous pair and fasten together (synapsis)
- CROSSING OVER HAPPENS HERE
- Crossing over is the exchange of segments during synapsis
What is the longest phase of meiosis
prophase 1
a tetrad or bivalent is actually just
two chromosomes and four chromatids
The process of pairing or fastening together the homologous chromosomes is called ______
synapsis
crossing over occurs at
chiasmata
How are homologous chromosomes held together?
The synaptonemal complex
Its a protein lattice that looks like railroad tracks and connects paired homologous chromosomes.
Synaptonemal complexes have _________ and __________ that hold the homologous chromosomes in place.
transverse filaments and cohesion complexes
T/F: there is no interphase before meiosis II.
True.
Memorize this summary
Meiosis is responsible for alot of genetic diversity. It is accomplished via _______ and _______
independent assortment and crossing- over
Independent assortment occurs only in ________
meiosis I
_________ scrambles pieces of DNA from maternal and paternal genes which ensures that genes assort independently from one another.
recombination
___________ is known as trisomy 21.
down syndrome.
Trisomy 21 is a result of
a genetic disorder caused by the presence of all or part of a third copy of chromosome 21.
- physical growth delays
- mild to moderate intellectual disability
- characteristic facial features
What is cellular senescence?
Essentially irreversible arrest of cell proliferation (growth) that occurs when cells experince potentially oncogenic stress.
-its a deteriorative process which naturally slows down and terminates the functional life of a cell.
What is the Hayflick limit
The number of divisions that cells complete upon reaching the end of their replicative life span
What causes cellular senescence
- Decline in functional efficiency of specialized non dividing cells (nerve cells, muscles cells)
- Decline in division capacity of actively dividing cells (replicative senescence) Eg: lympocytes, epithelial cells
What are some physiological changes seen in cellular senescnece
- build up of calcium ions
- loss of rRna
- Decline in transcription
- decline in protein synthesis
- decline in energy production
what are some subcellular changes seen in cellular senescence
- change in fluidity and permeability of plasma membrane
- decrease in granular ER
- degeneration of mitochondria
- senescence-associated secretory phenotype
What is the DNA damage theory
The accumulation of damaged DNA inhibits cell functions and division
What is the telomere theory
there is a shortening of telomeres with each division
List 3 pathological process involved in cell death
- Autolysis: destruction of a cell through the action of its own enzymes
- apoptosis: programmed cell death
- necrosis: uncontrolled cell death
Histology slide prep
- tissue collection
- fixation
- embedding
- sectioning
- mounting
- staining
- observing with a microscope
What is formalin fixation
It prevents tissue damage and its helps preserve tissue morphology. It enables long-term storage
Hematoxilin vs. Eosin Stain
Hematoxylin: binds to negatively charged structures (ex: nucleus)
Eosin: Acid dye adheres to positively charged structures (proteins in cytoplasm)
What is trichrome stains best used for
identifying connective tissue
Blue: collagen, cartilage
red: cytoplasm, muscle fibers
yellow/orange: blood vessels
black/brown: nuclei
What stain would you use to detect polysaccharides such a glycogen, glycoprotein, and glycolipids
Periodic acid-schiff (PAS)
nuclui: blue/purple
carbohydrates: magenta
What are the different types of tissue sectioning?
longitudinal, cross section, oblique
What are the four tissues in the human body
- Nervous tissue (initiate and transmit nerve impulses)
- brain
- spinal cord
- nerves
- Muscle tissue (contract to produce movement)
- cardica
- smooth
- skeletal
- Epithelial tissue (line body surfaces and form glands)
- Lining of GI tract organs and other hollow organs
- skin surface
- Lining of GI tract organs and other hollow organs
- Connective tissue (support and protect body parts)
- fat and other soft padding tissue
- bone
- tendon
Why do we study histology?
to understand NORMAL tissue structures
Epithelium is a sheet of cells that covers the (list 3 things)
- covers the body surface
- lines the body cavity
- form glands
Match
simple squamos, simple cuboidal, simple columanr, pseudostratified ciliated columnar, and stratified squamos
with
esophagus, respiratory tract, air sacs of the lungs, kidney, and intestine
- simple squamous = air sacs of the lung
- simple cuboidal = kidney
- simple columnar = intestine
- pseudostratified ciliated columar = respiratory tract
- stratified squamous = esophagus
Epithelial tissue have little/ lot extracellular space and specialized/unspecialized junction
little extracellular space and specialized junction
epitheilial cells are polarized meaning they have ____ and ______ regions
apical and basal regions
*attached to basement mebrane (basal lamina + reticular layer)
T/F epithelial tissue is vascular
FALSE. Epithelial tissue is avascular (no blood vessels)
List the function of epithelium
think PASSIFS
Protection
absorption
secretion
sensation
ion transfort
fluid filtration
slippery surface (by mucus secretion for lubrication)
When naming epithelia, first name the _____ and then the _______
number of layers, and then shape
what are the 3 cell shapes
squamous, cuboidal, columnar
What are the names of the layers in epithelia
- simple, one-cell layer, all cells are attached to the basement membrane
- stratified, multiple cell layers
Modes of secretion
merocine: secretory vesicles released
apocrine: apical portion of cell is pinched off
holocrine: entire cell is secreted
Important apical specializations to know
- cilia
- microvili
- stereocilia
- keratin `
