Module 2 (Molecular Basis of the Cell Cycle) Flashcards
This phase of the cell cycle is referred to as the resting stage, not because it is not doing anything, but simply because it is not undergoing cell division. So, during interphase, the cell is busy undergoing synthesis of cellular materials.
Interphase
Main function of G2 checkpoint
To check if all chromosomes are properly attached to mitotic spindle
This is the phase that occurs immediately after cell division when the daughter cells are half the size of the parent cell
Gap 1
During Gap 1, the small daughter cell undergoes synthesis of _________ for growth and normal functioning
cytoplasmic materials
Before any cell can undergo reproduction (division), the genetic material must first be replicated to ________ for both daughter cells. What stage of interphase is this?
ensure equal genetic material; S-phase
A cell that enters the S phase is committed to _____________
completing the cell cycle
During this stage, the cell completes its growth
Gap 2 (G2 Phase)
In Gap 2, it’s essential before finally undergoing cell division, the cell must first undergo ___________ for cell division
synthesis of materials
State all material synthesised in interphase; per stage.
Gap 1:
State all material synthesised in interphase; per stage.
Gap 1:
State all material synthesised in interphase; per stage.
Gap 1: synthesis of cytoplasmic materials
Gap 2: synthesis of the DNA
Gap 3: synthesis of materials for cell division
After G1, cells that divide slowly or cease dividing enter the what phase instead of the S phase?
Gap 0
in G0, the cell is not committed to enter division, thus can perform other functions. Give three.
- Transmission (neuron)
- Storage of Glucose (liver cells)
- Secretion (glandular cells)
The M – Phase is the division phase that involves _________ and _______
karyokinesis and cytokinesis
What process is the division of nucleus.
karyokinesis
What process is the division of cytoplasm.
cytokinesis
What are two types of karyokinesis
mitosis and meiosis
Type of karyokinesis that occurs in somatic (body) cells
Mitosis
What are the purposes of mitosis?
organismal growth and tissue repair
What are the end products of mitosis and their ploidy?
two daughter diploid cells
In animal cytokinesis, The plasma membrane forms a depression or cleft called _________,
cleavage furrow
In plant cytokinesis, A network of microtubules and microfilaments form a scaffold at the equatorial plane, called ________ to guide the assembly of vesicles from the Golgi apparatus. The vesicles called ________, contain phospholipids to form the new cell membrane and sugars to form the new ______.The vesicles fuse forming a single _______ that expands until it divides the cytoplasm, producing two daughter cells
a. phragmoplast;
b. phragmosomes;
c. cell wall
d.cell plate
Meiosis occurs in _________ and is responsible for ________ and ________ of species.
a. gametogenic cells;
b. organismal reproduction
c. perpetuation of species
Meiosis I is also known as ______ because the chromosome number is reduced from diploid to haploid after this division.
a. Reduction Division
However, since the sister chromatids are still attached after meiosis 1, meiosis II is required to separate them, thus called _______.
Equational Division
These are Protein kinases (enzyme) activated by cyclins
Cyclin-dependent Kinases (CDKs)
Type of cell division cycle (cdc) proteins that bind to CDKs and activate them
Cyclins
State the cyclins and their corresponding CDKs
Cyclin C – binds to CDK3
Cyclin D – binds to CDK4
Cyclin E – binds to CDK2
Cyclin A – binds to CDK2 and CDK1
Cyclin B – binds to CDK1
Inhibits CDKs to ensure that they are activated only when needed
Cyclin-dependent kinase inhibitors (CKIs)
P21
– inhibits _______
– if the amount of P21 increases, the cell enters ____
– if the amount of P21 decreases, the cell enters the ______
a. CDK2
b.G0
c. S-phase and divides
Important for separating the chromosomes during anaphase
Anaphase Promoting Complex/Cyclosome (APC/C)
CDK3-C complex that promotes what?
G0/G1 transition
Is a transcription factor that is required for the synthesis of cyclin E, a cyclin required
for G1/S transition
E2F
Explain the transition between G1 to S-phase
Cyclin D binds with CDK 4 to form CDK4-D complex that phosphorylates pRB to release E2F, that is need to synthesize Cyclin E, which binds to CDK2 to form CDK2-E complex that promotes transition to S phase
Cyclin A binds to CDK2 to form CDK2-A complex that promotes _____DNA Replication. Called the _________. Promotes the degradation of ____-
- DNA replication
- S-phase promoting factor
- cyclin E
Explain the transition between S to G2 Phase.
Cyclin A binds with CDK! to form CDK1-A complex that promotes S-phase to G2 phase, promotes cyclin B synthesis and degradation of Cyclin E.
Explain G2/M transition.
Cyclin B binds to CDK1 to form CDK!-B complex that promotes G2/M transition, degrades cyclin A, and promotes APC/C—known as the Maturation promoting Factor.
Explain Anaphase/G1 Transition
APC/C degrades securin to activate separase that allows the separation of sister chromatids. Promoting Anaphase to G1 transition degrades cyclin b, and promotes cyclin C synthesis.
A checkpoint protein found in G1 checkpoint
found in G1 checkpoint
A checkpoint protein found in G1 checkpoint
P53
How does P53 signal cell cycle arrest?
P53 signal P21 to inhibit CDK2 and CDK1, preventing progression of cell cycle
How does P53 signal apoptosis?
It inhibits Bcl2 to release Bax, which signals the release of Cytochrome C from mitochondria, which binds to Apaf1, forming apoptosome, which binds to caspace 9 to form apoptosome-caspace 9 complex, that interacts with caspace 3 and 7 to promote apoptosis.
A checkpoint protein found in G2
Ataxia Telangiectasia Mutated (ATM)
