Ch 12: Cell Cycle Flashcards
Define a Chromosome
A single long double helix of DNA wrapped around histones
A structure containing genetic information in the form of genes
Define sister chromatids
Chromatid copies that remain attached at a centromere
True or False: 2 sister chromatids attached at a centromere are counted as one chromosome
True
Homologous chromosomes are:
Chromosomes that contain the code for the same genes but present with different alleles
The spindle apparatus is formed by:
Microtubules formed by MTOCs
A centrosome is formed by:
Two centrioles at 90 degree angles to eachother
MTOC stands for
Microtubule Organization Center
Centrosomes are this acronym
MTOCs
An = B
Describe what the A and B coefficient/quantity is
A = Ploidy of a cell. If A=2 that means there are 2 homologous chromosomes paired together (for example human cells
B = Total number of chromosomes in a cell (46 in humans)
Define a cell plate
In a plant cell, after telophase, a cell wall will be built to separate the daughter cells. This is a cell plate
Define a cleavage furrow
When actin tightens to squeeze the cell membrane of the parent cell to separate the parent cell into two daughter cells
“The butt thing”
List the steps of the M phase
PPMAT
Prophase Prometaphase Metaphase Anaphase Telophase
Define a tumor supressor
Slows or stops cell cycle if DNA is damaged
Define the function of p53
Slows or stops cell if DNA is damaged, and can trigger apoptosis if damage is too bad
Define apoptosis
Spontaneous cell death
pop
What happens during prophase
- Centromeres begin to form spindle apparatus
- Chromosomes condense for transport
What happens prometaphase
- Nuclear envelope breaks down
- Microtubules contact chromosomes at kinetochores
What happens during metaphase
- Chromosomes migrate to the middle of a cell
What happens during anaphase
- Sister chromatids separate into daughter chromosomes
- Daughter chromosomes are pulled to opposite poles of the spindle apparatus
What happens during telophase
- Nuclear envelopes form around the 2 groups of daughter chromosomes
- Chromosomes decondense
Define proto-oncogene
A protein that promotes cell division when conditions are ideal to proceed (i.e. DNA is in-tact)
The MPF dimer is made up of a ___ and a ___
Cyclin, Ckd (cyclin-dependent kinase)
MPF stands for:
Mitosis-promoting factor
The cyclin subunit of MPF functions as a _____________
regulatory protein
Microtubules facilitate chromosome movement during anaphase using _______
Kinetochore proteins
The G0 state describes:
A cell that is permanently stuck in the G1 phase
A cell that has had its cell cycle arrested
Cell cycle length varies among cell types primarily due to:
A difference in the length of time that the G1 phase takes
Rapidly dividing cells essentially eliminate this phase of the cell cycle
G1
MPF functions to:
Induce mitosis in all eukaryotes
Cdk functions to:
Catalyze the transfer of a phosphate group from ATP to the target protein
TL;DR: Catalyzes phosphorylation
In mitosis, chromosome count only doubles during _____
Anaphase and Telophase
Acronym for remembering the phases of mitosis
PPMAT
Prophase Prometaphase Metaphase Anaphase Telophase
Meiosis produces _ daughter cells
4
Ploidy refers to:
The number of sets of chromosomes
This motor protein “walks” along microtubules to facilitate vesicle/organelle transport
Kinesin
Cdk has an _____ and an _____
Active site, inactive
Cdk functioning is dependent on ______
Cyclin binding to a Cdk
Cancer involves a loss of _______
Cell cycle control
Social control of the cell cycle in multicellular organisms refers to:
Cells being signaled to divide only when it is in the best interest of the whole multicellular organism
The regulatory protein E2F triggers:
Genes required for DNA synthesis to be expressed
When E2F is first produced, its function is blocked by the ______
Rb tumor suppressor
Extra Info: Rb stands for retinoblastoma, cancer of the retina [Lead to the discovery of Rb tumor suppressor]
When E2F has an Rb bound to it E2F is ____
Deactivated
As long as Rb is bound to E2F, the cell will remain in the __ phase
G1
MPF permits a cell to pass from the G1 phase to the S phase by:
Phosphorylating Rb, which releases it from E2F
The G1 checkpoint works by:
Cyclin bound to Cdk phosphorylating the Rb protein bound to E2F, thus activating E2F to prepare for the S phase
After the G1 checkpoint is passed, Cyclin is ubiquitinated which means:
It is tagged for destruction so that the cell doesn’t keep preparing for the S phase beyond what is necessary
Bacteria go through _____ instead of mitosis
Binary fission
During binary fission, what happens?
DNA copies are pulled to opposite ends of the bacteria cell, and then the cell divides.
No need for any of the other steps in eukaryotes due to the nature of prokaryotes