Cell Cycle Flashcards
How do prokaryotes reproduce?
Binary fission
How does binary fission occur?
In binary fission, the chromosome replicates (beginning at the origin of replication), and the two daughter chromosomes actively move apart
What are the 3 stages of interphase?
G1
S
G2
What are the two components of the mitotic phase?
Mitosis and cytokinesis
Is cytokenisis park of mitosis?
NO
What happens at the G1 checkpoint?
If a cell receives a go-ahead signal at the G1 checkpoint, it will usually complete the S, G2, and M phases and divide.
If the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state called the G0 phase
What two types of regulatory proteins are involved with cell control?
Cyclins
Cdks (Cyclin dependent kinases)
How do CDK and cyclins regulate the cell cycle?
Cdk builds up in G1, S, G2. It joins with cyclin to form MPF at the G2 checkpoint. During M, cyclin is degraded, and the cycle loops.
What are two types of cell inhibition?
Density-dependent inhibition: crowded cells stop dividing.
Anchorage dependence: some cells must be attached to a surface in order to divide
What kind of cells do not demonstrate anchorage or density inhibition?
Cancer cells
What three things need to be kept track of in mitosis?
Chromosomes
Spindle Apparatus
Nucleus
DNA in cells is packaged in __________.
chromosomes
What are sister chromatids?
Either of the two identical copies (chromatids) formed by the replication of a single chromosome
What joins sister chromatids?
Centromere
What is a homologous chromosome?
Two different copies of a chromosome that diploid organisms (like humans) inherit, one from each parent.
What is the mitotic spindle made from?
Microtubules
Where does the assembly of spindle microtubules begin?
Centrosome
An _____ extends from each centrosome
aster
What is the name of spindle fibers that attach to the centromere?
kinetochores
________ microtubules from opposite poles overlap and push against each other, elongating the cell
Nonkinetochore
What happens in prophase?
Start to build mitotic spindle- the centrosome is duplicated and are pushed to poles
Chromosomes are in the process of condensing, can see DNA
Nuclear membrane intact
What happens in prometaphase?
Chromosomes finish condensing
Spindle apparatus finished, kinetochores attach to centromeres
Nuclear envelope fragments
What happens in metaphase?
DNA is condensed. Chromosomes line up single file across cell.
What happens in anaphase?
Sister chromatids separate, are dragged to opposite sides by kinetochores
