Cell Division-Mitosis and Meiosis: Part 2: The Cell Cycle Flashcards
What is the Cell Cycle?
Living and dividing cells pass through a regular sequence of growth and division called the Cell Cycle.
Why is the rate and time of the phases of cell division important?
It is important so the organism can have a normal growth, development, and maintenance.
What phase do the cells that lose the ability to divide stay in?
G0 (G-zero)
Do all the cells divide at the same rate? If no, give some examples.
No, skin cells and cells that line the digestive tract divide continuously throughout ones life. Some nerve and muscle cells lose the ability to divide so they stay in G0.
What type of proteins regulate the Cell Cycle?
Cyclin, internal regulators (make sure the the cell does not undergo mitosis until certain conditions are met), and growth factors. Growth factors are external regulators that speed up, slow down, or stop the cell cycle.
What are the stages that the Cell Cycle consist of?
The Cell Cycle consists of 5 stages. G1, S ,G2 (which together make up interphase), Mitosis (division of the nucleus, and cytokinesis (division of the cytoplasm).
How many checkpoints do the cells have to pass so they can move from one phase to another?
They must pass 3 checkpoints.
G1 or First Gap Phase
Newly divided cells enter this phase right after completing Mitosis. During this phase, the cell increases in size and prepare to replicate its DNA.
G1 checkpoint
If the cell is health and contains adequate resources, and if the the DNA is undamaged, the cell can proceed to the next phase (S). If not, the cell either dies or stays in the G0 phase to rest.
S-Phase
DNA is synthesized throughout the process of replication.
S-Phase checkpoint
DNA synthesis is continuously monitored for any replication errors. If there are no errors, the cell can proceed to the next phase (G2).
G2
The cell has to produce cell organelles and other cellular components that will populate two new functioning daughter cells.
G2 checkpoint
All chromosomes must be fully replicated with no damage or errors. Only then, the cell can enter the next phase, Mitosis (M).
