Cell Cycle
What are the two major phases of the cell cycle?
Interphase and Mitosis
Cells divide at different rates because of what 3 factors?
Age, size, and location/type
What is the formula for surface area of a cube?
length x width x # of sides (6)
What are the role of spindle fibers?
to move chromosomes to opposite sides of the cell
Why are checkpoints important in cells?
It keeps the cell from moving on before it is ready.
What are the three subphases of interphasde?
Skin cells typically replace themselves about every 2-3 weeks while liver cells replace themselves about every 10-18 months. Explain why there is a difference in their life cycles?
Skin cells take more wear and tear than liver cells and get damaged and need replaced more often. This results in shorter life cycles.
What is the formula for the volume of a cube?
Length x width x height
Why is the DNA tightly bound during mitosis but loosely bound during synthesis?
It is condensed so the DNA is easier to move.
It is loosely bound so the DNA is easier to get to and read to make a copy.
What happens during the G1 checkpoint?
the cell checks to ensure that the DNA is undamaged so it can replicate correctly.
What happens during the Gap 2 phase?
Additional cell growth
What is the G0 stage?
phase of cell cycle where no cell division takes place
Why is the surface area to volume ratio important in regarding the size of a cell?
If the cell grows too big, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume.
If a cell is too small, it could not contain all the necessary organelles.
What are histones?
protein that packs together DNA
What happens during the G2 checkpoint?
The cell checks to ensure that the cell is of adequate size and the DNA is replicated correctly.
What happens during the Synthesis phase?
the cell replicates its DNA
By staying in the G1 phase for a longer or shorter period of time
What determines the rate at which materials move into and out of a cell?
the cell's surface area
What are kinases?
enzymes that lower the activation energy to allow cell division to take place.
Some cells are temporarily in a G0 stage. Give an example and explain why it would want to temporarily be in a G0 stage?
Lymphocytes. They allow the immune system to remember the bacteria and viruses you have been exposed to so that you do not get sick again.
During what phase of the cell cycle does a cell spend most of its time?
G1 of Interphase
What is an example of a cell that would be permanently in the G0 stage and why?
Neuron cells. They have axons and dendrites that would lose their connections if the cell divided.
cell 1 has a length of 2 cm. Cell 2 has a length of 4 cm. What is the surface area to volume ratio of the two cells? Which cell would be better suited to survive and why?
cell 1 - 3:1
cell 2 - 1.5:1
Cell 1 is better suited to survive as it can bring materials into and out of the cell easier due to the higher surface area to volume ratio.
What are cyclins?
proteins that determine the progression through the cell cycle
What happens to the surface are to volume ratio as the cell grows in size?
It decreases.