Cell Cycle Flashcards
Ordered series of events involving cell growth and cell division that produces two new daughter cells
Cell Cycle
Two major phases of the cell cycle
- Interphase
- Mitotic Phase
The cell grows and Dna is replicated
Interphase
Replicated DNA and cytoplasmic contents are distributed and the cell divides
Mitotic Phase
Cell undergoes normal growth processes while also preparing for cell division
Interphase
Three stages of Interphase
- G1 Phase
- G2 Phase
- S Phase
Cell grows and more organelles are produced, increasing the volume of the cytoplasm
G1 Phase
First Gap
G1 Phase
Known as “Decision-Making Step”
G1 Phase
The cell is quite active at the biochemical level
G1 Phase
Synthesis of DNA
S Phase
DNA Replication can proceed through the mechanisms that result in the formation of sister chromatids
S Phase
Orchestrates the movement of chromosomes during mitosis
S Phase
Rod-like objects that help organize cell division
Centrioles
There may be additional cell growth. Final preparation for the mitotic phase.
G2 Phase
Multistep process during which the duplicated chromosomes are condensed, aligned, and separated and then are divided into two new identical daughter cells
Mitotic Phase
Second Gap
G2 Phase
Cell is in quiescent state that occurs when the cells exit the cell cycle. Some cells are not actively preparing to divide.
G0 Phase
Life span of skin cells
14 Days
Life span of red blood cells
120 Days
Life span of liver cells
300-500 Days
Life span of Internal Lining of Intestine
4-5 Days
Life span of Smooth Muscle of Intestine
16 Years
Length of the cell cycle
24 Hours
Length of the G1 Phase
9 Hours
Length of the S Phase
10 Hours
Length of the G2 Phase
4 1/2 Hours
Length of the M Phase
1/2 Hour
Lack of Human Growth Hormone (HGH) may result in
Dwarfism
Too much Human Growth Hormone (HGH) may cause
Gigantism
To prevent cell from continuing to divide there are internal control mechanisms called.
Cell Cycle Checkpoints
Three main cell cycle checkpoints
- G1 Checkpoint
- G2 Checkpoint
- M Checkpoint
Determines whether all conditions are favorable for cell division to proceed
G1 Checkpoint
Also known as “Restriction Point” Checkpoint
G1 Checkpoint
Ensure that all of the chromosomes have been replicated and that the DNA is not damaged.
G2 Checkpoint
Also known as “Spindle Checkpoint”
M Checkpoint
Determines whether all sister chromatids are correctly attached to the spindle microtubules.
M Checkpoint
Responsible for the progress of the cell through the various checkpoints
- Cyclins
- Cyclins-Dependent Kinases
These halt the cell
Negative Regulators
Group of tumor-suppresor proteins common in many cells.
- Retinoblastoma Protein (Rb)
- p53
- p21
They act primarily at the G1 Checkpoint
- Retinoblastoma Protein (Rb)
- p53
- p21
Programmed cell death
Apoptosis
Halts the cell cycle and recruits enzymes to repair the DNA
p53
This trigger apoptosis to prevent duplication of damaged chromosomes
p53
Monitors cell size
Retinoblastoma protein (Rb)
