The Cell Cycle Flashcards
Cell Cycle
Represents the processes that occur between one cell division and the new cell division in a cell’s life
What are the three main stages
1.) Interphase
2) Mitosis
3) Cytokinesis
Interphase
The cell spends most of its life here performing its specialised functions and then prepares for cell division when the time comes. It can be broken into three stages
G1 Phase
the cell grows after cell division to reach full size, the cell will perform its specialised function. this is the longest part of the cell cycle for most cells.
S Phase (Synthesis)
The DNA is replicated creating two identical copies of each chromosome. As well, the centriole pair duplicates to create two pairs
G2 Phase (Gap Two)
The cell prepares for mitosis by undergoing rapid growth of its cytoplasm. The cell increases the synthesis of the proteins needed to make the spindle fibres used in mitosis. The DNA is checked for replication errors that might have occurred during DNA replications in S phase which prevents mutations from being passed to daughter cells.
Mitosis
This process sorts and divides the duplicated chromosomes into two identical sets of DNA so that each daughter cell gets one cell.
Cytokinesis
The process that divided the cytoplasm in half to create two seperate daughter cells
Cytokinesis in Animal Cells
a cleavage furrow forms to constrict the cell membrane in the middle of the cell and divides it
Cytokinesis in Plant Cells
instead of making a cleavage furrow, plant cells make a cell plate in the middle of the cell. It is made up of be vesicles which contain the materials needed to build a cell wall. The vesicles fuse at the middle of the cell to create a new cell wall which completely seperated the the two daughter cell.
What are the four stages of Mitosis? (Remember PMAT)
- Prophase
- Metaphase
- Anaphase
- Telophase
G0 Phase (Gap Zero)
When a cell reaches adulthood, they will never divide again. The cell won’t progress in the cell cycle and instead will head into G0, where they will continue their functions until they die.
Prophase
- Centrosomes migrate to opposite poles.
- Spindle fibers begin to form
- Chromatin begins to condense and becomes visible
- Nucleolus begins to disappear
Prometaphase
Spindle fibers attach to the centrosomes of the chromosomes.. and the nuclear membrane has almost dissolved
Metaphase
Chromosomes along at the cells equator, this ensures that each daughter cell can get one chromatid from each chromosome
Anaphase
Spindle fibers shorten, pulling sister chromatids apart towards opposite poles, once separated, each chromatid is now a chromosome
Telophase
Chromosomes decondense back into chromatins. A new nuclear membrane forms around each set of chromosomes.. and spindle fibers break down
G1 Checkpoint
ensures that the parent cell has grown large enough for synthesis of the cell contents and check for DNA errors
G2 Checkpoint
ensures that the genetic materials has been completely replicated to ensure correct number of chromosomes are in each daughter cell.. if there are are errors, programmed cell death is initiated
Mitosis spindle checkpoint
ensures that the spindle apparatus has attached to the centromere of the sister chromatids to be pulled apart in anaphase
Importance of Spindle Finers
Spindle fibers attach to the centromere of chromosomes, which ensures that each daughter cell recieves the same amount of chromosomes.. and in metaphase, these spindle fibers will align the chromosomes in the equatorial plate.
