Cell Cycle And Mitosis Flashcards
What is mitosis needed for?
-Produce new cells for growth and replacement of damaged cells.
-To reproduce asexually.
What is the product of mitosis?
Two genetically identical cells.
What are the stages of the cell cycle?
-G1
-S
-G2
-Mitosis
-Cytokinesis
What happens in the G1 phase and how long for?
-Growth of cytoplasm and new organelles.
-Cell grows in size.
-Protein synthesis from new organelles.
-For 10 hours.
What happens in the S (synthesis) phase and for how long?
-Synthesis for DNA
-DNA is replicated.
-For 9 hours.
What happens in the G2 phase and how long for?
-Organelles grow and divide.
-Energy stores are increased (ATP is synthesised) within the cell so it increases further in size.
-For 4 hours.
What is the total length of the cell cycle?
24 hours
What is the G0 phase?
-Where a cell would move out of the cell cycle.
-Only happens if the cell/ DNA of the cell is damages or the cell has differentiated and specialised.
How is the cell cycle contolled?
By checkpoints to check if the cell is viable or not at:
-G1 (end of G1 before S)
-G2 (end of G2 before mitosis).
-Spindle assembly (metaphase)- during mitosis.
What are the 4 stages of mitosis?
-Prophase
-Metaphase
-Anaphase
-Telophase
What happens in prophase?
-Chromosomes become more distinct (coil up and shorten) becoming visible and condensing.
-Centriole divides and moves to opposite poles of the cell.
-Nucellar envelope disintegrates.
-Nucleolus becomes more distinct.
What happens in metaphase?
-Centrioles are now at opposite poles and begin to produce spindle fibres.
-Spindles attach to the centromere of the chromosomes.
-Chromosomes are pulled to the metaphase plate (equator) of the cell.
What happens in anaphase?
-Spindle fibres contract which requires ATP.
-Chromatids are pulled to opposite poles of the cell.
What happens in telophase?
Chromatids reach poles of the spindles.
-The chromatids begin to uncoil and become less distinct.
-Nuclear envelope begins to reform.
What happens in cytocenisis?
-The cell divides.
How does cytokinesis happen in animal cells?
The edges of the cell begin to constrict and makes the cytoplasm splits.
How does cytokinesis happen in plant cells?
A cell wall is laid between the two cells.
What is the equation for mitotic index?
Number of cells with condensed chromosomes / total number of cells
What is the process called where cells divide in prokaryotic cells?
Binary fission.
What cells divide in mitosis?
Eukaryotic cells.
What is the process of binary fission?
-The circular and plasmid DNA duplicates.
-The cell grows.
-The cell then divides into 2, genetically identical cells when the cytoplasm splits.
-Number of plasmids vary as the number varies in the parent cell.
What is different about mitosis and binary fission?
Binary fission is a lot quicker of a process than mitosis.
When looking at mitosis through a microscope why might two students calculate different mitotic index’s?
-Different fields of views.
-Cells undergo cell division at different rates and times.
