Cell Division Flashcards
What are the phases of the cell cycle?
4
- G1 phase
- S (Synthesis) phase
- G2 phase
- Mitosis phase
- Cytokinesis
(S)ynthesis, (M)itosis
What are the phases of mitosis?
(4)
- Prophase
- Metaphase
- Anaphase
- Telephase
What happens during the G1phase?
(Gap 1)
(3)
- Protein synthesis at a rapid rate
- Metabolic reactions in cytoplasm
- Rapid growth
What happens during the S phase?
(Synthesis)
(1)
Replication of DNA in the nucleus
What happens during G2 phase?
(Gap 2)
(3)
- # of organelles increases
- chromatin begins to condense into chromosomes
- Microtubules begin to form
Second growth
What is Mitosis?
(1)
When a nucleus divides into two genetically identical sister nuclei
What happens during prophase?
First stage of mitosis
- Chromatin becomes supercoiled
- Mitotic spindle begins to form
- Centromeres attach to the spindle
- Centrosomes move to opposite poles of cell
- Nuclear membrane desintigrates
What happens during metaphase?
Second stage of mitosis
(1)
- Chromosomes move to metaphase plate(Centrosomes are now at opposite ends)
What happens during anaphase?
Third stage of mitosis
(2)
- Sister chromatids split
- The resulting 2 chromosomes move towards the poles
movement of chromosomes is due to shortening of microtubules of spindle
What happens during telophase?
Fourth stage of mitosis
(4)
- Chromosomes are at each pole
- Nuclear membrane and nucleoli reappear
- Mitotic spindle disappears
- Chromosomes uncoil
What happens during Cytokinesis?
The last phase of cell division
(3)
- Inward pinching of cell membrane causing cleavage furrow that separates the two daughter cells (animal cells)
- Cell plate formation (plant cells)
- The daughter cells now have genetically identical nuclei
Explain cell plate formation in plant cells
Cytokinesis
(3)
- Vesicles move to equator forming two membranes
- Middle lamella is formed through the pectin and cellulose deposited between the membranes
- The daughter cells remain attached
What happens to chromosomes during the S phase?
(DNA)
(3)
- DNA chromatin replicates creating genetic material doubles
- In the chromosome, sister chromatins are held together by the centromere
- Sister chromatids will separate during the end of mitosis
What happens to chromosomes during the G2 phase?
(DNA)
(2)
- The chromatin is uncoiled, with histones, and not visible
- Chromatin begins to supercoil into chromosomes
chromosomes are visible
What are cancer cells?
(1)
Cells that have lost control of division and divide uncontrollably
What are cyclins?
(What do they do?)
Proteins that control the cell going through the cell cycle
How do cyclins control the cell’s cell cycle?
- There are four cyclins trigger different stages
- Cyclins bind to CDK’s and activate them
- CDK’s phosphorylate other proteins that perform specific functions in the cell cycle
CDK: Cyclin dependent kinases
Why could cyclins be a potential cancer treatment?
If the cyclins of cancer cells could be specifically targetted it could be possible to interrupt the cancerous cell’s cell cycle and kill it
