T1.6 Cell Divison Flashcards
Three main steps of the cell cycle?
Interphase, Mitosis, Cytokinesis
4 steps of mitosis in order
PMAT
Prophase, Metaphase, Anaphase, Telophase
% of cell cycle spent in interphase
~90% of cell life
Two major metabolic activites occuring during interphase
DNA replication and protein synthesis
Interphase phases in order
G1, S, G2
G1 phase
Growth -> organelles duplicate
S phase
Each chromosome is duplicated to create sister chromatids
G2 phase
some growth, preparing for divison, checking everything over with cyclins
Mitosis
Chromsomes replicate to form sister chromatids so that cell division can occur
Prophase
- Chromosomes supercoil and create sister chromatid
- Spindle microtubules/fibers form and reach from poles
- nuclear membrane disintegrate
Metaphase
middle
- Sister chromatids align themselves on equator
- fibers attach to centromeres on each chromosome
Centromere
Middle of chromosome, where the spindle fibers attach to
Anaphase
away
Centromeres divide and chromosomes are pulled to opposite poles
sister chromatids are seperated and called chromosomes again
Telophase
chromosomes uncoil, nuclear envelope begins to reappear, looks more seperated
Cytokinesis
Divison of the cytoplasm
Animal cell cytokinesis
- Clevage furrow created
- Contractile proteins aid in the pinching in of cell membrane
Plant Cell cytokinesis
- Vesicles move to equator and fuse together, creating 2 cell membranes.
- Vesicles bring pectin in to be deposited between the two new membranes. Forms the middle lamella
- Cellulose is deposited by exocytosis adjacent to middle lamella, forming the cell wall (cell plate)
Is the cell wall intracellular or extracellular
extracellular
Cyclins
Ensure that tasks are preformed at the correct time in the cell cycle
What are cyclins considered to be?
The “pace-maker” of the cycle
Tumor
Abnormal group of cells that develop at stage
Maglinant tumor
Life-threatening, cancer, abnormal cells and abnormal growth
Benign tumor
Unlikely to do much harm, abnormal growth of normal cells
Mutation
a random change to the base sequence of genes
Most gene mutations do not cause cancer
Oncogenes
Genes were mutations do cause cancer
Carcinogen
chemicaal or agent that causes cancer
Mutagens
Agents that cause mutations
Not all are carcinogenic, but are correlated
Tumorigenesis
Formation of a tumor
Primary tumor
Initial mass of cells created by uncontrolled division of cancer cells
Metastasis
Movement of cells from primary tumor to set up a secondary tumor in other parts of the body
Steps of metastasis
ALTS
- Attachment
- Local breakdown
- Transport
- Secondary tumor forms (metastasis)
Purpose of mitosis
To ensure that each daughter cell has the correct and identical amount of chromosomes.
Also to divide cell before cell becomes too big
Why does supercoiling occur?
Chromosomes may be very large, so if they are coiled very tightly they can be moved around more easily during division
Difference between sister chromatids and chromosomes?
Sister chromatids are identical copies of one chromosome being linked by a centromere
Chromosomes are these two chromatids formed together
ngl not sure about this one
Mitotic index equation
Total # of cells in a mitosis phase/Total # of cells in the sample
% at Rest equation
(Total # of cells in interphase / Total # of cells in the sample) x 100
How does cancer develop?
When the cell cycle is improperly regulated, ex: too many stimulating proteins, mutation in oncogenes, and a mutation in tumor suppressor genes
Which mitosis phases is the genetic material called sister chromatids?
prophase until they seperate in anaphase
