Lecture #14: Mitosis and the cell cyle Flashcards
Development (zygote to adult)
Zygote -> Blastula -> gastrula -> neural tube -> Juvenille -> Adult -> testis -> sperm OR ovary -> egg
- Zygote = diploid (2n)
- sperm/egg = haploid (1n) (meiosis)
Mitosis
- starts with 1 2n cell (diploid)
- 1 replication of genes
- 1 division
- end with 2 2n cells
- genetically identical to each other and the parent cell
- occurs in body (somatic) cells
- produces somaic cells for genetic repair
Meiosis
starts with 1 2n cell (diploid)
1 replication of genes
2 divisions
Ends with 4 1N cells
Every cell is genetically unique
Occurs in testis and ovaries
Produces gametes (sex cells (eggs + sperm))
Cell cycle (mitosis)
Protophase, prometaphase, metaphase, anaphase, telophase, cytokinesis, G1, p53 checkpoint, s (synthesis), G2
- G0 occurs after G1 in some circumstances
P53 checkpoint
- checks for DNA damage
- repairing DNA
- leads to cell destruction (apatosis)
G0
normal cell that stopped dividing
- occurs after G1
Homologus pair of chromosomes
same types of genes, not exact form of gene
Centromere
contains kinectechore
Telomeres
at the ends of centromeres
Sister chromatids
- should be genetically identical
- same gene, same form of gene
- occurs after synthesis
Protophase
Chromosomes become visible (condense)
- able to move around more efficiently
Prometaphase
- divide and begin to move to opposite poles
- nuclear envelope disintegrates
Anaphase
Chromatids seperate; chromosomes move to opposite poles
Telophase
Chromosomes decondense (becomes invisible)
- nuclear envelopes reforms
- chromosomes at opposite poles
- two (almost) seperate cells
Interphase
Can’t see/barely see chromosomes
- includes G1, p53 checkpoint, G2, and G0
Spindle
generated from centromeres, consisiting of microtubules used to seperate chromosomes
Spindle poles
opposite ends of the cell, spindle spans entire cells
Why do cells stop dividing?
Lack of:
- chemical signal
- space
- nutrients
Programmed cell death (apotosis)
- infected cell
- cell is no longer needed for development
- damaged cell (ex: p53)
Telomeres become too short
Cancer
cell divison out of control
Metastasis
spread to 2+ site
Proto-oncogenes
Mutate to oncogenes (cancer-causing form of gene), (control cell divison)
Pro
forward, in front
meta
adjacent, beyond
ana
toward, against, again, back
Telo
end, final
cyto
cell
kinesis
move
cytokinesis
divison of cell contents
G1, S, and G2 are part of
Interphase
p53 is a protein important during checkpoint…
G1
The kinetochore is found on the
centromere
The nuclear envelope disappears during
prometaphase
