Unit 2 Flashcards
Cell Cycle and Mitosis
What is better a 6:1 volume to surface area ratio or 1:1
6:1
What happens in prophase
“prepare”- chromatin condenses into chromosomes, spindles form, nuclear envelope breaks down, centrioles go to poles
What happens in metaphase
“meet in middle” (chromosomes): spindle fibers connect to the centromeres
What happens in anaphase
“away”- chromosomes split up and move to poles
What happens in telophase?
“two nuclei”- nuclear envelopes reform, cleavage furrow forms, chromosomes relax into chromatin, spindle fibers disappear
What is the difference between Chromatin and Chromosomes?
Chromatin: relaxed, seen in interphase/good for DNA replicating, tangle, unorganized, loosely coiled
Chromosomes: supercoiled, seen in cell divison, x-shape, organized
How many chromosomes are found in human body cells?
46 (23 in sex cells)
What are the three treatments of cancer?
1) surgery
2) chemotherapy
3) radiation
What are the two drugs commonly used in chemotherapy? (what do they do?)
Cytoxan: stops the S-phase/DNA replication
Taxol: stops spindle fibers from forming
What are cyclins?
internal regulators that regulate the timing of the cell cycle
What causes cancer?
defect in mitosis (cyclins are ignored)- often due to a defect in the p53 gene (tumor suppressor gene)
What happens in G1 phase?
Cells grow
What happens in the S phase?
New DNA is made/chromosomes are replicated
What happens in the G2 phase?
Organelles required for cell division are produced
When is the G0 phase?
After G1 (cells that never divide stay here: RED BLOOD CELLS, SPERM CELLS, EGG CELLS, NEURONS, CARDIAC CELLS
