BIOLOGY STUDY GUIDE
Chapter 12: The Cell Cycle
Rudolf Virchow: Cell theory: New cells arise by splitting pre-existing cells
Meiosis vs. Mitosis - 2 types of cell division
Gametes vs. Somatic Cells
MITOTIC CELL DIVISION
12.1 How Do Cells Replicate?
1. copy the DNA
2. separate the copies
3. divide the cytoplasm into two complete cells
The Cell Cycle: 4 Phases : 1 cycle is 24 hours
- orderly sequence of events
- eukaryotic cell
- identical daughter cells
- G1 Phase (2x longer than G2)
- S Phase
- G2 Phase
*Cytokinesis is not part of M phase
EUKARYOTIC CELL REPLICATION
- Wound Repair
COPY THE DNA- INTERPHASE + S PHASE
Chromosome "colored body" - threadlike structures
Interphase "There is more to the cell then just chromosomes"
Unreplicated chromosomes: single relaxed chromatins
S phase: DNA replication, part of interphase
Replicated chromosomes: Replicated chromosomes, 2 sister chromatids DIVIDE THE COPIES- M PHASE
M Phase "mitotic or meiotic phase" - dividing phase
M Phase: Prophase "before phase"
Condensed Replicated Chromosomes: sister chromatids held together by the centromere
Formation of Spindle Apparatus
MTOC "Microtubule-organizing centers": Anything that organizes microtubules
Polar microtubules: Two overlapping microtubules "pole to pole"
Prophase: Chromosomes are condensing and the formation of the spindle apparatus is taking
Centrosomes which contain two centrioles move to the opposite sides of the nucleus. These
now produce microtubules then eventually polar microtubules.
M Phase Prometaphase "before middle-phase"
Chromosomes have condensed
Nuclear envelope: disintegrates
Microtubules: attach to chromosomes
2 Kinetochore: structure on sister chromatids
M Phase Metaphase "middle phase"
Completion of Spindle Apparatus
M Phase Anaphase "against phase"
Sister chromatids are pulled apart
Independent daughter chromosomes move to opposite poles
M Phase Telophase "end phase"
Nuclear envelope re-forms