Chapter 9 Notes
Cell division: ability of an organism to produce more of their own kind is the BEST way to distinguish
living from non-living things
Single Cell: division creates a new organisms
Multi-cellular: allows multicell eukaryotes to develop from a single cell, and then renew, repair and
replace cells as needed
Division: results in the distribution of IDENTICAL genetic material to two daughter cells. Almost never
any mistakes made
DNA Vocab:
Genome: all the DNA in a cell (either multiple or Single DNA molecule
Chromosomes: Package of DNA molecules
Chromatin: complex strands of protein and DNA wound together
Somatic cells: two sets of chromosomes (non-reproductive)
Gametes: one set of chromosomes (reproductive)
Each type of organisms has a specific # of chromosomes
1st step: DNA is replicated and chroomosomes condense
Each duplicated chromosome consist of 2 sister chromatids
Attached most closely at the centromere
During cell division, sister chromatids split and carry a copy of the SNA to a new cells
Two steps
Mitosis: division of genetic material in the nucleus
Cytokinesis: division of the cytoplasm
Later we’ll talk about meiosis (cell division w/ only 1 set of chromosomes
Cell Cycle: First seen in 1882. Developed dyes to observe chromosomes during mitosis/cytokinesis
Phases:
Think of as a 3-step process: Replication, alignment, separation
Mitotic (M) phase: includes mitosis and cytokinesis
Interphase: includes cell growth and copying of chromosomes in preparation for cell division
G1: First Gap
S: synthesis: chromosomes are duplicated
G2: Second gap
Stages of Mitosis: include the alignment and separation of chromosomes
Prophase:
Prometaphase
Metaphase
Anaphase
Telophase
Cell cycle Control System: remember signal transduction pathways?
Molecules regulate progression through cycle. Can be internal or external
G1: most important: most things OK if cells gets through this checkpoint
Cyclins and Cyclin-dependent Kinases: proteins and protein complexes that control cell cycle
Example: platelet-derived growth factor
Cancer cells: do not respond to these signals
Make own growth factor
May act as through growth factor is there