1. Chapter 6-
Cell cycle-growth

2. BINARY FISSION Bacteria dividing Completed Reproduction of Bacteria
Bacteria dividing
Completed

3. Some can reproduce every 20 minutes
Reproduction of Bacteria
The time of reproduction depends on how desirable the conditions are. (example- leaving milk out vs keeping them in the refridgerator)
Some can reproduce every 20 minutes
(one bacteria could be an ancestor to millions in less than a day)
“EXPONTENTIAL GROWTH”

4. Binary Fission Bacterial Cell & Nucleiod DNA Ring Step 1
DNA replicates
Binary Fission
Step 2
DNA (chromosomes) move to opposite ends and attach to cell membrane
Step 3-Cell grows in the middle
Step 4 – Cell wall forms between the two daughter cells

5. Cell Cycle Stages in growth & division G1 Phase S Phase G2 Phase
M Phase
Cytokinesis

6. G1 Phase
First growth stage
Cell increases in size
Cell copies all of its organelles

7. Synthesis Phase (Replication)
Copying of all of DNA’s instructions
Chromosomes duplicated

8. CHROMOSOMES- preparing for cell division- make copies of itself
CHROMATIDS- identical copies of DNA (each chromosome will turn into 2 chromatids)
CENTROMERE- center where the two identical halves are attached

9. G2 Phase
Time between DNA synthesis & mitosis
Cell continues growing
Needed proteins produced
Organelles move to opposite ends of cell

10. M Phase (MITOSIS) division of the nucleus- in 4 steps
Cell growth & protein production stop
Cell’s energy used to make 2 daughter cells
Called mitosis or karyokinesis (nuclear division)

11. PROPHASE
CHROMATIN condenses into CHROMOSOMES- two identical chromosomes are attached at the center called a CENTROMERE
CENTRIOLES- move to opposite poles and produce SPINDLE FIBERS
SPINDLE FIBERS appear and attach to centromeres
NUCLEAR MEMBRANE- starts to disintegrate
NUCLEOLUS disappears

12. METAPHASE
SPINDLE FIBERS align the chromosomes in the middle of the cell
( “meet” at the equator)

13. ANAPHASE
Individual chromosomes get pulled apart at the centromere and are carried to opposite poles via spindle fibers
(pulled “apart”)

14. TELOPHASE CHROMOSOMES thin out into chromatin again
SPINDLE FIBERS disappear
NUCLEAR MEMBRANE- starts to form making two new nuclei
NUCLEOLUS reappears

15. Cytokinesis
Occurs after chromosomes separate
Forms two, identical daughter cells

16. CYTOKINESIS
CLEAVAGE FURROW develops- Cell membrane begins forming and grows outwardly to meet the rest of the cell membrane-

17. G 0 cycle Cells exiting the cell cycle DNA is no longer copied
there is no growth
Example-fully developed brain cells (neurons)

18. Human Chromosomes

19. KARYOTYPE (Pg 147)
A photomicrograph of the chromosomes in a dividing cell.
Chromosomes are paired up and arranged in order from longest to shortest

20. HOMOLOGOUS CHROMOSOMES
Two copies of each chromosome.
(one copy of each chromosome from each parent)