1. What events occur during each of the four phases of mitosis?
The Cell Cycle
What events occur during each of the four phases of mitosis?

2. Characteristics of living organisms
All Living things, including individual cells, can reproduce.
Reproduction is the process by which cells or organisms make more cells or organisms like themselves.
Unicellular Organisms: Cell reproduction produces a new organism
Multicellular Organisms: cell reproduction is used for growth and to replace damaged or dying cells.
Living things are:
Based on a genetic code
Grow and develop
Respond to their environment
Made up of cells
Reproduce
Maintain a stable internal environment= homeostasis
Obtain and use material and energy
Taken as a group, living things evolve
*In your notes, fill out this graphic organizer for the 8 characteristics of living things.

3. Prokaryotic Cell Division:
Simple
Binary Fission
Cell’s genetic information is copied, then the cell splits in two.
Two new cells identical to parents cell.
Bacteria
ASEXUAL REPRODUCTION
Paramecium cell division
In Mitosis: Cells divide among non-sex cells

4. Chromatin Chromatids Chromosomes DNA
> In your notes, write the difference between each of the orange words found on this page.
Chromosomes
DNA

5. DNA Chromatin Chromosomes Sister Chromatids
Blueprint of life, nucleic acid
Chromatin
granular genetic material, spread out in nucleus of non-dividing cells.
Cannot be seen with microscope
Chromosomes
condensed genetic material in dividing cells
Can be seen
Sister Chromatids
Identical copies of Chromosomes joined by a centromere (“centro-” middle)

7. The Cell Cycle: The Cell Cycle
If a cell simply divided into two, would each of the new daughter cells have all the chromosomes as the original cell (parent cell)?
Eukaryotic cells are multicellular, which means copying their chromosomes is much more complex.
The Cell Cycle
Interphase- growth and preparation
Mitosis- cell division
Cytokinesis- division of cytoplasm, formation of two cells.

8. Interphase
Cell spends MOST of life here, growing and preparing to divide
Three parts:
G1= Gap 1= Cell Grows and carries out routine functions
increase in cell size
S= Synthesis phase= cell’s chromosomes are copied.
“Critical Stage” if duplicated incorrectly
centrioles also duplicated
G2= Gap 2= Cell prepares for the nucleus to divide
Produces extra organelles and cytoplasm in preparation for division

10. Cell Cycle Checkpoints
There are checkpoints throughout the cell cycle
G1, S, G2, M
Make sure cell is ready to move onto the next phase (has all necessary organelles, copied DNA, etc.)
Once the cell has past the G1 checkpoint, it will complete the cell cycle
Some cells stay in the G1 phase all their life (muscle cell, brain cells)
Cell Cycle
Checkpoints

11. Cell Cycle Regulators Cyclins
Protein that regulates the timing of the cell cycle in eukaryotic cells
Levels of cyclins rise and fall throughout the cell cycle
Cyclin-dependent Kinases (cdks)
Enzymes that are activated when they bind with cyclin and they make the cell cycle continue

12. Regulators Internal Factors within the cell that control cell cycle
Cyclin and CDKs
Allow cell cycle to proceed only when certain processes have occurred
Replication of chromosomes
Chromosome Attachment to spindle before anaphase
External
Factors Outside the cell
Growth factors molecules that bind to cell surface that signal cell to divide
Similar cells have molecules that have opposite effect so that when it becomes to crowded, cells stop dividing

14. Consists of mitosis and cytokinesis
Cell Division
Produces two daughter cells
Usually takes place quickly
Two stages
Mitosis= division of cell nucleus, this is how organisms repair tissue and grow and develop
Cytokinesis= division of cell cytoplasm
Can overlap, so that cytokinesis occurs as Mitosis is still happening.
Nerve cells- non dividing
Muscle cells- non dividing
Skin cells- divide all the time
Digestive tract cells- divide all the time
M Phase
Consists of mitosis and cytokinesis

15. Life Span of Some Human Cells
Cell type
Life span
Cell division
Lining of esophagus
2-3 days
Can divide
Lining of small intestine
1-2 days
Lining of the large intestine
6 days
Red blood cells
Less than 120 days
Cannot divide
White blood cells
10 hours to decades
Many do not divide
Smooth muscle
Long-lived
Cardiac (heart) muscle
Skeletal muscle
Neurons (nerve) cells
Most do not divide