1. Chapter Five: Cell Growth and Division

2. Section One: The Cell Cycle
Cell Cycle: the regular patter of growth, DNA duplication, and cell division that occurs in eukaryotic cells.
4 Main Stages
Gap 1 (G1)
Synthesis (S)
Gap 2 (G2)
Mitosis (M)

3. Section One: The Cell Cycle
Gap 1 (G1)
Cell carry out normal functions but increase in size
Organelle number increases
Stage the cell stays in the longest
Must pass a checkpoint before going into synthesis

4. Section One: The Cell Cycle
Synthesis (S)
The cell makes a copy of its DNA
Cell contains two complete sets of DNA

5. Section One: The Cell Cycle
Gap 2 (G2)
Cells carry out their normal functions and continue to grow
Checkpoint before Mitosis

6. Section One: Cell Cycle
Mitosis (M)
Includes mitosis and cytokinesis
Mitosis: the division of the cell nucleus and its contents
Nuclear membrane dissolves, duplicated DNA condenses around proteins and separates, and two new nuclei form
Cytokinesis: the process that divides the cell cytoplasm resulting into two daughter cells that are gentically identical to the original cell

7. Section One: The Cell Cycle
Rates of cell division vary based on cell type, the needs for that cell, and age
Cell that divide rarely are said to be in the G0 stage
Cell size is limited

8. Section Two: Mitosis and Cytokinesis
Chromosomes
One long continuous thread of DNA that consists of numerous genes along with regulatory information
Human body has 46 chromosomes
Must condense itself before mitosis can begin
Allows them to divide evenly during mitosis
DNA is loosely organized during interphase to allow easy access to genes so proteins can be made

9. Section Two: Mitosis and Cytokinesis
Chromosomes
At almost all times during the cell cycle your chromosomes are wrapped around histones
Histones: a protein the organizes chromosomes around which they are wrapped
Looks like beads on a string
Helps to compact DNA
Chromatin: the loose combo of DNA and proteins

10. Section Two: Mitosis and Cytokinesis
Chromosomes
Futher condensing occurs as mitosis gets closer and closer
Chromatid: one half of a duplicated chromosome
Each chromosome was copied during the S stage
Together the two chromatids are called sister chromatids
They are held together at the centromere
Telomeres: the ends of DNA molecules that is made of repeating nucleotides that do not form genes

11. Section Two : Mitosis and Cytokinesis
Interphase and Mitosis
Interphase
Duplication of organelles and DNA replication
One cell should have two full sets of DNA and be large enough to divide
Mitosis
Prophase
Metaphase
Anaphase
Telophase

12. Section Two: Mitosis and Cytokinesis
Prophase
Chromatin condenses into chromosomes
Nuclear envelope breaks down
Centrioles move to opposite sides (poles) of the cell
Spindle fibers form

13. Section Two: Mitosis and Cytokinesis
Metaphase
Spindle fibers attach to each chromosome
They align the chromosomes along the center of the cell

14. Section Two: Mitosis and Cytokinesis
Anaphase
Sister chromatids separate and go to opposite ends of the cell
Spindle fibers shorten pulling the sister chromatids apart

15. Section Two: Mitosis and Cytokinesis
Telophase
Nuclear membranes start to form
Chromosomes begin to uncoil
Spindle fibers fall apart

16. Section Two: Mitosis and Cytokinesis
Cytokinesis: divides the cytoplasm into two cells and completes the full stage of the cell cycle
Animal cells: membrane forms a furrow that is pulled inward by tiny filaments like a drawstring
Plant cells: a cell plate forms between the two nuclei

17. Section Three: Regulation of the Cell Cycle
Cell Cycle Regulation
Regulated by internal and external factors
External Factors
Cell to cell contact
Growth factors: group of proteins that stimulate cell division
Hormones
Internal Factors
Kinases and Cyclins
Kinases transfer phosphate groups from one molecule to another and are activated by cyclins

18. Section Three: Regulation of the Cell Cycle
Cell Cycle Regulation
Apoptosis: programmed cell death
Internal and external signals activate genes that produce self destructive enzymes
Ex. Webbing of fingers and toes

19. Section Three: Regulation of the Cell Cycle
Cancer
Uncontrolled cell division
Arises when regulation of the cell cycle breaks down
Treated with chemotherapy or radiation
Tumors form
Benign tumors: cancer cells stay clustered together and are usually harmless
Malignant tumors: cancer cell break away, or metastasize, from the tumor and spread to other parts of the body.\
Carcinogens
Substances known to produce or promote cancer
Tobacco smoke and air pollutants
Some are carried by viruses

20. Section Four: Asexual Reproduction
The creation of offspring from a single parent and does not involve joining sex cells
The offspring are usually genetically identical to the parent
Binary Fission: type of asexual reproduction by dividing into two roughly equal parts

21. Section Four: Asexual Reproduction
Advantages
Usually more efficient if the environment remains favorable
Less time and energy
Disadvantages
No genetic variation

22. Section Four: Asexual Reproduction
Some organisms reproduce asexually through mitosis
Ex. Cutting a stem off a plant and repotting it
Can go through budding, fragmentation, or vegetative reproduction

23. Section Five: Multicellular Life
Multicellular Organisms
Levels of Organization
Cell
Tissues: groups of cells that work together to perform a similar function
Organs: groups of tissues that work together to perform a similar function
Organ systems: groups of organs that carry out similar functions
Work to maintain homeostasis

24. Section Five: Multicellular Life
Cell Specialization
Cell differentiation: the process by which unspecialized cells develop into their mature forms and functions
Stem Cells: a unique type of body cell that has the ability to divide and renew themselves for a long period of time, remain undifferentiated in form, and develop into a variety of specialized cell types.

25. Section Five: Multicellular Life
Stem Cell Types
Adult
In the brain, liver, bone marrow, skeletal muscle, dental pulp, and fat
Also found in children and umbilical cord blood
Can be taken out of a patient and put back in
Embryonic
Come from donated embryos grown in a clinic
Can form any cell type in the human body