1. Do Now
How can you visually distinguish between newly formed cells and older cells?

2. Regulating the Cell Cycle 5.3

3. Apoptosis Means “a falling off” Programmed cell death. What causes it?
When internal or external signals activate genes that help produce self destructing enzymes.
Nucleus shrinks and breaks apart. Immune cells recognize this and “gobble up” the cell and recycle its parts.
Fun Fact- Blood cells only live about 120 days, Colon cells only 4 days, Skin cells 2-3 weeks!

5. Apoptosis During Embryo Development
Example:
A human embryo has webbed fingers/toes. The cells between the digits undergo apoptosis during later development resulting in a baby born with unwebbed fingers/toes

6. Uncontrolled Division
Cancer cells continue to divide and form tumors
Benign - cells remain clustered in one area and are often easier to remove
Malignant- some cells break away and spread through the body via bloodstream
Tumors - cause harm because the cells in that area don’t do their specialized function

7. 5.4 - Asexual Reproduction
Creating of identical offspring from a single parent
Most prokaryotes reproduce through Binary fission
Very similar to mitosis
Both form two identical daughter cells BUT prokaryotes have no nucleus and have much less DNA which forms a circular shape, not several chromosomes.

9. Asexual Eukaryotes Flatworms and sea stars = fragmentation
Many plants can reproduce asexually through stems or underground structures that are connected to the original plant (runners)
Some organisms reproduce sexually and asexually!
Sea anemones bud or break off small pieces asexually and also make eggs/sperm

10. Pros and Cons of Asexual Reproduction
More efficient if the environment stays the same
Doesn’t require finding a mate! Less time and energy
Cons:
No diversity
Could all be wiped out if susceptible to a disease or environmental condition

11. 5.4 Multicellular Life
Cells -> tissues -> organs -> organ systems -> organisms

12. Cell differentiation
Process by which unspecialized cells develop into their mature forms/functions
Almost each cell in your body has a full set of DNA but only uses specific genes needed to carry out its job

13. Examples of Differentiated cells
Skin cells - help prevent infection and dehydration
Bone cells- for a hard matrixes that support and protect organs
Intestinal cells- have large surface area to increase absorption of nutrients

14. Stem Cells Divide and renew themselves Remain undifferentiated
Develop into a variety of specialized cell types
When it divides it either forms 2 stem cells or one stem cell and one specialized cell