1. Specialized Cells & Cell Origins
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Essential Questions:
Do all cells have the same structure?
How did complex cells come to be?

2. Levels of Organization

3. Cell Differentiation
Process by which an unspecialized cell becomes specialized.
Stem cells are undifferentiated and depending on where they are on an embryo, they will develop into a specific cell type.

4. Specialized Cells: Blood Cells
Red Blood Cells
Function: Carry Oxygen
Structure: large surface area to hold oxygen molecules; contains protein called hemoglobin, which binds to oxygen; have no nucleus
White Blood Cells
Function: Fight infection & protect body from pathogens
Structure varies depending on type of leukocyte
Platelets
Function: Help blood clot
Structure: When activated, cells produce long finger-like projections (made of protein!) that are sticky; have no nucleus

5. Specialized Cells: Neurons
Function – carry electrical nerve impulses to different parts of the body
Structure
Can be very long
Myelin sheath covers the axon to help speed the neural impulses
Cell body contains the nucleus and other cell organelles

6. Specialized Cells: Muscle Cells
3 Types of Muscle: Skeletal, Smooth, & Cardiac
Function – movement
Skeletal: moves bones
Smooth: moves food via peristalsis
Cardiac: moves blood
Structure: long, tubular cells

7. Specialized Cells: Epithelial Cells
Epithelial cells line all surfaces of your body
Function
Secretion, Absorption, Protection, Cellular transport, Detection of sensations
Structure
Some have cilia to help move substances
Reproduce rapidly

8. Specialized Cells: Bone Cells

9. Specialized Cells: Root Cells
Roots help support plants & absorb nutrients
Each root is lined with root hairs
Root hairs increase the surface area of the root
How do root hairs affect the plant’s ability to absorb nutrients?

10. Specialized Cells: leaf Cells
Cuticle helps prevent water loss
Stomata open and close to let gases in and out of plant
Guard Cells surround stomata to control their opening and closing
Mesophyll layers contain chloroplasts and absorb sunlight
Xylem & Phloem are tubes that transport water and food throughout the plant

11. Where did complex cells come from?

12. Endosymbiotic Theory
Prokaryotic cells are believed to be the first cells to exist because they are more simple than eukaryotic cells.
Theory that more complex cells arose by one simple cell engulfing another.
Evidence:
Chloroplasts & mitochondria replicate similar to bacteria
Chloroplasts & mitochondria have their own DNA & ribosomes, which are similar to bacteria DNA & ribosomes
Chloroplasts & mitochondria have their own membranes
Believed to be the explanation for how a eukaryotic cell has specialized organelles