CELL BIOLOGY
1. Most cells are capable of performing all of life's basic functions

2. Cells have three subdivision   Fig. 2.7
* cell (plasma) membrane encloses the cell
* nucleus contains genetic information (DNA)
* cytoplasm contains organelles (little organs), cytosol (gelatinous-like liquid) and cytoskeleton (scaffolding)

3. Nucleus      Figs. 2.14-2.17
* gene is a segment of the DNA that codes for a protein
* RNA copies the genetic information from DNA
* ribosomes uses the instructions from RNA to make proteins
* proteins comprised of the 20 amino acids

4. Endoplasmic reticulum    Fig. 2.18
* synthesizes proteins and lipids
* rough ER reticulum is studded with ribosomes
* smooth ER has no ribosomes
Q: is the smooth or rough ER involved in protein synthesis?

5. Golgi apparatus     Fig. 2.19
* modifies proteins and sends them to various locations within and outside the cell
* modifies lipids and carbohydrates

6. Lysosomes
* digest extracellular and intracellular material
* peroxisomes detoxify toxic molecules

7. Mitochondria     Fig. 2.20
* produce the usable form or energy: ATP (adenosine triphosphate)
* convert energy nutrients (carbohydrates, fat and protein) into ATP
* three multi-step processes (glycolysis, Krebs cycle and electron transport chain) are involved in converting glucose to ATP

8. Cytosol contains
* free floating ribosomes
* transport vesicles
* enzymes and other molecules

9. Cytoskeleton is comprised of various proteins involved in  Figs. 2.21-2.22
* supporting the cell structure
* binding cells together
* moving materials within the cell
* moving the cell itself
 

PLASMA (CELL) MEMBRANE

1. Phospholipid bilayer with membrane proteins
* phosphate head is hydrophilic
* lipid tail is hydrophobic
Q: How do phospholipids arrange themselves together

2. This bilayer is a barrier preventing molecules from entering/exiting the cell
* water soluble (hydrophilic) molecules cannot enter unless very small
* lipid soluble (hydrophobic) molecules enter freely unless very big
Q: what type of molecules are hydrophilic?

3. Membrane proteins allow     Fig. 2.8
* transportation of material into the cell
* communication with environment and between cells

4. What determines direction of flow?
* molecules flow down their concentration gradients (from high to low concentration)
* molecules can flow up their gradient if energy is used Fig. 2.11

5. Hydrophobic molecules can flow freely down gradient
* hydrophilic molecules can only flow across if they have a special membrane protein