Biology Class 5 Flashcards
(43 cards)
Pathway of secreted/lysosomal proteins
- Translation begins in cytoplasm, then finishes in rough ER
- Signal sequence is detected in membrane of rough ER, while ribosome binds to its receptor in cytoplasm
- Protein finishes translation & signal sequence is cleaved
- Protein goes to golgi body, then enters through plasma membrane, then goes to outside of cell
Pathway of membrane-bound proteins
- Translation begins in cytoplasm, then finishes in rough ER
- Has multiple of signal sequences and each time it is found on the membrane of the rough ER
- Ribosome binds to its receptor in cytoplasm
- Final protein is weaved in and out of the membrane of the rough ER
- Clatherin then cleaves and pulls the protein outwards and creates a vesicle
- Vesicle fuses with golgi body, then another vesicle fuses with plasma membrane
Signal sequence is not removed from final protein
Plasma Membrane components
- Phospholipids (head = polar, tail is non-polar)
- Proteins
- Carbohydrates
- Cholesterol (helps stabilize & creates fluidity
Electrolytes
Free ions in solution produced as a result of dissolving ionic substance
Van’t Hoff Factor (i)
- Cannot be 0
- # of ions produced per molecule of an electrolyte
Colligative properties
Properties that depend on amount of solute particles but not on the identity
- taste is not a colligative propertie
Examples of colligative properties
- Vapour pressure (decreases)
- Freezing point (decreases)
- Boiling point (increases)
- Osmotic pressure (increases)
Freezing point depression
Formula: freezing point ΔTf = i x m x Kf
Kf of water = -1.86
Fp ∝ [particles]
Vapour pressure depression
Pressure of the vapour that evaporates from the liquid
VP ∝ [particles]
- more solutes will keep the solvent grounded, therefore VP will decrease
Boiling Point Elevation
The temperature at which VP is equivalent to atm pressure
Formula: boiling point ΔTb = i x m x Kb
Kb of water = 0.5
bp = [particles]
Osmotic Pressure Elevation
Pressure required to resist the movement of water by osmosis
Formula: π = i x R X M X T
Diffusion vs Osmosis
Moving particles from high to low []
Moving water from high to low []
Hypotonic, Hypertonic, isotonic
Hypotonic: less particles than another solution
Hypertonic: more particles than another solution
Isotonic: equal amount of particles
Passive transport vs active transport
Passive
- doesn’t require energy
- moved down gradient
1. Simple diffusion
2. Facilitated diffusion
Active
- requires energy
- moves against gradient
1. Primary
2. Secondary
Primary vs Secondary active transport
Primary - uses ATP directly to move against gradient
Secondary - uses ATP indirectly to move against gradient
Simple vs facilitated diffusion
Simple
- doesn’t need help moving down the gradient
- moves hydrophobic, non-polar molecules
Eg. CO2, O2, steroids, cholestrol
Facilitated
- needs help moving down gradient (helper proteins)
- moved hydrophilic, polar molecules
Eg. amino acids, ions, glucose
Helper proteins
- Pores - not specific
- Channels - highly specific
- Shape shifters - bind, change shape, then pass through
Na+/K+ Atpase
- primary active transporter
- moves 2 k+ in and 3 Na+ out
- RMP is -70mV
- sets up Na+ for secondary transport
G-protein adenyl cyclase
- GDP is bound to g-protein if no ligand is bound to receptor. If a ligand is bound to the receptor, GDP leaves and GTP binds
- A subunit of the G-protein leaves and binds to adenyl cyclase
- Adenyl cyclase converts ATP to cAMP
- cAMP activates cAMP dependent kinases
- cAMP kinases phosphorylate enzymes
- Changes enzyme activity in cell and amplify signal which is fast & temporary
G-Protein phopholipase C
- GDP is bound to g-protein if no ligand is bound to receptor. If a ligand is bound to the receptor, GDP leaves and GTP binds
- A subunit of the G-protein leaves and binds to phospholipase C
- Phospholipase C breaks down phosphoinositol bisphosphate into inositol triphosphate & diacylglyceral
- I3 will increase intracellular Ca2+ levels
- Diacylglycerol will activate kinases which will change enzyme activity
Types of filaments of cytoskeleton
Microtubule
Microfilament
Intermediate filament
Microtubule
Protein(s): alpha & beta tubulin
Diameter: large
Use: mitotic spindle, cilia & flagella, intracellular transport
Microfilament
Protein(s): actin
Diameter: small
Use: muscle contraction, pseudopod formation, cytokinesis
Intermediate filament
Protein(s): several different protein types
Diameter: medium
Use: structural roles
