Bio 202 Test 2

ch 4, 5, 6

What is the effect of submerging cells in a hypertonic solution?

water moves out of the cell, cell shrinks

What is the effect of submerging cells in a hypotonic solution?

water move into the cell, cell swells and burst

What are the properties of the sodium potassium pump (how many ions move and in what direction when hydrolyzing an ATP.)

1 ATP = 3 sodium ions out and 2 potassium ions in, against gradient, maintains resting potential

How do large molecules enter and exit cells.

bulk transport: endocytosis (into cell) and exocytosis (out of cell)

How does oxygen and carbon dioxide move across the plasma membrane.

simple diffusion

What are integral proteins.

proteins embedded in the membrane

How does glucose move across the plasma membrane.

facilitated diffusion (carrier proteins)

What transport proteins work together by passive mechanism.

facilitated diffusion: channel proteins and carrier proteins

What transport proteins work by active mechanism.

pumps (antiport & symport)

What factors affect the rate of diffusion (Fick’s law).

surface area - larger = faster

molecular weight - smaller = faster

distance - shorter = faster

concentration gradient - bigger = faster

permeability

What are the properties of osmosis. Is it active or passive.

diffusion of water, low solute to high solute, passive

What the properties of facilitated diffusion. Is it active or passive.

high to low, uses proteins, passive

What are symports.

2 substances moving in the same direction

The types of receptors that function as enzymes.

receptor tyrosine kinase and receptor acetylcholine esterase

What is the difference between hydrophobic messengers and hydrophilic messengers

hydrophobic messenger: enter cell, bind intracellular receptors, affect gene expression

hydrophilic messenger: stays outside, bind extracellular receptor, causes internal changes

Know all the steps of the G-protein coupled receptor (in-order)

1. ligand binds to g-protein coupled receptor

2. receptor activates g-protein

3. GDP swaps with GTP on the alpha subunit

4. alpha subunit separates from beta-gamma and activates the effector protein (enzyme), adenylyl cyclase (AC)

5. AC converts ATP to cAMP (second messenger)

6. cAMP activates Protein Kinase A (PKA)

7. PKA phosphorylates target proteins bring a cellular response

Know the different parts of the action potential and values of resting potential, peak potential, threshold

resting potential: -70mV

threshold: -50mV to -55mV (voltage gated sodium channels open)

depolarization: sodium ion influx

peak: +30mV (VGSC inactive and voltage gated potassium channels open)

repolarization: potassium ion efflux

hyperpolarization: below -70mV (slow closing of VGKC)

return to resting: refractory period (VGKC closed)

The different part of the neuron and the function of each part

dendrites - receives signals (graded potential)
soma - processes signals (graded potential)

axon hillock - decision point (action potential)

axon - carries electrical signal (action potential)

myelin sheath - insulates and speeds up signal

nodes of Ranvier - gaps with all the voltage gated channels

axon terminals - release neurotransmitters

The role of the sodium ions in the action potential

depolarization

The properties of the potassium leak channels

always open, slowly diffuse out, maintains resting potential

What membrane proteins does the resting membrane potential depends on

sodium-potassium pump, potassium leak channels, and sodium leak channels

What are the properties of the voltage gates sodium channels

opens at threshold (-50mV to -55mV), closed at rest (-70mv), inactive after peak (+30mV), depolarizes

What is summation

adding of multiple graded potentials together (temporal: time, spatial: location)

What is saltatory conductance

action potential jump node to node

PLC and CAMK steps

1. ligand binds to g-protein coupled receptor

2. receptor activates g-protein

3. GDP swaps with GTP on the alpha subunit

4. alpha subunit separates from beta-gamma and activates the effector protein (enzyme), phospholipase C (PLC)

5. PLC converts PIP2 to IP3 + DAG

6. DAG, directly, + IP3 (releases calcium ions from ER), indirectly, activate Protein Kinase C (PKC)

7. PKC phosphorylates target proteins bring a cellular response

8. calcium ions also cause formation of ca-calmodulin complex

9. the complex activates ca-calmodulin dependent protein kinase (CAMK)

10. CAMK phosphorylates target proteins bring a cellular response