Membrane Proteins Flashcards Preview

Unit 1 -AH Biology > Membrane Proteins > Flashcards

Flashcards in Membrane Proteins Deck (17):
1

Give two membrane proteins by which ions and molecules can progress through a membrane.

Channel Proteins

Transporter Proteins

2

Describe the two types of channel proteins.

Ligand-gated: signal molecules bind to channels causing a conformational change, opening the channel and allowing ions/molecules to pass through.

Voltage-gated: change in ion concentrations causes a conformational change, opening the channel and allowing ions/molecules to pass through.

3

Describe transporter proteins

Ions/molecules bind to transporter protein, this causes a conformational change and the protein passes the molecules through to membrane.

4

State the definition of the term 'facilitated diffusion'

The process of passive movement across a membrane through specific membrane proteins.

5

What is signal transduction?

Extracellular hydrophobic signal molecules bind to receptor proteins, triggering a signal-transduction pathway. This causes a specific intracellular response, involving cascades occur to amplify the signal.

This can change the uptake or secretion of molecules or rearrange the cytoskeleton.

6

What is the role of the Sodium Potassium pump?

Moving sodium ions out of the cell and moving potassium ions into the cell to generate a new ion gradient.

7

Describe 4 reasons the Na/K pump is important.

Maintains osmotic balance in animal cells -low ion concentration increases water concentration

Generation of sodium ion gradient for glucose symport

Generation of sodium ion gradient in kidney tubules - gradient created between lumen of tubule to cell

Maintain ion gradient for resting potential.

8

State the two stable conformational states of the Na/K pump

Open towards inside of cell with high affinity for Na+ ions

Open towards outside of cell with high affinity for K+ ions

9

Describe the 6 stages of how the Na/K pump works

1. 3 Na+ ions bind

2. ATP hydrolyses, phosphorylation occurs, conformational change occurs.

3. Na+ ions released

4. 2 K+ ions bind, triggering dephosphorylation

5. Conformational change occurs to original state

6. K+ ions are released

10

Explain what the resting potential of a cell is.

Imbalance in electrical charge in a cell. K channels allow K+ to leak back out pf the cell causing a net positive charge outside of cell

11

How does a nerve impulse pass along a neuron?

As a wave of depolarisation

12

Describe the 5 stages of triggering a nerve impulse.

1. Neurotransmitter binds to ligand gates channel

2. Channel opens to allow Na+ to diffuse into neuron

3. Na+ movement causes depolarisation

4. Depolarisation reaches critical level

5. Voltage gated channel opens to allow Na+ to diffuse into cell, creating a domino effect

13

Describe the 5 stages of resetting the resting potential

1. Voltage gated channel opens to allow Na+ to pass through

2. Voltage builds up so Na+ channel closes and K+ channel opens

3. K+ diffuses out of neuron to reverse depolarisation

4. Resting potential is restored so K+ channel closes

5. Na/K pump resets ion gradient

14

Describe the term 'coupled transport'

movement of one material down a concentration gradient, causing another material to move up against the concentration gradient

15

Describe active transport.

The protein conformational change requires the binding of ATP

16

State 3 examples of specific transmembrane proteins

Sodium Channels

Glucose Transporters

Proton Pumps

17

Explain what an aquaporin is.

Specific channel protein that allows polar water molecules pass through the pore.