Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Membranes and Receptors > Session 2 > Flashcards

Session 2 Flashcards

1
Q

What can pass through membranes?

A

Hydrophobic molecules

Small, uncharged polar molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What cannot pass through membranes?

A

Large, uncharged polar molecules

Ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What passive diffusion?

A

It is dependent on permeability and concentration gradient.

The rate of passive transport increases linearly with increasing concentration gradient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is facilitated diffusion?

A

Has specific proteins in the bilayer that allow molecules through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two carrier molecules in models for facilitated diffusion?

A

Carrier molecules, usually gated pores (use ping pong transport)
Protein channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is active transport?

A

Allows the transport of ions or molecules against unfavourable concentrations and/or electrical gradients. Uses energy from the hydrolysis of ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do voltage gated ion channels work?

A

There is a voltage sensor, when the optimal voltage is detected, the channel opens to allow ions through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do ligand gated ion channels work?

A

A molecule will bind (the ligand) which causes the channel to open and let the ion through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Co-Transporters?

A

A membrane transporter than can move more than one molecule per reaction cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 types of transporters? (Classified by how many molecules they can carry)

A

Uniport - Single molecule. One direction
Symport - Two molecules. Same direction.
Antiport - Two molecules. Opposing direction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the Na+ Glucose co transport system work?

Extra point - Where is it in the body?

A

Entry of Na+ provides energy for the entry of Glucose against the gradient. (Symport)
Extra Point - Small intestine and Kidney.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 2 subunits of Na+/K+ ATPase?

A

Alpha - binding sites for K+, Na+, Ouabain and ATP

Beta - Glycoprotein for directing the pump to the surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Does Na+/K+ ATPase use active or passive transport?

A

Uses ATP to pump ions so active transport.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What molecule inhibits the Na+/K+ ATPase?

A

Ouabain binding to the alpha subunit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of co transport does the Na+/K+ ATPase pump use?

A

Antiport - 2K+ in ans 3Na+ out.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the importance of Na+/K+ ATPase?

A

It forma Na+/K+ gradients which are necessary for other things such as electrical excitability.
Also drives secondary active transport which has many roles eg control of pH, cell volume, Ca2+ concentration and nutrient uptake.

17
Q

What is the main role of K+ channels?

A

They allow K+ (High concentration from Na pump) to diffuse down the concentration gradient. They are the main cause of membrane potential being -70mV.

18
Q

What is the main role of Ca2+ ATPase?

Extra point - Does it use active or passive transport?

A

It controls the resting Ca2+ concentration

Extra point - It uses active transport.

19
Q

What is the main role of Plasma membrane Ca2+ ATPase?

Extra point - What are the 3 main points about the exchanger?

A

It removes residual Ca2+ from the cell and bring in H+

Extra point - It is active, an antiport and high high affinity low capacity.

20
Q

What is the main role of SERCA?

Extra point - What are the 3 main points about the exchanger?

A

It removes residual Ca2+ into the S/ER in exchange for H+

Extra point - Active, Antiport, high affinity low capacity.

21
Q

What is the main role of the Na+/Ca2+ exchanger?

Extra point - What are its important properties?

A

It expels 1Ca2+ from the cell for 3Na+ in using the Na+ gradient set by the Na+/K+ ATPase (removes most of the Ca2+)
Extra point - It uses secondary active transport, Antiport, low affinity high capacity, Electrogenic (Current flows in the direction of the Na+ gradient) and activity is membrane potential dependent.

22
Q

What happens to the Na+/Ca2+ exchanger in Ischaemia?

Extra point - Why?

A

The exchanger reverses so Na= in and Ca2+ out (Ca2+ is highly toxic)
Extra point - ATP is depleted so the Na+ pump is inhibited which causes it to accumulate in the cell –> depolarisation.

23
Q

What are the acid extruders of a cell?

A

Na+/H+ exchanger.

NBC

24
Q

What are the base extruders of a cell?

A

Anion exchanger Cl-/HCO3-

25
Q

How does the Na+/H+ exchanger work?

A

It is electroneutral with 1Na+ in and 1H+ out.
Uses the concentration gradient set by Na+/K+ ATPase.
raises intracellular pH

26
Q

What activates and inhibits the Na+/H+ exchanger?

A

Activated by growth factors

Inhibited by Amiloride.

27
Q

How does the NBC exchanger work?

A

Uses the concentration gradient set by the Na+/K+ ATPase to bring Na+ and HCO3- in and H+/Cl- out. So raises the intracellular pH and regulated cell volume.

28
Q

How does the Anion exchanger work?

A

It acidifies the cell by removing base.

Involved in cell volume regulation.

29
Q

How can ion transport regulate cell volume?

A

Osmotically active ions are transported in or out of the cell and water follows.

30
Q

What are the osmotically active ions and organic osmolytes?

A

Osmotically active ions are Na+ K+ Cl-

Organic osmolytes are amino acids.

31
Q

What happens to the ions if the cell is swelling?

A

They move out of the cell so water follows and is lost.

32
Q

What happens to the ions if the cell is shrinking?

A

They move into the cell so water follows and is gained.

33
Q

What is the goal of renal anti hypertensive therapy?

A

To reduce the reuptake of Na+ so less water is reabsorbed. Therefore reducing blood volume.

34
Q

How does aquaporin (A protein) work in the kidneys?

Extra point - What causes its inclusion in the membrane?

A

It allows water to cross the membrane more easily into the cells.
Extra point - Anti diuretic hormone

35
Q

How do Loop diuretics prevent the movement of water back into the renal cells?

A

They prevent Na+ reuptake in the thick ascending limb.

36
Q

How does Amiloride prevent the movement of water back into kidney cells?

A

It prevents Na+ uptake in the distal convoluted tubule and proximal tubule.

37
Q

What does Aldosterone do to the Na+ transporters in the kidneys?
Extra point - What can be used to treat high levels of it?

A

It up regulates the transporters.

Extra point - Spironolactone

38
Q

What does a faulty CFTR protein cause?

A

An accumulation of Cl- in a cell so water moves into the cell via osmosis resulting in sticky mucus in the lumen.

39
Q

What happens to cause Diarrhoea?

A

CFTR is phosphorylated by Protein Kinase A which causes it to become overly active.
Therefore Cl- is transported into the kumen (excessively)
Water follows by osmosis resulting in symptoms.

Membranes and Receptors (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions