Brainscape's Knowledge GenomeTM

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


See full index

Cell Biology Midterm 1 > Membrane Transport + Potential > Flashcards

Membrane Transport + Potential Flashcards

1
Q

What do cells use electrochemical gradients for? (4 points)

A
  • Transport
  • ATP Production (mitochondria, bacteria, chloroplasts)
  • Cell Signalling (action potential)
  • Other functions (e.g. opening and closing stroma)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of transport diffusion is the slowest out of simple, channel mediated, and transporter mediated?

A
  • Transporter mediated is slowest
  • simple diffusion and channel mediated are faster because molecules can just go right through without a conformational change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the example of passive transport that brings glucose in the cell?

A

GLUT Trasnporters

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

Difference between GLUT1 and GLUT2?

A

-GLUT 1 is expressed mainly in red blood cells and other tissues
-GLUT 2 is expressed in the liver and gut epithelium
Mutations in these GLUT transporters can lead to disease (neuro diseases that associated with epilepsy)

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

3 different forms of energy that powers conformational change? (Active transport)

A
  • coupled transport (help of another solute)
  • ATP-driven pump (uses ATP hydrolysis)
  • light-driven pump
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What type of transport can coupled transport be?

A

-antiporters or uniporters 9secondary active transport)
antiporters–> transports two molecules across the membrane in DIFFERENT directions
symporters–> transports two molecules across the membrane in the SAME direction

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

What is an example of coupled transport?

A

Na+ - glucose cotransporter (type of symporter)

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

What are the 3 classes of ATP driven pumps?

A
  • P Type
  • ABC
  • V Type
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What drives the conformational change of P-type pumps

A
  • During the pumping stage, P-type pumps are phosphorylated by ATP which drives the conformational change to move solutes against its concentration gradient
  • specifically, the conformational change is by the amino acids shift in position, which is shifted by the phosphorylation and dephosphorylation of asparic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Some of the roles of P-Type pumps inside the cell?

A
  • Maintain calcium levels in the cytoplasm/cytosol - keep them low
    • Some of them pump calcium in the ER and the plasma membrane
  • Create Na+/K+ gradients (eg in plants and fungi)
  • Transport of important trace metal ions such as iron, magnesium, cobalt, copper, manganese, and zinc copper
  • Many are drug targets for drug development
  • They are responsible for primary transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Typical P-Pump Structure?

A

10 transmembrane α helices connected to three

cytosolic domains

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

What are the 3 cytosolic domains of a P-Type Pump?

A
  • Nucleotide binding domain: uses atp to move solute across the membrane
  • Phosphorylated aspartic acid: this domain is phosphorylated. The phosphate is from ATP
  • Activator domain:
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the structure of the ABC Transporter and what do they transport?

A
  • ABC transporters contain two highly conserved ATPase, domains or ATP-binding cassettes on the cytoplasmic side and two hydrophobic domains
  • Transport of sterols, lipids, sugars, vitamins, nucleotides, peptides, amino acids, etc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

difference between bacteria ABC pump and eukaryotic ABC pump

A

Some ABC transporters export solutes and take in solutes. In eukaryotes, the transporter mainly only exports solutes out of the cell

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

What are 3 types of membrane transport flip flops

A
  • Flippase (P-Type ATPase)
    - flips phospholipid from outer to inner membrane layer
  • Floppase (ABC flippase)
    - flops phospholipids from inner to outer membrane layer or out of membrane
  • Scramblases
    - move in both directions (do not require ATP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the types of channels associated with PASSIVE transport?

A
  • Water Channels (aquaporins)

- Ion channels (Voltage, ligand and mechanically)

17
Q

What channel proteins are selective?

A

While some channel proteins can be non-selective, the majority of them are selective. Selective channel proteins include aquaporins, and most ion channels (sodium, potassium, calcium, chloride)

18
Q

What is the structure of water channels?

A

One half of the channel (left side) is hydrophobic and the other side that are the carbonyl bonds

19
Q

What are the 3 properties of ion channels?

A
  • Selectivity
  • Gating–> They can open and close in confirmation
  • desensitization/inactivation–> Many gated channels can be stimulated to open for a certain amount of time and it just closes up again
20
Q

What is the selectivity filter on Ion channels?

A

Selectivity filter is the point in which the channel becomes very narrow, only allowing only 1 and sometimes a specific ion through
- This controls which ions can pass through the channel

21
Q

How does an Ion channel open and close?

A
  • This happens through the movement of inner helices
22
Q

What is associated with the voltage-gated ion channels?

A
  • neurons, membrane potential
23
Q

What is membrane potential?

A

-The membrane potential is created by the Na+/K+ pump (10%) and the activity of K+ leak channels (90%)

24
Q

What is resting membrane potential?

A

-cells are at rest; there are equal charges on both sides of the membrane which means voltage or membrane potential is 0

25
Q

What are the 3 conformational states of voltage-gated Na+ Ions

A

-Closed, Open and inactivated

26
Q

What happens as soon as membrane potential shifts enough near the Na+ Channels?

A

As soon as the membrane potential shifts enough near the channel, Sodium ions will flow through and as they move into the axon, the membrane is depolarized and voltage increases. When It becomes depolarized, it opens up the neighbouring sodium channel

27
Q

How is action potential triggered?

A

An action potential is triggered by a depolarization of the plasma membrane that is, by a shift in the membrane potential to a less negative value inside.

  • action potential is depolarized (goes up) when sodium channel opens up and sodium rushes in the cell.
  • it then gets depolarized (down) when potassium leak channels open up and K+ leaks out of the cell
28
Q

how does membrane potential restore to its initial negative value

A

the Na+ channels automatically inactivate and voltage-gated K+
channels open

29
Q

What is hyperpolarization?

A

-when channels don’t close right at resting potential and a lot of potassium leaks out. This goes below resting potential

Cell Biology Midterm 1 (6 decks)

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