Unit 1: Cells and Proteins 3 Flashcards Preview

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Flashcards in Unit 1: Cells and Proteins 3 Deck (33)
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1
Q

Uniports do what?

A

Transport a molecule from one side of the membrane to another down a concentration gradient

2
Q

Transporter proteins change _______ so that molecules can be transported across membrane

A

conformation

3
Q

What are the three types of transporter proteins?

A

Uniports, Symports and Antiports

4
Q

Symport: Two molecules transported …

A

in the same direction

5
Q

Antiport: Two molecules transported in …

A

Opposite directions

6
Q

Transport proteins are passive or active?

A

Both !

7
Q

For the Na+/K+ transporter, energy comes from

A

ATP

8
Q

For the glucose/Na+ symport energy comes from

A

electrochemical gradient

9
Q

For bacterial rhodopsin, energy comes from

A

light

10
Q

A good example of a passive glucose transporter is

A

GLUT 1, 3 & 4

11
Q

In passive transporters such as the GLUT 1, 3 & 4, there is high affinity binding sites for

A

glucose and glucose is readily uptaken dwon the concentration gradient

12
Q

Na+/K+ATPase transporter is responsible for

A

maintaining an Na+/K+ gradient across the plasma membrane

13
Q

Na+/K+ATPase: Stage 1, here the transporter sites have a high affinity for?

A

Three Na+ ions

14
Q

Na+/K+ATPase: Stage 2, Na+ binds and ATP is

A

reduced with a phosphate attaching to the transporter

15
Q

Na+/K+ATPase: Stage 3, The attachment of a phosphate to the transporter results in a

A

conformational change

16
Q

Na+/K+ATPase: Stage 4, The conformational change of the transporter results in the transporter

A

opening to the extracellular side, releasing Na+

17
Q

Na+/K+ATPase: Stage 6, the transporter is

A

dephosphorylated returning it to its initial state.

18
Q

Na+/K+ATPase: Stage 7, K+ ions are released into the

A

Cytoplasm

19
Q

Glucose/Na+ symport is described as ________ transport

A

secondary active

20
Q

In the glucose/Na+ symport binding of either molecules enhances the

A

binding for the other molecules

21
Q

In the glucose/Na+ symport, when all the binding sites are filled a what takes place?

A

conformational change

22
Q

The glucose/Na+ symport is used to actively transport glucose out of the

A

intestine and kidney tubules

23
Q

Channel Proteins are _______ of molecule movement.

A

passive facilitators

24
Q

Three examples of channel proteins are:

A
  1. Aquaporins
  2. Ligand-gated ion channels
  3. Voltage-gated ion channels
25
Q

Aquaporins 1,2 and 3 are expressed in the kidney tissue where they are involved in

A

water re-absorption from urine

26
Q

AQP1 is involved with what and is expressed where?

A

concentration of urine ad in the proximal kidney tubule

27
Q

Mutations of AQP2 in humans results in

A

failed insertion of channels on the apical membrane of collecting duct cells

28
Q

No Aquaporins on the collecting duct cells due to mutations gives rise to insensitivity to ADH resulting in a form of

A

nephrogenic diabetes insipidus.

29
Q

Propagation of a Nerve Impulse: Stage 1, Na+ channels open and Na+ flows into axon causing

A

depolarisation

30
Q

Propagation of a Nerve Impulse: Stage 2, Na+ channels close when the __________ is reached.

A

Action potential

31
Q

Propagation of a Nerve Impulse: Stage 3, Ka+ channels open, allowing efflux of K+ to _______ membrane

A

repolarise

32
Q

Propagation of a Nerve Impulse: Stage 4, the axon becomes _______

A

hyperpolarised

33
Q

Propagation of a Nerve Impulse: Stage 5, the K+ channels close nad the Na+/K+ATPase pumps what where?

A

potassium back into the axon and sodium out during the refractory.