Unit 1: Cells and Proteins 3

Question 1

Uniports do what?

Answer 1

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

Question 2

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

Answer 2

conformation

Question 3

What are the three types of transporter proteins?

Answer 3

Uniports, Symports and Antiports

Question 4

Symport: Two molecules transported …

Answer 4

in the same direction

Question 5

Antiport: Two molecules transported in …

Answer 5

Opposite directions

Question 6

Transport proteins are passive or active?

Answer 6

Both !

Question 7

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

Answer 7

ATP

Question 8

For the glucose/Na+ symport energy comes from

Answer 8

electrochemical gradient

Question 9

For bacterial rhodopsin, energy comes from

Answer 9

light

Question 10

A good example of a passive glucose transporter is

Answer 10

GLUT 1, 3 & 4

Question 11

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

Answer 11

glucose and glucose is readily uptaken dwon the concentration gradient

Question 12

Na+/K+ATPase transporter is responsible for

Answer 12

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

Question 13

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

Answer 13

Three Na+ ions

Question 14

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

Answer 14

reduced with a phosphate attaching to the transporter

Question 15

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

Answer 15

conformational change

Question 16

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

Answer 16

opening to the extracellular side, releasing Na+

Question 17

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

Answer 17

dephosphorylated returning it to its initial state.

Question 18

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

Answer 18

Cytoplasm

Question 19

Glucose/Na+ symport is described as ________ transport

Answer 19

secondary active

Question 20

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

Answer 20

binding for the other molecules

Question 21

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

Answer 21

conformational change

Question 22

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

Answer 22

intestine and kidney tubules

Question 23

Channel Proteins are _______ of molecule movement.

Answer 23

passive facilitators

Question 24

Three examples of channel proteins are:

Answer 24

1. Aquaporins
2. Ligand-gated ion channels
3. Voltage-gated ion channels

Question 25

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

Answer 25

water re-absorption from urine

Question 26

AQP1 is involved with what and is expressed where?

Answer 26

concentration of urine ad in the proximal kidney tubule

Question 27

Mutations of AQP2 in humans results in

Answer 27

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

Question 28

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

Answer 28

nephrogenic diabetes insipidus.

Question 29

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

Answer 29

depolarisation

Question 30

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

Answer 30

Action potential

Question 31

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

Answer 31

repolarise

Question 32

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

Answer 32

hyperpolarised

Question 33

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

Answer 33

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