2-5: Transport in Bacterial Cells

Question 1

List the different forms of passive and active transport

Answer 1

Passive = simple diffusion, facilitated diffusion
Active = simple transport, ABC transporters, group transport

Question 2

Channel proteins are what whereas carrier proteins are what?

Answer 2

Nonspecific, specific

Question 3

What is a commonly used chemical gradient used to power active transport?

Answer 3

Proton motive force

Question 4

What is the sodium proton antiporter

Answer 4

Exchanges protons for Na+ ions to maintain pH/Na+ homeostasis

Question 5

When would H+ enter the cell in the sodium/proton antiporter

Answer 5

When the cell is under basic/alkaline conditions

Question 6

kWhen would Na+ leave the cell using the Na+/H+ antiporter?

Answer 6

Under high salt conditions

Question 7

What is the lac permease symporter

Answer 7

Proton motive force used to drive uptake of lactose/disaccharides. Used to acquire nutrients

Question 8

What is group translocation

Answer 8

Active transport where the transported substance bound by transporter and chemically modified during transport

Question 9

Give an example of group translocation

Answer 9

Phosphotransferase system used for glucose uptake. A phosphate bond in PEP is hydrolyzed (releases energy) and the sugar is phosphorylated (first step in metabolism)

Question 10

Describe the structure of ABCs

Answer 10

2 cytoplasmic ATPase domains provide energy, transmembrane domain provides selective channel, substrate binding protein binds molecule with high affinity and delivers it to the channel

Question 11

What is a substrate binding protein, difference between gram types and archaea

Answer 11

AKA periplasmic binding proteins. Binds and delivers substrate to channel in ABC transport.

Gram(-) = free floating
Gram(+) and archaea = tethered to CM