Lecture 8 transport

Question 1

Passive transport, how does it work? does it use energy?

Answer 1

does not require energy, has to be a favorable concentration gradient (higher to lower conc)

Question 2

simple diffusion. What kind of movement is it? does it use a protein or energy? what type of transport is it?

Answer 2

movement of substances from higher to lower conc. No protein or energy involved. type of passive transport

Question 3

What kind of substances move into cell by simple diffusion?

Answer 3

small, uncharged molecules (h2o, ethanol, gases)

Question 4

facilitated diffusion- what is it? what does it move? energy expenditure? protein?

Answer 4

movement of larger molecules down a favorable conc gradient thru a membrane protein. uses no energy (type of facilitated diff)

Question 5

Facilitated diff occurs thru a structure called a _______ in the outer membrane these often come in _______. An example of this found in gram - bacteria is __________________________________.

Answer 5

porins, trimers, outer membrane protein F

Question 6

Some porins are specific, letting in certain sugars. What are the two sugars we talked about?

Answer 6

maltose (maltose receptor), glucose

Question 7

aquaporin - what type of transport is it? energy expenditure?

Answer 7

transports water more efficiently. facilitated diff, no energy used.

Question 8

In aquaporins, the channel narrows allowing single water molecules go thru that __________ H bonded to other water molecules. This exposes the partial _______ charge which makes it attracted to the _________ charged __________ (amino acid).

Answer 8

are not; negative; positively; arginine

Question 9

Active transport- energy expenditure? Across what membrane?

Answer 9

transport across inner mem, requires energy

Question 10

simple transport - energy expenditure? protein? what type of transport?

Answer 10

involves one protein and requires energy. type of active transport

Question 11

What are the three types of proteins in simple transport?

Answer 11

uniport, symport, antiport

Question 12

______________ is a disaccharide that moves thru the inner mem of gram - bac _______________ using __________ ___________ (type of symporter)

Answer 12

lactose; E. coli ; lactose permease

Question 13

Where does the energy for lactose permease come from?

Answer 13

proton gradient (glucose/ other carbon brken down)

Question 14

Proton motive force is generated where?

Answer 14

in the periplasm

Question 15

proton motive force is also used to power _____ ___________ to generate ATP

Answer 15

ATP synthase

Question 16

is atp generated thru lactose permease?

Answer 16

no, only used to move lactose across inner mem

Question 17

group translocation (active transport) how does it work?

Answer 17

compound is moved thru inner mem channel protein and is chemically modified as it passes thru

Question 18

in group translocation the channel protein is also an ______ aka _________ because it chemically modifies the compound being transported (adds a phosphate grp).

Answer 18

enzyme; kinase

Question 19

What powers group translocation? What kind of system is it? Where is the energy transferred?

Answer 19

phosphoenolpyruvate; phosphotransferase system; PEP to membrane protein

Question 20

the phosphotransferase sys is a _________ of events in which each protein component gets ______________ and then passes the phosphate to the next component.

Answer 20

cascade; phosphorylated

Question 21

PEP contains an _______ where 2 carbons are double bonded to one another. These are fairly ________. energy comes from breaking this high energy bond.

Answer 21

enol; unstable

Question 22

What two transport systems work together to keep glucose moving into the cell?

Answer 22

facilitated diff and group translocation

Question 23

In order for group trans and facilitated diff to work together, the glucose conc in the _______ must always be _______ than that of outside the cell.

Answer 23

periplasm; lower