Transport of substance through cell Membranes

Question 1

the two type of membrane proteins are?

Answer 1

channel proteins and carrier proteins

Question 2

what are channel proteins?

Answer 2

watery spaces all the way through the molecule, allows diffusion of water and selected molecules and ions

Question 3

what are carrier proteins?

Answer 3

they mind with molecules and have conformational change in their protein molecule then move the substance to the other side of the membrane.

Question 4

what is different in active transport than in normal diffusion?

Answer 4

active transport takes place with the help of carrier proteins against the concentration gradient

Question 5

define simple diffusion?

Answer 5

diffusion through membrane opening or intracellular space without interaction with carrier proteins.

Question 6

rate of diffusion is determined by?

Answer 6

amount of substance available
the velocity of kinetic motion
number and size of membrane openings

Question 7

define facillated diffusion ?

Answer 7

diffsuion with the help of carrier protein

Question 8

the pores that allow rapid movement of water through cell membrame are ?

Answer 8

aquaporins

Question 9

example of aquaporins in book?

Answer 9

erythrocytes

Question 10

describe the structure of potassium channel?

Answer 10

tetrameric with 4 identical protein subunits surrounding a central pore. has pore loops on the top of channel pore that has selectivity filter.

Question 11

what does the selectivity filter of potassium channels have ?

Answer 11

carbonyl oxygens

Question 12

function of carbonyl o2?

Answer 12

it dehydrates the k+ ions and allows it to past the channel

Question 13

diameter of NA channels?

Answer 13

0.3 to 0.5

Question 14

selectivity filter of NA ions have?

Answer 14

negatively charged amino acids

Question 15

what does the -ve charged amino acids do?

Answer 15

they attarcted the small dehydrated Na Ions from the surrounding hydrating water molecules.

Question 16

the opening and closing of gates is operated in what two ways?

Answer 16

1. voltage gating

2. chemical ligand gating

Question 17

what charge on the inside makes the Na gated to be closed?

Answer 17

-ve on the inside

Question 18

what charge on the inside makes the K+ gates to be open?

Answer 18

+ve charge on the inside

Question 19

example of chemical gating?

Answer 19

acetylcholine

Question 20

the pore that acetyl choline opens is what diameter and allows what ions to move past?

Answer 20

0.65 nanometer and allows +ve and uncharged ions to pass through

Question 21

the difference between simple diffusion and facillated diffusion?

Answer 21

the rate of simple diffusion increases with the concentration of the diffusing substance but facilated diffusion reaches Vmax and stops.

Question 22

the rate at which the substance diffuse inwards in equal t0?

Answer 22

concentration of the substance to the outside

Question 23

rate of net diffusion?

Answer 23

concentration of inside - concentration of outside

Question 24

what the nernst equation ?

Answer 24

the electrical diff that will balance out the concentration diff of univalent ions can be determend by nernst equation.

Question 25

osmotic pressure is detemined by?

Answer 25

the number of particles per unit volume of fluid

Question 26

in primary active transport energy is derived from?

Answer 26

directly from ATP or some other high energy phosphate compound.

Question 27

in secondary active trans the energy is derived from?

Answer 27

energy is stored in the form of ionic concentrayion difference of secondary molecules or ions on the both side of the membrane

Question 28

primary active transport, transports what ions

Answer 28

Na, K+ , hydrogen, calcium and chloride

Question 29

carrier protein has how many globular proteins?

Answer 29

2 aplha and beta

Question 30

the sizes of alpha and beta are?

Answer 30

100,00 and 55,000

Question 31

how many binding site for Na on the large globular protein?

Answer 31

3 on the inside

Question 32

binding site for K+ ?

Answer 32

2 on outside

Question 33

why Na k+ pump is electrogenic ?

Answer 33

it trasnports 3 Na ions to outside and 2 K+ ions insdie overall transporting one +ve charge to outside making the inside negative and causing an electric potential across the membrane

Question 34

calcium is found 100,000 times more in what place?

Answer 34

in extracellular fluid than intra

Question 35

where is calcium transported through the carrier protein?

Answer 35

to the outside of the cell or to other organelles like the sarcoplasmic reticulum of the muscle fiber.

Question 36

hydrogen is trasnported to where?

Answer 36

gastric glands of stomach

and late distal tubules or cortical collecting duct of kidneys

Question 37

what cells of gastric glands has the most potent mechanism of active transport of hydrogen?

Answer 37

parietal cells.

Question 38

what is the need of H2 ions in gasrtric glands?

Answer 38

to make hcl

Question 39

what cels in kidneys H2 is transported to?

Answer 39

intercalated cells

Question 40

the transport of h2 in kidney is from where to where?

Answer 40

from the blood into the renal tubular fluid

Question 41

why into the renal tubular fluid?

Answer 41

to eliminate excess H2 from body fluids