Exam 1: Chapter 5: Transport

Question 1

transport

Answer 1

can be the movement of individual ions across a membrane or glucose crossing the intestinal epithelia to enter the blood stream

Question 2

the second law of thermodynamics

Answer 2

isolated system can only change in certain ways

this applies to equilibrium

Question 3

what is equilibrium?

Answer 3

internal stability without change; homeostasis

Question 4

passive transport…

Answer 4

seeks equilibrium

Question 5

fish in fresh water

Answer 5

water is hypotonic to the fish, concentration of ions in the fish is much larger

Question 6

simple diffusion

Answer 6

passive transport, movement occurs with the concentration gradient

Question 7

electric gradients (diffusion)

Answer 7

can have an effect on diffusion of charged solutes across membranes

Question 8

influences on simple diffusion

Answer 8

attraction and repulsion

Question 9

what can cross membranes via simple diffusion?

Answer 9

small, non-polar molecules

Question 10

gated ion channels

Answer 10

take many forms; positive ions in, negative ions out

Question 11

selectively permeable channels

Answer 11

movement is the result of both concentrations and electrical gradients

Question 12

charges of cells in animals

Answer 12

positive charge on the outside, negative charge on the inside

Question 13

Na+ movement

Answer 13

not at equilibrium, tends to move into the cells

Question 14

K+ movement

Answer 14

not at equilibrium, leaks out of cell

Question 15

concentration gradients can cause

Answer 15

electrical gradients that alter concentration gradients

Question 16

donnan equilibrium

Answer 16

the membrane is permeable to more than one kind of ion; attraction and repulsion develops due to ion movement

Question 17

facilitated diffusion

Answer 17

can work with polar organic solvents; proceeds in the direction of electrochemical equilibrium

Question 18

facilitated diffusion movement occurs…

Answer 18

quickly

Question 19

in facilitated diffusion, solvents must bind to…

Answer 19

transporter proteins

Question 20

example of facilitated diffusion

Answer 20

glucose movement across the membrane; requires specific transporters in blood cells

Question 21

active transport

Answer 21

uses energy for transport and can do transport against a concentration or electrochemical gradient

Question 22

active transport is a type of

Answer 22

carrier mediated transport

Question 23

a receptor protein may undergo

Answer 23

conformational change in the process of facilitating transport

Question 24

what is the source of energy for active transport?

Answer 24

main soure is ATP; GTP can also be used

Question 25

how much ATP is used in the kidney for transport?

Answer 25

40%

Question 26

Na+/K+/ATP pump

Answer 26

3 Na+ out, 2 K+ in; creates a negative potential on the inside; against concentration gradient, requires ATP

Question 27

primary vs secondary active transport

Answer 27

In primary active transport, the energy is derived directly from the breakdown of ATP.
In the secondary active transport, the energy is derived secondarily from energy that has been stored in the form of ionic concentration differences between the two sides of a membrane.

Question 28

Na+-K+-ATPase

Answer 28

consists of a pump, an enzyme, and a transporter

hydrolyzes ATP, and is primary type, because it relies on being phosphorylated during its action

Question 29

Na+-K+-ATPase steps

Answer 29

1. ATP is bound, about to bind Na+
2. ATP is hydrolyzed, phosphorylated, Na+ binds
3. releases Na+, can bind K+
4. de-phosphorylated and K+ attatches

Question 30

example of secondary active transport

Answer 30

glucose into an epithelial cell of the vertebrate small intestine

Question 31

role of cotransporter protein in glucose movement

Answer 31

links the movement of Na+ and glucose; for every 2 Na+ ions it moves across the membrane, it must carry a molecule of glucose across in the same direction

Question 32

osmotic pressure

Answer 32

water transport; osmosis of water is colligative

Question 33

colligative properties depend on:

Answer 33

the number of dissolved entities per unit volume, not the chemical nature

Question 34

3 most important colligative properties

Answer 34

osmotic pressure, freezing point, and water vapor pressure

Question 35

freezing temperature

Answer 35

highest temperature that causes freezing

Question 36

water vapor pressure

Answer 36

measures the tendency of a solution to evaporate

Question 37

colligative properties change with changes in…

Answer 37

concentration of the dissolved entities

higher concentration increases osmotic pressure but lowers freezing point and vapor pressure

Question 38

osmolarity

Answer 38

how osmotic pressure is expressed

Question 39

osmosis

Answer 39

diffusion of water from lower osmotic pressure to higher osmotic pressure; water moves from hypo to hyper

Question 40

aquaporins

Answer 40

water pores; water in the form of H2O is allowed to pass through

Question 41

where are aquaporins present?

Answer 41

RBCs, the brains, and kidney-tubule epithelia

Question 42

what do aquaporins play a role in?

Answer 42

urine formation, tears and sweat, aqueous humor, and blood-brain barrier

Question 43

aquaporin shape

Answer 43

tetramers

Question 44

mammalina RBC are ________ to water

Answer 44

highly permeable

Question 45

some aquaporins are controlled by

Answer 45

protein kinases and have sites for phosphorylation

Question 46

vassopressin

Answer 46

antidiuretic hormone (ADH)

Question 47

blood plasma has a high concentration of

Answer 47

proteins; help water to enter the blood stream in capillaries by osmosis

Question 48

blood pressure forces water

Answer 48

out of the blood in the capillaries