chp 8 10/25/14

Question 1

Plasma membrane has ____ function.

Answer 1

dual

Question 2

Plasma membrane prevent ____ of cytosol into the environment

Answer 2

loss

Question 3

Plasma membrane _____ exchange of substances _____ membrane with the environment.

Answer 3

allow, across

Question 4

There are ____ categories for the movement of substances through a membrane.

Answer 4

2

Question 5

What are the two categories for movement of substances.

Answer 5

passive diffusion and active diffusion.

Question 6

_____ diffusion by an energy coupled transport process

Answer 6

actively

Question 7

_____ diffusion not triggered by a energy coupled transport.

Answer 7

passively

Question 8

Name some specific methods by which substances move across membranes

Answer 8

simple diffusion through the lipid bi-layer, facilitated, active transport, simple diffusion through an aqueous protein-lined channel,

Question 9

_____ is a spontaneous process in which a substance moves from a region of high concentration to a region of low concentration …. eventually eliminating concentration gradient.

Answer 9

Diffusion

Question 10

What 2 qualifications must be met before a nonelectrolyte (besides chg.) can diffuse passively across a plasma membrane.

Answer 10

1 substance must have a concentration gradient

2 membrane must be permeable to the substance

Question 11

A membrane may be permeable to a given solute either, because the solute can pass _____ through the lipid layer, because that solute can _____ traverse an aqueous pore that spans the membrane

Answer 11

directly, transverse

Question 12

Dialysis uses what principle

Answer 12

diffusion

Question 13

a measure of the polarity (or nonpolarity) of a substance

Answer 13

partition coefficient

Question 14

Partition coefficient is

Answer 14

the rate of solubility in a nonpolar solvent

Question 15

in the partition coefficient the more soluble a molecule in the membrane,

Answer 15

the faster it will penetrate the membrane

Question 16

factors that affect the simple diffusion of a molecule

Answer 16

partition coefficient, size,

Question 17

the smaller the molecule the ____ it will faster through the membrane

Answer 17

faster

Question 18

very small uncharged molecules such as ________ are thought to slip between adjacent phospholipids.

Answer 18

O2, CO2, NO, H2O

Question 19

Larger polar molecules such as ________ have poor membrane penetrability.

Answer 19

sugars, amino acids, and phosphorylated intermediates

Question 20

_______ is the movement of a molecule across a membrane by the aid of a protein that does not just form a channel but instead binds the ligand and undergoes a conformational change delivering the molecule across the membrane.

Answer 20

facilitated diffusion

Question 21

_____ is the movement of a molecule across a membrane with a protein that binds and moves it across the membrane.

Answer 21

facilitated diffusion

Question 22

Proteins that operate in facilitated diffusion are termed ______

Answer 22

transport proteins.

Question 23

Transport proteins were called

Answer 23

carrier proteins

Question 24

_____ term applied to some transport proteins that move uncharged molecules like glucose

Answer 24

permease

Question 25

what is a model of facilitated diffusion?

Answer 25

alternating conformation model

Question 26

Transport proteins remain in ____ in the membrane and translocates solute by ______ between 2 conformations.

Answer 26

place, alternating

Question 27

transport protein might bind to solute in one conformation and deposit it on the __________.

Answer 27

other side of the membrane in another conformation

Question 28

The solute's binding and release may trigger the transport protein to revert _____

Answer 28

to its original conformation

Question 29

what is an example of model facilitated diffusion

Answer 29

glucose permease, glut1

Question 30

concentration outside the cell is 5nm the concentration is

Answer 30

much lower

Question 31

glucose has a ____ permeability coefficient

Answer 31

low

Question 32

Facilitating transport proteins share ____ of enzymes

Answer 32

properties

Question 33

transport proteins are ______ for the solutes they transport.

Answer 33

specific

Question 34

Transport proteins can be _____ with solute, so a maximum transport rate occurs when all binding sites are occupied with solute.

Answer 34

saturated

Question 35

The velocity of glucose uptake can be saturated, all the transporters are occupied =

Answer 35

Vmax

Question 36

Km for D-glucose for this transporter is about ___

Answer 36

1.5 mM

Question 37

what is Km

Answer 37

measures the affinity of the transporter for glucose

Question 38

Transporters will also bind other ______ molecules that are similar in structure to D-glucose

Answer 38

6-carbon sugar molecules

Question 39

What sugars can competitively inhibit the uptake of D-glucose into erythrocytes.

Answer 39

D mannose Km=20mM | D-galactose Km=30mM

Question 40

The gradient of high glucose levels outside the cell is maintained immediately _____

Answer 40

phosphorylating glucose upon its entering the cell

Question 41

Some facilitated glucose transporters are regulated by ______ .......like insulin.

Answer 41

hormones

Question 42

When secreted into the blood stream during high glucose levels, insulin stimulates muscle and fat cells to place more _______ in the plasma membrane.

Answer 42

glucose transporters

Question 43

a common form of ____ involves mutations that alter the sequences of the transmembrane segments of the transporter preventing transport across the plasma membrane

Answer 43

diabetes

Question 44

In a ___________ the transport proteins for cysteine and other amino acids is missing from the membrane

Answer 44

kidney disease, cystinuria

Question 45

carries a only one kind of solute across the membrane

Answer 45

uniport

Question 46

cooperative channel which moves two substances simultaneously in the same directions, e.g. Na+ and glucose. Due to concentration gradient, Na+ moves downhill and releases enough free energy to move glucose uphill.

Answer 46

symport

Question 47

exchanges one solute for another by transporting them in opposite directions e.g. cl- for HCO3

Answer 47

antiport

Question 48

movement of water readily from hypotonic solution to a hypertonic solution. Many cells are much more water permeable than explained by simple osmosis through the bi-layer.

Answer 48

Osmosis

Question 49

proteins that allow the passive movement of water from one side to the other

Answer 49

aquaporins

Question 50

The hormone, ____, stimulates water retention by the collecting ducts of the kidney, by way of these channels.

Answer 50

vasopressin

Question 51

a mutation in this aquaporin channel, in which persons excrete large amounts of urine because their kidneys don't respond to vasopressin.

Answer 51

congenital nephrogenic diabetes insipidus

Question 52

Most biological membranes are impermeable to charged substances, including small ions such as

Answer 52

Na+, K+, Ca2+, and Cl-

Question 53

A variety of proteins termed ______ have been identified

Answer 53

ion channels

Question 54

The diffusion of ions through a channel is __ ____, from high to low concentration

Answer 54

always downhil

Question 55

ion channels are ____..... they allow passage of ions in either direction with net flux of the ions depending on the electrochemical gradient

Answer 55

bidirectional

Question 56

how many ion channes have been discovered

Answer 56

75

Question 57

what do all 75 ion channels have in common

Answer 57

all are glycoproteins, all have several a-helical membrane-spanning regions, hydrophilic portions protrude into the aqueous cytosol or extracellular matrix

Question 58

most of the ion channels that have been identified can exist in either an open or closed confirmation such channels are

Answer 58

gated

Question 59

usually open. allow ions to move back and forth across the membrane without regulation

Answer 59

open channels

Question 60

gated channels

Answer 60

chemically or ligand gated, usually closed, voltage-gated, mechanically-gated

Question 61

check out the technique of ________ in studying ion channels

Answer 61

patch clamping

Question 62

most channels exist in on e of three possible configurations, which is regulated by various stimuli

Answer 62

close, open, inactivated

Question 63

Voltage Gated Channels fall into what two categories.

Answer 63

multimeric, monomeric

Question 64

Voltage gated channels that such as the potassium channel, and several protein subunits combine to form the 3-D structure of the transport protein

Answer 64

multimeric

Question 65

Voltage gated channels fallinto two categories such as the sodium channel one large polypeptide folds into the transport protein having multiple domains

Answer 65

monomeric

Question 66

a single transmembrane alpha helix in each subunit or in each domain serves a _____ function

Answer 66

sensory

Question 67

as the membrane potential changes, the S4 _____ shifts in such a way that the channel pore opens.

Answer 67

voltage sensor

Question 68

S4 can shift and close the channel, making a condition that can quickly re-open when the membrane volatge stimulus reoccurs, termed

Answer 68

channel gating

Question 69

The movement of ions through the channel results in movement of the cytoplasmic N-terminus domain, termed the ______, into the open pore causing it to be inactivated

Answer 69

inactivating particle

Question 70

Today there are a considerable number of inherited ion channel diseases named collectively _____, caused by mutation in K+, Na+, Ca2+, and Cl- channels that are known to exist in human and animal models

Answer 70

channelopathies

Question 71

inside the cell potassium is ____, and inside the cell sodium is ____

Answer 71

high, low

Question 72

depends on integral membrane proteins that selectively bind a particular solute and move it across the membrane against its concentration gradient in a process driven by eneregy requiring changes in the protein's conformation

Answer 72

active transport

Question 73

active transport drives the movement of ions _______

Answer 73

in only one direction

Question 74

proteins that carry out active transport are often referred to as

Answer 74

pumps

Question 75

Such _____ movement of ions requires being coupled to an _____ reaction such as: atp hydrolysis, absorbance of light,

Answer 75

endergonic, exergonic

Question 76

some exergonic reactions

Answer 76

ATP hydrolysis, absorbance of light, transport of electrons, flow of another substance down its concentration gradient.

Question 77

example of active transport

Answer 77

sodium-potassium pump

Question 78

termed ______ in nonexciteable cells

Answer 78

membrane potential

Question 79

termed a ______ in a neurons and muscle cells

Answer 79

resting potential

Question 80

Cells lining our intestine are able to take up molecules like glucose or amino acids from the lumen into the cells even when the celluar

Answer 80

sodium-glucose symport

Question 81

_____ seems like active transport, however, the driving exergonic reaction here is the use of the Na+ gradient established by the Na+/K+ pump

Answer 81

sodium-glucose symport

Question 82

The epithelial lining of the stomack contains a H+/K+ -ATPase which secretes a solution of concentrated acid (up to 0.16 NHCL) into the stomach chamber.

Answer 82

example of transport proteins and medicine

Question 83

finally the glucose molecules move into the blood stream by _____ through a glucose transporter

Answer 83

facilitated diffusion

Question 84

mitochondrion basics are _______, meaning they grow and divide within the cell and generate some of the proteins that function there, and take up others from the cytoplasm

Answer 84

semiautonomous

Question 85

mitochondrion have what

Answer 85

their own dna and ribosomes

Question 86

how many mitochondrion are in each cell

Answer 86

varies with each cell

Question 87

space between the membranes is termed ____

Answer 87

intermembrane space

Question 88

mitochondrion structure infoldings of membrane are termed

Answer 88

cristae

Question 89

mitochondrion structure solutionwithin inner membrane is termed the _____

Answer 89

matrix