Lecture 2: Membrane Transport Mechanisms

Question 1

Which of the following would have to be a transmembrane protein?

A receptor protein
A protein binding to the cytoskeleton
A channel protein
A phosphorylase

Answer 1

A channel protein

Question 2

Which organelle is directly associated with synthesis of proteins for secretion?

Answer 2

Rough endoplasmic reticulum

Question 3

Pits coated with what, are associated with endocytosis?

Answer 3

Clathrin

Question 4

Which process does not require the presence of mitochondria? And what does it do?

Answer 4

Glycolysis - breakdown of glucose to pyruvic acid

Question 5

Which of the following transport mechanisms requires energy, other than kinetic energy?

Osmosis
Diffusion
Active transport
Facilitated diffusion

Answer 5

Active transport

Question 6

Which ion is most concentrated in the extracellular matrix?

Answer 6

Sodium

Question 7

The Na/K pump is an example of which kind of transport?

Answer 7

Primary active transport

Question 8

The sodium-glucose pump is an example of what kind of transport?

Answer 8

Secondary active transport

Question 9

The sodium-calcium pump is an example of which kind of transport?

Answer 9

Secondary active transportation

Question 10

Glucose transporters employ which type of transport?

Answer 10

Facilitated diffusion

Question 11

What mechanism will likely be used to move water from an extracellular environment across an epithelial cell layer, into the extracellular matrix on the opposite side of the epithelial cell layer?

Answer 11

Sodium channels and sodium ATPase pumps

Water then follows via osmosis

Question 12

movement of particles from areas of high concentration to low concentration

Answer 12

diffusion

Question 13

what is the difference between diffusion and net diffusion?

Answer 13

net diffusion is across a permeable membrane

Question 14

movement of a solvent from high to low concentration areas, across a semipermeable membrane

Answer 14

osmosis

solvent is water

Question 15

describe how osmotic pressure is built up

Answer 15

water mvt across a membrane will cause a build up of water on one side and an increase in pressure on the other side

Question 16

what does effective osmotic pressure tell us?

Answer 16

different things can pass through the same membrane with different amounts of ease

Question 17

a type of protein that opens a link between the inside and outside cell matrix

Answer 17

an integral protein = channel protein

Question 18

what are the two categories of transport?

Answer 18

energy independent
or
dependent

Question 19

types of energy independent transport

Answer 19

diffusion
osmosis
facilitated diffusion

Question 20

non-gated channels

Answer 20

always open

examples: aquaporins, ion channels

Question 21

gated channels

Answer 21

open under specific conditions
ligand gated
voltage gated

Question 22

type of transport that requires ATP

Answer 22

energy dependent

active transport

Question 23

what type of transport is the only means of transportation that is not carrier mediated?

Answer 23

simple diffusion

Question 24

what is involved in calculating diffusion?

Answer 24

flow rate
permeability
area
concentrations

Question 25

list substances that can diffuse across the phospholipid bilayer

Answer 25

oxygen CO2 nitrogen alcohols

Question 26

what factors can increase permeability of a substance across a membrane?

Answer 26

increase lipid solubility decrease size of solute decrease membrane thickness

Question 27

what differentiates facilitated diffusion from simple diffusion?

Answer 27

facilitated is carrier mediated requires a uniporter occurs down an electrochemical gradient

Question 28

the maximum particles that can be carried at one time in facilitated diffusion

Answer 28

Vmax

Question 29

is carrier mediated transport stereospecific?

Answer 29

yes | different transports are required for different molecules

Question 30

describe the rate of simple diffusion

Answer 30

non-gated | flows at a constant rate

Question 31

describe the rate of facilitated diffusion

Answer 31

exponential rate that increases towards Vmax

Question 32

movement of particles against a gradient

Answer 32

active transport

Question 33

transport that utilizes ATPase as a transporter

Answer 33

primary active transport

Question 34

transport that utilizes ATP and multiporters

Answer 34

secondary active transport

Question 35

primary active transport

Answer 35

energy derived from direct breakdown of ATP | ATPase serves as transporter, up it's electrochemical gradient

Question 36

secondary active transport

Answer 36

one particle is going up it's gradient and the second is going down it's gradient primary creates conc. differences, energy built up from this differences is the power used for secondary multiporters used

Question 37

types of multiporters

Answer 37

symporters - 2 particles in same direction antiporter - 2 particles in opposite direction

Question 38

what is the most common solute in secondary active transport?

Answer 38

sodium

Question 39

if sodium moves down it's electrochemical gradient, why is this classified as secondary active transport?

Answer 39

because the energy given off by it's mvt down, powers the transport of another particle up it's gradient

Question 40

if sodium is moving down it's electrochemical gradient, what direction is it going?

Answer 40

from extra- to the intracellular matrix

Question 41

sodium/calcium antiporters move 3 Na for every 1 Ca particle. why does it take 3 Na to move 1 Ca?

Answer 41

because sodium is much smaller | calcium is much heavier

Question 42

____ sodium particles are moved for every ____ potassium particles.

Answer 42

3 Na per 2 K

Question 43

what is the difference between uniporter and multiporter?

Answer 43

uniporters can only transport one particle at a time

Question 44

describe potassium channels

Answer 44

``` non-gated channels have carbonyl oxygens that serve as selectivity filters function to ensure on K+ can get through even though Na is smaller than K ```

Question 45

how can body compartment volumes be altered?

Answer 45

by mvt of water we have no mechanism to directly move water so we move Na and water follows it

Question 46

cells in which an action potential can be induced

Answer 46

excitable cells | ex. - neurons and muscle cells

Question 47

neurons do not have ____ gated channels in the cell membrane.

Answer 47

voltage gated channels

Question 48

dendrites are characterized by the presence of _____ gated channels, and can conduct ____ potentials.

Answer 48

ligand gated channels | local potentials

Question 49

the _____ of the axon contains voltage gated channels.

Answer 49

axolemma

Question 50

what region of the axon contains synaptic vesicles and mitochondria?

Answer 50

terminal boutons in the distal axon telodendria

Question 51

which part of a neuron is capable of developing an action potential?

Answer 51

axolemma

Question 52

the carrier proteins of primary active transport are commonly referred to as ?

Answer 52

ATPase pumps

Question 53

another term for symporters

Answer 53

co-transporters

Question 54

another term for antiporters

Answer 54

counter-transporters