Membrane transport

Question 1

Uniporters –

Answer 1

 Uniporters – recognize specific molecules

Question 2

what is a symporter

Answer 2

Symporters – utilize a cation (along its concentration gradient) with
another molecule (ion, sugar, amino or oligopeptide)

Question 3

what is an antiporter

Answer 3

Antiporter – transports ion (along its concentration gradient) while
another substance is transported in the opposite direction

Question 4

do aqua porins follow the osmostic pressure gradient

Answer 4

yes

Question 5

does most movement across the cell require energy

Answer 5

Most movement in nonexcitable cells occurs through some expenditure of energy,
either by primary or secondary active transport.

Question 6

what are the 2 types of passive transport

Answer 6

simple diffusion / passive diffusion

Question 7

passive diffusion can be described by what law

Answer 7

ficks law

Question 8

does Simple Diffusion Occurs over all concentration ranges.

Answer 8

yes

Question 9

The rate of diffusion is linearly related to what

Answer 9

The rate of diffusion is linearly related to the concentration gradient
such that if the concentration gradient increases, the concentration
increases from an area of high concentration to low concentration

Question 10

is the rate of diffusion is limited by a

carrier?

Answer 10

Unlike facilitated diffusion, the rate of diffusion is not limited by a
carrier

Question 11

The passive diffusion of a molecule across a membrane is
______ proportional to the ______ of the membrane and
difference in concentration of the molecule and _____
proportional to the thickness of the membrane.

Answer 11

The passive diffusion of a molecule across a membrane is
directional proportional to the surface area of the membrane and
difference in concentration of the molecule and inversely
proportional to the thickness of the membrane.

Question 12

passive transport utilizes

Answer 12

Utilizes gated channels or carrier proteins.

Question 13

Rate of facilitated diffusion is greater than passive

diffusion at_____

Answer 13

Rate of facilitated diffusion is greater than passive

diffusion at lower solute concentrations.

Question 14

can facilitated diffusion become saturated

Answer 14

Rate of uptake, Vmax, can become saturated

Question 15

how can Vmax can be increased in faciliated diffusion

Answer 15

Vmax can be increased by adding more carrier proteins.

Question 16

does Binding of the substance to the carrier results in

conformational change ?

Answer 16

yes Binding of the substance to the carrier results in
conformational change in protein and translocation of
the substance

Question 17

does the Na/K pump require ATP

Answer 17

YES

Question 18

What is an example of primary active transport

Answer 18

sodium K pump

Question 19

secondary active transport is also known as

Answer 19

 Also known as cotransporter

Question 20

give 2 examples of secondary active transport

Answer 20

Na+-glucose and Na+-galactose transport in
intestinal epithelium
❑ Na+/H+ antiport in renal and intestinal cells

Question 21

what is unique about the sodium pump

Answer 21

The sodium/potassium pump , the active portion is the original
transport of sodium against its concentration gradient.
 The subsequent events are secondary.
 The sodium pump results in passive movement of ions through
channels.
 Clfollowing to preserve electroneutrality.
 Water following the osmotic pressure gradient

Question 22

what are the 3 kinds of ion channels

Answer 22

Types of Channels
➢ Ligand-gated channels
➢ Voltage-gated channels
➢ Gap junction channels

Question 23

what are the 3 main types of Vesicular Membrane Transport

Answer 23

Exocytosis
Endocytosis
Transcytosis

Question 24

Pinocytosis and Phagocytosis are a form of

Answer 24

➢ Endocytosis

Question 25

what kind of channel is this : respond to the binding of a ligand specific
for that channel, such as ACh.

Answer 25

 Ligand-gated channels – respond to the binding of a ligand specific
for that channel, such as ACh.

Question 26

what kind of channel is this : open in response to a change in
membrane potential

Answer 26

 Voltage-gated channels – open in response to a change in

membrane potential

Question 27

what kind of channel is this : formed between two adjacent cells and open to
allow passage of ions and small molecules between the cells

Answer 27

Gap junctions – formed between two adjacent cells and open to
allow passage of ions and small molecules between the cells

Question 28

does membrane transport require ATP

Answer 28

yes

Question 29

give 4 examples of Second messenger systems

Answer 29

Second messenger systems include cAMP, cGMP, calcium, and

inositol triphosphate.

Question 30

what do second messenger systems activate

Answer 30

The pathways can activate protein kinases or, in the case of

calcium, calmodulin.

Question 31

list 3 important second messengers

Answer 31

Cyclic-AMP (cAMP)
• Derivative of ATP
2. Cyclic-GMP (cGMP)
• Derivative of GTP
3. Calcium ions

Question 32

what is the function of adenalate cyclase

Answer 32

change atp to cAMP

Question 33

Activated g proteins triegger the release of what molecule

Answer 33

calcium

Question 34

phospholipase c triggers what receptor cascade

Answer 34

Production of diacylglycerol (DAG) and inositol
triphosphate (IP3
) from membrane phospholipids

• May further activate more calcium ion channels through
protein kinase C (PKC)

• Calcium ions may activate calmodulin which causes further
cellular changes

Question 35

t/f horomones can bind to Intracellular Receptors

and alter rate of DNA transcription in nucleus

Answer 35

true

Question 36

can lipophillic proteins go thru the membrane

Answer 36

yes