Question 1

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n)_______
A)active antiport
B)active uniport
C)passive antiport
D)active symport
E)passive symport

Accepted Answer

The answer of A transport system that moves one solute...

Question 2

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?
A)the largest
B)the smallest
C)the most negative
D)the most positive
E)both the largest and the most negative

Accepted Answer

The smallest proteins move the farthest during SDS-polyacrylamide gel electrophoresis because they are able to penetrate the gel matrix more easily due to their smaller size.

Question 3

Usually,optical tweezers drag integral proteins a limited distance before they encounter a barrier that causes their release;upon release,they typically spring backward.What does this suggest?
A)the presence of solid barriers
B)the presence of elastic barriers
C)the attachment of the proteins to the cytoskeleton
D)the attachment of the proteins to the endoplasmic reticulum
E)the presence of rubber in the membrane

Accepted Answer

The fact that the integral proteins encounter a barrier and then spring backward suggests the presence of an elastic barrier rather than a solid barrier. This could be due to the nature of the protein itself or the properties of the membrane surrounding it.

Question 4

Which protein in the red blood cell membrane appears to be responsible for the exchange of bicarbonate ions and chloride ions across the red blood cell membrane?
A)glycophorin A
B)glycophorin D
C)band 3
D)glyceraldehyde 3-phosphate
E)alpha-actinin

Accepted Answer

Band 3 is known as the anion exchanger protein, which facilitates the exchange of bicarbonate ions and chloride ions across the red blood cell membrane. Glycophorin A and D are involved in the stabilization of the lipid bilayer, whereas glyceraldehyde 3-phosphate is an enzyme involved in glycolysis and alpha-actinin is a cytoskeletal protein found in muscle cells.

Question 5

Which protein(s)below is(are)thought to be involved in and influence the stability of red blood cell membranes and the cells themselves by imparting strength,elasticity,and pliability to the membrane?
A)actin and tropomyosin
B)spectrin
C)band 3
D)ankyrin
E)All of these are correct.

Accepted Answer

The answer of Which protein(s)below is(are)thought to be involved in...

Question 6

What happens to phospholipid mobility when the cell is treated with agents that disrupt the underlying membrane skeleton?
A)Their mobility is unchanged.
B)Their mobility is increased because the fences that normally restrict their diffusion are removed.
C)Their mobility is decreased because the fences that normally restrict their diffusion are removed.
D)Their mobility is increased because the treatment raises the temperature.
E)Their mobility is decreased because the treatment lowers the temperature.

Accepted Answer

The answer of What happens to phospholipid mobility when the...

Question 7

A channel that opens in response to the binding of a specific molecule,which is usually not the solute that passes through the channel is called a ________.
A)voltage-gated channel
B)charge-gated channel
C)ligand-gated channel
D)positive-gated channel
E)electric-gated channel

Accepted Answer

A ligand-gated channel opens when a specific molecule, known as a ligand, binds to a receptor on the channel. This binding event causes a conformational change in the channel, allowing solutes to pass through. The other options, voltage-gated channels and charge-gated channels, open in response to changes in membrane potential and charge, respectively. Positive-gated and electric-gated channels are not commonly used terms in the field of biology.

Question 8

The movement of water through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration is called ________.
A)diffusion
B)osmosis
C)denaturation
D)metabolism
E)solubility

Accepted Answer

This is the definition of osmosis, where water molecules move across a semipermeable membrane in response to a concentration gradient of solute particles. Diffusion is the movement of particles from an area of high concentration to low concentration, and denaturation and metabolism are not related to this process. Solubility refers to the ability of a substance to dissolve in a solvent.

Question 9

What is thought to be important in maintaining the native structure of the Kv channel membrane protein and promoting its function as a voltage-gated channel.
A)negatively charged cholesterol
B)positively charged sphingolipids
C)negatively charged phospholipids
D)positively charged phospholipids
E)negatively charged sphingolipids

Accepted Answer

Negatively charged phospholipids are thought to be important in maintaining the native structure of the Kv channel membrane protein and promoting its function as a voltage-gated channel. This is because the negatively charged phospholipids help to stabilize the protein's structure and interact with positively charged amino acid residues in the protein, which are important for voltage sensing and activation.

Question 10

An important aspect of transport by facilitated transporters and pumps is ________.
A)conformational shifts
B)rigidity
C)softness
D)$\alpha$-helix
E)$\beta$-pleated sheet

Accepted Answer

Facilitated transporters and pumps undergo conformational shifts to transport molecules across the membrane. Rigidity and softness are not specific aspects of facilitated transporters and pumps. The options in the format of F1F1F1S1 and F1F1F10-helix/sheet are not related to facilitated transporters and pumps.

Question 11

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?
A)They move at a much greater rate than the wild type protein.
B)They move at a much smaller rate than the intact protein.
C)They do not move at all.
D)They are not inserted into the membrane so nothing can be learned about their mobility.
E)They flip to the opposite leaflet.

Accepted Answer

The answer of Integral membrane proteins have been engineered to...

Question 12

In the Na+/glucose cotransporter,_____ moving down its gradient drives the transport of _____ against its gradient.
A)Na+ ions,K+ ions
B)Na+ ions,glucose
C)glucose,Na+ ions
D)glucose,K+ ions
E)K+ ions,glucose

Accepted Answer

The answer of In the Na+/glucose cotransporter,_____ moving down its...

Question 13

_________ can be used to trap integral proteins and drag them through the membrane with a known force,using forces generated by a focused laser beam.This yields information about the presence of membrane barriers.
A)FRAP
B)SPT
C)Fluorescence recovery after photobleaching
D)Optical tweezers
E)SDS-PAGE

Accepted Answer

Optical tweezers can be used to trap integral proteins and drag them through the membrane with a known force, using forces generated by a focused laser beam. This yields information about the presence of membrane barriers.

Question 14

The sodium-potassium pump makes the cell interior more ______ by pumping ____ sodium ions out of the cell for every ____ potassium ions pumped in.
A)negative,3,2
B)negative,2,3
C)positive,3,2
D)positive,2,3
E)negative,4,3

Accepted Answer

The sodium-potassium pump contributes to the cell's negative interior by actively transporting 3 sodium ions out of the cell and 2 potassium ions into the cell, using ATP for energy. This results in a higher concentration of positive ions outside the cell compared to inside, thus maintaining the negative charge of the cell interior.

Question 15

You modify the gene for an integral membrane protein so that the cytoplasmic portions of the protein are deleted.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?
A)They move much greater distances than the intact protein.
B)They move much smaller distances than the intact protein.
C)They do not move at all.
D)They are not inserted into the membrane so nothing can be learned about their mobility.
E)They flip to the opposite leaflet.

Accepted Answer

The answer of You modify the gene for an integral...

Question 16

Why are the proteins being separated on an SDS polyacrylamide gel attracted equally to the positive electrode?
A)They carry a relatively uniform positive charge distribution
B)They carry a relatively uniform negative charge distribution.
C)They are all the same molecular weight.
D)They are all the same size.
E)They all have the same degree of hydrophobicity.

Accepted Answer

SDS (sodium dodecyl sulfate) binds to and denatures proteins, causing them to unfold and have a uniform negative charge distribution. Therefore, they are all attracted equally to the positive electrode in the gel electrophoresis process.

Question 17

_________ is the movement of a substance from an area of high concentration to an area of lower concentration.
A)Denaturation
B)Osmosis
C)Diffusion
D)Transport
E)Defusion

Accepted Answer

Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration. This can occur across a membrane or within a solution.

Question 18

What is the distinguishing characteristic of a P-type pump?
A)It must be pumped during the cycle.
B)It must be phosphorylated during the cycle.
C)It must be protonated during the cycle.
D)It must be deprotonated during the cycle.
E)It must be potassiumated during the cycle.

Accepted Answer

The distinguishing characteristic of a P-type pump is that it must be phosphorylated during the cycle, which is why it is called a "P-type" pump. The phosphorylation causes a conformational change in the pump that allows it to transport ions across the membrane.

Question 19

A channel that opens in response to changes in ionic charge across a membrane is called a ________.
A)voltage-gated channel
B)charge-gated channel
C)ligand-gated channel
D)positive-gated channel
E)electric-gated channel

Accepted Answer

A channel that opens in response to changes in ionic charge across a membrane is known as a voltage-gated channel. This type of channel is sensitive to changes in the electrical potential difference (voltage) across the membrane and opens or closes accordingly.

Question 20

Diffusion during which the substance to be transported binds selectively to a membrane-spanning protein,which helps the process along,is called ________.
A)osmosis
B)facilitated osmosis
C)simple diffusion
D)facilitated diffusion
E)active transport

Accepted Answer

Facilitated diffusion is a form of passive transport where a substance is transported across a cell membrane with the help of a membrane-spanning protein. The protein acts as a facilitator or carrier, allowing the substance to move from an area of higher concentration to an area of lower concentration. This process does not require energy and is selective, meaning only certain substances can bind to specific carrier proteins.

Quiz 4: The Structure and Function of the Plasma Membrane

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n) _______

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

Usually,optical tweezers drag integral proteins a limited distance before they encounter a barrier that causes their release;upon release,they typically spring backward.What does this suggest?

Which protein in the red blood cell membrane appears to be responsible for the exchange of bicarbonate ions and chloride ions across the red blood cell membrane?

Which protein(s) below is(are) thought to be involved in and influence the stability of red blood cell membranes and the cells themselves by imparting strength,elasticity,and pliability to the membrane?

What happens to phospholipid mobility when the cell is treated with agents that disrupt the underlying membrane skeleton?

A channel that opens in response to the binding of a specific molecule,which is usually not the solute that passes through the channel is called a ________.

The movement of water through a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration is called ________.

What is thought to be important in maintaining the native structure of the Kv channel membrane protein and promoting its function as a voltage-gated channel.

An important aspect of transport by facilitated transporters and pumps is ________.

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

In the Na+/glucose cotransporter,_ moving down its gradient drives the transport of _ against its gradient.

_________ can be used to trap integral proteins and drag them through the membrane with a known force,using forces generated by a focused laser beam.This yields information about the presence of membrane barriers.

The sodium-potassium pump makes the cell interior more __ by pumping sodium ions out of the cell for every potassium ions pumped in.

You modify the gene for an integral membrane protein so that the cytoplasmic portions of the protein are deleted.When the gene is inserted in cells,what happens to the mobility of this protein in the membrane?

Why are the proteins being separated on an SDS polyacrylamide gel attracted equally to the positive electrode?

_________ is the movement of a substance from an area of high concentration to an area of lower concentration.

What is the distinguishing characteristic of a P-type pump?

A channel that opens in response to changes in ionic charge across a membrane is called a ________.

Diffusion during which the substance to be transported binds selectively to a membrane-spanning protein,which helps the process along,is called ________.