BIO membrane

While transport requires the cell to expend some of its own energy, transport does not.

active passive

Transport proteins that actually bind to the specific substance being transported across the membrane are called Blank 1Blank 1 channel proteins.

carrier

Ion ... have a hydrated interior that spans the membrane and allows ions to diffuse through.

channels

During transport, carrier proteins use the energy in one substance's concentration to actively transport another substance.

coupled gradient

Each cycle of the sodium-potassium pump moves ______ out of the cell and ______ into the cell.

3 sodium ions; 2 potassium ions

Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration. This net movement is called .

Diffusion

Net movement of a substance from a region where it has a higher concentration to a region where it has a lower concentration is called which of the following?

Diffusion

Based on the direction of movement, bulk transport can be divided into two main categories:

Endocytosis Exocytosis

When a channel protein or carrier protein assists in diffusion, which of the following is observed?

Facilitated diffusion

The cytoplasm contains ions and molecules dissolved in

H2O

Which of the following is true of the sodium-potassium pump?

It can transport as many as 300 Na+ ions per second.

Which of the following describes passive transport?

It does not require an expenditure of energy by the cell itself.

Which of the following are true of the plasma membrane?

It is selectively permeable. It is fluid.

Which of the following describes the sodium-potassium pump?

It uses energy from ATP to alter the conformation of the carrier protein. It is an active transport mechanism. It moves sodium ions and potassium ions across the membrane in opposite directions.

The sodium-potassium pump actively pumps ions into the cell and ions out of the cell.

K Na

During the Na/K pump cycle, the protein binds a molecule of ATP and soon after, the ATP is hydrolyzed and a phosphate is transferred to an amino acid in the pump's structure. What is the affinity of the pump for sodium and potassium ions at this point?

Low affinity for sodium and high affinity for potassium

In which of the following is ATP used directly in active transport?

The transport of Na+ across the plasma membrane.

Select the statements that are true about ions.

They are repelled by the hydrophobic interior of the lipid bilayer. They interact well with polar molecules.

During facilitated diffusion, how do carrier proteins transport solutes across the membrane?

They bind specifically to the solute being transported.

Select the statements that are true of gated channels?

They can open and close in response to chemical stimuli. They can open and close in response to electrical stimuli. They have a hydrated interior through which polar molecules and ions can move when open.

Which of the following is true of channel proteins?

They have a hydrophilic interior through which polar molecules can pass.

During coupled transport,

energy released as one substance moves down its concentration gradient is used to move another substance up its concentration gradient. energy from ATP is used to create a concentration gradient.

Diffusion that is assisted by a channel protein or carrier protein is called ... diffusion.

facilitated

Channel proteins that can be opened or closed in response to a specific stimulus are called channels.

gated

The most abundant molecule in the cytoplasm is the molecule.

h2o

What is the immediate source of the energy needed to power the sodium-potassium pump?

hydrolysis of ATP

Cellular are said to be selectively because they allow some substances to pass through easily while other substances pass through very slowly or not at all.

membranes permeable

Plasma membranes allow some substances to pass through easily while other substances only pass through very slowly or not at all. For that reason, plasma membranes are considered which of the following?

selectively permeable

Energy released from the hydrolysis of ATP is used to change the conformation of the sodium-potassium pump which results in changes in

the protein's affinity for Na+ and K+.

True or false: The use of energy from ATP during active transport may be direct or indirect.

true

Transport that requires a cell to expend some of its own energy, typically from , is called transport.

ATP Active

The transport of sodium and potassium ions from areas of concentration to areas of concentration requires more than one-third of all the energy expended by a non-dividing animal cell.

Active Low high

Why do ions need membrane transport proteins to help them cross the plasma membrane?

Because of their charge

Of the 2 types of transport proteins that mediate facilitated diffusion, only proteins actually bind with the substance being transported while proteins simply provide a hydrophilic space for the substance to move through.

Carrier Channel

Which of the following are required for the sodium potassium pump in cells to work?

Carrier Proteins ATP

Transport proteins that have a hydrophilic interior space through which specific substances can move across the membrane in either direction are called ... proteins.

Channel

Many substances that are repelled by the hydrophobic interior of the lipid bilayer can readily diffuse across the plasma membrane with the help of specific proteins or proteins. These transporter proteins are typically transmembrane proteins.

Channel Carrier

Which type of transport proteins use energy from ATP indirectly?

Coupled transport proteins

Which of the following best describes the amount of energy used by animal cells in the active transport of Na+ and K+ from areas of low concentration to areas of high concentration?

More than one-third of all the energy expended by an animal cell that is not actively dividing is used in the transport of Na+ and K+.

How do active and passive transport differ? Choose all that apply.

Only active transport can move a substance against its concentration gradient. Only active transport relies on an expenditure of energy by the cell itself, usually from ATP.

Why is active transport such an important cell process?

Only active transport can move a substance from an area where it has a lower concentration to an area where it has a higher concentration.

How do carrier proteins differ from channel proteins?

Only carrier proteins actually bind to the substance being transported.

Transport that occurs without a cell expending any of its own energy is called transport.

Passive

Which type of transport proteins use energy from ATP directly?

Protein pumps

The plasma membrane can best be described as which of the following?

Selectively permeable

Which of the following statements about ion channels are true?

Some can be opened or closed in response to a specific stimulus. They are used to transport ions across the membrane.

Substances that cannot easily cross the lipid bilayer can still diffuse across the plasma membrane with the help of which of the following?

Specific channel proteins or carrier proteins