Biol Ch5 Hw

During the coupled transport of glucose, the glucose transporter acts as

a symporter

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

Because of their charge

The following substances all move across the plasma membrane of red blood cells by diffusion. Which ones move by facilitated diffusion?

Bicarbonate ions Chloride ions Glucose

Which of the following statements correctly describe how glucose can be transported across the plasma membrane?

By coupled transport By facilitated diffusion

When a cell is placed in a solution, water will move in or out of the cell depending on the concentration of the solution, relative to the one in the cell. Match solutions to the movement of water below.

Cell is placed in hypertonic solution. -Water moves out of the cell. Cell is placed in a hypotonic solution. -Water moves into the cell. Cell is placed in an isotonic solution. - No net movement of water in or out of the cell.

The red blood cell carrier that functions in the uptake and release of carbon dioxide, transports bicarbonate ions in one direction and transports ______ ions in the opposite direction.

Chloride

True or false: Regarding the Na/K pump: Phosphorylation of the protein which reduces its affinity for Na+ occurs after dephosphorylation of the protein reduces its affinity for K+.

F

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

Facilitated diffusion

Which of the following involve passive transport?

Facilitated diffusion Diffusion

while ______________transport requires the cell to expend some of its own energy,

active passive

Water flow across the plasma membrane is facilitated by special channel proteins called _____

aquaporins

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

Hydrolysis of ATP

How does the glucose transporter facilitate diffusion of glucose into the cell?

It binds glucose and then it changes its conformation "dragging" glucose through the lipid bilayer.

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 accurately describes the glucose transporter that enables facilitated diffusion of glucose into the cell?

It is a carrier protein that can change its conformation.

Which of the following describes the sodium-potassium pump?

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

Which of the following accurately describe osmotic pressure?

It is exactly counterbalanced by the hydrostatic pressure when the cell reaches an equilibrium. It is the force needed to stop osmotic flow.

Which of the following are features of the sodium-potassium pump?

It transports both sodium ions and potassium ions against their respective concentration gradients. It uses energy from ATP to alter the conformation of the carrier protein.

Which of the following accurately describes the hydrostatic pressure inside a cell if it is transferred from a hypertonic environment to a hypotonic environment?

It will increase

Molecules and ions dissolved in water diffuse across the plasma membrane due to which of the following?

Molecules and ions dissolved in water move down their concentration gradient until equilibrium is reached. Molecules and ions dissolved in water are in constant random motion.

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+.

e coupled transport of glucose molecules across the cell membrane uses energy released from the concentration gradient of

Na

Animal cells are more likely than plant cells to rupture when placed in which of the following solutions?

A hypotonic solution.

What is the cause of hereditary diabetes insipidus?

A non-functional aquaporin.

Which of the following are strategies that organisms use to maintain osmotic balance?

A rigid cell wall that can withstand the pressure that builds up inside the cell due to the inflow of water by osmosis Adjust the concentration of solutes inside the cell to match the surrounding environment. Contractile vacuole inside the cell that actively pumps water out of the cell

During coupled transport, carrier proteins create a concentration gradient using energy from

ATP Up

Which of the following describes a mechanism used by red blood cells to prevent glucose from passively leaving the cell, even though its intracellular concentration is high?

After glucose enters the cell, it is phosphorylated so it can no longer bind to the glucose transporter and leave the cell.

The sodium-potassium pump is which of the following?

An antiporter

Which of the following terms are used to describe carrier proteins that actively transport two different types of molecules together?

Antiporter Symporter

During the coupled transport of glucose which of the following are true?

As sodium moves along its concentration gradient, it releases the energy needed to move glucose against its concentration gradient. Glucose molecules move into the cell against their concentration gradient.

During the coupled transport of glucose what occurs?

As sodium moves back into the cell down its concentration gradient, it releases the energy needed to move glucose up its concentration gradient. Sodium ions move back into the cell down their concentration gradient.

Place the following molecules in order according to their capability to cross the lipid bilayer of the plasma membrane without the help of transport proteins. Start with molecules that cross most easily on top.

Nonpolar Small Polar Large Polar

Which of the following best describes the relationship between solute concentration and rate of diffusion during facilitated diffusion by carrier proteins?

As solute concentration increases, the rate of diffusion increases but eventually it remains constant once it reaches a maximum rate.

Why are bacterial cells less likely than animal cells to burst in a hypotonic solution?

Bacterial cells have strong cell walls.

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.

Facilitated diffusion by carrier proteins differs from simple diffusion due to which of the following?

Only facilitated diffusion by carrier proteins reaches a saturation point where all carriers are occupied & rate of transportation cannot increase.

How do phagocytosis and pinocytosis differ?

Only pinocytosis involves intake of liquids.

The diffusion of water across a selectively permeable membrane is called

Osmosis

Which processes require the cell to expend some of its own energy, usually from ATP?

Phagocytosis Receptor-mediated endocytosis Pinocytosis

During transport via the sodium-potassium pump which of the following occurs?

Sodium ions inside the cell bind with the carrier protein. Phosphorylation of the carrier protein causes it to change shape and release sodium ions outside the cell.

The combined concentration of all ___________ in a solution determines the osmotic concentration of the solution.

Solutes

Which of the following statements about channel proteins is not true?

Some channel proteins use energy from ATP to facilitate net movement of a substance up its concentration gradient.

Suppose the concentration of oxygen inside of a cell is equal to the concentration outside. Which of the following statements are true?

Some oxygen molecules will move into the cell. Some oxygen molecules will move out of the cell.

Suppose the concentration of oxygen is higher outside of a cell than inside. Which of the following statements are true?

Some oxygen molecules will move out of the cell. Some oxygen molecules will move into the cell. The net movement of oxygen will be into the cell.

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

Which of the following substances are transported across membranes by carrier proteins?

Sugars Amino acids Ions

What determines the osmotic concentration of an aqueous solution?

The concentration of all solutes in it.

In cell membranes, what is the main barrier to the free passage of water-soluble ions and molecules?

The interior of the lipid bilayer

How does facilitated diffusion by carrier proteins differ from simple diffusion?

The rate of transport by simple diffusion increases as the concentration gradient increases.

This diagram shows two solutions separated by a membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which statement is true?

The solution on the right has a higher concentration of free water molecules.

If two solutions have unequal concentrations of solutes, which one will be considered hypertonic?

The solution with the higher solute concentration

The 2 solutions shown in this diagram are separated by a selectively permeable membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which of the following statements are true?

The water level will rise on the left side of the U-tube Net movement of water across the membrane is toward the left. The solution on the left is hypertonic.

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.

Select the statements that are true about ions.

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

How do red blood cells promote the movement of glucose into the cell?

They phosphorylate glucose after it enters the cell in order to maintain a steep concentration gradient for unphosphorylated glucose.

Which of the following are methods of passive transport?

Transport of water by aquaporins Osmosis

Which types of cells carry out endocytosis and exocytosis?

Virtually all eukaryotic cells

The diffusion of which molecules across a selectively permeable membrane is called osmosis?

Water

If a cell is placed in a hypertonic solution (relative to the inside of the cell), which of the following will happen?

Water diffuses out of the cell, causing the cell to shrink.

Amino acids, sugars and ions are transported across the plasma membrane by ____________ proteins

carrier

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

carrier

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

Transport proteins that have a hydrophilic interior space through which polar molecules can move across the plasma membrane 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

A protein carrier transports Na+ along its concentration gradient into the cell and at the same time ejects Ca2+ against its concentration gradient out of the cell. This is an example of

countertransport.

If a cell is transferred from a hypotonic environment to a hypertonic environment, the hydrostatic pressure inside the cell will .

decrease

The disease hereditary (or nephrogenic) _________ insipidus is caused by a non-functional aquaporin.

diabetes

The disease hereditary (or nephrogenic)______________ insipidus is caused by a non-functional aquaporin.

diabetes

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

endocytosis exocytosis

An aqueous solution with a lower concentration of solutes will have a _______________ concentration of free water molecules.

higher

Water is attracted to charged or polar solutes, forming _______________ around them.

hydration shells

The plasma membrane surrounding animal cells cannot withstand the osmotic pressure which results when these cells are placed in a _______ solution

hypotonic

If two solutions have the same concentration of solutes (all solutes), they are ______________ solutions.

isotonic

An aqueous solution with a higher concentration of solutes will have a ____________ concentration of free water molecules.

lower

Order the following substances according to how easily they can cross the lipid bilayer of the plasma membrane without the help of transport proteins. List the substances that cross most easily first.

nonpolar polar ions

The force needed to stop the net inflow of water into a solution by osmosis is called .

osmotic pressure

Endocytosis of discrete particles is called _______ while endocytosis of liquids is called ________.

phagocytosis pinocytosis

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

potassium Sodium

In the coupled transport of glucose and Na+ across the membrane, the molecules are moving in the ___________direction. The transporter is therefore a (an

same symporter

Because channels and carrier proteins usually allow one or a few types of molecules to cross the membrane, the membrane is said to be

selectively permeable.

Carrier proteins that transport 2 different types of molecules or ions in the same direction are called __________while those that transport 2 different types of molecules or ions in opposite directions are called ________

symporters antiporters

In an aqueous solution the solvent is

water

The movement of ____________ and other small hydrophilic molecules, such as glycerol and urea, across a membrane, is facilitated by specialized channels called aquaporins.

water

When 10 grams of sugar are dissolved in 1 L of water, _______ s the solvent and ___________ is the solute

water sugar

Which of the following statements about channel proteins are true?

Each channel protein is usually selective for only one type of ion or molecule, although some are selective for more than one type. They are used to transport ions and polar molecules across the membrane. Some can be opened or closed in response to a specific stimulus.

Phagocytosis is one of the major types of which of the following?

Endocytosis

What is the name of the process during which the plasma membrane surrounds and envelopes smaller cells, solid particles, or liquids.

Endocytosis

Which of the following processes requires the cell to expend energy (typically from the hydrolysis of ATP)?

Endocytosis

Transport by the sodium-potassium pump requires which of the following?

Energy A carrier protein

The fusion of a secretory vesicle with the plasma membrane in order to discharge the contents of the vesicle is called .

Exocytosis

Which of the following are types of endocytosis?

Receptor-mediated endocytosis Pinocytosis Phagocytosis

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

Selectively permeable