AP Bio membranes and transport test

What is the solute potential for a 0.3M NaCl solution at 10oC? (-iCRT) R=0.0831

-14.1 bars

Potatoes weigh 5.5g before and 4.0g after. What is the % change?

-27%

If the solute potential is -7.3 bars and the pressure potential is 3.5 bars, what is the water potential? (Ψ = Ψs + Ψp)

-3.8 bars

Calculate solute potential (Ψs) for the McIntosh if the temp was 30 degrees C? (solute = sucrose)

-7.6 bars

In what ways do the membranes of the Eukaryotic cell vary?

-Certain proteins are unique to each membrane -The inner and outer portions of the membrane are different

Phagocytosis can be considered a type of:

-Endocytosis -Bulk transport

Cholesterol:

-Helps maintain membrane fluidity -Is found in animal membranes only

Solute Potential

-iCRT (measured in bars). For pure water it is zero

What is the Pressure potential of an open container?

0 bars

What is the pressure potential for water in an open container?

0 bars

What is the ionization constant for glucose?

1

Bags were placed in a 0.5M solution. Which bag was the most hypertonic at the beginning?

A

cholesterol

A steroid found in animal plasma membranes that helps keep them fluid

fluid-mosaic model

Model for the cell membrane based on the changing location and pattern of protein molecules in a fluid phospholipid layer

diffusion

Movement of molecules or ions from a region of higher to lower concentration; it requires no energy and tends to lead to an equal distribution

Active Transport

Movement of substances against the concentration gradient through protein carrier

bulk transport

Movement of substances too large for protein transport into or out of cell. Includes Endocytosis and exocytosis.

Water will move?

Out of the cell

Which transport does not require energy?

Passive

Which process includes facilitated diffusion, diffusion of a solute across a membrane, and osmosis?

Passive Transport

facilitated diffusion

Passive movement of substances through protein carriers

Engulfing of bacteria by white blood cells is called?

Phagocytosis

Which form of active transport is being shown? (Inside of the cell is tan colored)

Pinocytosis

Bags were placed in a 0.5M solution. Which bag(s) was/were isotonic to the solution at the end?

A, C and E

Selectively permeable

Ability of plasma membranes to regulate the passage of into and out of the cell; allowing some to pass through and preventing the passage of others

The picture is an example of...

Active Transport

Serves as ID marker for membrane:

B

You put potatoes in 3 solutions (water, 0.5M, and 1.0M. What is true?

Potato should gain the most weight in water

turgor pressure

Pressure of the cell contents against the cell wall; determined by the water content of the vacuole and provides internal support

receptor protein

Protein located in the plasma membrane or within the cell; binds to a substance and sends a message into the cell to respond

enzymatic protein

Protein that catalyzes a specific reaction

carrier protein

Protein that combines with and transports a molecule or ion across the plasma membrane. (protein changes shape in process)

channel protein

Protein that forms a channel that allows a particular molecule or ion to cross the plasma membrane.

Proton pump

Protein that performs Active transport of H+ across membrane

junction protein

Proteins that assist cell-to-cell communication at the plasma membrane

As molarity increases, if temperature stays the same, solute potential will __________________. (-iCRT)

Be a more negative number

lysis

Bursting of a cell

What kinds of molecules pass through a cell membrane most easily?

Small and hydrophobic

isotonic solution

Solution that is equal in solute concentration to that of the cytoplasm of a cell; causes a cell to neither gain nor lose water by osmosis

If you looked at red blood cells under a microscope and saw the blood cells exploded, what would you say happened?

The cells were placed in a hypotonic solution.

Which of the following is responsible for getting charged (or polar) molecules across the cell membrane?

C

Water Potential

The measure of the relative tendency of water to move from one area to another. Water travels toward the LOWER one

Pinocytosis

Cell Engulfing small particles/liquid droplet (cell drinking)

Cell mediated Endocytosis

Cell Engulfing substance after receptors stimulated (cholesterol for ex. is taken in this way)

Phagocytosis

Cell engulfing large particle

aquaporin

Channel protein through which water can diffuse across a membrane.

plasmolysis

Contraction of the cell contents in plants due to the loss of water resulting in cell membrane pulling away from cell wall

Found in animal membranes only - helps with fluidity:

D

osmosis

Diffusion of water through a differentially permeable membrane

Hydrophobic region of the cell membrane?

E

A person would never have pure water put into their veins in a hospital because their cells would...

Expand/burst

If we assume the membrane in impermeable to the molecules shown, but permeable to water, then water should move?

From side B toward side A

hypertonic solution

Higher solute concentration (less water) than the cytoplasm of a cell; causes a cell to lose water by osmosis

The tails of a phospholipid are...

Hydrophobic

An outside solution of 0.4M would be __________ to the McIntosh (blue line) apples.

Hypertonic

When cells are placed in a __________ solution they begin to swell.

Hypotonic

If the water potential outside the cell is 2.5 bars and inside the cell is -2.5 bars, which way should water go?

Into the cell

solute

Liquid portion of a solution that serves to dissolve the solute

What happens to a cell in a hypertonic solution?

Loses water

hypotonic solution

Lower solute (more water) concentration than the cytoplasm of a cell

A saltwater snail is placed in freshwater. What happens to its cells?

They swell

In the U-Tube diagram , if the membrane is permeable to only water, which way will it go?

Toward side B

sodium-potassium pump

Type of active transport that moves Na+/K+ across membranes (3Na+ out and 2 K+ in. Requires 1 ATP)

Osmosis is the diffusion of _____ across a selectively permeable membrane.

Water

Co-transport

When a molecule can only be carried across the membrane with a second molecule (usually linked to a pump)

Electrochemical Gradient

a difference in ions and in charge across a membrane (results in membrane potential)

The sodium-potassium pumps requires energy to move ions across the cell membrane against their concentration gradient so it is a type of

active transport

Peripheral/Extrinsic Proteins are:

bound to the surface of the membrane

What is most likely to passively diffuse across the phospholipid bilayer?

carbon dioxide

The difference in the concentration of a substance from one location to another is called

concentration gradient

Osmosis is:

diffusion of water across a selective membrane

What type of transport is this?

facilitated diffusion

If a cell containing 5% salt is placed into a glass of water with 20% salt, the glass of water is _______ compared to the cell.

hypertonic

Water pass quickly through cell membranes because:

it moves through aquaporins in the membrane

phospholipid

main component of the cell membrane. Has a hydrophilic & hydrophobic portion

Which functional process is not a result of proteins in the membrane?

maintaining fluidity of membrane

What is the voltage across a membrane called?

membrane potential

Which of these are the major structural components of all cell membranes?

phospholipids and proteins

Receptor-mediated endocytosis

proteins on surface stimulate a cell to engulf particles. Cholesterol taken in this way

When a plant cell is submerged in a very hypotonic solution, what is likely to occur?

the cell will become turgid (stiff)

What is true according to the fluid mosaic model of the membrane structure?

the hydrophobic tails of the phospholipids face each other

membrane potential

voltage across a membrane

flaccid

when a plant cell is somewhat wilted (opposite of turgid)