Transport across the plasma membrane & plasmolysis

What is diffusion?

Random movement of particles from their greater concentration to their lesser concentration.

What is a concentration gradient?

The difference between solute concentrations across a membrane.

What is osmosis?

Water moving through selectively permeable membrane.

What is a hypertonic solution?

Higher concentration of solutes than in cytosol of cell.

What happens to a cell when a hypertonic solution has been added to it?

It causes the cell to crenate/shrivel.

What is a hypotonic solution?

Lower concentration of solutes than in cytosol of cell.

What happens to a cell when a hypotonic solution has been added to it?

Causes cell to swell.

What is crenation?

To shrink or shrivel

What is hemolysis?

To burst a red blood cell.

What is a isotonic solution?

Same solute concentration on both sides of membrane.

What happens to red blood cells when an isotonic solution is added?

Cells biconcave disk.

What is a red blood cell?

An erythrocyte that is typically a biconcave disk in humans without a neucleus.

What makes blood red?

Hemoglobin.

What is the function of a red blood cell?

To facilitate oxygen transport from the lungs to the cells, and carbon dioxide from cells to lungs.

What is a solute?

A fluid that can contain disolved substances.

What is a solvent?

Substance disolved in a solution.

In the dialysis bag experiment, sucrose and red dye molecules are?

Solvents

If there is no concentration gradient, a substance will not have a net movement. True or False?

True

An isotonic solution will_______an RBC.

Cause no change to

A hypertonic solution will_______an RBC.

Crenate

A hypotonic solution will ______an RBC.

Hemolyze.

White blood cells engulf bacteria. This is an example of diffusion. True or False?

False

Food cooking on the stove in the kitchen can be smelled in the living room. This is an example of diffusion. True or False?

True

Oxygen in lungs moves into the blood stream and carbon dioxide moves in the opposite direction. This is an example of diffusion. True or False?

True

what is a semipermeable membrane?

is a membrane that will allow certain molecules or ions to pass through it by diffusion.

what are other terms for the word semipermeable membrane?

selectively permeable membrane, a partially permeable membrane or a differentially permeable membrane.

what are two examples of a selectively permeable membrane?

phospholipid bilayers, and the intermembrane of and egg.

a test tube with blood in it has a particular solution added to it. after several minutes, the solution is not clear anymore, but becomes red. which solution was added to the blood to obtain this result?

distilled water.

a 0.8% saline solution would be ______ to the cytosol of the cell.

hypotonic.

if a 50% sugar solution had been used in the dialysis bag in activity 1, there would be a faster rate of osmosis. True or False?

True

if you placed a peeled apple or potato in a 5% salt solution, it would ________.

lose weight.

a person's hands become wrinkled after spending a long, relaxing time in the tub. tub water does not have as many solutes in it compared with the human body. the hands look wrinkled because _______.

the tub of water is hypotonic to body cells and water enters the cells.

when a person becomes dehydrated, the amount of water in the extracellular fluids such as blood decreases, causing the solute concentration of these fluids to increase. state whether osmosis resulted in water entering or leaving cells.

osmosis resulted in water leaving cells, because the blood decreases, causing the solute concentration of these fluids to increase, which is an example of the cells being crenate.

severe vomiting and diarrhea causes a loss of water and solutes from extracellular fluids. if a person was only given water, what effect would this have on the solute concentration of extracellular fluids? would osmosis result in water entering or leaving cells?

osmosis would result in water entering the cell, because it is in a hypotonic solution.

in the dialysis bag experiment what was the solvent and what was the solute?

solute= red die, sucrose.

solvent= water.

in the dialysis bag experiment which direction did osmosis occur?

both ways, net movement into bag.

in the dialysis bag experiment which direction did diffusion of solutes occur?

solutes did not move. membrane impermeable.

in the dialysis bag experiment did net osmosis and diffusion of solutes stop? did the two solutions become isotonic? explain.

not isotonic because the water and sucrose did not balance out. net osmosis and diffusion of solutes did not stop because equilibrium was not met.

in the dialysis bag experiment, what represented the plasma membrane, intracellular fluid, and extracellular fluid?

plasma membrane= dialysis bag.

intracellular fluid= sucrose.

extracellular fluid= distilled water.

conclusion: state what drives osmosis and diffusion of solutes, and when does the net movement of both stop?

osmosis and diffusion occur to maintain equilibrium in the body, and it stops when equilibrium has been met.

describe how RBC shape changes when placed in 0.9% saline solution.

isotonic, biconcave disk

describe how RBC shape changes when placed in 5% saline solution.

crenate, hypertonic

describe how RBC shape changes when placed in distilled water.

hypotonic, swell

describe how extracellular solute concentration affects osmosis across the plasma membrane.

water diffuses from lower solute concentration to a higher solute concentration.

describe how water movement affects the cell shape.

the more water there is in the cell the larger it gets.

conclusion: state which solutions caused osmosis in RBC's.

all of them. 0.9% saline solution, 5% saline solution, and distilled water.

what is plasmolysis?

water leaves the central vacuole and the cytoplasm shrinks.

what does plasmolyzed mean?

term to describe a cell when plasmolysis has already taken place.

what is a protoplast?

the cytoplasm enclosed by plasma membrane in plant cells.

what is a Elodea?

common aquatic plant that lives in fresh water.

what does flaccid cell mean?

when the plasma membrane is not tightly against the cell wall. (loose, limp)

what does turgid cell mean?

swollen, especially due to high fluid content. when plasma membrane is tightly against the cell wall.

what is turgor pressure?

pressure of the protoplast on the cell wall owing to uptake of water.

what is water potential?

combined force created by solute concentration and physical pressure.

what is osmotic potential?

The potential (capability) of water molecules to move from a hypotonic solution to a hypertonic solution across a semi permeable membrane.

what is a vacuole and what does it do?

a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid. stores food and waste in cells.

what is a cell wall?

rigid layer of polysaccharides lying outside the plasma membrane of cells.

which solution is hypertonic and which is hypotonic in the plant cell lab?

hypertonic= 5% NaCl

hypotonic= distilled water

which solution has the greatest osmolarity in the plant cell experiment?

distilled water

would you expect pond water to be isotonic, hypertonic, or hypotonic to Elodea cells? explain.

hypotonic because water enters the plant, and protoplast wants to push up against cell walls.

what is differential or, selective permeability?

It allows nutrients to enter the cell but keeps out undesirable substances.