Transport in Cells wkst

Animal cells in hypertonic solutions are described as...

"lysed"-plasma membrane ruptures

Plant cells in hypertonic solutions are described as...

"turgid"-swollen

Which types of cells in Model 2 have a permeable, rigid cell wall?

Plant cells only.

Model 2, which cells show a net decrease in water?

A-Crenated animal cell & D-Plasmolysed plant cell; both are in hypertonic (syrup or 10% NaCl) solution

20. Lettuce salad + salt added = wilted lettuce and water accumulated at bottom of bowl.

Adding salt to the lettuce salad, causes a higher concentration of salt outside cells than inside cells so intracellular water moves out of the cells by osmosis, causing lettuce to wilt. The water that moved out of the cells accumulates at the bottom of the bowl.

22. How does the Paramecium's contractile vacuole help it survive in a hypotonic solution?

Contractile vacuole must move water from lower (inside Paramecium) to higher (outside Paramecium) concentration-it moves water against a concentration gradient so energy is required to pump out excess water from inside the Paramecium.

Model 2, which cells show no net change in water?

B-Normal animal cell & E-Normal plant cell; both are in isotonic (1% NaCl) solution

Model 2, which cells show a net increase in water?

C-Lysed animal cell & F-Turgid plant cell; both are in hypotonic (distilled water) solution

What structure on the plant cell prevents lysis from occurring in a hypotonic solution?

Cell wall prevents plant cell from being lysed or bursting.

21. In extreme cases, people can die from drinking too much water-why?

Drinking excess water, osmosis causes water to enter the blood. Blood becomes more dilute or hypotonic to body's cells. Water moves from blood to inside the cells, causing cells to swell and burst. This damages the brain by increasing pressure around the brain, which may lead to death.

Describe the concentration of the extracellular solution of cells B & E, relative to the concentration of the intracellular solution of cells B & E.

Extracellular concentration of solutions of B & E = intracellular concentration of solutions of B & E.

Describe the concentration of the solution surrounding cells A and D (extracellular), relative to the concentration of the solution inside cells A and D (intracellular).

Extracellular fluid around cells A & D is more concentrated that intracellular fluid inside cells A & D.

Describe the concentration of the extracellular solution of cells C & F, relative to the intracellular solution of cells C & F.

Extracellular solution around C & F is less concentrated than intracellular solution inside cells.

The cell diagram in Model 1, where is the higher concentration of water-inside or outside the cell?

Higher concentration of water outside the cell.

When animal cells are in a hypertonic solution, they undergo lysis. Plant cells do not undergo lysis, they become turgid. Describe lysis.

Lysis occurs when the cell membrane bursts under increased internal pressure.

In which direction are water molecules moving, into or out of the cell?

More water is moving out of the cell.

Is the net direction of water movement into or out of the cell?

Net direction of water movement is out of the cell.

Model 2, what happened to the animal cell in the hypertonic solution?

Net movement of water out of the cell causes cell membrane to become "crenated"-cell membrane contracts.

Model 2, what happened to the plant cell in the hypertonic (concentrated) solution?

Net movement of water out of the cell causes cell membrane to become "plasmolysed"-it has pulled away from the cell wall.

Which types of cells in Model 2 have a selectively permeable membrane?

Plant and animal cells both have selectively permeable cell membranes.

Diffusion is the movement of molecules across a membrane from an area of high concentration to an area of low concentration. Is the cell in Model 1 undergoing diffusion?

The cell in undergoing diffusion-water is moving from a higher to lower concentration. The sugar molecules are not undergoing diffusion-they are too large. Sugar molecules can enter cells through channel proteins, which require energy (ATP) to function.

What will eventually happen to the concentration on both sides of the membrane, based on the random movement of molecules?

The concentration on both sides of the membrane will eventually reach DYNAMIC EQUILIBRIUM. The concentration of solutes will be the same on both sides of the membrane as water continues to move back and forth.

Which solution in Model 1 is more concentrated-the solution inside or outside the cell?

The solution outside the cell is more concentrated. The ratio of solute outside the cell is higher than inside the cell.

What does the thickness of the arrow indicate in Model 2?

Thicker arrow means more water molecules moving in that direction.

19. How does spraying water on produce change its appearance?

Water is absorbed by produce (plants) by osmosis causing cells to swell and the produce to appear firmer, which improves appearance.

Considering the size of the sugar and water molecules, which molecules are able to move through the selectively permeable membrane?

Water molecules are small enough to pass through.

Is the cell in Model 1 undergoing diffusion?

Yes, water molecules are diffusion from an area of higher concentration to an area of lower concentration.

In Model 2, an isotonic extracellular solution is.....

equally as concentrated as the intracellular solution.

The solution outside the cell will become (more/less) concentrated with the net movement of the water.

less

In Model 2, hypotonic extracellular solution is.....

less concentrated that intracellular solution.

The solution inside the cell will become (more/less) concentrated with the net movement of water.

more

In Model 2, a hypertonic extracellular solution is.......

more concentrated that intracellular solution.

Plant cells in hypertonic solutions change in appearance because...

the vacuole swells with water causing the cell to become very stiff.