HOMEOSTASIS AND THE PLASMA MEMBRANE
GHAPTER
Section 9.2 Gellular Transport
Study the Diagram
Study the diagram and read the caption. Then answer the questions.
Osmosis
Water
Water
molecules
molecules
Plasma
membrane
Osmosis occurs when water molecules move through the plasma
membrane. The molecules molre from an area of higher water
concentration to an area of lower water concentration.
1.
Draw an arrow across the plasma membrane in the diagram to show which way water molecules
move during osmosis.
2.
Osmosis is a type of diffusion. In osmosis, what substance moves?
3.
In osmosis, the moving substance
+.
After osmosis, there is a balance of water molecules inside and outside the cell. Draw water
molecules in the diagram above to show what the cell looks like after osmosis.
passes
through
a
membrane.
Osmosis Worksheet
MULTTPLE cHOTcE. Choose
onswers the guestion.
the one olternotive thot best completes the stqtement or
1) Inside one osmosis bag, A, is a 50% glucose solution and side bog B is aZO%glucose
solution. Both bogs are put into beokers contoining 100% woter.
A) Bog A will gain weight.
B) Bo9 B will goin weight.
C) Both bogs will gain weight
D) Both bogs will loose weight.
E) Both bogs will remoin the same.
2) AO.9%NoCl solutionisisotonictoredbloodcells.Whichof thesedescribestheresults
if red blood'cells ore ploced into a 9% solution of NoCl?
A) They will burst.
B) They will shrink.
C) Nofhing will hoppen.
D) They will expond but not burst.
E) None of the obove.
3) The U-shaped tube in the f igure below is divided by a membrone thot
storch but permeoble to woter. which of the following wiil occur?
is impermeoble to
fi,fi
loN
5$lsfih.
-H*TE&
idry;tusna
A) Woter will move from the right to the left.
B) Woter will move from the left to the right.
C) Starch will move from the right to the left.
D) Starch will move from the left to the right.
E) Nothing will happen. The membrone blocks the passoge of oll the molecules.
4)
Wallwayis o new general herbicide for aguotic plants. fts moin ingredient is o marine salt
solution. Tt is eff ective ogainst freshwoter but not saltwoter plants. ft works by breoking
down the cell walls of the plants. The freshwoter plonts dies becouse their cells
A) swellond burst.
B) shrink ond ceose to function.
C) remoin the some size but rnalfunction.
D) are crushed by the weight of the plont.
5) Aredbloodcellshososoltconcentrotionof O.9%.Whotwill happenif itisplocedintoa
0.8% solt solution? The red blood cell will
A) shrink if its membrone is permeable to both the solt ond the woter.
B) shrink if its membrane is impermeable to the solt ond permeoble to the water.
C) mointoin its shope, ie nothing will hoppen.
D) swell ond probably burst becouse its membrone is impermeoble to salt ond permeoble to
woter.
E) swell ond probably burst becouse its membrane is impermeable to woter ond permeoble to
solt.
6) Two beokers (below) are connected by o tube portioned by o membrone permeoble to
woter but not to protein. Which one of the following stotements best describes whot will
hoppened to this system?
?E
protdn
4iS Pronirt
A) Water will only move from A to B.
B) Woter will only move from B to A.
C) Water will move egually in both directions so that there will be no net chonge in the
system.
D) Woter will move in both directions, but the net f low will be from A to B.
E) Water will move in both directions, but the net f low will be from B to A.
OSMOSIS WORKSHEET
Nome:
Part One: Color the correct box in the chaft below:
STATEMENT
Isotonic
Cell(s)
Hypotonic
Cell(s)
Hypeftonic
Cell(s)
1. The concentration of dissolved substances (stuff) in the
solution is lower than the concentration inside the cell.
2. When a cell is placed in this solution, water will enter the
cell bv osmosis resultinq in osmotic (turqor) pressure.
3. The concentration of dissolved substances (stuff) in the
solution is the same as the concentration inside the cell.
4. The concentration of dissolved substances (stuff) in the
solution is hiqher than the concentration inside the cell.
5. When this solution is injected into the body no cell
disruption occurs because no net osmosis occurs.
6. Putting a plant in this solution will result in water loss and
cause the olant to wilt.
7.
In a hypotonic solution, animal cells experience osmosis and a pressure builds up in the cell. What causes the
pressure? How is the cell potentially affected by this situation?
B. Why does a plant like celery get limp when placed in a hypeftonic solution?
9,
A salt water protozoan(a single celled protest) is transferred to a freshwater lake. What might happen to the
protozoan?
10. In the figure of the U-tube below, side "A" is pure water and side "8" is a
of side "B" rising? Which side is HYPERTONIC compared to the other?
11.
10olo starch
solution. Why is the level
Pure water is always what (Hypertonic, Hypotonic, or Isotonic) compared to any cell? Why?