1. The cell membrane (also known as the plasma membrane) surrounding every cell is composed primarily of ______.

A.DNA

B.Protein

C. Carbohydrates

D.Phospholipids

DNA

Protein

Carbohydrate

s

Phospholip

ids

25% 25%25%25%

A phospholipid molecule: composed of a phosphate group and two fatty acid tails.

2. The phospholipids in the cell membrane are arranged in a bilayer (double layer). How are the phospholipid molecules arranged in this bilayer?

A.The nonpolar (hydrophobic) ends of the molecules faces inwards

B.The polar (hydrophilic) ends of the molecules faces inwards

C.The fatty acid tails of the molecules faces inward

D.Both A and C

E.Both B and C The nonpolar (hyd

rophob...

The polar (hydro

philic) e

...

The fatty acid

tails

of th...

Both A and C

Both B and C

20% 20% 20%20%20%

The hydrophilic phosphate groups facing outwards helps the cell interact with the watery environment on both sides of the membrane.

The hydrophobic fatty acid tails in the interior of the membrane help create a barrier for many molecules to allow control of movement.

3. Channels through the phospholipid membrane are formed by

A.Proteins

B.DNA

C.Cellulose

D.Cholesterol

Proteins

DNA

Cellulose

Cholestero

l

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4. The term permeability means

A.The ability of a substance to bend

B.The ability of a substance to allow gases or liquids to pass through

C.The ability of a substance to dissolve

D.The ability of a substance to exist for a long time with out deteriorating.

The ability of a

substa

nce...

The ability of a

substa

nce...

The ability of a

substa

nce...

The abilit

y of a

substa

nc...

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Permeable surface Impermeable surface(not permeable)

5. In diffusion, molecules move from _________________ concentration in a process that __________________ additional energy.

A.high to low; requires

B.high to low: does NOT require

C.low to high; requires

D.low to high; does NOT require

high to

low; re

quires

high to

low: d

oes NOT re

...

low to high; r

equires

low to high; d

oes NOT r..

.

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Additional energy is not required, because diffusion occurs due to the random motion of the molecules.

6. A hypotonic solution is one that

A. contains a higher concentration of solutes (dissolved particles)

B. contains an equal concentration of solutes

C. contains a lower concentration of solutes.

D. is at a higher temperature

E. is at a lower temperature

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Prefix reminders:Hypo = below

Hypothermia is to have a body temperature below normal.

Hyper= aboveHyperactive is to have high energy.

Iso= equalAn isoceles triangle has two equal sides.

7. If a cell with a 0.7 %sucrose concentration inside is placed in a solution that has a 0.5% sucrose concentration, the process of osmosis will occur. In this case,

A.sucrose will move into the cell

B.sucrose will move out of the cell

C.the cell will expand due to water gain

D.the cell will shrink due to water loss

E.both A and C

F. both B and D sucro

se w

ill move in

to th

...

sucro

se w

ill move out o

f ...

the ce

ll will

expand due ..

the ce

ll will

shrin

k due t.

..

both A

and C

both B an

d D

17% 17% 17%17%17%17%

O.5% sucrose

0.7 % sucrose

Sucrose is too large to move through the selectively membrane.(Osmosis is occurring is a hint to this since it means the movement of water.)

Remember that while the solutions are described in terms of the solute concentration it is the water that moves.

The solution that has a lower solute concentration, has a higher water concentration.Water will move from the hypotonic (low solute / higher water) towards the hypertonic (higher solute /lower water)

0.7 %sucrose(99.7% water)

0.5% sucrose(99.5% water)

The shell-less egg in fresh water (hypotonic) gained mass (water).

Water Corn Syrup

Paramecium living in fresh water ponds has to constantly pump out the water that flows into the cell.

8. If a cell with a 0.9% salt concentration inside is placed in a 1% salt solution, osmosis occurs. Which of the following will happen

A. the cell will shrink due to water loss

B. salt will move out of the cell

C. the cell will expand due to water gain

D. salt will move out of the cell

E. both A and D

F. both B and C th

e cell w

ill sh

rink due t..

.

salt

will move

out of t

he...

the ce

ll will

expand due...

salt w

ill move out o

f the ...

both A and D

both B an

d C

17% 17% 17%17%17%17%

Salt is an ionic compound that can not move through the nonpolar barrier of the phospholipid membrane (without specialized channels).

In osmosis, water will move in the direction of the higher SOLUTE (lower water) concentration. Thus hypertonic solutions, such as one high in salt, causes cells to lose water. • Drinking salt water will dehydrate our cells• Plants will wilt in a hypertonic solution.

9. Which kind(s) of solution outside of a cell could cause it to swell and potentially lyse (burst open)?

A. a hypertonic solution

B. a hypotonic solution

C. an isotonic solution

D. both A and C

E. both B and C a hyperto

nic so

lution

a hypoto

nic so

lution

an isoto

nic so

lution

both A

and C

both B and C

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10. A saline (salt) solution is used for fluid infusions into the blood stream. This solution needs to be ____ with blood cells.

A. hypotonic

B. hypertonic

C. isotonic

hypotonic

hypertonic

isoto

nic

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11. In an isotonic solution

A. the cell swells

B. the cell shrinks

C. there is NO movement of water in or out of the cell

D. an equal amount of water moves into the cell as moves out

the ce

ll swells

the ce

ll shrin

ks

there

is N

O move

ment o...

an equal amount o

f wat..

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12. When a cell is placed in an isotonic solution,

A. there is no NET movement of water

B. there is a dynamic equilibrium

C. there is a static equilibrium

D. both A and B

E. both A and C

there

is no N

ET m

oveme..

there

is a dynamic

equil...

there

is a st

atic e

quilibriu

m

both A and B

both A and C

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Net change = Inputs- Outputs. No net change when inputs and outs are balanced.

Dynamic equilibrium= an equilibrium (balance) is when there is motion but the inputs equal the outputs.

13. When a substance is secreted from a cell in a process in which a vesicle fuses with the plasma membrane to release the substance to the outside, it is called

A. endocytosis

B. exocytosis

C. osmosis

D. halitosis

endocyto

sis

exocy

tosis

osmosis

halito

sis

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14. O2 is a small, nonpolar molecule. If it is present outside the cell in high concentration it can enter the cell by

A. Diffusion through the membrane

B. Passive transport

C. Active transport

D. A and B

E. A and C

Diffusio

n thro

ugh th

e ...

Passiv

e tran

sport

Active

transp

ort

A and B

A and C

20% 20% 20%20%20%

15. Glucose is a larger polar molecule. If it is present outside of the cell in high concentration, it can enter the cell by

A. Facilitated diffusion

B. Passive transport

C. Active transport

D. A and B

E. A and C

Facil

itate

d diffusio

n

Passiv

e tran

sport

Active

transp

ort

A and B

A and C

20% 20% 20%20%20%

16. An amino acid (a large polar molecule) is present outside the cell in low concentration. It can be brought into the cell by

A. Facilitated diffusion through specialized channels

B. Passive transport

C. Active transport

D. A and B

E. A and CFa

cilita

ted diff

usion th

r...

Passiv

e tran

sport

Active

transp

ort

A and B

A and C

20% 20% 20%20%20%

In facilitated diffusion, a channel allows the substance to move through the membrane. But no energy is provided, so it is a type of passive transport and it can only move the substance from high concentration to low concentration.Active transport is required to move from low to high concentration.

• High to low only• Does not require energy

• Can move from low to high

• Requires energy (ATP)

17. When a white blood cell engulfs a bacterium, the process of _________ has occurred.

A.Endocytosis

B.Excocytosis

C.Osmosis

D.Dialysis

Endocyto

sis

Excocy

tosis

Osmosis

Dialysis

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18. What will happen for the following set-up in which two different liquids are separated by a selectively-permeable membrane. The dots represent solute particles that can not move through the membrane.

A.Water will move to the right

B.Water will move to the left

C.The system will remain in equilibrium

Wate

r will

move to th

e r...

Wate

r will

move to th

e left

The syste

m will

remain in

...

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(lower concentration of water)

1. D2. D3. A4. B5. B6. C7. C8. A9. B10.C11.D12.D13.B14.D15.D16.C17.A18.A