Question 1

Which of the following best describes the primary structural component of the plasma membrane that forms a barrier to most substances?

Accepted Answer

A phospholipid bilayer with hydrophobic tails facing inward and hydrophilic heads facing outward

Question 2

A solution contains 0.1 M glucose and is separated by a semipermeable membrane from a solution containing 0.05 M NaCl. Assuming the membrane is permeable only to water, in which direction will water move?

Accepted Answer

From the glucose solution to the NaCl solution

Question 3

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses membrane proteins to move substances down their concentration gradient

Question 4

A dialysis bag containing a mixture of glucose, ovalbumin (protein), and starch is placed in deionized water. After one hour, which substance(s) would you expect to find outside the bag?

Accepted Answer

Glucose only

Question 5

Which of the following best explains why plant cells do not burst when placed in a hypotonic solution, while animal cells do?

Accepted Answer

Plant cells have a rigid cell wall that limits expansion

Question 6

If a red blood cell is placed in a 2 M NaCl solution, what is the most likely observation under a microscope?

Accepted Answer

The cell will shrink and appear crinkled

Question 7

Which of the following is NOT a function of the plasma membrane?

Accepted Answer

Synthesis of proteins

Question 8

A 0.1 M solution of glucose is considered isotonic to a 0.05 M solution of NaCl. Why?

Accepted Answer

Because NaCl dissociates into two ions, doubling its effective particle concentration

Question 9

Which experimental result would indicate that glucose diffused out of the dialysis bag into the surrounding water?

Accepted Answer

A color change to orange in Benedict's test of the outside solution

Question 10

Which of the following best describes osmosis?

Accepted Answer

The movement of water from a region of lower solute concentration to higher solute concentration across a semipermeable membrane

Question 11

If you failed to rinse the outside of the dialysis sac after removing it from the test tube, how would this affect your experimental results?

Accepted Answer

You might falsely detect the presence of solutes outside the bag due to contamination from the sac's exterior

Question 12

Which of the following statements about diffusion is correct?

Accepted Answer

Diffusion results in the net movement of molecules from high to low concentration

Question 13

Which of the following best explains why a 300 mM glucose solution is isotonic to a 150 mM NaCl solution?

Accepted Answer

NaCl dissociates into two particles, so 150 mM NaCl yields 300 mM total particles

Question 14

Which of the following is a correct description of active transport?

Accepted Answer

Movement of substances against their concentration gradient using energy

Question 15

A plant cell is placed in a hypertonic solution. What is the most likely observation?

Accepted Answer

The plasma membrane pulls away from the cell wall as the cytoplasm shrinks

Question 16

Which of the following is true regarding the movement of ions across the plasma membrane?

Accepted Answer

Ions require membrane proteins to cross the membrane

Question 17

Which of the following best describes the role of carbohydrates on the external surface of the plasma membrane?

Accepted Answer

They function in cell recognition and adhesion

Question 18

Which of the following would be the best experimental evidence that starch did NOT diffuse out of the dialysis bag?

Accepted Answer

No color change when Lugol's solution is added to the outside solution

Question 19

Which of the following best explains why the flow of water during osmosis depends on the number of solute particles rather than their chemical nature?

Accepted Answer

Osmosis is driven by differences in solute concentration, not solute identity

Question 20

Which of the following is a correct definition of molarity ($$M$$)?

Accepted Answer

$$M = \frac{	ext{moles of solute}}{	ext{liters of solution}}$$

Bio 100 LAB 2 Chaper 2 UPDATED

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