Chapter 5

Question 1

Chose the most accurate statement about selectively permeable membranes
A) only large ions may pass
B) the membrane regulates the movement of molecules
C) Only half of the membrane is permeable
D) the membrane is permeable only part of the time

Answer 1

B, The membrane regulates the movement of molecules

Question 2

The amino acids that are facing the fatty acid tails in the membrane would be expected to be _____, while the amino acids that are facing the cytoplasm and extracellular fluid would probably be ______

Answer 2

Hydrophobic; hydrophilic

Question 3

The process whereby small molecules move from an area of high concentration to an area of low concentration is

Answer 3

diffusion

Question 4

which of the following would probably have the greatest difficulty moving through a cell’s membrane?
A) glucose
B) molecular oxygen (O2)
C) carbon dioxide
D) water

Answer 4

A, glucose

Question 5

Distilled water is 100% water with no solutes. A cell placed in distilled water will

Answer 5

swell and burst (lyse)

Question 6

Solutes can be thought of as particles in a solution. Choose the CORRECT statement about the particles (solutes) inside and outside a cell.
A) in a hypotonic solution, there are more particles outside the cell
B) lysis usually occurs when a cell is exposed to hypertonic solutions
C) in an isotonic solution, the number of particles is equal
D) in a hypertonic solution, there are more particles inside the cell

Answer 6

C, in an isotonic solution, the number of particles is equal

Question 7

Pretend that you have a balloon that is permeable to water but not to fructose. The balloon is filled with a solution of 50% fructose and 50% water and is immersed in a beaker containing a solution of 10% fructose and 90% water. Which of the following will occur
A) fructose will leave the balloon
B) water will leave the balloon
C) fructose will enter the balloon
D) water will enter the balloon

Answer 7

D, water will enter the balloon

Question 8

Bacteria living in your mouth are swollen but do not lyse, thanks to their cell wall. Your saliva is ____ relative to the bacteria.

Answer 8

Hypotonic

Question 9

If a solution containing 0.7% NaCl were isotonic to a cell, then:

Answer 9

a 1.5% solution would be hypertonic

Question 10

A molecule of oxygen (O2) carried in the blood enters the cells of your tissues by:

Answer 10

simple diffusion

Question 11

ATP is required for

Answer 11

active transport

Question 12

The assisted transport of a molecule across the cell membrane WITHOUT expenditure of energy is

Answer 12

facilitated transport

Question 13

The assisted transport of a molecule across the cell membrane AGAINST the concentration gradient and requiring the use of ATP is

Answer 13

Active transport

Question 14

Enzymes do what

Answer 14

speed up the metabolic reactions

Question 15

The substance that an enzyme works upon is called a

Answer 15

substrate

Question 16

an enzymes specificity for a particular substrate is caused by

Answer 16

substrate/active site shapes

Question 17

Enzymes mostly belong to which group of organic molecules

Answer 17

proteins

Question 18

The unfolding of an enzyme due to unacceptably high temperatures, high salt concentrations, or extremes of pH is called

Answer 18

denaturing the enzyme

Question 19

If an enzyme is saturated with substrate, the most effective way to produce more products would be

Answer 19

add more enzyme

Question 20

Which of the following statements about ATP molecule is TRUE?
A) actually, all of these statements are true
B) it contains five phosphate groups
C) it contains the sugar glucose
D) it releases energy when one phosphate group leaves ATP
E) extremely stable bonds link the second and third phosphate groups

Answer 20

D, it releases energy when one phosphate group leaves ATP