Campbell Biology Concepts & Connections

Martha R. Taylor, Jean L. Dickey, Eric J. Simon, Kelly Hogan, Jane B. Reece

Chapter 3

The Molecules of Cells - all with Video Answers

Educators

MD

HM

Chapter Questions

Problem 1

Complete the following table to help you review the structures and functions of the four classes of organic molecules.
(TABLE CAN'T COPY)

Eric Goldman

Eric Goldman

Numerade Educator

Problem 2

A glucose molecule is to starch as (Explain your answer.)
a. a steroid is to a lipid.
b. a protein is to an amino acid.
c. a nucleic acid is to a polypeptide.
d. a nucleotide is to a nucleic acid.

Jennifer Stoner

Jennifer Stoner

Numerade Educator

Problem 3

What makes a fatty acid an acid?
a. It does not dissolve in water.
b. It is capable of bonding with other molecules to form a fat.
c. It has a carboxyl group that can donate an $\mathrm{H}^{+}$ to a solution.
d. It contains only two oxygen atoms.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 4

Cows can derive nutrients from cellulose because
a. they produce enzymes that recognize the shape of the glucose-glucose bonds and hydrolyze them.
b. they re-chew their cud to break down cellulose fibers.
c. their digestive tract contains microorganisms that can hydrolyze the bonds of cellulose.
d. they convert cellulose to starch and can digest starch.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 5

Of the following functional groups, which is/are polar, tending to make organic compounds hydrophilic?
a. carbonyl
b. amino
c. hydroxyl
d. all of the above

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 6

Unsaturated fats
a. have double bonds in their fatty acid chains.
b. have fewer fatty acid molecules per fat molecule.
c. are associated with greater health risks than are saturated fats.
d. are more common in animals than in plants.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 7

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture
a. DNA.
b. proteins.
c. cellulose.
d. sucrose.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 8

Which of the following substances is a major component of the cell membrane of a fungus?
a. cellulose
b. chitin
c. cholesterol
d. phospholipids

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 9

Which structural level of a protein would be least affected by a disruption in hydrogen bonding?
a. primary structure
b. secondary structure
c. tertiary structure
d. quaternary structure

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 10

Circle and name the functional groups in this organic molecule. What type of compound is this? For which class of macromolecules is it a monomer?
(FIGURE CAN'T COPY)

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 11

Most proteins are soluble in the aqueous environment of a cell. Knowing that, where in the overall three-dimensional shape of a protein would you expect to find amino acids with hydrophobic
R groups?

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 12

Sucrose is broken down in your intestine to the monosaccharides glucose and fructose, which are then absorbed into your blood. What is the name of this type of reaction? Using this diagram of sucrose, show how this would occur.
(FIGURE CAN'T COPY)

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 13

Explain the role of complementary base pairing in the functions of nucleic acids.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 14

What are the two types of secondary structures found in polypeptides, and what maintains them? What stabilizes the tertiary structure of a polypeptide?

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 15

The diversity of life is staggering. Yet the molecular logic of life is simple and elegant: Small molecules common to all organisms are ordered into unique macromolecules. Explain why carbon is central to this diversity of organic molecules. How do carbon skeletons, chemical groups, monomers, and polymers relate to this molecular logic of life?

Eric Goldman

Numerade Educator

Problem 16

How can a cell make many different kinds of proteins out of only
20 amino acids? Of the myriad possibilities, how does the cell "know" which proteins to make?

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 17

Given that the function of egg yolk is to nourish and support the developing chick, explain why egg yolks are so high in fat, protein, and cholesterol.

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 18

Enzymes usually function best at an optimal pH and temperature. The following graph shows the effectiveness of two enzymes at various temperatures.
(FIGURE CAN'T COPY)
a. At which temperature does enzyme A perform best? Enzyme B?
b. One of these enzymes is found in humans and the other in thermophilic (heat-loving) bacteria. Which enzyme would you predict comes from which organism?
c. From what you know about enzyme structure, explain why the rate of the reaction catalyzed by enzyme A slows down at temperatures above $40^{\circ} \mathrm{C}\left(140^{\circ} \mathrm{F}\right)$

Ioannis Markopoulos

Ioannis Markopoulos

Numerade Educator

Problem 19

Another aspect of the Nurses' Health Study introduced in Module 3.9 looked at the percentage of change in the risk of coronary heart disease associated with substituting one dietary component for another. These results estimated that replacement of $5 \%$ of energy from saturated fat in the diet with unsaturated fats would reduce the risk of heart disease by $42 \%,$ and that the replacement of $2 \%$ of energy from trans fat with unsaturated fats would reduce the risk by $53 \% .$ Explain what these numbers mean.

Noah Boudrie

Numerade Educator