Question 1

If a DNA sample were composed of 20% guanine,what would be the percentage of cytosine?

Accepted Answer

A) 20 
B) 30 
C) 40 
D) 60 
A) 20 
B) 30 
C) 40 
D) 60

Question 2

Which of the following structures is formed by the atoms involved when a carbon atom is bound by single covalent bonds to four other atoms?

Accepted Answer

A) sphere 
B) cube 
C) tetrahedron 
D) line 
E) plane 
A) sphere 
B) cube 
C) tetrahedron 
D) line 
E) plane

Question 3

Which bonds maintain the primary structure of a protein?

Accepted Answer

A) disulfide bonds 
B) hydrogen bonds 
C) ionic bonds 
D) peptide bonds 
A) disulfide bonds 
B) hydrogen bonds 
C) ionic bonds 
D) peptide bonds

Question 4

How will brief heating (to 95°C)affect macromolecular structures in aqueous solution?

Accepted Answer

A) Unsaturated fatty acid tails will become saturated. 
B) Proteins will unfold (denature). 
C) Starch will hydrolyze into monomeric sugars. 
D) Proteins will hydrolyze into amino acids. 
A) Unsaturated fatty acid tails will become saturated. 
B) Proteins will unfold (denature). 
C) Starch will hydrolyze into monomeric sugars. 
D) Proteins will hydrolyze into amino acids.

Question 5

Figure 3.4
-Which functional group shown in Figure 3.4 is characteristic of alcohols?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 6

Which of the following is a monomer used to build a biological polymer?

Accepted Answer

A) amino acid 
B) disaccharide 
C) triglyceride 
D) DNA 
A) amino acid 
B) disaccharide 
C) triglyceride 
D) DNA

Question 7

In a normal cellular protein,where would you expect to find a hydrophilic amino acid such as asparagine?

Accepted Answer

A) in the interior of the folded protein,away from water 
B) on the exterior surface of the protein,interacting with water 
C) in the transmembrane portion,interacting with lipid fatty acid chains 
D) on the exterior surface of the protein,interacting with water,or in a transmembrane portion,interacting with lipid fatty acid chains 
A) in the interior of the folded protein,away from water 
B) on the exterior surface of the protein,interacting with water 
C) in the transmembrane portion,interacting with lipid fatty acid chains 
D) on the exterior surface of the protein,interacting with water,or in a transmembrane portion,interacting with lipid fatty acid chains

Question 8

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together.What would happen to DNA molecules treated with these enzymes?

Accepted Answer

A) The two strands of the double helix would separate. 
B) The phosphodiester linkages of the polynucleotide backbone would be broken. 
C) The pyrimidines would be separated from the deoxyribose sugars. 
D) All bases would be separated from the deoxyribose sugars. 
A) The two strands of the double helix would separate. 
B) The phosphodiester linkages of the polynucleotide backbone would be broken. 
C) The pyrimidines would be separated from the deoxyribose sugars. 
D) All bases would be separated from the deoxyribose sugars.

Question 9

If cells are grown in a medium containing radioactive 35S,which of these molecules will be radioactively labeled?

Accepted Answer

A) triacylglycerols 
B) nucleic acids 
C) proteins 
D) starch 
A) triacylglycerols 
B) nucleic acids 
C) proteins 
D) starch

Question 10

A scientist suspects that food in an ecosystem may have been contaminated by radioactive nitrogen over a period of several months.Which of the following should be isolated from mammals living in the ecosystem and examined for radioactivity in order to test the hypothesis?

Accepted Answer

A) glycogen 
B) phospholipids 
C) hair 
D) fat 
A) glycogen 
B) phospholipids 
C) hair 
D) fat

Question 11

Which of the following are pyrimidines?

Accepted Answer

A) adenine and thymine 
B) adenine and guanine 
C) cytosine and uracil 
D) cytosine and guanine 
A) adenine and thymine 
B) adenine and guanine 
C) cytosine and uracil 
D) cytosine and guanine

Question 12

Humans can digest starch but not cellulose because

Accepted Answer

A) the monomer of starch is glucose,whereas the monomer of cellulose is glucose modified by the addition of a nitrogen-containing group. 
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose. 
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. 
D) humans harbor starch-digesting bacteria in the digestive tract but not cellulose-digesting bacteria. 
A) the monomer of starch is glucose,whereas the monomer of cellulose is glucose modified by the addition of a nitrogen-containing group. 
B) humans have enzymes that can hydrolyze the β glycosidic linkages of starch but not the α glycosidic linkages of cellulose. 
C) humans have enzymes that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. 
D) humans harbor starch-digesting bacteria in the digestive tract but not cellulose-digesting bacteria.

Question 13

How many peptide bonds are present in a polypeptide that contains 45 amino acids?

Accepted Answer

A) 90 
B) 46 
C) 45 
D) 44 
A) 90 
B) 46 
C) 45 
D) 44

Question 14

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group.When placed in water,it

Accepted Answer

A) will function only as an acid because of the carboxyl group. 
B) will function only as a base because of the amino group. 
C) will function as both an acid and a base. 
D) will function as neither an acid nor a base. 
A) will function only as an acid because of the carboxyl group. 
B) will function only as a base because of the amino group. 
C) will function as both an acid and a base. 
D) will function as neither an acid nor a base.

Question 15

Which of the following statements about the 5' ends of RNA polymers is correct?

Accepted Answer

A) The 5' ends have hydroxyl groups attached to the number 5 carbons of ribose. 
B) The 5' ends have phosphate groups attached to the number 5 carbons of ribose. 
C) The 5' ends have phosphate groups attached to the number 5 carbons of the nitrogenous base. 
D) The 5' ends have nitrogenous bases attached to the number 5 carbons of ribose. 
A) The 5' ends have hydroxyl groups attached to the number 5 carbons of ribose. 
B) The 5' ends have phosphate groups attached to the number 5 carbons of ribose. 
C) The 5' ends have phosphate groups attached to the number 5 carbons of the nitrogenous base. 
D) The 5' ends have nitrogenous bases attached to the number 5 carbons of ribose.

Question 16

Figure 3.4
-During the synthesis of a polypeptide,the next amino acid in the growing polymer is added to which functional group shown in Figure 3.4?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 17

Which of the following functional groups may be used to form polymers via dehydration reactions?

Accepted Answer

A) only hydroxyl groups 
B) only carbonyl groups 
C) only carboxyl groups 
D) either hydroxyl or carboxyl groups 
E) either carbonyl or carboxyl groups 
A) only hydroxyl groups 
B) only carbonyl groups 
C) only carboxyl groups 
D) either hydroxyl or carboxyl groups 
E) either carbonyl or carboxyl groups

Question 18

A nutritional supplement developed for athletes is shown to contain only carbon,hydrogen,nitrogen,and oxygen.Based on these data,you may safely conclude that

Accepted Answer

A) the food does not contain protein. 
B) the food does not contain nucleic acids. 
C) the food does not contain carbohydrates. 
D) the food does not contain lipids. 
A) the food does not contain protein. 
B) the food does not contain nucleic acids. 
C) the food does not contain carbohydrates. 
D) the food does not contain lipids.

Question 19

Which of the following is an example of a dehydration reaction?

Accepted Answer

A) the reaction of two monosaccharides,forming a disaccharide with the release of water 
B) the reaction of a small polypeptide,forming amino acids with the release of water 
C) the reaction of a two amino acids,forming peptide bond with the consumption of water 
D) the reaction of a fat,forming glycerol and fatty acids with the consumption of water 
A) the reaction of two monosaccharides,forming a disaccharide with the release of water 
B) the reaction of a small polypeptide,forming amino acids with the release of water 
C) the reaction of a two amino acids,forming peptide bond with the consumption of water 
D) the reaction of a fat,forming glycerol and fatty acids with the consumption of water

Question 20

Figure 3.7
-Which of the following types of molecules is shown in Figure 3.7?

Accepted Answer

A) pentose 
B) fructose 
C) α glucose 
D) β glucose 
E) ribose 
A) pentose 
B) fructose 
C) α glucose 
D) β glucose 
E) ribose

Exam 3: Carbon and the Molecular Diversity of Life

If a DNA sample were composed of 20% guanine,what would be the percentage of cytosine?

Which of the following structures is formed by the atoms involved when a carbon atom is bound by single covalent bonds to four other atoms?

Which bonds maintain the primary structure of a protein?

How will brief heating (to 95°C)affect macromolecular structures in aqueous solution?

Figure 3.4 -Which functional group shown in Figure 3.4 is characteristic of alcohols?

Which of the following is a monomer used to build a biological polymer?

In a normal cellular protein,where would you expect to find a hydrophilic amino acid such as asparagine?

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together.What would happen to DNA molecules treated with these enzymes?

If cells are grown in a medium containing radioactive 35S,which of these molecules will be radioactively labeled?

A scientist suspects that food in an ecosystem may have been contaminated by radioactive nitrogen over a period of several months.Which of the following should be isolated from mammals living in the ecosystem and examined for radioactivity in order to test the hypothesis?

Which of the following are pyrimidines?

Humans can digest starch but not cellulose because

How many peptide bonds are present in a polypeptide that contains 45 amino acids?

A carbon skeleton is covalently bonded to both an amino group and a carboxyl group.When placed in water,it

Which of the following statements about the 5' ends of RNA polymers is correct?

Figure 3.4 -During the synthesis of a polypeptide,the next amino acid in the growing polymer is added to which functional group shown in Figure 3.4?

Which of the following functional groups may be used to form polymers via dehydration reactions?

A nutritional supplement developed for athletes is shown to contain only carbon,hydrogen,nitrogen,and oxygen.Based on these data,you may safely conclude that

Which of the following is an example of a dehydration reaction?

Figure 3.7 -Which of the following types of molecules is shown in Figure 3.7?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development,stem Cells,and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition,nutrition,and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons,synapses,and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Ecological Communities

Ecosystems and Energy

Conservation Biology and Global Change

Filters

If cells are grown in a medium containing radioactive ³⁵S,which of these molecules will be radioactively labeled?