Question 1

Most of the enzymes that catalyze biochemical reactions involving amino acids recognize the L stereoisomer.

Accepted Answer

A) True 
 B)False  True

Question 2

Describe the general structure of amino acids.

Accepted Answer

For 19 out of the 20 amino acids, a central carbon atom is attached to an amino group, a carboxyl group, a hydrogen atom, and a side group. Proline has a ring structure where the central carbon atom is attached to a carboxyl group and an imino group.

Question 3

When DNA is heated, the hydrogen bonds break and allow the two strands of DNA to separate from one another. Which sequence of DNA would be most resistant to heating, and therefore stay double stranded longer?

Accepted Answer

A)  AATTGGCC 
B)  ATGCATTC 
C)  AGGAGCTC 
D)  TGGCTTAG 
E)  TACCAATT 
A)  AATTGGCC 
B)  ATGCATTC 
C)  AGGAGCTC 
D)  TGGCTTAG 
E)  TACCAATT C

Question 4

How many hydrogen bonds are formed between adenine and thymine?

Accepted Answer

A)  one 
B)  two 
C)  three 
D)  four 
E)  six 
A)  one 
B)  two 
C)  three 
D)  four 
E)  six

Question 5

Figure 3.16
The molecule in the accompanying figure is the pyrimidine ____, which is typically found in DNA but not RNA.

Accepted Answer

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

Question 6

Glycerol forms the backbone of ____.

Accepted Answer

A)  triglycerides only 
B)  polysaccharides and nucleic acids 
C)  nucleic acids only 
D)  polypeptides only 
E)  triglycerides and phospholipids 
A)  triglycerides only 
B)  polysaccharides and nucleic acids 
C)  nucleic acids only 
D)  polypeptides only 
E)  triglycerides and phospholipids

Question 7

Reactions that remove the equivalent of a water molecule when subunits are joined to make a larger molecule are called ____ reactions.

Accepted Answer

A)  equilibrium 
B)  hydration 
C)  hydrolysis 
D)  redox 
E)  dehydration synthesis 
A)  equilibrium 
B)  hydration 
C)  hydrolysis 
D)  redox 
E)  dehydration synthesis

Question 8

In an elegant set of experiments, which protein did Anfinsen study in order to understand how the three-dimensional structure of proteins is determined?

Accepted Answer

A)  ovalbumin 
B)  chaperonin 
C)  ribonuclease 
D)  insulin 
E)  hemoglobin 
A)  ovalbumin 
B)  chaperonin 
C)  ribonuclease 
D)  insulin 
E)  hemoglobin

Question 9

In proteins, structural segments called ____ provide flexibility that allow parts of the protein to bend, fold, or move.

Accepted Answer

A)  random coils 
B)  peptide bonds 
C)  b sheets 
D)  a helices 
E)  b polysaccharides 
A)  random coils 
B)  peptide bonds 
C)  b sheets 
D)  a helices 
E)  b polysaccharides

Question 10

Excessive heat or extremes of pH often cause denaturation of proteins, which means that the proteins ____.

Accepted Answer

A)  have fallen apart into individual monomer subunits 
B)  are no longer biological molecules 
C)  have broken into many separate domains 
D)  are no longer in a functional three-dimensional conformation 
E)  are highly reactive 
A)  have fallen apart into individual monomer subunits 
B)  are no longer biological molecules 
C)  have broken into many separate domains 
D)  are no longer in a functional three-dimensional conformation 
E)  are highly reactive

Question 11

Sterol regulatory element binding proteins (SREBPs) are involved in regulating the synthesis of ____.

Accepted Answer

A)  proteins 
B)  lipids 
C)  nucleic acids 
D)  carbohydrates 
E)  amino acids 
A)  proteins 
B)  lipids 
C)  nucleic acids 
D)  carbohydrates 
E)  amino acids

Question 12

The most abundant organic molecules in the world are nucleic acids .

Accepted Answer

A) True 
 B)False

Question 13

The two strands of a DNA double helix are held to each other by ____ bonds between nitrogenous bases.

Accepted Answer

A)  phosphodiester 
B)  disulfide 
C)  glycosidic 
D)  hydrogen 
E)  peptide 
A)  phosphodiester 
B)  disulfide 
C)  glycosidic 
D)  hydrogen 
E)  peptide

Question 14

Which molecule is the main structural component of biological membranes?

Accepted Answer

A)  starch 
B)  triglyceride 
C)  protein 
D)  phospholipid 
E)  steroid 
A)  starch 
B)  triglyceride 
C)  protein 
D)  phospholipid 
E)  steroid

Question 15

Figure 3.14
The two amino acids depicted above both have side chains ( R groups) that are ____.

Accepted Answer

A)  acidic and polar 
B)  uncharged and nonpolar 
C)  basic and polar 
D)  acidic and nonpolar 
E)  uncharged and polar 
A)  acidic and polar 
B)  uncharged and nonpolar 
C)  basic and polar 
D)  acidic and nonpolar 
E)  uncharged and polar

Question 16

Chitin is a reinforcing fiber in the external skeleton of arthropods.

Accepted Answer

A) True 
 B)False

Question 17

Figure 3.11 (Question 41)
The two amino acids in the accompanying figure both have side chains ( R  groups) that are ____.

Accepted Answer

A)  acidic and polar 
B)  uncharged and nonpolar 
C)  basic and polar 
D)  acidic and nonpolar 
E)  uncharged and polar 
A)  acidic and polar 
B)  uncharged and nonpolar 
C)  basic and polar 
D)  acidic and nonpolar 
E)  uncharged and polar

Question 18

Are saturated or unsaturated fats generally solids at room temperature? Explain why there is a difference in the fluidity of these two related molecules.

Accepted Answer

Saturated fats are generally solids at r

Question 19

Figure 3.5
The molecule in the accompanying figure is mannose, an example of a ____ sugar.

Accepted Answer

A)  triose 
B)  hexose 
C)  pentose 
D)  heptose 
E)  tetrose 
A)  triose 
B)  hexose 
C)  pentose 
D)  heptose 
E)  tetrose

Question 20

The unique sequence of monomer subunits in a protein is the ____ structure of the protein.

Accepted Answer

A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
E)  linear 
A)  primary 
B)  secondary 
C)  tertiary 
D)  quaternary 
E)  linear

Exam 3: Biological Molecules: the Carbon Compounds of Life

Most of the enzymes that catalyze biochemical reactions involving amino acids recognize the L stereoisomer.

Describe the general structure of amino acids.

When DNA is heated, the hydrogen bonds break and allow the two strands of DNA to separate from one another. Which sequence of DNA would be most resistant to heating, and therefore stay double stranded longer?

How many hydrogen bonds are formed between adenine and thymine?

Figure 3.16 The molecule in the accompanying figure is the pyrimidine ____, which is typically found in DNA but not RNA.

Glycerol forms the backbone of ____.

Reactions that remove the equivalent of a water molecule when subunits are joined to make a larger molecule are called ____ reactions.

In an elegant set of experiments, which protein did Anfinsen study in order to understand how the three-dimensional structure of proteins is determined?

In proteins, structural segments called ____ provide flexibility that allow parts of the protein to bend, fold, or move.

Excessive heat or extremes of pH often cause denaturation of proteins, which means that the proteins ____.

Sterol regulatory element binding proteins (SREBPs) are involved in regulating the synthesis of ____.

The most abundant organic molecules in the world are nucleic acids .

The two strands of a DNA double helix are held to each other by ____ bonds between nitrogenous bases.

Which molecule is the main structural component of biological membranes?

Figure 3.14 The two amino acids depicted above both have side chains ( R groups) that are ____.

Chitin is a reinforcing fiber in the external skeleton of arthropods.

Figure 3.11 (Question 41) The two amino acids in the accompanying figure both have side chains ( R groups) that are ____.

Are saturated or unsaturated fats generally solids at room temperature? Explain why there is a difference in the fluidity of these two related molecules.

Figure 3.5 The molecule in the accompanying figure is mannose, an example of a ____ sugar.

The unique sequence of monomer subunits in a protein is the ____ structure of the protein.

Introduction to Biological Concepts and Research

Life, Chemistry, and Water

Cells

Membranes and Transport

Energy, Enzymes, and Biological Reactions

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

Cell Division and Mitosis

Meiosis: the Cellular Basis of Sexual Reproduction

Mendel, Genes, and Inheritance

Genes, Chromosomes, and Human Genetics

Dna Structure, Replication, and Organization

Gene Expression: From Dna to Protein

Regulation of Gene Expression

Bacterial and Viral Genetics

Dna Technology: Making and Using Genetically Altered Organisms, and Other Applications

Genomes and Proteomes

The Development of Evolutionary Thought

Microevolution: Genetic Changes Within Populations

Speciation

Paleobiology and Macroevolution

Systematic Biology: Phylogeny and Classification

The Origin of Life

Prokaryotes and Viruses

Protists

Seedless Plants

Seed Plants

Fungi

Animal Phylogeny, Acoelomates, and Protostomes

Deuterostomes: Vertebrates and Their Closest Relatives

The Plant Body

Transport in Plants

Plant Nutrition

Reproduction and Development in Flowering Plants

Plant Signals and Responses to the Environment

Introduction to Animal Organization and Physiology

Information Flow and the Neuron

Nervous Systems

Sensory Systems

The Endocrine System

Muscles, Bones, and Body Movements

The Circulatory System

Defenses Against Disease

Gas Exchange: the Respiratory System

Digestive Systems and Animal Nutrition

Regulating the Internal Environment: Osmoregulation, Excretion, and Thermoregulation

Animal Reproduction

Animal Development

Ecology and the Biosphere

Population Ecology

Population Interactions and Community Ecology

Ecosystems

Biodiversity and Conservation Biology

Animal Behavior

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