Question 1

In an enzyme-catalyzed reaction,

Accepted Answer

A)  a substrate does not change. 
B)  the rate decreases as substrate concentration increases. 
C)  the enzyme can be permanently changed. 
D)  the enzyme can place strain on the substrate. 
E)  the rate is not affected by substrate concentration. 
A)  a substrate does not change. 
B)  the rate decreases as substrate concentration increases. 
C)  the enzyme can be permanently changed. 
D)  the enzyme can place strain on the substrate. 
E)  the rate is not affected by substrate concentration.

Question 2

What is the difference between nucleosides and nucleotides?

Accepted Answer

A)  Only nucleotides have nitrogenous bases. 
B)  Only nucleotides contain a phosphate group. 
C)  Nucleotides have the pentose sugar ribose,whereas nucleosides have the pentose sugar deoxyribose. 
D)  In nucleosides the monomers are joined by phosphodiester bonds;in nucleotides the monomers are joined by hydrogen bonds. 
E)  Nucleosides are the monomers of DNA,whereas nucleotides are the monomers of RNA. 
A)  Only nucleotides have nitrogenous bases. 
B)  Only nucleotides contain a phosphate group. 
C)  Nucleotides have the pentose sugar ribose,whereas nucleosides have the pentose sugar deoxyribose. 
D)  In nucleosides the monomers are joined by phosphodiester bonds;in nucleotides the monomers are joined by hydrogen bonds. 
E)  Nucleosides are the monomers of DNA,whereas nucleotides are the monomers of RNA.

Question 3

The 5'-carbon of deoxyribose in DNA is attached to

Accepted Answer

A)  adenine. 
B)  a phosphate group. 
C)  guanine. 
D)  a pyrimidine. 
E)  hydrogen. 
A)  adenine. 
B)  a phosphate group. 
C)  guanine. 
D)  a pyrimidine. 
E)  hydrogen.

Question 4

What is the nucleotide sequence of the complementary strand of the DNA molecule 5'-AATGCGA-3'?

Accepted Answer

A)  3'-CCGTTAT-5' 
B)  3'-AATGCGA-5' 
C)  3'-GGCATAG-5' 
D)  3'-TTACGCT-5' 
E)  5F'-AGCGTAA-3' 
A)  3'-CCGTTAT-5' 
B)  3'-AATGCGA-5' 
C)  3'-GGCATAG-5' 
D)  3'-TTACGCT-5' 
E)  5F'-AGCGTAA-3'

Question 5

Ribozymes are

Accepted Answer

A)  enzymes that are made up of ribose sugar. 
B)  ancient catalysts that no longer exist. 
C)  RNA catalysts. 
D)  present in bacterial cells only. 
E)  less active than protein enzymes. 
A)  enzymes that are made up of ribose sugar. 
B)  ancient catalysts that no longer exist. 
C)  RNA catalysts. 
D)  present in bacterial cells only. 
E)  less active than protein enzymes.

Question 6

Both DNA and RNA include

Accepted Answer

A)  pentoses. 
B)  hexoses. 
C)  fructoses. 
D)  maltoses. 
E)  amyloses. 
A)  pentoses. 
B)  hexoses. 
C)  fructoses. 
D)  maltoses. 
E)  amyloses.

Question 7

Nucleotides in RNA are connected to one another in the polynucleotide chain by

Accepted Answer

A)  covalent bonds between bases. 
B)  covalent bonds between sugars. 
C)  covalent bonds between sugar and phosphate. 
D)  hydrogen bonds between purines. 
E)  hydrogen bonds between any bases. 
A)  covalent bonds between bases. 
B)  covalent bonds between sugars. 
C)  covalent bonds between sugar and phosphate. 
D)  hydrogen bonds between purines. 
E)  hydrogen bonds between any bases.

Question 8

The enzyme sucrase increases the rate at which sucrose is broken down into glucose and fructose.Sucrase works by

Accepted Answer

A)  increasing the amount of free energy of the reaction. 
B)  lowering the activation energy of the reaction. 
C)  decreasing the equilibrium constant of the reaction. 
D)  supplying energy to speed up the reaction. 
E)  changing the shape of the active site. 
A)  increasing the amount of free energy of the reaction. 
B)  lowering the activation energy of the reaction. 
C)  decreasing the equilibrium constant of the reaction. 
D)  supplying energy to speed up the reaction. 
E)  changing the shape of the active site.

Question 9

You are given a reaction and are told it is at "saturation." To determine if this is true,you should add _______ and see if the reaction rate _______.

Accepted Answer

A)  ATP;increases 
B)  more substrate;increases 
C)  a competitive inhibitor;decreases 
D)  a downstream product;decreases 
E)  a noncompetitive inhibitor;decreases 
A)  ATP;increases 
B)  more substrate;increases 
C)  a competitive inhibitor;decreases 
D)  a downstream product;decreases 
E)  a noncompetitive inhibitor;decreases

Question 10

The hydrolysis of sucrose to glucose and fructose is exergonic.However,if sucrose is dissolved in water and the solution is kept overnight at room temperature,there is no detectable conversion to glucose and fructose.Why?

Accepted Answer

A)  The change in free energy of the reaction is positive. 
B)  The activation energy of the reaction is high. 
C)  The change in free energy of the reaction is negative. 
D)  This is a condensation reaction. 
E)  The free energy of the products is higher than the free energy of the reactants. 
A)  The change in free energy of the reaction is positive. 
B)  The activation energy of the reaction is high. 
C)  The change in free energy of the reaction is negative. 
D)  This is a condensation reaction. 
E)  The free energy of the products is higher than the free energy of the reactants.

Question 11

What accounts for the stability of the double-stranded DNA molecule?

Accepted Answer

A)  The hydrogen bonds between purines and pyrimidines 
B)  Phosphodiester bonds between the nitrogenous bases 
C)  Strong hydrogen bonds between the sugar and phosphate groups 
D)  Its double-helix shape 
E)  The direct bonding of the base to the phosphate molecule 
A)  The hydrogen bonds between purines and pyrimidines 
B)  Phosphodiester bonds between the nitrogenous bases 
C)  Strong hydrogen bonds between the sugar and phosphate groups 
D)  Its double-helix shape 
E)  The direct bonding of the base to the phosphate molecule

Question 12

The phenomenon of complementary base pairing is based on

Accepted Answer

A)  the alternation of sugar-phosphate groups. 
B)  the relative sizes of purines and pyrimidines. 
C)  evolutionary relationships. 
D)  the differences found in RNA and DNA. 
E)  All of the above 
A)  the alternation of sugar-phosphate groups. 
B)  the relative sizes of purines and pyrimidines. 
C)  evolutionary relationships. 
D)  the differences found in RNA and DNA. 
E)  All of the above

Question 13

A protein can best be defined as a polymer

Accepted Answer

A)  of amino acids. 
B)  containing one or more polypeptide chains. 
C)  containing 20 amino acids. 
D)  containing 20 peptide linkages. 
E)  containing double helices. 
A)  of amino acids. 
B)  containing one or more polypeptide chains. 
C)  containing 20 amino acids. 
D)  containing 20 peptide linkages. 
E)  containing double helices.

Question 14

The side chain of leucine is a hydrocarbon.In a folded protein,leucine would likely not be found

Accepted Answer

A)  in the interior of a cytoplasmic enzyme. 
B)  on the exterior of a protein embedded in a membrane. 
C)  on the exterior of a cytoplasmic enzyme. 
D)  in the interior of a protein embedded in a membrane. 
E)  Both a and c 
A)  in the interior of a cytoplasmic enzyme. 
B)  on the exterior of a protein embedded in a membrane. 
C)  on the exterior of a cytoplasmic enzyme. 
D)  in the interior of a protein embedded in a membrane. 
E)  Both a and c

Question 15

Single-stranded RNA can fold in on itself,creating three-dimensional structures for the bonding and recognition of other molecules.The folds are stabilized by _______ bonds.

Accepted Answer

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

Question 16

Which statement about enzyme inhibitors is false?

Accepted Answer

A)  A competitive inhibitor binds the active site of the enzyme. 
B)  An allosteric inhibitor binds a site on the active form of the enzyme. 
C)  A noncompetitive inhibitor binds a site other than the active site. 
D)  Noncompetitive inhibition cannot be overcome by the addition of more substrate. 
E)  Competitive inhibition can be overcome by the addition of more substrate. 
A)  A competitive inhibitor binds the active site of the enzyme. 
B)  An allosteric inhibitor binds a site on the active form of the enzyme. 
C)  A noncompetitive inhibitor binds a site other than the active site. 
D)  Noncompetitive inhibition cannot be overcome by the addition of more substrate. 
E)  Competitive inhibition can be overcome by the addition of more substrate.

Question 17

Which statement about enzymes is true?

Accepted Answer

A)  Enzymes are proteins. 
B)  Enzymes have a specific amino acid sequence. 
C)  Enzymes are highly specific. 
D)  Enzymes lower the energy barrier of a reaction. 
E)  All of the above 
A)  Enzymes are proteins. 
B)  Enzymes have a specific amino acid sequence. 
C)  Enzymes are highly specific. 
D)  Enzymes lower the energy barrier of a reaction. 
E)  All of the above

Question 18

Coenzymes differ from enzymes in that coenzymes

Accepted Answer

A)  are active only outside the cell. 
B)  are polymers of amino acids. 
C)  bind to the active site of an enzyme. 
D)  are specific for one reaction. 
E)  are always carriers of high-energy phosphate. 
A)  are active only outside the cell. 
B)  are polymers of amino acids. 
C)  bind to the active site of an enzyme. 
D)  are specific for one reaction. 
E)  are always carriers of high-energy phosphate.

Exam 3: Nucleic Acids, Proteins, and Enzymes

In an enzyme-catalyzed reaction,

What is the difference between nucleosides and nucleotides?

The 5'-carbon of deoxyribose in DNA is attached to

What is the nucleotide sequence of the complementary strand of the DNA molecule 5'-AATGCGA-3'?

Ribozymes are

Both DNA and RNA include

Nucleotides in RNA are connected to one another in the polynucleotide chain by

The enzyme sucrase increases the rate at which sucrose is broken down into glucose and fructose.Sucrase works by

You are given a reaction and are told it is at "saturation." To determine if this is true,you should add _______ and see if the reaction rate _______.

The hydrolysis of sucrose to glucose and fructose is exergonic.However,if sucrose is dissolved in water and the solution is kept overnight at room temperature,there is no detectable conversion to glucose and fructose.Why?

What accounts for the stability of the double-stranded DNA molecule?

The phenomenon of complementary base pairing is based on

A protein can best be defined as a polymer

The side chain of leucine is a hydrocarbon.In a folded protein,leucine would likely not be found

Single-stranded RNA can fold in on itself,creating three-dimensional structures for the bonding and recognition of other molecules.The folds are stabilized by _______ bonds.

Which statement about enzyme inhibitors is false?

Which statement about enzymes is true?

Coenzymes differ from enzymes in that coenzymes

Introduction

The Chemistry and Energy of Life

Cells: the Working Units of Life

Cell Membranes and Signaling

Pathways That Harvest and Store Chemical Energy

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

DNA and Its Role in Heredity

From Dna to Protein: Gene Expression

Regulation of Gene Expression

Genomes

Biotechnology

Genes, Development, and Evolution

Processes of Evolution

Reconstructing and Using Phylogenies

Speciation

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

The Evolution of Plants

The Evolution and Diversity of Fungi

Animal Origins and Diversity

The Plant Body

Plant Nutrition and Transport

Plant Growth and Development

Reproduction of Flowering Plants

Plants in the Environment

Fundamentals of Animal Function

Nutrition and Digestion

Breathing

Circulation

Muscle and Movement

Neurons, Sense Organs, and Nervous Systems

Nervous and Endocrine Control

Water and Salts: Excretion

Animal Reproduction

Animal Development

Immunology: Animal Defense Systems

Animal Behavior

The Distribution of Earths Ecological Systems

Populations

Ecological and Evolutionary Consequences of Interactions Within and Among Species

Ecological Communities

The Global Ecosystem

Filters

You are given a reaction and are told it is at "saturation." To determine if this is true,you should add _ and see if the reaction rate _.