Question 1

Fatty acids are

Accepted Answer

A)  carboxylic acids with long hydrocarbon tails. 
B)  linked to glycerol in fats by phosphodiester bonds. 
C)  saturated hydrocarbons. 
D)  large polymers of monosaccharides. 
E)  generally present in water-soluble proteins. 
A)  carboxylic acids with long hydrocarbon tails. 
B)  linked to glycerol in fats by phosphodiester bonds. 
C)  saturated hydrocarbons. 
D)  large polymers of monosaccharides. 
E)  generally present in water-soluble proteins.

Question 2

Refer to the figure below.   Polysaccharide A functions as an energy source in plants, whereas polysaccharides B and C function as structural polymers in the woody tissues of plants.Based on their molecular structures, which property of these polysaccharides could be important in distinguishing these two different functions?

Accepted Answer

A)  F1F1F1S1F1F1F10F1F1F1S1F1F1F10versus F1F1F1S1F1F1F10 glycosidic linkage 
B)  A requirement for glucose as the monomer 
C)  An ability to form hydrogen bonds between chains 
D)  The number of carbon atoms in the monomer 
E)  A monomer linkage between carbons 1 and 4 
A)  F1F1F1S1F1F1F10F1F1F1S1F1F1F10versus F1F1F1S1F1F1F10 glycosidic linkage 
B)  A requirement for glucose as the monomer 
C)  An ability to form hydrogen bonds between chains 
D)  The number of carbon atoms in the monomer 
E)  A monomer linkage between carbons 1 and 4

Question 3

Why does a starchy food like bread become hard when it dries out?

Accepted Answer

A)  In the absence of water, unbranched starch molecules aggregate together by forming hydrogen bonds. 
B)  Cellulose molecules in the cells aggregate in the absence of water. 
C)  The release of carbon dioxide from drying starch causes the food to harden. 
D)  The remaining water and heat cause the polysaccharide chains to bind together. 
E)  Mold growth interferes with α linkages, causing the food to harden. 
A)  In the absence of water, unbranched starch molecules aggregate together by forming hydrogen bonds. 
B)  Cellulose molecules in the cells aggregate in the absence of water. 
C)  The release of carbon dioxide from drying starch causes the food to harden. 
D)  The remaining water and heat cause the polysaccharide chains to bind together. 
E)  Mold growth interferes with α linkages, causing the food to harden.

Question 4

Suppose you have a ball-and-stick model of the amino acid l-valine.What common household item could be used to assist you in drawing d-valine?

Accepted Answer

A)  Candle 
B)  Mirror 
C)  String 
D)  Rubber band 
E)  Cup 
A)  Candle 
B)  Mirror 
C)  String 
D)  Rubber band 
E)  Cup

Question 5

Lipids play important roles in a number of functions.Which is not one of those functions?

Accepted Answer

A)  Vision 
B)  Energy storage 
C)  Membrane structure 
D)  Storage of genetic information 
E)  Chemical signaling 
A)  Vision 
B)  Energy storage 
C)  Membrane structure 
D)  Storage of genetic information 
E)  Chemical signaling

Question 6

You are trying to determine something about the structure of a particular enzyme.For one of your experiments, you mutate the protein to include some cysteine residues in sections you think might be folded close to each other.You place properly folded original proteins and mutant proteins into a denaturing solution (urea), then back into a physiological solution.You find that the mutant has 100 percent enzymatic activity while the nonmutant protein has 90 percent enzymatic activity.What is the best explanation for this observation?

Accepted Answer

A)  Urea bound to cysteine residues, stabilizing the protein structure. 
B)  The cysteine residues formed a covalent bond that was not broken during denaturation, thus stabilizing protein structure. 
C)  The cysteine residues destabilized the structure. 
D)  Proteins without cysteine residues cannot fold back to their native shape after denaturation. 
E)  Adding cysteine residues gave the enzyme a more reactive active site. 
A)  Urea bound to cysteine residues, stabilizing the protein structure. 
B)  The cysteine residues formed a covalent bond that was not broken during denaturation, thus stabilizing protein structure. 
C)  The cysteine residues destabilized the structure. 
D)  Proteins without cysteine residues cannot fold back to their native shape after denaturation. 
E)  Adding cysteine residues gave the enzyme a more reactive active site.

Question 7

Phospholipids form a bilayer that

Accepted Answer

A)  dissolves in a liquid environment. 
B)  is impermeable to other molecules. 
C)  is held together by covalent interactions. 
D)  is broken down by hydrolysis. 
E)  has a hydrophobic core. 
A)  dissolves in a liquid environment. 
B)  is impermeable to other molecules. 
C)  is held together by covalent interactions. 
D)  is broken down by hydrolysis. 
E)  has a hydrophobic core.

Question 8

Refer to the figure below.   Many more _______ form between chains of cellulose than between chains in starch or glycogen.This helps explain why cellulose strands pack so tightly together.

Accepted Answer

The answer of Refer to the figure below.  ...

Question 9

When an egg is exposed to extreme heat, it turns from a liquid into a solid.The egg remains solid when it cools.All of the following are reasons for this except:

Accepted Answer

A)  Water has been removed from the egg proteins. 
B)  The hydrogen bonds and hydrophobic interactions in the egg proteins have been broken. 
C)  Denatured proteins in the egg have lost secondary and tertiary structure. 
D)  Denatured proteins in the egg have aggregated. 
E)  Amino acid side chains have been chemically modified. 
A)  Water has been removed from the egg proteins. 
B)  The hydrogen bonds and hydrophobic interactions in the egg proteins have been broken. 
C)  Denatured proteins in the egg have lost secondary and tertiary structure. 
D)  Denatured proteins in the egg have aggregated. 
E)  Amino acid side chains have been chemically modified.

Question 10

Carbohydrates

Accepted Answer

A)  are a store of genetic information. 
B)  are the main structure of the plasma membrane. 
C)  are a base from which other molecules can be made. 
D)  cannot be chemically modified. 
E)  aid in the folding of proteins. 
A)  are a store of genetic information. 
B)  are the main structure of the plasma membrane. 
C)  are a base from which other molecules can be made. 
D)  cannot be chemically modified. 
E)  aid in the folding of proteins.

Question 11

Which is not a correct monomers → polymer construction?

Accepted Answer

A)  Monosaccharides → polysaccharide 
B)  Amino acids → protein 
C)  Celluloses → triglyceride 
D)  Nucleotides → nucleic acid 
E)  Monosaccharides → oligosaccharide 
A)  Monosaccharides → polysaccharide 
B)  Amino acids → protein 
C)  Celluloses → triglyceride 
D)  Nucleotides → nucleic acid 
E)  Monosaccharides → oligosaccharide

Question 12

Which amino acid is small enough to fit into tight corners of protein molecules?

Accepted Answer

A)  Proline 
B)  Glycine 
C)  Cysteine 
D)  Asparagine 
E)  Glutamine 
A)  Proline 
B)  Glycine 
C)  Cysteine 
D)  Asparagine 
E)  Glutamine

Question 13

Which peptide could be found inside a phospholipid bilayer membrane because of its hydrophobic properties? Capital letter abbreviations for amino acids, which can be found in Table 3.2, are used to indicate peptide sequences.

Accepted Answer

A)  RKE 
B)  HGD 
C)  GTC 
D)  LMV 
E)  STA 
A)  RKE 
B)  HGD 
C)  GTC 
D)  LMV 
E)  STA

Question 14

Which description applies to polysaccharides, polypeptides, and polynucleotides?

Accepted Answer

A)  They contain simple sugars. 
B)  They are broken down in hydrolysis reactions. 
C)  They are located in cell membranes. 
D)  They contain nitrogen. 
E)  Their molecular weights are less than 30,000 Da. 
A)  They contain simple sugars. 
B)  They are broken down in hydrolysis reactions. 
C)  They are located in cell membranes. 
D)  They contain nitrogen. 
E)  Their molecular weights are less than 30,000 Da.

Question 15

In condensation reactions, the atoms that make up a water molecule are derived from

Accepted Answer

A)  oxygen. 
B)  one of the reactants. 
C)  both reactants. 
D)  carbohydrates. 
E)  the enzyme. 
A)  oxygen. 
B)  one of the reactants. 
C)  both reactants. 
D)  carbohydrates. 
E)  the enzyme.

Question 16

Refer to the figure below.   Which structure represents the straight-chain form of the sugar shown in the figure above?

Accepted Answer

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

Question 17

Three different proteins, A, B, and C, from a plant were studied.In each case, a glycine residue was changed to an alanine.Changes in the biological activities of the mutated proteins were then measured, and the results are shown in the table below.   Which statement about structure-function relationships in proteins is supported by the data?

Accepted Answer

A)  Each unique amino acid sequence results in a protein with a unique function. 
B)  A protein's function changes only when changes in primary structure alter its tertiary structure. 
C)  Substitution of a nonpolar amino acid for another nonpolar amino acid is sufficient to allow a protein to retain its biological activity. 
D)  Amino acids located at the beginning of a polypeptide chain have less importance in determining biological function than amino acids in the middle or far end of the chain. 
E)  Every amino acid substitution in a protein's primary structure leads to a change in the protein's function. 
A)  Each unique amino acid sequence results in a protein with a unique function. 
B)  A protein's function changes only when changes in primary structure alter its tertiary structure. 
C)  Substitution of a nonpolar amino acid for another nonpolar amino acid is sufficient to allow a protein to retain its biological activity. 
D)  Amino acids located at the beginning of a polypeptide chain have less importance in determining biological function than amino acids in the middle or far end of the chain. 
E)  Every amino acid substitution in a protein's primary structure leads to a change in the protein's function.

Question 18

Refer to the figure below.   The compound shown is a lipid.Based on its structure, what is its likely function?

Accepted Answer

A)  Protection from desiccation 
B)  Hormonal signaling 
C)  Energy storage 
D)  Radiant energy capture 
E)  Insulation 
A)  Protection from desiccation 
B)  Hormonal signaling 
C)  Energy storage 
D)  Radiant energy capture 
E)  Insulation

Question 19

The R groups of amino acids have certain properties and allow for amino acids to be organized into all of the following groups except

Accepted Answer

A)  positively charged and hydrophilic. 
B)  negatively charged and hydrophilic. 
C)  uncharged hydrophilic. 
D)  positively charged and hydrophobic. 
E)  nonpolar hydrophobic. 
A)  positively charged and hydrophilic. 
B)  negatively charged and hydrophilic. 
C)  uncharged hydrophilic. 
D)  positively charged and hydrophobic. 
E)  nonpolar hydrophobic.

Question 20

When they need energy, cells break down glycogen and starch into glucose using

Accepted Answer

A)  combustion. 
B)  hydrolysis. 
C)  salt bridges. 
D)  condensation. 
E)  glycoproteins. 
A)  combustion. 
B)  hydrolysis. 
C)  salt bridges. 
D)  condensation. 
E)  glycoproteins.

Exam 3: Proteins, Carbohydrates, and Lipids

Fatty acids are

Why does a starchy food like bread become hard when it dries out?

Suppose you have a ball-and-stick model of the amino acid l-valine.What common household item could be used to assist you in drawing d-valine?

Lipids play important roles in a number of functions.Which is not one of those functions?

Phospholipids form a bilayer that

Refer to the figure below. Many more _______ form between chains of cellulose than between chains in starch or glycogen.This helps explain why cellulose strands pack so tightly together.

When an egg is exposed to extreme heat, it turns from a liquid into a solid.The egg remains solid when it cools.All of the following are reasons for this except:

Carbohydrates

Which is not a correct monomers → polymer construction?

Which amino acid is small enough to fit into tight corners of protein molecules?

Which peptide could be found inside a phospholipid bilayer membrane because of its hydrophobic properties? Capital letter abbreviations for amino acids, which can be found in Table 3.2, are used to indicate peptide sequences.

Which description applies to polysaccharides, polypeptides, and polynucleotides?

In condensation reactions, the atoms that make up a water molecule are derived from

Refer to the figure below. Which structure represents the straight-chain form of the sugar shown in the figure above?

Refer to the figure below. The compound shown is a lipid.Based on its structure, what is its likely function?

The R groups of amino acids have certain properties and allow for amino acids to be organized into all of the following groups except

When they need energy, cells break down glycogen and starch into glucose using

Studying Life

Small Molecules and the Chemistry of Life

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Energy, Enzymes, and Metabolism

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

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Neurons, Glia, and Nervous Systems

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The Mammalian Nervous System: Structure and Higher Functions

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Gas Exchange

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Salt and Water Balance and Nitrogen Excretion

Animal Behavior

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