End-of Chapter Quiz 5

Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? 5′-ATGC-3′ with 5′-GCAT-3′ 5′-purine-pyrimidine-purine-pyrimidine-3′ with 3′-purine-pyrimidine-purine-pyrimidine-5′ 5′-AGCT-3′ with 5′-TCGA-3′ 5′-GCGC-3′ with 5′-TATA-3′ All of these pairs are correct.

5′-ATGC-3′ with 5′-GCAT-3′

Which of the following lists represents the chemical components of a nucleotide? A nitrogenous base, an amino acid, and a phosphate group A nitrogenous base, an amino acid, and a pentose sugar A nitrogenous base, a phosphate group, and a pentose sugar A nitrogenous base, a fatty acid, and an amino acid A series of nitrogenous bases, a nucleic acid backbone, and a hexose sugar

A nitrogenous base, a phosphate group, and a pentose sugar

Which functional group can act as a base? A) amino B) carbonyl C) carboxyl D) methyl

A) amino

Which functional group can act as an acid? A) carboxyl B) methyl C) amino D) carbonyl

A) carboxyl

What do Alzheimer's, Parkinson's, and mad cow disease have in common? All are associated with plaque buildup in arteries (atherosclerosis). All are associated with the buildup of lipids in brain cells due to faulty lysosome activity. All are caused by the buildup of misfolded proteins in cells. All are associated with the buildup of misfolded proteins in cells. All cause the misfolding of nucleic acids.

All are associated with the buildup of misfolded proteins in cells.

Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the shape of an enzymatic protein? A change in salt concentrations or pH Heating the protein Treating the protein with a chemical that breaks hydrogen bonds Denaturing the protein All of the listed responses are correct.

All of the listed responses are correct.

Which of the following is true regarding complementary base pairing in DNA and RNA molecules? Although a DNA molecule demonstrates complementary base pairing between two DNA polynucleotides to form a double helix, an RNA molecule can base-pair only along stretches of nucleotides in the same RNA molecule, such as in transfer RNA molecules. Complementary base pairing within single strands of DNA and RNA gives them particular three-dimensional structures that are necessary for their function. Although the base pairing between two strands of DNA in a DNA molecule can be thousands to millions of base pairs long, base pairing in an RNA molecule is limited to short stretches of nucleotides in the same molecule or between two RNA molecules. Complementary base pairing promotes an antiparallel orientation in the structure of DNA and RNA molecules. None of the listed responses is correct.

Although the base pairing between two strands of DNA in a DNA molecule can be thousands to millions of base pairs long, base pairing in an RNA molecule is limited to short stretches of nucleotides in the same molecule or between two RNA molecules.

What functional group are present in all amino acids?

Amino group (-NH2) and (-COOH).

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions? C60H102O51 C60H111O51 C60H100O50 C6H12O6 C60H120O60

C60H102O51

Which of the following molecules is a monosaccharide? C45H84O8PN C25H43O8 C51H98O6 C6H12O6 C22H49O10N5

C6H12O6

Which of the following components of a tossed salad will pass through the human digestive tract and be digested the least? Protein (in the bacon bits) Sugar (in the dressing) Oil (in the dressing) Starch (in the croutons) Cellulose (in the lettuce)

Cellulose (in the lettuce)

High cholesterol levels are considered a major risk factor for heart disease. If it is so bad for humans, why does the body make cholesterol in the first place? Cholesterol aids in the formation of amino acids that are used to build proteins. Cholesterol is the precursor for many important molecules such as sex hormones. Cholesterol is an important constituent of nucleotides. Cholesterol is not important for humans anymore. It is a holdover from hunter-gatherer days when food was scarce. Cholesterol is an important energy storage molecule.

Cholesterol is the precursor for many important molecules such as sex hormones.

The lipids that form the main structural component of cell membranes are __________. A) carbohydrates B) triacylglycerols C) proteins D) phospholipids E) cholesterol

D) phospholipids

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________. DNA fatty acids sucrose cellulose proteins

DNA

What is the process by which monomers are linked together to form polymers? Dehydration reaction Coiling Hydrolysis Monomerization Protein formation

Dehydration reaction

When a protein is denatured, why does it lose its functionality? Denaturation breaks the covalent bonds that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function. Denaturation breaks the intramolecular bonds, such as hydrogen bonds and van der Waals interactions, that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function. The protein's pH changes, and the change causes the protein to lose its functionality. Denaturation destroys the primary structure of the protein, and the protein breaks down to monomers. Different amino acids are substituted into the sequence, so the protein's properties change.

Denaturation breaks the intramolecular bonds, such as hydrogen bonds and van der Waals interactions, that hold the protein in its three-dimensional shape. Without the proper shape, the protein cannot function.

Nutritionally, saturated triacylglycerols are considered to be less healthful than unsaturated triacylglycerols. What is the difference between them? Saturated triacylglycerols are fats; unsaturated triacylglycerols are carbohydrates. For carbon skeletons of equal length, saturated triacylglycerols have more hydrogen atoms than unsaturated triacylglycerols do. Saturated triacylglycerols are liquid at room temperature. Saturated triacylglycerols have more double bonds than unsaturated triacylglycerols do. All of the listed responses are correct.

For carbon skeletons of equal length, saturated triacylglycerols have more hydrogen atoms than unsaturated triacylglycerols do.

The sex hormones estradiol and testosterone belong to which class of molecules? Nucleic acids Lipids Amino acids Carbohydrates Proteins

Lipids

Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass? Cows and other herbivores are exceptions and make some cellulose-digesting enzymes. The flat teeth and strong stomach of herbivores break the cellulose fibers so that the cows get enough nutrition from the cell contents. They have to eat a lot of grass. Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units. All of the listed responses are correct.

Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.

Which of the following represents a specific description of a polypeptide? Amino acids linked by hydrolysis Carbohydrates with a hydrogen bond holding them together Organic monomers covalently bonded Organic molecules linked by dehydration reactions None of the listed responses is correct.

None of the listed responses is correct.

Which of the following is a true statement comparing phospholipids and triacylglycerols (fats and oils)? Phospholipid molecules have a distinctly polar "head" and a distinctly nonpolar "tail," whereas triacylglycerols are predominantly nonpolar. Phospholipids are the primary storage form for fats in our bodies. Both molecules contain a phosphate group. In nature, phospholipids occur in fused rings (sterol form), whereas triacylglycerols maintain a straight-chain form. Triacylglycerols may be saturated or unsaturated, but all phospholipids are saturated.

Phospholipid molecules have a distinctly polar "head" and a distinctly nonpolar "tail," whereas triacylglycerols are predominantly nonpolar.

The α helix and β pleated sheet represent which level of protein structure? Primary structure Secondary structure pentiary structure Quaternary structure Tertiary structure

Secondary structure

In what polysaccharide form do plants store glucose to be available later as an energy source? Starch Protein Fatty acids Cellulose Glycogen

Starch

Amylase is an enzyme that breaks down starch. Why can the same enzyme not break down cellulose? Starch is made of glucose; cellulose is made of fructose. The monosaccharide monomers in cellulose are bonded together differently than those in starch. Cellulose molecules are much too large. The enzyme cannot attack cellulose because of its helical shape. The bonds between the monosaccharide monomers in cellulose are much stronger.

The monosaccharide monomers in cellulose are bonded together differently than those in starch.

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? The two strands of the double helix would separate. All bases would be separated from the deoxyribose sugars. The phosphodiester linkages of the polynucleotide backbone would be broken. The purines would be separated from the deoxyribose sugars. The pyrimidines would be separated from the deoxyribose sugars.

The phosphodiester linkages of the polynucleotide backbone would be broken.

Which of the following statements concerning unsaturated fats is true? They are more common in animals than in plants. They have fewer fatty acid molecules per fat molecule. They have double bonds in the carbon chains of their fatty acids. They contain more hydrogen than do saturated fats having the same number of carbon atoms. They generally solidify at room temperature.

They have double bonds in the carbon chains of their fatty acids.

Which of the following are pyrimidines found in the nucleic acid DNA? Thymine and adenine Guanine and cytosine Adenine and guanine Uracil and guanine Thymine and cytosine

Thymine and cytosine

Which of the following lists ranks these molecules in the correct order by size from smallest to largest? Water, sucrose, glucose, protein Protein, water, glucose, sucrose Water, protein, sucrose, glucose Glucose, water, sucrose, protein Water, glucose, sucrose, protein

Water, glucose, sucrose, protein

If a small droplet of triacylglycerol molecules is suspended in water, the fat molecules form a "ball of spaghetti" with no particular orientation. But if a droplet of phospholipid molecules is put in water, all the molecules point outward, toward the water. Phospholipids are forced into this orientation because phospholipids have __________. two charged or polar ends two fatty acid molecules pointing in different directions a charged or polar end and an uncharged or nonpolar end both a saturated fatty acid and an unsaturated fatty acid three fatty acid molecules, all pointing in different directions

a charged or polar end and an uncharged or nonpolar end

The peptide bond is __________. a covalent bond joining simple sugars together to form a polypeptide a hydrogen bond joining nucleotides together to form a nucleic acid a hydrogen bond joining amino acids together to form a polypeptide a covalent bond joining amino acids together to form a polypeptide a covalent bond joining nucleotides together to form a nucleic acid

a covalent bond joining amino acids together to form a polypeptide

A glucose molecule is to starch as __________. a protein is to an amino acid a nucleic acid is to a polypeptide a nucleotide is to a nucleic acid an amino acid is to a nucleic acid a steroid is to a lipid

a nucleotide is to a nucleic acid

In a hydrolysis reaction, __________, and in this process, water is __________. a monomer is broken up into its constituent polymers; produced monomers are assembled to produce a polymer; consumed a polymer is broken up into its constituent monomers; produced a polymer is broken up into its constituent monomers; consumed monomers are assembled to produce a polymer; produced

a polymer is broken up into its constituent monomers; consumed

Manufacturers make vegetable oils solid or semisolid at room temperature by __________. adding hydrogen atoms to the single-bonded carbon atoms of the fatty acid hydrocarbon chains adding hydrogen atoms to the fatty acid hydrocarbon chains, thereby converting carbon-carbon double bonds to single bonds removing hydrogen atoms and forming additional double bonds in the fatty acid hydrocarbon chains removing hydrogen atoms and forming additional single bonds in the fatty acid hydrocarbon chains None of the listed responses is correct.

adding hydrogen atoms to the fatty acid hydrocarbon chains, thereby converting carbon-carbon double bonds to single bonds

Based on complementary base pairing, you would expect the percentage of __________ to be equal to the percentage of __________. adenine; guanine adenine; cytosine thymine; cytosine adenine; thymine thymine; guanine

adenine; thymine

Protein molecules are polymers (chains) of __________. sucrose molecules amino acid molecules purines and pyrimidines fatty acid molecules DNA molecules

amino acid molecules

Lipids differ from other large biological molecules in that they __________. do not contain nitrogen and phosphorus atoms do not have specific shapes do not contain carbon are much larger are not truly polymers

are not truly polymers

Which of the following categories includes all others in the list? monosaccharide starch carbohydrate polysaccharide disaccharide

carbohydrate

At a conference, the speaker's grand finale was sautéing mealworms (insect larvae) in butter and serving them to the audience. They were crunchy (like popcorn hulls) because their exoskeletons contain the polysaccharide __________. palmitic acid cellulose collagen chitin glycogen

chitin

The type of bond that forms to join monomers (such as sugars and amino acids) into polymers (such as starch and proteins) is a(n) __________ bond. van der Waals peptide covalent hydrogen ionic

covalent

Carbohydrates are used in our bodies mainly for __________. membrane construction energy storage and release lipid storage building genetic material structural molecules, such as hair and fingernails

energy storage and release

Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by __________. peptide bonds ester linkages phosphodiester linkages glycosidic linkages ionic bonds

ester linkages

A polysaccharide that is used for storing energy in human muscle and liver cells is __________. glucose starch glycogen cellulose chitin

glycogen

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the a form. Which of the following could amylase break down? starch and chitin glycogen and cellulose starch, amylopectin, and cellulose glycogen, starch, and amylopectin cellulose and chitin

glycogen, starch, and amylopectin

The subunits (monomers) in cellulose are linked together by __________. ester linkages peptide bonds ionic bonds phosphodiester linkages glycosidic linkages

glycosidic linkages

Which of the following terms can be correctly used to describe compounds that do not mix with water? hydrophilic hydrogen-bonded phospholipids proteins hydrophobic

hydrophobic

The fatty acid tails of a phospholipid are __________ because they __________. hydrophilic; consist of units assembled by dehydration reactions hydrophobic; dissolve easily in water hydrophobic; consist of units assembled by dehydration reactions hydrophilic; are easily hydrolyzed into their monomers hydrophobic; have no charges to which water molecules can adhere

hydrophobic; have no charges to which water molecules can adhere

The structural level of a protein least affected by a disruption in hydrogen bonding is the secondary level. All structural levels are equally affected. quaternary level. tertiary level primary level.

primary level.

The polysaccharide that you are most likely to have eaten recently is __________. lactose glucose chitin ribose starch

starch

The overall three-dimensional shape of a single polypeptide is called its __________. secondary structure tertiary structure quaternary structure double helix primary structure

tertiary structure

The "primary structure" of a protein refers to __________. coiling due to hydrogen bonding between amino acids the α helix or β pleated sheets the sequence of amino acids along a polypeptide chain interactions among the side chains or R groups of the amino acids the weak aggregation of two or more polypeptide chains into one functional macromolecule

the sequence of amino acids along a polypeptide chain

One characteristic shared by sucrose, lactose, and maltose is that __________. they are all polysaccharides they are all indigestible by humans they are all monosaccharides they all contain fructose they are all disaccharides

they are all disaccharides