Chpt 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 is true regarding complementary base pairing in DNA and RNA molecules? (eText Concept 5.5) 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. 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. 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.

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 C60H120O60 C60H100O50 C6H12O6

C60H102O51

Which of the following molecules is a monosaccharide? (eText Concept 5.2) C25H43O8 C6H12O6 C45H84O8PN C22H49O10N5 C51H98O6

C6H12O6

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? (eText Concept 5.3) Cholesterol is the precursor for many important molecules such as sex hormones. 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 aids in the formation of amino acids that are used to build proteins. Cholesterol is an important constituent of nucleotides.

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

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________. (eText Concept 5.5) sucrose cellulose DNA fatty acids proteins

DNA

When a protein is denatured, why does it lose its functionality? (eText Concept 5.4) The protein's pH changes, and the change causes the protein to 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. Different amino acids are substituted into the sequence, so the protein's properties change. Denaturation destroys the primary structure of the protein, and the protein breaks down to monomers.

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? (eText Concept 5.3) Saturated triacylglycerols have more double bonds than unsaturated triacylglycerols do. 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 are fats; unsaturated triacylglycerols are carbohydrates. All of the listed responses are correct.

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

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? glycogen, starch, and amylopectin starch and chitin glycogen and cellulose cellulose and chitin starch, amylopectin, and cellulose

Glycogen, starch, and amylopectin

Which of the following is a true statement comparing phospholipids and triacylglycerols (fats and oils)? (eText Concept 5.3) Phospholipids are the primary storage form for fats in our bodies. Triacylglycerols may be saturated or unsaturated, but all phospholipids are saturated. Both molecules contain a phosphate group. In nature, phospholipids occur in fused rings (sterol form), whereas triacylglycerols maintain a straight-chain form. Phospholipid molecules have a distinctly polar "head" and a distinctly nonpolar "tail," whereas triacylglycerols are predominantly nonpolar.

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

Which of the following describes a difference between DNA and RNA? (eText Concept 5.5) RNA molecules generally consist of a single polynucleotide chain, whereas DNA molecules generally consist of two polynucleotide chains organized into a double helix. Both molecules contain adenine, guanine and cytosine, but DNA also contains thymine and RNA also contains uracil. They contain different sugars. The first and second listed responses correctly describe differences between DNA and RNA. The first three listed responses correctly describe differences between DNA and RNA.

The first three listed responses correctly describe differences between DNA and RNA.

Amylase is an enzyme that breaks down starch. Why cannot the same enzyme break down cellulose? (eText Concept 5.2) Starch is made of glucose; cellulose is made of fructose. The bonds between the monosaccharide monomers in cellulose are much stronger. The enzyme cannot attack cellulose because of its helical shape. The monosaccharide monomers in cellulose are bonded together differently than those in starch. Cellulose molecules are much too large.

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? All bases would be separated from the deoxyribose sugars. The two strands of the double helix would separate. 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 polynuclieotide backbone would be broken.

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

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

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 __________. (eText Concept 5.3) two charged or polar ends a charged or polar end and an uncharged or nonpolar end both a saturated fatty acid and an unsaturated fatty acid two fatty acid molecules pointing in different directions three fatty acid molecules, all pointing in different directions

a charged or polar end and an uncharged or nonpolar end

The peptide bond is __________. (eText Concept 5.4) a hydrogen bond joining nucleotides together to form a nucleic acid a covalent 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 simple sugars together to form a polypeptide

a covalent bond joining amino acids together to form a polypeptide

Which of the following lists represents the chemical components of a nucleotide? (eText Concept 5.5) a series of nitrogenous bases, a nucleic acid backbone, and a hexose sugar a nitrogenous base, a phosphate group, and a pentose sugar a nitrogenous base, an amino acid, and a phosphate group a nitrogenous base, a fatty acid, and an amino acid a nitrogenous base, an amino acid, and a pentose sugar

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

A glucose molecule is to starch as __________. (eText Concept 5.5) a protein is to an amino acid a nucleic acid is to a polypeptide a steroid is to a lipid a nucleotide is to a nucleic acid an amino acid is to a nucleic acid

a nucleotide is to a nucleic acid

In a hydrolysis reaction, __________, and in this process water is __________. (eText Concept 5.1) monomers are assembled to produce a polymer ... consumed a polymer is broken up into its constituent monomers ... produced monomers are assembled to produce a polymer ... produced a polymer is broken up into its constituent monomers ... consumed a monomer is broken up into its constituent polymers ... produced

a polymer is broken up into its constituent monomers...consumed

Manufacturers make vegetable oils solid or semisolid at room temperature by __________. (eText Concept 5.3) removing hydrogen atoms and forming additional double bonds in 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 single bonds in the fatty acid hydrocarbon chains adding hydrogen atoms to the single-bonded carbon atoms of 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 __________. (eText Concept 5.5) adenine ... thymine adenine ... cytosine thymine ... cytosine adenine ... guanine thymine ... guanine

adenine...thymine

What do Alzheimer's, Parkinson's, and mad cow disease have in common?(eText Concept 5.4) All are associated with the buildup of misfolded proteins in cells. All cause the misfolding of nucleic acids. All are caused by the buildup of misfolded proteins in cells. 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 associated with the buildup of misfolded proteins in cells

One characteristic shared by sucrose, lactose, and maltose is that __________. (eText Concept 5.2) they are all disaccharides they all contain fructose they are all monosaccharides they are all indigestible by humans they are all polysaccharides

all disaccharides

Enzyme molecules require a specific shape to perform their catalytic function. Which of the following might alter the shape of an enzymatic protein? (eText Concept 5.4) heating the protein denaturing the protein treating the protein with a chemical that breaks hydrogen bonds a change in salt concentrations or pH All of the listed responses are correct.

all of the responses

Protein molecules are polymers (chains) of __________. (eText Concept 5.4) sucrose molecules amino acid molecules purines and pyrimidines DNA molecules fatty acid molecules

amino acid molecules

Lipids differ from other large biological molecules in that they __________. (eText Concept 5.3) do not have specific shapes are much larger do not contain carbon are not truly polymers do not contain nitrogen and phosphorus atoms

are not truly polymers

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

carbohydrate

Which of the following components of a tossed salad will pass through the human digestive tract and be digested the least? (eText Concept 5.2) protein (in the bacon bits) sugar (in the dressing) oil (in the dressing) cellulose (in the lettuce) starch (in the croutons)

cellulose (in lettuce)

Which of the following is a polymer? (eText Concept 5.1) glucose, an energy-rich molecule cellulose, a plant cell wall component fructose, a component of sucrose triacylglycerol, or fat testosterone, a steroid hormone

cellulose, a plant cell wall component

Which type of protein shields a newly forming protein from cytoplasmic influences while it is folding into its functional form? (eText Concept 5.4) enzymes receptor proteins chaperonins fibrous proteins antibodies

chaperonins

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 __________. (eText Concept 5.2) collagen chitin cellulose palmitic acid 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. (eText Concept 5.1) peptide ionic covalent van der Waals hydrogen

covalent

What is the process by which monomers are linked together to form polymers? (eText Concept 5.1) protein formation coiling hydrolysis monomerization dehydration reaction

dehydration reaction

Carbohydrates are used in our bodies mainly for __________. (eText Concept 5.2) lipid storage structural molecules, such as hair and fingernails membrane construction building genetic material energy storage and release

energy storage and release

Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by __________. (eText Concept 5.3) glycosidic linkages phosphodiester linkages ionic bonds peptide bonds ester linkages

ester linkages

In what polysaccharide form do plants store glucose to be available later as an energy source? (eText Concept 5.2) glycogen fatty acids starch protein cellulose

fatty acids

Which of the following carbohydrate molecules has the lowest molecular mass? (eText Concept 5.2) lactose sucrose chitin glucose cellulose

glucose

A polysaccharide that is used for storing energy in human muscle and liver cells is __________. (eText Concept 5.2) glycogen starch glucose chitin cellulose

glycogen

The subunits (monomers) in cellulose are linked together by __________. (eText Concept 5.2) ester linkages glycosidic linkages peptide bonds phosphodiester linkages ionic bonds

glycosidic linkages

Which of the following terms can be correctly used to describe compounds that do NOT mix with water? (eText Concept 5.3) hydrophilic phospholipids proteins hydrophobic hydrogen-bonded

hydrophobic

The fatty acid tails of a phospholipid are __________ because they __________. (eText Concept 5.3) hydrophobic ... dissolve easily in water hydrophilic ... consist of units assembled by dehydration reactions hydrophobic ... have no charges to which water molecules can adhere 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

The sex hormones estradiol and testosterone belong to which class of molecules? (eText Concept 5.3) proteins lipids amino acids carbohydrates nucleic acids

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? (eText Concept 5.2) They have to eat a lot of grass. The flat teeth and strong stomach of herbivores break the cellulose fibers so that the cows get enough nutrition from the cell contents. Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units. Cows and other herbivores are exceptions and make some cellulose-digesting enzymes. All of the listed responses are correct.

microorganisms in their digestive tract hydrolyze the cellulose to individual glucose units

What is a distinguishing feature of most naturally occurring unsaturated fats? (eText Concept 5.3) Most unsaturated fats have trans double bonds, causing a kink in the hydrocarbon chain wherever they occur. Nearly all naturally occurring unsaturated fats have cis double bonds. All organisms share an equal ratio of saturated and unsaturated fatty acids. They all share four fused rings as a carbon skeleton. They are distinguished from other lipid forms by their chief role as components of cell membranes.

nearly all naturally occurring unsaturated fats have cis double bonds

Which of the following represents a specific description of a polypeptide? (eText Concept 5.4) organic monomers covalently bonded carbohydrates with a hydrogen bond holding them together amino acids linked by hydrolysis organic molecules linked by dehydration reactions None of the listed responses is correct.

none

Which of the following is the major energy storage compound of plant seeds? (eText Concept 5.3) amylose cellulose glycogen oils lipids

oils

The lipids that form the main structural component of cell membranes are __________. (eText Concept 5.3) triacylglycerols cholesterol phospholipids carbohydrates proteins

phospholipids

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

primary

Cellulose is a __________ made of many __________. (eText Concept 5.2) polypeptide ... monomers protein ... amino acids carbohydrate ... fatty acids polymer ... glucose molecules lipid ... triacylglycerols

protein...amino acids

The α helix and β pleated sheet represent which level of protein structure? (eText Concept 5.4) secondary structure tertiary structure pentiary structure primary structure quaternary structure

secondary structure

The polysaccharide that you are most likely to have eaten recently is __________. (eText Concept 5.2) glucose chitin ribose lactose starch

starch

Carbohydrates can function in which of the following ways? (eText Concept 5.2) information storage enzymatic catalysis energy storage structural support structural support and energy storage

structural support and energy storage

The overall three-dimensional shape of a single polypeptide is called its __________. (eText Concept 5.4) secondary structure quaternary structure tertiary structure double helix primary structure

tertiary structure

In a 1-4 glycosidic linkage, __________. (eText Concept 5.2) the number 1 carbon in one nucleotide is bound to the number 4 carbon in another nucleotide there are four possible isomers of the structure the number 1 carbon in one monosaccharide is bound to the number 4 carbon in another monosaccharide one monosaccharide is bound to four others one glycerol molecule is bound to four fatty acids

the number 1 carbon in one monosaccharide is bound to the number 4 carbon in another monosaccharide

The "primary structure" of a protein refers to __________. (eText Concept 5.4) the weak aggregation of two or more polypeptide chains into one functional macromolecule coiling due to hydrogen bonding between amino acids the sequence of amino acids along a polypeptide chain interactions among the side chains or R groups of the amino acids the α helix or β pleated sheets

the sequence of amino acids along a polypeptide chain

Which of the following are pyrimidines found in the nucleic acid DNA? (eText Concept 5.5) adenine and guanine thymine and adenine thymine and cytosine guanine and cytosine uracil and guanine

thymine and cytosine

Which of the following lists ranks these molecules in the correct order by size from smallest to largest? (eText Concept 5.4) glucose, water, sucrose, protein protein, water, glucose, sucrose water, protein, sucrose, glucose water, sucrose, glucose, protein water, glucose, sucrose, protein

water, glucose, sucrose, protein