Biology, Chapter 5

Which of the following components of a tossed salad will pass through the human digestive tract and be digested the least? A. cellulose (in the lettuce) B. oil (in the dressing) C. sugar (in the dressing) D. protein (in the bacon bits) E. starch (in the croutons)

A

Which of the following is true regarding complementary base pairing in DNA and RNA molecules? A. 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. B. 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. C. Complementary base pairing promotes an antiparallel orientation in the structure of DNA and RNA molecules. D. Complementary base pairing within single strands of DNA and RNA gives them particular three-dimensional structures that are necessary for their function. E. None of the listed responses is correct.

A

In a hydrolysis reaction ______ and in this process water is ____

A polymer is broken up into its constitute monomers.... consumed

Based on complementary base pairing, you would expect the percentage of __________ to be equal to the percentage of __________.

Adenine, Thymine

What do Alzheimer's, Parkinson's, and mad cow disease have in common?

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

Which of the following carbohydrate molecules has the lowest molecular mass A. Cellulose B. Glucose C. Sucrose D. Lactose E. Chitin

B

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 __________.

Chitin

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

The type of bond that joins to form monomers into polymers is a _____ bond

Covalent

Which of the following lists ranks these molecules in the correct order by size from smallest to largest? A. protein, water, glucose, sucrose B. water, protein, sucrose, glucose C. water, sucrose, glucose, protein D. water, glucose, sucrose, protein E. glucose, water, sucrose, protein

D

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture __________.

DNA

What is the process by which monomers are linked together to form polymers?

Dehydration Reaction

When a protein is denatured, why does it lose its functionality?

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.

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

E

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

E

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

E

Which of the following molecules is a monosaccharide? A. C51H98O6 B. C25H43O8 C. C45H84O8PN D. C22H49O10N5 E. C6H12O6

E

Which of the following represents a specific description of a polypeptide? A. organic molecules linked by dehydration reactions B. organic monomers covalently bonded C. amino acids linked by hydrolysis D. carbohydrates with a hydrogen bond holding them together E. None of the listed responses is correct.

E

Carbohydrates can function in which of the following ways? A. Energy storage B. Structural support C. Enzymatic Catalyst D. Information storage E. Structural support and Energy storage

E.

Which of the following is a polymer? A. Testosterone, a steroid hormone B. Triacylglycerols, or fat C. Glucose, an energy rich molecule D. Fructose, a component of Sucrose E. Cellulose, a plant cell wall component

E.

Carbohydrates are used in our bodies mainly for __________.

Energy Storage and release

Nutritionally, saturated triacylglycerols are considered to be less healthful than unsaturated triacylglycerols. What is the difference between them?

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

Term describing a compound that does not mix with water

Hydrophobic

Generally, animals cannot digest (hydrolyze) the glycosidic linkages between the glucose molecules in cellulose. How then do cows get enough nutrients from eating grass?

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

What is a distinguishing feature of most naturally occurring unsaturated fats?

Nearly all naturally occurring unsaturated fats have cis double bonds.

Which of the following is a true statement comparing phospholipids and triacylglycerols

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

The polysaccharide that you are most likely to have eaten recently is __________.

Starch

Amylase is an enzyme that breaks down starch. Why cannot the same enzyme break down cellulose?

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

One characteristic shared by sucrose, lactose, and maltose is that __________.

They are all disaccharides

Which of the following are pyrimidines found in the nucleic acid DNA?

Thymine and Cytosine

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 __________.

a charged or polar end and an uncharged or nonpolar end

The peptide bond is __________.

a covalent bond joining amino acids together to form a polypeptide

A glucose molecule is to starch as _________ is to _______

a nucleotide is to a nucleic acid

Manufacturers make vegetable oils solid or semisolid at room temperature by __________.

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

Protein molecules are polymers (chains) of __________.

amino acid molecules

Lipids differ from other large biological molecules in that they __________.

are not truly polymers

Which type of protein shields a newly forming protein from cytoplasmic influences while it is folding into its functional form?

chaperonins

Some lipids are formed when fatty acids are linked to glycerol. These subunits are linked together by __________.

ester linkages

A polysaccharide that is used for storing energy in human muscle and liver cells is __________.

glycogen

The subunits (monomers) in cellulose are linked together by __________.

glycosidic linkages

The fatty acid tails of a phospholipid are __________ because they __________.

hydrophobic, have no charges to which water molecules can adhere

The sex hormones estradiol and testosterone belong to which class of molecules?

lipids

What is the major energy storage compound of plant seeds

oils

The lipids that form the main structural component of cell membranes are __________.

phospholipids

Cellulose is a ____ made of many____

polymer, glucose molecules

The α helix and β pleated sheet represent which level of protein structure?

secondary structure

In what polysaccharide form do plants store glucose to be available later as an energy source?

starch

examples of polymers include

starches and proteins

examples of monomers include

sugars and amino acids

The overall three-dimensional shape of a single polypeptide is called its __________.

tertiary structure

In a 1-4 glycosidic linkage, __________.

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 __________.

the sequence of amino acids along a polypeptide chain