Biology Chapter 5

If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain?

75

Which of the following statements about the formation of polypeptides from amino acids is true?

A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.

The peptide bond is (?)

A covalent bond joining amino acids together to form a polypeptide

The components of nucleic acids are (?)

A nitrogenous base, a pentose sugar, and a phosphate

Carbohydrates, more commonly known as sugars, are made up of carbon, oxygen, and hydrogen atoms. The smallest unit of a carbohydrate is a monosaccharide. Two monosaccharides make up a disaccharide, and many monosaccharides make up a polysaccharide. Disaccharides and polysaccharides can be hydrolyzed back into the individual monosaccharide units. Select the statement that is incorrect.

All carbohydrates have the general formula Cn(H2O)n.

Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?

Alzheimer's and Parkinson's only

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

C18H32O16

A simple sugar is composed of equal parts carbon and water, which gave rise to the general name of any sugar as a (?)

Carbohydrate

Which part of an amino acid is always acidic?

Carboxyl functional group

What does the term insoluble fiber refer to on food packages?

Cellulose

Which of the following is a polymer?

Cellulose, a plant cell wall component

The molecule with four fused rings that is found in animal membranes and is the precursor of vertebrate sex hormones is

Cholesterol

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.

Covalent

A shortage of phosphorus in the soil would make it especially difficult for a plant to manufacture (?)

DNA

Which of the following statements best summarizes the differences between DNA and RNA?

DNA nucleotides contain a different sugar than RNA nucleotides

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart

Lactose, the sugar in milk, is a (?) because it can be split into two monosaccharides.

Disaccharide

Carbohydrates are used in our bodies mainly for

Energy Storage and Release

The secondary structure of a protein results from (?)

Hydrogen bonds

The two strands of a DNA double helix are held together by (?) that form between pairs of nitrogenous bases.

Hydrogen bonds

Which is the term for compounds that do not mix with water?

Hyrdophobic

The sex hormones estrogen, progesterone, and testosterone belong to which class of molecules?

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?

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

The proper three-dimensional shape and folding of a protein is assisted by (?)

Molecules called Chaperonins

A (?) cannot be hydrolyzed any further.

Monosaccharide

Which monomers make up RNA?

Nucleotides

Which of these is rich in unsaturated fats?

Olive oil

(?) structure describes the alpha-helices and beta-sheets that are formed by hydrogen bonding between backbone atoms located near each other in the polypeptide chain.

Secondary

The molecule shown the accompanying figure is a

Steroid

Sugars are molecules that have (?) C:H:O and are called (?)

a 1:2:1 ratio of; carbohydrates

Sugars have a(n) (?) group that interacts with a (?) group that forms ring structures when the dry molecule is placed in water.

carbonyl (-C=O); hydroxyl (-OH)

When comparing saturated and naturally occurring unsaturated fats, the unsaturated fats have (?) and are (?) at room temperature.

cis double bonds; liquids

Identify three possible components of a DNA nucleotide.

deoxyribose, phosphate group, thymine

In living organisms, DNA exists as a (?) with the strand(s) (?)

double helix; running antiparallel

One of the primary functions of RNA molecules is to

function in the synthesis of proteins

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are in the α form. Which of the following could amylase break down?

glycogen, starch, and amylopectin

The secondary structure of a peptide backbone is stabilized by (?) forming either a(n) (?) or a(n) (?)

hydrogen bonds; α helix; β pleated sheet

Protein molecules are polymers (chains) of (?)

Amino Acid molecules

A polysaccharide that is used for storing energy in human muscle and liver cells is (?)

Glycogen

Which one of the following is NOT a component of each monomer used to make proteins?

A phosphorus atom, P

Proteins are polymers of (?)

Amino acids

Which of the following is not attached to the central carbon atom in an amino acid?

An oxygen

Lipids

Are made from glycerol, fatty acids, and nitrogen

Steroids are considered to be lipids because they

Are not soluble in water

Starch and cellulose (?)

Are polymers of glucose

A function of cholesterol that does not harm health is its role (?)

As a component of animal cell membranes

The subunits (monomers) in cellulose are linked together by (?)

Glycosidic linkages

The tertiary structure of a protein includes all of the following interactions except (?) bonds.

Peptide

What type of bond joins the monomers in a protein's primary structure?

Peptide

Tertiary structure is NOT directly dependent on (?)

Peptide bonds

A nucleotide is composed of a(n) (?)

Phosphate group, a nitrogen-containing base, and a five-carbon sugar

The lipids that form the main structural component of cell membranes are (?)

Phospholipids

A carbohydrate that yields many monosaccharides when hydrolyzed is a (?)

Polysaccharide

(?) structure is the sequence of amino acids in a protein.

Primary

The sequence of amino acids in a protein is called the (?) structure of the protein.

Primary

Which polymers are composed of amino acids?

Proteins

(?) structure is the result of two or more protein subunits assembling to form a larger, biologically active protein complex.

Quaternary

(?) structure is achieved when a protein folds into a compact, three-dimensional shape stabilized by interactions between side-chain R groups of amino acids.

Tertiary

In a dehydration synthesis reaction, (?) is always formed as a by-product of the reaction.

Water

Sickle-cell anemia is a disease that is caused by (?) in the (?) of the protein.

A single amino acid change; primary structure

Nitrogenous bases are classified as either purines or pyrimidines. Examples of purines are (?)

Adenine and Guanine

All of the following contain amino acids EXCEPT

Cholesterol

(?) is always involved in hydrolysis reactions.

Water

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

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 (?)

Chitin

Which of the following is NOT a polymer?

Glucose

One characteristic shared by sucrose, lactose, and maltose is that (?)

They are all disaccharides

Macromolecules, the molecules of life, include all of the following except (?)

Trace elements

True or false? Enzymes in the digestive tract catalyze hydrolysis reactions.

True

Which of these is NOT a lipid?

RNA