AP UNIT 1B BIOCHEMISTRY

Multiple Choice
Identify the choice that best completes the statement or answers the question.

Organic chemistry is a science based on the study of

a.	functional groups.
b.	vital forces interacting with matter.
c.	carbon compounds.
d.	water and its interaction with other kinds of molecules.
e.	inorganic compounds.

How many electron pairs does carbon share in order to complete its valence shell?

a.	1
b.	2
c.	3
d.	4
e.	8

What type(s) of bond(s) does carbon have a tendency to form?

a.	ionic
b.	hydrogen
c.	covalent
d.	A and B only
e.	A, B, and C

What is the reason why hydrocarbons are not soluble in water?

a.	The majority of their bonds are polar covalent carbon to hydrogen linkages.
b.	The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
c.	They are hydrophilic.
d.	They exhibit considerable molecular complexity and diversity.
e.	They are lighter than water.

The two molecules shown in the following figure are best described as

a.	optical isomers.
b.	radioactive isotopes.
c.	structural isomers.
d.	nonradioactive isotopes.
e.	geometric isomers.

The two molecules shown in the following figure are best described as

a.	enantiomers.
b.	radioactive isotopes.
c.	structural isomers.
d.	nonisotopic isomers.
e.	geometric isomers.

Research suggests that side effects from Ritalin, the drug used to treat attention deficit disorder, may be caused by contamination of enantiomers, or molecules that

a.	have identical three-dimensional shapes.
b.	are mirror images of one another.
c.	lack an asymmetric carbon.
d.	differ in the location of their double bonds.
e.	differ in their electrical charge.

Which is the best description of a carbonyl group?

a.	an oxygen joined to a carbon by a single covalent bond
b.	a nitrogen and two hydrogens joined to a carbon by covalent bonds
c.	a carbon joined to two hydrogens by single covalent bonds
d.	a sulfur and a hydrogen joined to a carbon by covalent bonds
e.	a carbon atom joined to an oxygen by a double covalent bond

What is the name of the functional group shown in the following figure?

a.	carbonyl
b.	ketone
c.	aldehyde
d.	carboxyl
e.	hydroxyl

Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen?

a.	an alcohol such as ethanol
b.	a monosaccharide such as glucose
c.	a steroid such as testosterone
d.	an amino acid such as glycine
e.	a hydrocarbon such as benzene

Which two functional groups are always found in amino acids?

a.	ketone and aldehyde
b.	carbonyl and carboxyl
c.	carboxyl and amino
d.	phosphate and sulfhydryl
e.	hydroxyl and aldehyde

A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?

a.	carboxyl
b.	sulfhydryl
c.	hydroxyl
d.	amino
e.	phosphate

Use the figure below to answer the following questions.

Which is a hydroxyl functional group?

a.	Group A
b.	Group B
c.	Group C
d.	Group D
e.	Group E

Which is an amino functional group?

a.	Group A
b.	Group B
c.	Group C
d.	Group D
e.	Group E

Which is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules?

a.	Group A
b.	Group B
c.	Group C
d.	Group D
e.	Group E

Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by which process?

a.	connecting monosaccharides together (condensation reactions)
b.	the addition of water to each monomer (hydrolysis)
c.	the removal of water (dehydration reactions)
d.	ionic bonding of the monomers
e.	the formation of disulfide bridges between monomers

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

a.	Dehydration reactions assemble polymers, and hydrolysis breaks down polymers.
b.	Hydrolysis only occurs in the urinary system, and dehydration reactions only occur in the digestive tract.
c.	Dehydration reactions can occur only after hydrolysis.
d.	Hydrolysis creates monomers, and dehydration reactions break down polymers.
e.	A and C are correct.

If 128 molecules of the general type shown in the figure below were covalently joined together in sequence, the single molecule that would result would be a

a.	polysaccharide.
b.	polypeptide.
c.	polyunsaturated lipid.
d.	monosaccharide.
e.	disaccharide.

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?

a.	as a pentose
b.	as a hexose
c.	as a monosaccharide
d.	as a disaccharide
e.	as a polysaccharide

Which of the following is true of both starch and cellulose?

a.	They are both polymers of glucose.
b.	They are geometric isomers of each other.
c.	They can both be digested by humans.
d.	They are both used for energy storage in plants.
e.	They are both structural components of the plant cell wall.

Which of the following is true of cellulose?

a.	It is a polymer composed of sucrose monomers.
b.	It is a storage polysaccharide for energy in plant cells.
c.	It is a storage polysaccharide for energy in animal cells.
d.	It is a major structural component of plant cell walls.
e.	It is a major structural component of animal cell plasma membranes.

Triacylglycerol is a

a.	protein with tertiary structure.
b.	lipid made with three fatty acids and glycerol.
c.	lipid that makes up much of the plasma membrane.
d.	molecule formed from three alcohols by dehydration reactions.
e.	carbohydrate with three sugars joined together by glycosidic linkages.

What is the molecule illustrated in the figure below?

a.	a saturated fatty acid
b.	an unsaturated fatty acid
c.	a polyunsaturated triacylglyceride
d.	a trans polyunsaturated triacylglyceride
e.	a steroid similar to cholesterol

The molecule shown in the figure below is a

a.	polysaccharide.
b.	polypeptide.
c.	saturated fatty acid.
d.	triacylglycerol.
e.	unsaturated fatty acid.

A polypeptide can best be described as a

a.	monomer of a protein polymer.
b.	polymer containing 20 amino acid molecules.
c.	polymer containing 19 peptide bonds.
d.	polymer containing 20 peptide bonds.
e.	polymer of amino acids.

The chemical reaction illustrated in the figure below results in the formation of a (an)

a.	ionic bond.
b.	peptide bond.
c.	glycosidic linkage.
d.	ester linkage.
e.	phosphodiester linkage.

Which bonds are created during the formation of the primary structure of a protein?

a.	peptide bonds
b.	hydrogen bonds
c.	disulfide bonds
d.	phosphodiester bonds
e.	A, B, and C

What maintains the secondary structure of a protein?

a.	peptide bonds
b.	hydrogen bonds
c.	disulfide bonds
d.	ionic bonds
e.	phosphodiester bonds

The figure below shows the

a.	1-4 linkage of the glucose monomers of starch.
b.	1-4 linkage of the glucose monomers of cellulose.
c.	double helical structure of a DNA molecule.
d.	helix secondary structure of a polypeptide.
e.	pleated sheet secondary structure of a polypeptide.

Altering which of the following levels of structural organization could change the function of a protein?

a.	primary
b.	secondary
c.	tertiary
d.	quaternary
e.	all of the above

Which of the following descriptions best fits the class of molecules known as nucleotides?

a.	a nitrogenous base and a phosphate group
b.	a nitrogenous base and a pentose sugar
c.	a nitrogenous base, a phosphate group, and a pentose sugar
d.	a phosphate group and an adenine or uracil
e.	a pentose sugar and a purine or pyrimidine

All of the following nitrogenous bases are found in DNA except

a.	thymine.
b.	adenine.
c.	uracil.
d.	guanine.
e.	cytosine.

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

a.	RNA is a protein, whereas DNA is a nucleic acid.
b.	DNA is a protein, whereas RNA is a nucleic acid.
c.	DNA nucleotides contain a different sugar than RNA nucleotides.
d.	RNA is a double helix, but DNA is single-stranded.
e.	A and D are correct.