Mastering Biology 4

Which molecule is not a carbohydrate?
Starch
Cellulose
Glycogen
Lipid

A lipid is a hydrophobic polymer, not a carbohydrate.

Which of the following statements about monosaccharide structure is true?
All monosaccharides contain carbon, hydrogen, oxygen, and nitrogen atoms.
Monosaccharides can be classified according to the spatial arrangement of their atoms.
A six-carbon sugar is called a pentose.
Aldoses and ketoses differ in the position of their hydroxyl groups.

Monosaccharides can be classified according to the spatial arrangement of their atoms.

True or false? Peptidoglycan is a polysaccharide found only in bacteria.

True

Which complex carbohydrate contains only a-1,4-glycosidic linkages?

Amylopectin
Cellulose
Amylose
Glycogen

Amylose

Which of the following complex carbohydrates is listed with its correct function?

Amylose: main component of plant starch
Cellulose: structural component of plant cell walls
Starch: primary energy-storage molecule in animals
Chitin: constituent of bacterial cell walls

Cellulose: structural component of plant cell walls

Which polysaccharide contains a modified monosaccharide?

Peptidoglycan

What is the major structural difference between starch and glycogen?

whether glucose is in the α or β form
the amount of branching that occurs in the molecule
the types of monosaccharide subunits in the molecules
the type of glycosidic linkages in the molecule

the amount of branching that occurs in the molecule

A molecule with the chemical formula C6H12O6 is probably a _____.

nucleic acid
monosaccharide
fatty acid
polysaccharide

monosaccharide

The molecule shown in the accompanying figure is _____.

a hexose
fructose
a pentose
maltose

hexose

Starch and cellulose _____.

are used for energy storage in plants
are structural components of the plant cell wall
are polymers of glucose
are cis-trans isomers of each other

are polymers of glucose

Humans can digest starch but not cellulose because _____.

starch monomers are joined by covalent bonds and cellulose monomers are joined by ionic bonds
humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose
the monomer of starch is fructose, while the monomer of cellulose is glucose
the monomer of starch is glucose, while the monomer of cellulose is galactose

humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose

Which polymers are composed of amino acids?

Carbohydrates
Proteins
Nucleic acids
Monomers

proteins

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

A carboxyl functional group
An oxygen
An amino functional group
A side chain ("R group")

An oxygen

Which part of an amino acid is always acidic?

Side chain ("R group")
Amino functional group
Carboxyl functional group
None of the above

Carboxyl functional group

Which monomers make up RNA?
Polymers
Amino acids
Simple sugars
Nucleotides

Nucleotides

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.
A bond can form between any carbon and nitrogen atom in the two amino acids being joined.
The reaction occurs through the addition of a water molecule to the amino acids.
Polypeptides form by condensation or hydrolysis reactions.

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

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

True

Which statement is true of polymers?

They are often made by a hydrolysis process.
Their synthesis generally consumes water.
They are always made by condensation reactions.
They are always made of monomers.
None of the above.

They are always made of monomers

The organic molecule called DNA is an example of ….

a protein.
a polymer made of amino acids.
a polymer made of nucleotides.
a monomer.
a polymer made of nucleotes.

a polymer made of nucleotides

Glycogen is _____.

a transport protein that carries oxygen
a polysaccharide found in plant cell walls
a source of saturated fat
a polysaccharide found in animals
the form in which plants store sugars

a polysaccharide found in plant cell walls

glucose + glucose —> _____ by _____.

sucrose + water … dehydration synthesis
maltose + water … dehydration synthesis
cellulose + water … hydrolysis
lactose + water … hydrolysis
starch + water … dehydration synthesis

maltose + water … dehydration synthesis

Which of these is a source of lactose?

milk
starch
potatoes
sugar cane
sugar beets

milk

Which of these is a polysaccharide?

cellulose
glucose
lactose
sucrose
galactose

cellulose

_____ is the most abundant organic compound on Earth.

Glycogen
Lactose
Glucose
Starch
Cellulose

cellulose

Sucrose is formed when glucose is joined to fructose by a(n) _____.

phosphodiester linkage
ester linkage
ionic bond
peptide linkage
glycosidic linkage

glycosidic linkage

Plant cell walls consist mainly of _____.

chitin
cellulose
peptidoglycan
chlorophyll
None of the choices is correct.

cellulose

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

amylopectin
polypeptides
starch
cellulose

cellulose

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

as a hexose
as a disaccharide
as a monosaccharide
as a polysaccharide

disaccharide

Polymers that contain sugars …

(a) may store hereditary information.
(b) may store energy.
(c) may protect cells.
Both (b) and (c).
(a), (b), and (c).

a b and c

Select the statement that is incorrect.

Complex sugars are carbohydrates.
All carbohydrates have the general formula Cn(H2O)n.
Simple sugars are carbohydrates.
Simple sugars contain only carbon, oxygen, and hydrogen atoms.

All carbohydrates have the general formula Cn(h20)N