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.:
A. Complex sugars are carbohydrates.
B. All carbohydrates have the general formula Cn(H2O)n.
C. Simple sugars are carbohydrates.
D. Simple sugars contain only carbon, oxygen, and hydrogen atoms.
B. All carbohydrates have the general formula Cn(H2O)n.
Glycogen is _____.
A. a polysaccharide found in plant cell walls
B. a transport protein that carries oxygena source of saturated fat
C. a polysaccharide found in animals the form in which plants store sugars
D. a source of saturated fat
E. the form in which plants store sugars
C. a polysaccharide found in animals the form in which plants store sugars
Which of these is a polysaccharide?
A. glucose
B. sucrose
C. lactose
D. galactose
E. cellulose
E. cellulose
Which of these is NOT a lipid?
A.phospholipid
B.RNA
C.cholesterol
D.steroids
E.wax
B.RNA
A function of cholesterol that does not harm health is its role _____.
A. as a component of animal cell membranes
B. All of cholesterol's effects cause the body harm.
C. as the primary female sex hormone
D. the most abundant male sex hormone
E. in calcium and phosphate metabolism
A. as a component of animal cell membranes
Which polymers are composed of amino acids?
A. Nucleic acids
B. Carbohydrates
C. Proteins
D. Monomers
C . proteins
Which of the following is not attached to the central carbon atom in an amino acid?
A. An oxygen
B. A side chain ("R group")
C. An amino functional group
D. A carboxyl functional group
A. An oxygen
Which monomers make up RNA?
A. Polymers
B. Nucleotides
C. Simple sugars
D. Amino acids
B. Nucleotides
Which of the following statements about the formation of polypeptides from amino acids is true?
A. A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
B. Polypeptides form by condensation or hydrolysis reactions.
C. The reaction occurs through the addition of a water molecule to the amino acids.
D. A bond can form between any carbon and nitrogen atom in the two amino acids being joined.
A. A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid.
The organic molecule called DNA is an example of ....
A. a polymer made of amino acids.
B. a polymer made of nucleotes.
C. a polymer made of nucleotides.
D. a protein.
E. a monomer.
C. a polymer made of nucleotides.
Which molecule is not a carbohydrate?
A. Lipid
B. Starch
C. Glycogen
D. Cellulose
A. Lipid
Which of the following statements about monosaccharide structure is true?
A. All monosaccharides contain carbon, hydrogen, oxygen, and nitrogen atoms.
B. Aldoses and ketoses differ in the position of their hydroxyl groups.
C. A six-carbon sugar is called a pentose.
D. Monosaccharides can be classified according to the spatial arrangement of their atoms.
D. Monosaccharides can be classified according to the spatial arrangement of their atoms.
Which of the following complex carbohydrates is listed with its correct function?
A. Cellulose: structural component of plant cell walls
B. Chitin: constituent of bacterial cell walls
C. Starch: primary energy-storage molecule in animals
D. Amylose: main component of plant starch
A. Cellulose: structural component of plant cell walls
Which polysaccharide contains a modified monosaccharide?
A. Peptidoglycan
B. Glycogen
C. Starch
D. Cellulose
A. Peptidoglycan
Polymers that contain sugars ...
A. (a) may store hereditary information.
B. (b) may store energy.
C. (c) may protect cells.Both
D. (b) and (c).
E. (a), (b), and (c).
E. (a), (b), and (c).
Which statement is true of sucrose?
(a) It's a disaccharide.
(b) It contains glucose.
(c) It's table sugar
.Both (a) and (c)
.(a), (b), and (c).
.(a), (b), and (c).
Dr. Haxton told one of his students, "To move in the bloodstream, fats need the help of phospholipids." What would a good student say?
A. Yes. Nonpolar molecules aren't compatible with water.
B. Sorry, Dr. Haxton! Help comes from cholesterol, not phospholipids
C. Not so. Fats are small enough to travel easily without help.
D. You have it backwards. Fats help phospholipids to travel
E. Right. Fats are too polar to travel alone in water.
A. Yes. Nonpolar molecules aren't compatible with water.
The presence of many C-C and C-H bonds causes fats to be ...
(a) rich in energy.
(b) insoluble in water.
(c) low in energy.
Both (a) and (b).
Both (b) and (c).
Both (a) and (b).
In fat synthesis,________and fatty acids combine to make fats plus________.
A. phosphate; glycerol
B. glucose; phosphate
C. esters; water
D. glycerol;water
E. esters; phosphate
D. glycerol; water
In the reaction that builds a fat,________ groups react with ________ groups.
A. sulfhydryl; carboxyl
B. hydroxyl; phosphate
C. phosphate; amino
D. hydroxyl; carboxyl
E. carboxyl; amino
D. hydroxyl; carboxyl
Triglycerides vary with respect to the number of ...
(a) hydrocarbon tails.
(b) C atoms in the tails.
(c) double bonds in the tails.
Both (b) and (c).
All of the above.
Both (b) and (c).
A food company hydrogenated a barrel of fat. The treatment ...
(a) made the fat less fluid.
(b) made the fat less saturated.
(c) lengthened the fat tails.
(d) put more bends (kinks) in the fat tails.
Both (a) and (d).
(a) made the fat less fluid.
The most unsaturated fats have ...
A. the longest hydrocarbon tails.
B. the fewest double bonds.
C. the most double bonds.
D. the highest ratio of H to C.
E. the shortest hydrocarbon tails.
C. the most double bonds.
What do DNA, proteins, and fats have in common?
A. They contain nitrogen.
B. They are polymers.
C. They are polar.
D. They contain phosphorus.
E. They contain carbonyl groups.
E. They contain carbonyl groups.
Phospholipids are most important for ...
preventing leakage from cells.
To find the best source of phospholipids, look at ...
A. cell walls.
B. nasal mucus.
C. membranes.
D. surfaces of leaves.
E. storage droplets.
C. membranes.
What do phosphoglycerides and fats have in common?
A. A strongly polar group.
B. A tendency to form bilayers.
C. Ester linkages.
D. A role in membrane structure.
E. Three fatty acid tails.
C. Ester linkages.
Which statement is true of phospholipids?
(a) Their synthesis uses fatty acids.
(b) Some of their tails have double bonds.
(c) They all ionize.
All the above.
Both (a) and (b).
All the above.
Which fact is most important in causing phospholipids to behave as they do in water?
A. Hydrocarbons attract one another.
B. Nonpolar groups repel water
C. Phosphate groups can bind together.
D. Hydrogen is more electronegative than oxygen.
E. Water molecules make hydrogen bonds.
E. Water molecules make hydrogen bonds.
In a membrane, the________of the phospholipids in one monolayer face the________of the phospholipids in the other monolayer.
(c) tails; tails
It is difficult for molecules to pass through the phospholipid bilayer because ...
A. hydrocarbons repel water.
B. polar molecules attract one another.
C. proteins hold phospholipids in place.
D. cholesterol holds phospholipids in place.
E. there is a water film between the monolayers.
polar molecules attract one another.
Which lipid is most amphipathic?
Phospholipid
What does cholesterol have in common with sex hormones?
Four linked rings.
Strong polarity
.Fatty acids.
Causes heart disease.
Ester linkages.
Four linked rings.
Proteins are polymers of _____.
A. nucleotides
B. CH2O units
C. glycerol
D. hydrocarbons
E. amino acids
E. amino acids
What type of bond joins the monomers in a protein's primary structure?
A. ionic
B. peptide
C. S - S
D. hydrophobic
E. hydrogen
peptide
The secondary structure of a protein results from _____.
A. hydrophobic interactions
B. hydrogen bonds
C. ionic bonds
D. peptide bonds
E. bonds between sulfur atoms
B. hydrogen bonds
Tertiary structure is NOT directly dependent on _____.
A. bonds between sulfur atoms
B. hydrophobic interactions
C. hydrogen bonds
D. peptide bonds
E. ionic bonds
D. peptide bonds
Which biological activity does NOT directly involve proteins?
A. Changing the shape of a cell.
B. Defending cells against viruses.
C. Breaking food polymers into smaller molecules.
D. Sensing light.
E. None of the above; proteins are involved in all of them.
E. None of the above; proteins are involved in all of them.
A major limitation of the ribbon model of a protein is:
(a) It's hard to see how the backbone folds.
(b) It can't show the orientation of key side chains.
(c) It gives a false sense of open space in the protein.
Both (a) and (c).
(a), (b), and (c).
(c) It gives a false sense of open space in the protein.
The human myoglobin protein contains 153 amino acids. If you take one guess at the amino acid sequence, what is your chance of being right?
One chance in 20x153.
One chance in 153.
One chance in 15320.
One chance in 18153.
One chance in 20153.
One chance in 20153.
A biochemist modified a protein so the amino acid lysine occurred where the amino acid aspartic acid previously occurred. This change could ...
a) alter the protein's secondary structure without affecting the primary structure.
(b) alter the protein's tertiary structure.
(c) affect the protein's backbone.
Both (b) and (c).
(a), (b), and (c).
(b) alter the protein's tertiary structure.
Identify the empirical formula of a free amino acid whose side chain is just H.
A. C2H5O2N
B. C2H5ON
C. CH6O2N
D. C2H4O2N
E. NONE OF The ABOVE
A. C2H5O2N
A certain amino acid side chain ionizes at low pH but not at very high pH. What else is true of this side chain?
A. It donates H+ to water at low pH
B. It is acidic.
C. It contains an amino group
D. It is one of 7 kinds of amino acids that share this property.
E. It contains a carboxyl group.
C. It contains an amino group
In a protein, peptide bonds connect ...
C-R to N-H.
C=O to N-H.
N-H to C-H.
C=O to C-R
.All the above.
C=O to N-H.
Amino acids are called "acids" because they ...
contain carboxyl groups in the backbone part.
A residue in the middle of a polypeptide has −CH3 as its side chain or R group. How many atoms does the residue contain?
7
9
10
12
13
10