STUDY QUESTIONS
BIOCHEMISTRY
1. The “backbone” of nucleic acid molecules is made of
phosphate groups.
c. purines.
d. pyrimidines.
a. nitrogenous bases. b. alternating sugars and
e. nucleosides.
2. What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell
membrane? a. Cysteine
b. Hydrophobic
c. Hydrophilic
d. Charged
e. Polar, but not
charged
3. Sucrose is a a. hexose.
b. lipid.
c. disaccharide.
4. DNA and RNA contain
a. pentoses.
b. hexoses.
5. The 20 different common amino acids have different
d. peptide linkages. e. primary structures.
d. glucose.
c. fructoses.
e. simple sugar.
d. maltoses.
a. amino groups.
e. amyloses.
b. R groups.
6. The primary structure of a protein is determined by its
a. disulfide bridges.
c. sequence of amino acids. d. branching. e. three-dimensional structure.
c. acid groups.
b. a helix structure.
7. When a protein loses its three-dimensional structure and becomes nonfunctional, it is
a. permanent.
b. reversible.
c. denatured.
d. hydrolyzed.
e. environmentalized.
8. A β pleated sheet organization in a polypeptide chain is an example of _______ structure.
a. primary
b. secondary c. tertiary
d. quaternary
e. coiled
9. A protein can best be defined as a polymer
a. of amino acids.
b. containing one or more
polypeptide chains. c. containing 20 amino acids.
d. containing 20 peptide linkages.
e. containing
double helices.
10. The four nitrogenous bases of RNA are abbreviated as
a. A, G, C, and T.
b. A, G, T, and N.
c. G, C, U, and N.
d. A, G, U, and T.
11. Polysaccharides, polypeptides, and polynucleotides all a. contain simple sugars.
condensation (dehydration synthesis) reactions.
c. are found in cell membranes.
e. have molecular weights less than 30,000 daltons.
e. A, G, C, and U.
b. are formed in
d. contain nitrogen.
12. DNA carries genetic information in its
a. helical form.
b. sequence of bases.
c. tertiary sequence.
d. sequence of amino acids.
e. phosphate groups.
13. A molecule often spoken of as having a head and tail is a(n)
c. RNA.
d. steroid.
e. triglyceride.
a. phospholipid.
14. A molecule that has an important role in long-term storage of energy is
c. glycogen. d. an amino acid.
e. hexose.
b. oligosaccharide.
a. a steroid.
b. RNA.
15. A type of molecule very often drawn with a single six-sided ring structure is a. sucrose. b. an amino acid.
c. glucose.
d. a fatty acid.
e. a steroid.
16. Starch and glycogen are different in that only one of them
a. is a polymer of glucose. b. contains ribose.
c. is made in plants.
e. can be digested by humans.
d. is an energy storage molecule.
17. Enzymes are
a. DNA.
b. lipids.
c. carbohydrates.
d. proteins.
e. amino acids.
18. The type of bond that holds two amino acids together in a polypeptide chain is a(n)
a. ionic bond.
b. disulfide bridge. c. hydrogen bond.
d. peptide bond.
e. dehydration bond.
19. Peptides have _______ and _______ end.
a. a start; a stop
b. a +; a –
c. an N terminus; a C terminus
e. an A; a Z
d. a 5’; a 3’
20. Quaternary structure is found in proteins
a. composed of subunits.
b. of membranes.
c. of the quadruple complex.
d. that change over time.
e. None of the above
21. A fat contains fatty acids and
e. None of the above
a. glycerol.
b. a base.
c. an amino acid.
d. a phosphate.
22. There are _______ different types of tripeptides (molecules with three amino acids linked together) that can
exist using the 20 common amino acids.
a. 3
b. 20
c. 60
d. 900
e. 8,000
23. A type of protein that functions by helping other proteins to fold correctly is called
a. foldzyme. b. renaturing protein.
c. chaperonin.
d. hemoglobin.
e. denaturing protein.
24. Why does bread become hard and stale?
a. Cellulose molecules aggregate in the absence of water. b. In the absence of water, unbranched starch forms
hydrogen bonds between polysaccharides, which then aggregate. c. The release of carbon dioxide causes the
bread to harden.
d. Water and heat cause the polysaccharide chains to bind together.
e. Mold
growth interferes with alpha linkages, causing the bread to harden.
25. Incorrect folding of a protein can have serious consequences. For instance, an accumulation of misfolded
proteins in the brain is a characteristic of
a. rickets.
b. Alzheimer’s disease.
c. hemophilia. d. excessively dry skin.
e. night blindness.
26. It is important to know the exact shape of a protein because the knowledge allows scientists to
a. create specific proteins to block the action of another protein.
b. create multi-protein machines to synthesize RNA.
c. synthesize antibodies that kill viruses.
d. predict whether the protein will form an a or b chain.
e. predict the energy required to break the protein’s bonds.
27. Spontaneous generation was disproved by
a. Miller.
b. Urey.
c. Redi and Pasteur.
d. Allan Hills.
e. van der Waal.
28. RNA molecules that act as catalysts are called
a. ribozymes. b. proteases. c. chaperonins.
d. disulfide bridges.
e. triglycerides.
29. Which of the following is not a carbohydrate?
e. Deoxyribose
a. Glucose
b. Starch
c. Cellulose
d. Hemoglobin
30. Which of the following statements about the primary structure of a protein is not true?
a. It may be branched.
b. It is determined by the structure of the corresponding DNA.
c. It is unique
to that protein.
d. It determines the tertiary structure of the protein.
e. It is the sequence of amino
acids in the protein.
31. All nucleic acids a. are polymers of nucleotides.
b. are polymers of amino acids.
stranded.
d. are double-helical.
e. contain deoxyribose.
c. are double-
32.Which of the following is not true of lipids?
a.They are insoluble in water.
b.They contain polar
covalent bonds.
c.They can store energy.
d.They can act as electrical insulation.
e.They can act as thermal insulation in animals.
33. Carbohydrates such as starch, glycogen and cellulose are
a.disaccharides.
b.monosaccharides.
c.polysaccharides.
d.oligosaccharides.
e.None of the above
34. Polysaccharides, polypeptides, and nucleic acids
a.are formed from condensation
(dehydration synthesis) reactions.
b.are small biomolecules.
c.are primarily composed of fatty
acids.
d.all contain nitrogen.
e.are all insoluble in water.
35. The primary structure of a protein is determined by its
a.disulfide bridges. b.helix structures.
c.order of amino acids
e.three-dimensional nature.
d.degree of branching.
36. All of the following elements are present in DNA except
a.oxygen.
b.nitrogen.
c.carbon.
d.sulfur.
e.phosphorus.
37. What are the components of fats and oils?
a. Three fatty acids and one glycerol
b. Amino acids
d. Three fatty acids, one glycerol, and a nitrogenous base
long alcohol
c. Phosphate group and a glycerol
e. One very long fatty acid and one very