ANSWER QUESTIONS 1-23 (3pts each) ON THE SCANTRON AND QUESTIONS 24-27 ON THE EXAM. TOTAL = 85 pts
1. All biomolecules contain carbon. What properties of carbon make it so versatile? It:
a. forms stable covalent bonds with itself
b. forms stable covalent bonds with H, O, and N
c. forms double bonds with itself, O and N
d. has a tetrahedral arrangement of its single bonds
e. forms complex 3-D structures.
Choose the correct answer
A: a, b and d
B: a, b, d and e
C: all the above
D: b, c and d
E: b, c, d, e
2. What principle underlies the structural organization of complex biomolecules? Complex molecules are:
A: constructed by polymerization of simple molecules
B: constructed from proteins, lipids and DNA as in mitochondria
C: multifunctional enzymes
D: RNA and proteins as in ribosomes
E: constructed from proteins, polysaccharides and lipids as in membranes
3. Which are the attributes of organelles? They:
a. are cellular inclusions surrounded by a membrane
b. contain genes
c. capture energy in the form of ATP
d. are dedicated to important cellular tasks
e. contain vacuoles with small inclusions
Choose the correct answer
A: a, b and c.
B: b, c and e
C: b, c and d.
D: a and d
E: c and d.
4. A major property of biomolecules, that reflects their fitness to specify life, is that they contain biological information. The information content of biomolecules results from the:
a. head-to-tail polymerization of the building block units which gives the molecule structural polarity.
b. sequence of the component building block units.
c. H-bond, van der Waals forces and ionic interactions which hold macromolecules together.
d. exclusion of water from the hydrophobic interactions which would otherwise dilute out the information.
Choose the correct answer
A: all the above
B: a and b
C: c and d
D: a, c and d
E: b, c and d.
5. Name the organelle involved in packaging and processing of proteins for secretion or delivery to other organelles.
A: Golgi apparatus
B: mitochondria
C: lysosome
D: peroxisome
E: rough endoplasmic reticulum
6 Compared with the hydrides of oxygen¹s nearest neighbors in the periodic table, water has a:
a. higher boiling point
b. lower melting point
c. lower heat of vaporization
d. higher surface tension
Choose the correct answer.
A. a and b
B. a and c
C. a and d
D. b and c
E. c and d
7. The unusual physical properties of water are due to its:
A. local tetrahedral symmetry
B. 33% ionic character of the O-H bond
C. dipole moment
D. potential to form H-bonds
E. potential to solvate ions
8 Nonpolar solutes interact with solvent molecules by:
A. forming highly organized cage-like (clathrate) H-bonded networks between themselves and water
molecules.
B. forming highly organized cage-like (clathrate) H-bonded networks between water molecules around themselves.
C. replacing the H-bonded network of water molecules with a more ordered dipole-dipole interaction.
D. increasing the randomization (entropy) of H-bonds.
E. increasing van der Waals interactions between themselves and water molecules
9. The three-dimensional structure of macromolecules is formed and maintained primarily through non-covalent interactions. Which of the following is NOT considered a non-covalent interaction?
A: hydrogen bonds
B: van der Waals interactions
C: peptide bond
D: ionic interactions
E: hydrophobic interactions
10: Characteristics of nucleic acid replication are:
A: semi-conservative and uni-directional
B: semi-conservative and bi-directional
C: conservative and uni-directional
D: conservative and bi-directional
E: degenerate and semi-processive
11: Properties of DNA are:
a. two anti-parallel chains
b. two complementary chains
c. hydrogen bonding is A=T and G=C
d. bases inside
e. sugar phosphate back bone outside
Choose the correct answer
A: b, c, d, e
B: a, b, d, e
C: a, c, d, e
D: a, b, c, e
E: all the above
12: Who first correctly described the secondary structure of nucleic acids?
A: Hershey and Chase
B: Watson and Crick
C: Avery, MacLeod and McCarty
D: Chargaff
E: Linus Pauling
13: Why do amino acids have optical properties?
A: because they are acids
B: because they are bases
C: because they are ampholytes
D: because the alpha-C is chiral (asymmetric)
E: because the side chains are all different
14: How would you classify this amino acid?
A: hydrophobic
B: hydrophilic
C: charged
D: dipole
E: polar but uncharged
15: The 3-D structure and function of a protein is determined by:
A: the number of amino acids
B: the linear sequence of amino acids
C: non-covalent interactions with water
D: non-covalent interactions with mRNA
E: non-covalent interactions with other macromolecules
16: The two types of secondary structure found in proteins are:
A: beta-bends and beta-barrels
B: amphipathic and ampholytic
C: non-covalent and charged
D: alpha-helix and beta-sheet
E: proline helix and pi-helix
17: Competitive inhibition of an enzyme catalyzed reaction is overcome by:
A: lower concentrations of enzyme
B: lower concentrations of enzyme and substrate
C: lower concentrations of substrate
D: higher concentrations of substrate
E: it cannot be overcome because it is irreversible
18: Enzyme accelerate reactions by:
A: increasing the time taken to reach equilibrium
B: lowering the energy of activation
C: altering the equilibrium constant for the reaction
D: having an active site that only fits the correct substrate
E: having a Km value that approximates the substrate concentration
19. The major replication enzyme is:
A. DNA polymerase III, a DNA-directed DNA polymerase
B. RNA polymerase, a DNA-directed RNA polymerase
C. reverse transcriptase, an RNA-directed DNA polymerase
D. reverse polymerase, an RNA-directed RNA polymerase
E. aminoacyl-tRNA synthetase
20. Which of the following enzymes have proof-reading capability to ensure the fidelity of the central dogma?
a. DNA polymerase III, a DNA-directed DNA polymerase
b. RNA polymerase, a DNA-directed RNA polymerase
c. reverse transcriptase, an RNA-directed DNA polymerase
d. reverse polymerase, an RNA-directed RNA polymerase
e. aminoacyl-tRNA synthetase
Choose the correct answer.
A. a
B. e
C. a, e
D. a, c, d, e
E. b, c, d
21 The ribosome is a rRNA-protein complex that provides:
A. a scaffold for mRNA
B. a site for docking tRNA charged with a specific amino acid
C. an enzyme for peptide bond synthesis
D. an enzyme for translocation of the mRNA through the ribosome
E. all the above
22. Oxidation reactions in metabolism ALWAYS involve:
A. addition of [O]
B. removal of [H]
C. removal of H+
D. addition of e-
E. removal of e-
23 The number of different types of enzyme catalyzed reactions is:
A. 6
B. 10
C. 64
D. hundreds
E. thousands
24. (3) What are the distinctive properties of all living systems?
Living systems have four distinctive properties:
they are complicated and highly organized;
biological structures, from macroscopic to microscopic, serve functional purposes;
they extract and utilize energy from the environment;
they have a remarkable capacity for self-replication.
25. (5) List the biological functions of nucleic acids.
genetic material, information transfer
hormone action, information transfer
structural components of ribosomes
catalysts = ribozymes
metabolism: energy transfer, coenzymes and vitamins
26. (5) describe how to measure an enzyme catalyzed reaction.
Constant, fixed amount of enzyme
Vary concentration of substrate
Measure loss of reactant (substrate) or appearance of product
We are measuring rates -- accurate timing of events
Graphical presentation of data
27. (3) What is a metabolic pathway?
Organized chemistry
The progressive summation of enzyme catalyzed reactions.
The product of the first enzyme is the substrate for the second, etc...........
The sum of the small discrete chemical reactions results in a major chemical transformation that is a metabolic pathway.
Answers.
1 C
2 A
3 D
4 B
5 A
6 C
7 D
8 B
9 C
10 B
11 E
12 B
13 D
14 C
15 B
16 D
17 D
18 B
19 A
20 C
21 E
22 E
23 A