Download Old Exam 1 Questions KEY

OLD EXAM 1 QUESTIONS ANSWERS
76. Which type of inhibitor binds to the active site of an enzyme?
a. allosteric inhibitor
b. competitive inhibitor **Allosteric and non-competitive are the
same thing
c. non-competitive inhibitor
d. feedback inhibitor
77. Hemoglobin is a tetramer, composed of four polypeptide subunits.
When one of the subunits binds an oxygen molecule, the affinity for
oxygen of other subunits increases, so additional oxygen uptake becomes
more likely. This is best described as the result of:
a. enzyme saturation
b. allosteric inhibition
c. allosteric activation
d. oxidative damage
78. If all of the molecules of an enzyme are saturated with substrate,
the most effective way to obtain a faster yield of products (increase the
reaction rate) is to
a. add more of the enzyme.
b. heat the solution to 90°C. – denatures the enzyme
c. add more substrate.
d. add an allosteric inhibitor.
79. If an enzyme is added to a solution where the substrates and
products are in equilibrium, what would occur?
a. Additional product would be formed.
b. Additional substrate would be formed.
c. The reaction would change from endergonic to exergonic.
d. The free energy of the system would change.
e. Nothing; the reaction would stay at equilibrium.
Which atom symbolized in the illustration, in which the large black dots
represent the nuclei and the small dots represent electrons in electron
shells, depicts an atom that is chemically unreactive, unlikely to form bonds
with another atom?
a.
b.
c.
d.
e.
A
B
C
D
E
Which atom symbolized in the illustration, in which the large black dots
represent the nuclei and the small dots represent electrons in electron
shells, depicts an atom with a valence of 2, meaning it can form two covalent
bonds?
a.
b.
c.
d.
e.
A
B
C
D
E
The four most abundant elements in living things are…
a.
b.
c.
d.
e.
carbon,
carbon,
oxygen,
carbon,
carbon,
sodium, chlorine, nitrogen
sulfur, phosphorus, hydrogen
hydrogen, calcium, sodium
hydrogen, nitrogen, oxygen
oxygen, sulfur, calcium
The reactive properties or chemical behavior of an atom depend on the number
of
a.
b.
c.
d.
valence shells in the atom.
orbitals found in the atom.
electrons in each orbital of the atom.
electrons in the outer valence shell in the atom.
Rank the following structures by their size from LARGEST TO SMALLEST:
condensed chromosome 13, nucleus, carbon atom, insulin, nucleotide.
a.
b.
c.
d.
nucleus, condensed chromosome 13, nucleotide, insulin, carbon atom
insulin, carbon atom, nucleus, condensed chromosome 13, nucleotide
condensed chromosome 13, nucleus, carbon atom, nucleotide, insulin
nucleus, nucleotide, insulin, condensed chromosome 13, carbon atom
e. nucleus, condensed chromosome 13, insulin, nucleotide, carbon
atom
If you were to place phospholipids into a beaker full of vegetable oil, which
picture shows what could be expected?
a.
b.
c.
d.
A
B
C
D
If you were to place phospholipids into a beaker full of water, which picture
shows what could be expected?
a.
b.
c.
d.
A
B
C
D
Which of the following accurately describes the phospholipids in a cell
membrane?
a. They can move laterally within the plane of the membrane fairly
freely.
b. They frequently flip-flop from one side of the membrane to the
other.
c. They occur in an uninterrupted bilayer, and restrict membrane
proteins to the surface of the membrane.
d. They often move out of the membrane and dissolve in the surrounding
solution.
Which of the following is true when comparing prokaryotes and eukaryotes?
a. prokaryotes are usually larger than eucaryotes
b. both prokaryotes and eukaryotes have nuclei
c. prokaryotes always have cell walls while eukaryotes never have cell
walls
d. prokaryotes and eukaryotes both contain ribosomes
The molecular formula C10H14O7N5P is for a biomolecule that can be described
as a
a.
b.
c.
d.
Carbohydrate
Nucleic Acid
Fatty Acid
Amino Acid
The molecular formula C18H32O2 is for a biomolecule that can be described as
a
a.
b.
c.
d.
Carbohydrate
Nucleic Acid
Fatty Acid
Amino Acid
Given what you know about the trafficking of proteins within a cell, what is
temporal order for the sequence of images in the figure above?
a. A-B-C
b.
c.
d.
e.
f.
A-C-B
B-C-A
B-A-C
C-A-B
C-B-A
Which of the structures shown above is a component of a nucleotide?
a.
b.
c.
d.
A
B
C
D
The above figure shows the chemical structures of common biological
macromolecules, labeled A-D.
Which of the structures shown above is an amino acid?
a.
b.
c.
d.
A
B
C
D
Which of the structures shown above is a carbohydrate?
a. A
b. B
c. C
d. D
Which of the structures shown above is a lipid?
a.
b.
c.
d.
A
B
C
D
The figures above show different amino acids. These amino acids can be linked
together via amide bonds to form polypeptide chains and proteins. The side
chains are shown in blue boxes. The peptide backbone atoms are in yellow
boxes. Which of the following polypeptides would be likely be soluble in
water?
a. SGYWNLP
b. GLAMICA
c. STAMINA
d. STYNQYS
The figures above show different amino acids. These amino acids can be linked
together via amide bonds to form polypeptide chains and proteins. The side
chains are shown in blue boxes. The peptide backbone atoms are in yellow
boxes. Which of the following polypeptides would be likely to insert into a
membrane?
a. SGYWNLP
b. GLAMICA
c. STAMINA
d. STYNQYS
Which functional group would make a macromolecule more hydrophilic?
a.
b.
c.
d.
e.
Hydroxyl group (-OH)
Methyl group (-CH3)
Amino group (-NH2)
Carboxyl group (-COOH)
All except B
Which of the five molecules (labeled A to E) diagrammed here is an amino
acid?
a.
b.
c.
d.
e.
A
B
C
D
E
Table salt (NaCl) is an example of what type of bonding
a. Hydrogen bonding
b. Ionic bonding
c. Covalent bonding
d. Hydrophobic interactions
In a single molecule of water, two hydrogen atoms are bonded to an oxygen
atom by
a. hydrogen bonds.
b. nonpolar covalent bonds.
c. polar covalent bonds.
Atoms form covalent bonds with each other by:
a. transferring electrons from one atom to the other.
b. sharing electrons.
c. sharing protons.
d. attraction of positive and negative charges.
e. sharing neutrons.
A compound contains lots of hydroxyl groups as its predominant functional
group. Which of the following statements is most likely to be true concerning
this compound?
a.
b.
c.
d.
e.
It
It
It
It
It
is probably a fat or lipid.
should dissolve in water.
should dissolve in a nonpolar solvent.
won't form hydrogen bonds with water.
is likely to be hydrophobic
Rank the following types of bonds in order from strongest to weakest
a.
b.
c.
d.
e.
hydrogen, ionic, covalent
covalent, ionic, hydrogen
ionic, hydrogen, covalent
hydrogen, covalent, ionic
ionic, covalent, hydrogen
Which of the following is true when comparing solutions with a pH of 4 and a
pH of 8?
a. The solution with a pH of 8 has a 4 times higher concentration of
hydrogen ions than a solution with a pH of 4.
b. The solution with a pH of 8 has 10,000 times higher concentration of
hydrogen ions than a solution with a pH of 4.
c. The solution with a pH of 8 has a 4 times lower concentration of
hydrogen ions than a solution with a pH of 4.
d. The solution with a pH of 8 has 10,000 times lower concentration of
hydrogen ions than a solution with a pH of 4.
e. The hydrogen ion concentration does not appreciably differ between a
solution with a pH of 8 versus that with a pH of 4.
A reaction will proceed spontaneously when:
a. The products of the reaction have more free energy than the reactants, therefore
the ΔG < 0.
b. The products of the reaction have more free energy than the reactants, therefore
the ΔG > 0.
c. The products of the reaction have less free energy than the reactants, therefore
the ΔG < 0.
d. The products of the reaction have less free energy than the reactants, therefore
the ΔG > 0.
e. The products of the reaction have the same amount of free energy as the
reactants, therefore the ΔG = 0.
In the following graph, both the red and blue curves represent the same chemical reaction.
In one case an enzyme is present and in the other case an enzyme is not present. Which
curve likely represents a reaction with enzyme present?
a. the red curve.
b. the blue curve.
c. the red curve minus the blue curve.
Secondary structure refers to the common structural motifs, such as α-helixes
and β-pleated sheets, which result from interactions between adjacent amino
acid side chains. What type of bond maintains the secondary structure of a
protein?
a.
b.
c.
d.
e.
peptide bonds
hydrogen bonds
disulfide bonds
ionic bonds
phosphodiester bonds
Which of the following is an INCORRECT statement?
a. Carbon bonds are stable at the different temperatures
associated with life
b. Organic compounds may contain functional groups
c. Organic molecules may occur in various shapes. The
structure of molecules determine their functions
d. Organic chemistry is the science of studying Hydrogen
containing molecules, which are found in living organisms
Which is true of the base pairing seen between two DNA
strands?
a. Cytosine bonds with adenine.
b. Guanine bonds with thymine.
c. Cytosine bonds with thymine.
d. Thymine bonds with adenine.
e. Adenine bonds with guanine.
Which type of bond must be broken for water to
vaporize?
a. ionic bonds
b. nonpolar covalent bonds
c. polar covalent bonds
d. hydrogen bonds
Which of the following can cross the membrane
unfacilitated?
a. Na+
b. ATP
c. O2
d. Methionine (an amino acid)
A function of mitochondria in plant cells is
a. to catabolize organic molecules converting that energy into
ATP.
b. to capture photons and convert that energy into organic
molecules.
c. help traffic proteins to the plasma membrane.
d. nothing. Plants don’t have mitochondria.
A function of the nucleus in a prokaryotic bacterium
is a. to house the genetic material for the cell.
b. to serve as the site of translation (protein synthesis).
c. to serve as the site of transcription (the making of RNA
from DNA).
d. nothing. There is no nucleus in a bacterium.
e. both A and C are correct.
Which of the following descriptions of a biological membrane is most
accurate?
a. A three layer structure made of lipids, proteins, and water with water
and protein in the middle and lipids on the outside.
b. Primarily a protein structure in which lipids function to regulate the
passage of other molecules.
A fluid structure in which proteins “float” in a semiliquid phospholipid bilayer
d.
A rigid structure in which phospholipids and proteins
are covalently bonded together.
e.
A rigid structure surrounding the cell usually made of
polysaccharides
c.
What type of transport protein can move 2 or more different molecules in opposite
directions?
a. Uniporter
b. Antiporter
c. Symporter
d. Multiporter
e. Diporter
How is the sodium-potassium pump able to move ions against their concentration
gradients?
a. Exocytosis
b. Facilitated diffusion
c. Expending ATP
d. Ion channels
e. Bulk transport
Which of the following is FALSE ?
Enzyme catalysis is dependent on the pH and
temperature of the reaction environment.
b.
Enzyme catalysis is dependent on the threedimensional structure or conformation of the enzyme.
c.
Enzymes provide activation energy for the reaction
they catalyze.
d.
Enzyme activity can be inhibited by a molecule that
binds to the enzyme far from the active site.
a.
96. Which statement or statements describe the role of the Golgi apparatus? It …
a. modifies carbohydrates bound to proteins.
b. processes proteins from the endoplasmic reticulum.
c. produces vesicles, some of which may fuse with the cell
membrane.
d. produces lysosomes.
e. All the above are correct.
140. In exergonic reactions, like the oxidation of glucose,
a. the end products have more total energy than the starting
reactants.
b. there is a net release of free energy.
c. a net input of energy from the surroundings must occur.
d. the reaction cannot proceed without enzymes that lower
the activation energy.
ATP is produced by _______ , ________ reactions and is used to drive ________, ________ reactions.
What words filled in these four spaces (in order) result in a true statement?
a. endergonic, catabolic; exergonic, anabolic
b. exergonic, anabolic; endergonic, catabolic,
c. exergonic, catabolic; endergonic, anabolic
d. endergonic, anabolic; exergonic, catabolic
157. Most of the ATP made during cellular respiration is produced
by
a. glycolysis.
b. oxidative phosphorylation.
c. substrate level phosphorylations.
d. direct synthesis of ATP by the tricarboxylic acid cycle.
161. Which of the following statements about NAD+ is FALSE?
a. NAD+ is reduced to NADH during both glycolysis and the
citric acid cycle.
b. NAD+ has more chemical potential energy than NADH.
c. NAD+ can receive electrons for use in electron transport
and oxidative phosphorylation.
d. In the absence of NAD+, glycolysis cannot proceed.
162. The ATP made during glycolysis is generated by
a. transfer of phosphate from a phosphorylated carbon
molecule to ADP, called substrate-level phosphorylation.
b. electron transport.
c. chemiosmosis.
d. oxidation of NADH to NAD+.
166. During glycolysis, when glucose is catabolized to pyruvate, most of the energy of
glucose is
a. transferred to ADP, forming ATP.
b. transferred directly to ATP.
c. retained in the pyruvate.
d. stored in the NADH produced.
169. Which of the following intermediary metabolites enters the
citric acid cycle and is formed, in part, by the removal of a
carbon (CO2) from one molecule of pyruvate?
a. glucose-6-phosphate
b. glyceraldehyde-3-phosphate
c. oxaloacetate
d. acetyl CoA
171. All of the following are products of the citric acid cycle EXCEPT
a. ATP.
b. NADH.
c. FADH2.
d. carbon dioxide.
e. water
174. Which of the following statements about the chemiosmotic mechanism of ATP synthesis is
TRUE?
a. electron transport from NADH to O2 pumps H+ from the intermembrane space into the
mitochondrial matrix.
The high concentration of H+ in the mitochondrial
matrix pulls water into the matrix through the ATP synthase
channel by osmosis, and the energy in this water flow is used
to power ATP synthesis.
c.
H+ movement down a concentration gradient from
the intermembrane space into the mitochondrial matrix
through ATP synthase results in ATP synthesis
d.
All these statements describe parts of the
chemiosmotic mechanism.
b.
176. The oxygen consumed during cellular respiration is involved directly in which process or
event?
a. glycolysis
b. accepting electrons (and H+) at the end of the
electron transport chain, forming water
c. the citric acid cycle
d. the oxidation of pyruvate to acetyl CoA
e. the phosphorylation of ADP to form ATP
180. Anaerobic fermentation adds reactions to glycolysis in
which ________ is ________.
a. NAD+; oxidized to NADH
b. NADH; oxidized to NAD+
c. pyruvate; converted to acetylCoA
d. ethanol; oxidized
181. Each of the following can be converted to an intermediate of glycolysis and produce some ATP
without entering the citric acid cycle EXCEPT
a. fatty acids
b. some amino acids
c. glucose and sucrose
d. glycerol
e. starch and glycogen
187. As ATP levels in the cytoplasm of a cell increase, the rate of glycolysis is
likely to
a. go up, because more ATP is available for the energy investment phase of
glycolysis.
b. go down, because elevated ATP results in feedback
inhibition of phosphoglucokinase.
c. remain unchanged, because the rate of glycolysis is
controlled by the availability of oxygen.
d. slow, because NAD+ is used up.