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. A
b. B
c. C
d. D
e. 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. A
b. B
c. C
d. D
e. E
The four most abundant elements in living things are…
a. carbon, sodium, chlorine, nitrogen
b. carbon, sulfur, phosphorus, hydrogen
c. oxygen, hydrogen, calcium, sodium
d. carbon, hydrogen, nitrogen, oxygen
e. carbon, oxygen, sulfur, calcium
The reactive properties or chemical behavior of an atom depend on the number of
a. valence shells in the atom.
b. orbitals found in the atom.
c. electrons in each orbital of the atom.
d. 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. nucleus, condensed chromosome 13, nucleotide, insulin, carbon atom
b. insulin, carbon atom, nucleus, condensed chromosome 13, nucleotide
c. condensed chromosome 13, nucleus, carbon atom, nucleotide, insulin
d. 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. A
b. B
c. C
d. D
If you were to place phospholipids into a beaker full of water, which picture shows what could be expected?
a. A
b. B
c. C
d. 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. Carbohydrate
b. Nucleic Acid
c. Fatty Acid
d. Amino Acid
The molecular formula C18H32O2 is for a biomolecule that can be described as a
a. Carbohydrate
b. Nucleic Acid
c. Fatty Acid
d. 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. A-C-B
c. B-C-A
d. B-A-C
e. C-A-B
f. C-B-A
Which of the structures shown above is a component of a nucleotide?
a. A
b. B
c. C
d. 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. A
b. B
c. C
d. 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. A
b. B
c. C
d. 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. Hydroxyl group (-OH)
b. Methyl group (-CH3)
c. Amino group (-NH2)
d. Carboxyl group (-COOH)
e. All except B
Which of the five molecules (labeled A to E) diagrammed here is an amino acid?
a. A
b. B
c. C
d. D
e. 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. It is probably a fat or lipid.
b. It should dissolve in water.
c. It should dissolve in a nonpolar solvent.
d. It won't form hydrogen bonds with water.
e. It is likely to be hydrophobic
Rank the following types of bonds in order from strongest to weakest
a. hydrogen, ionic, covalent
b. covalent, ionic, hydrogen
c. ionic, hydrogen, covalent
d. hydrogen, covalent, ionic
e. 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. peptide bonds
b. hydrogen bonds
c. disulfide bonds
d. ionic bonds
e. 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?
- 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?
- ionic bonds
b.nonpolar covalent bonds
c.polar covalent bonds
d.hydrogen bonds
Which of the following can cross the membrane unfacilitated?
- 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.
c.A fluid structure in which proteins “float” in a semi-liquid 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
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?
- Exocytosis
b.Facilitated diffusion
c.Expending ATP
d.Ion channels
e. Bulk transport
Which of the following is FALSE ?
a.Enzyme catalysis is dependent on the pH and temperature of the reaction environment.
b.Enzyme catalysis is dependent on the three-dimensional 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.
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.
b.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.
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.