Unit 1
Stearic acid (a fatty acid) has a single carboxyl group with a pKa of 4. At what pH will the concentration of stearic acid [HA] equal the concentration of stearate [A-].
A.1
B.2
C.3
D.4
E.Cannot be determined
What is 4?
Which best describes a spontaneous reaction under standard conditions?
A. ΔGo’ is positive and the reaction will proceed forwards
B. ΔGo’ is negative and the reaction will proceed forwards
C. ΔGo’ is negative and the reaction will proceed backwards
D. ΔGo’ is positive and the reaction will proceed backwards
B. ΔGo’ is negative and the reaction will proceed forwards
Pyruvate is ______ by NADH.
A.Oxidized
B.Reduced
C.None of the above
B. Reduced
Glycogen, cellulose, and starch are all __________________.
A. proteins
B. polysaccharides
C. nucleic acids
D. lipids
E. phospholipids
B. polysaccharides
Alanine is similar to serine in the same way that
A. Val is similar to Thr
B. Phe is similar to Tyr
C. Phe is similar to Trp
D. Ser is similar to Thr
B. Phe is similar to Tyr
Consider an enzyme-catalyzed reaction that follows Michaelis-Menten kinetics. If the concentration of substrate ([S]) is much greater than the Michaelis constant (Km), which of the following is true?
A.The reaction rate is approximately zero
B.The reaction rate is approximately equal to Vmax
C.The reaction rate is half Vmax
D.The reaction rate is dependent on enzyme concentration
B.The reaction rate is approximately equal to Vmax
Why is glycogen branching important?
A. Branching significantly alters the melting point
B. Branching increases the stability of glycogen
C. Branching increases glycogen synthesis and degradation by increasing the potential sites of action
D. Branching allows for more sugars other than glucose to be incorporated
C. Branching increases glycogen synthesis and degradation by increasing the potential sites of action
During glycolysis, the committed step is catalyzed by:
A) hexokinase
B) PFK-1
C) PFK-2
D) Aldolase
B) PFK-1
What sugar is the sweetest?
A) glucose
B) Ribose
C) Fructose
D) Sucrose
C) Fructose
Which of the following amino acids cannot be involved in hydrogen-bonding?
A. Asp
B. Val
C. Ser
D. Glu
B. Val
At what substrate concentration of an enzyme which has Km=0.09 will it reach the tenth of its maximal rate?
A.0.009
B.0.01
C.0.001
D.0.018
D.0.018
In animals, the carbon of glucose _____ be metabolically converted and utilized to synthesize fatty acids. In animals, the carbon of fatty acids ____ be metabolically converted and utilized to synthesize glucose.
A. Can, can
B. can, cannot
C. Cannot, can
D. Cannot, cannot
B. can, cannot
What is widely cited as one of the fastest known enzymes, converting over a million substrates per second?
A) hexokinase
B) DNA polymerase
C) Carbonic anhydrase
D) Rubisco
E) Fumarse
C) Carbonic anhydrase
If a 0.25 M buffer solution of acetic acid (pKa = 4.76) and sodium acetate has a pH of 4.00, what is the acetate concentration?
A. 0.037 M
B. 0.082 M
C. 0.12 M
D. 0.17 M
E. 0.213 M
A. 0.037 M
If the ΔG°’ for PEP carboxylase is 29.7 kJ/mol, and the cellular ratio of PEP to oxaloacetate is 1/1,000,000, what is the value for ΔG?
A.- 4.8 kJ/mol
B.- 2.1 kJ/mol
C.7.0 kJ/mol
D.- 11.4 kJ/mol
E.5.9 kJ/mol
A. -4.8 kJ/mol
Malate is either a product or a reactant in the reactions catalyzed by all of these enzymes except:
A) Malate dehydrogenase
B) Fumarase
C) Malate lyase
D) Citrate Synthase
E) Malyl-CoA thioesterase
D) Citrate Synthase
Spider silk is incrediablly strong due to a protein chain rich in:
A) proline and hydroxyproline
B) Glycine and Alaine repeats
C) Tryptophan clusters
D) Methionine helices
B) Glycine and Alaine repeats
What is the best explanation of why protein folding is thermodynamically favorable under physiological conditions?
A) Folding is driven by the increase in hydrogen bonds within the backbone, which increase the entropy of the system.
B) Folding occurs because the unfolded protein has a higher enthalpy than the folded protein due to ionic interactions
C) All protein folding is spontaneous due to the intrinsic nature of the amino acid geometry
D) Although the unfolded chain loses conformational entropy, the hydrophobic effect releases ordered water molecules, resulting in a net negative delta G
D) Although the unfolded chain loses conformational entropy, the hydrophobic effect releases ordered water molecules, resulting in a net negative delta G
Using the Nernst equation, calculate the midpoint potential of quinone/quinol redox couple with a concentration of 0.1M quinone and 0.001M quinol. ΔE°’ = 0.005 V.
A. 0.01 V
B. -0.05 V
C. -0.045 V
D. 0.055 V
D. 0.055 V
Cobalamin-dependent enzymes perform two distinct reactions. What is the correct oxidation state for each reaction.
A) Dehydration - CoII -> CoI, methylation - CoIII ->CoI
B) Adneosylation - Co III -> Co II, Carboxylation - Co 0 -> Co I
C) Methylation - Co III -> CoI, Adenosylation Co III -> Co II
D) Methylation - Co I -> Co III, carbozylation Co III -> CoII
C) Methylation - Co III -> CoI, Adenosylation Co III -> Co II
A) Oxaloacetate levels rise because gluconeogenesis slows.
B) beta oxidation decreases and fatty acid biosynthesis increases
C) Gluconeogenesis increases, diverting oxaloacetate out of the TCA cycle causing acetyl-CoA to accumulate
D) Glycolysis slows causing pyruvate to be fermented to lactate
C) Gluconeogenesis increases, diverting oxaloacetate out of the TCA cycle causing acetyl-CoA to accumulate
Horseshoe crabs have blue blood because they use:
A) Iron in hemoglobin
B) Nickel-based oxygen binding
C) Copper in hemocyanin
D) Vanadium oxides
C) Copper in hemocyanin