Question 1

Steps 6 and 7 of glycolysis are catalyzed by the enzymes glyceraldehyde 3-phosphate dehydrogenase and phosphoglycerate kinase, respectively. Together, they ...

Accepted Answer

A)  result in the oxidation of an aldehyde to a carboxylic acid. 
B)  produce both ATP and NADH. 
C)  couple the oxidation of a C-H bond to the activation of carrier molecules. 
D)  catalyze the only glycolytic reactions that create a high-energy phosphate linkage directly from inorganic phosphate. 
E)  All of the above. 
A)  result in the oxidation of an aldehyde to a carboxylic acid. 
B)  produce both ATP and NADH. 
C)  couple the oxidation of a C-H bond to the activation of carrier molecules. 
D)  catalyze the only glycolytic reactions that create a high-energy phosphate linkage directly from inorganic phosphate. 
E)  All of the above.

Question 2

The enzyme phosphoglucose isomerase converts glucose 6-phosphate to its isomer fructose 6-phosphate in the second step of glycolysis. The equilibrium constant for the reaction is 0.36. Evaluating the ΔG° of the reaction (ΔG° = -5.9 × log Kₑq), decide which of the following conclusions is true.

Accepted Answer

A)  The ΔG° is negative, therefore the reaction proceeds in the forward direction. 
B)  The ΔG° is negative, but whether or not the reaction proceeds would depend on ΔG, not ΔG°. 
C)  The ΔG° is positive, but in a cell that is active in glycolysis, the reaction can still proceed in the forward direction. 
D)  The ΔG° is positive, therefore the reaction proceeds in the reverse direction. 
A)  The ΔG° is negative, therefore the reaction proceeds in the forward direction. 
B)  The ΔG° is negative, but whether or not the reaction proceeds would depend on ΔG, not ΔG°. 
C)  The ΔG° is positive, but in a cell that is active in glycolysis, the reaction can still proceed in the forward direction. 
D)  The ΔG° is positive, therefore the reaction proceeds in the reverse direction.

Question 3

Sort the following molecules based on the amount of energy that is released when their phosphate bond is hydrolyzed as indicated. Your answer would be a four-letter string composed of letters A to D only, e.g. ADCB. Put the molecule with the highest amount of hydrolysis energy on the left.
(A)	ATP when hydrolyzed to ADP
(B)	Glucose 6-phosphate when hydrolyzed to glucose
(C)	1,3-bisphosphoglycerate when hydrolyzed to 3-phosphoglycerate
(D)	Phosphoenolpyruvate when hydrolyzed to pyruvate

Accepted Answer

Hydrolysis of phosphoenolpyruvate to py

Question 4

What is the end product of glycolysis in the cytoplasm of eukaryotic cells? How many carbon atoms does the molecule have?

Accepted Answer

A)  Acetyl CoA; it has two carbon atoms attached to coenzyme A 
B)  Phosphoenolpyruvate; it has three carbon atoms 
C)  Glucose 6-phosphate; it has six carbon atoms 
D)  Pyruvate; it has three carbon atoms 
E)  Glyceraldehyde 3-phosphate; it has three carbon atoms 
A)  Acetyl CoA; it has two carbon atoms attached to coenzyme A 
B)  Phosphoenolpyruvate; it has three carbon atoms 
C)  Glucose 6-phosphate; it has six carbon atoms 
D)  Pyruvate; it has three carbon atoms 
E)  Glyceraldehyde 3-phosphate; it has three carbon atoms

Question 5

The electron carriers NADH and FADH₂ donate their electrons to the electron-transport chain in the inner mitochondrial membrane, leading to ATP synthesis powered by an H⁺ gradient across the membrane. If, on average, the oxidation of each NADH or FADH₂ molecule in this pathway results in the production of 2.5 and 1.5 molecules of ATP, respectively, how many ATP (and GTP) molecules are produced on average as a result of the complete oxidation of one molecule of acetyl CoA in the mitochondrion? Consider only the citric acid cycle and oxidative phosphorylation.

Accepted Answer

A)  10 
B)  12 
C)  13.5 
D)  14.5 
E)  15 
A)  10 
B)  12 
C)  13.5 
D)  14.5 
E)  15

Question 6

For each of the following pairs, indicate whether they interact via hydrogen bonds (H) or ionic bonds (I), or do not favorably interact (N). Your answer would be a four-letter string composed of letters H, I, and N only, e.g. HNNI.
( )	ATP and Mg²?
( )	Urea and water
( )	Glucose and the enzyme hexokinase (which uses glucose as a substrate)
( )	A phospholipid tail and inorganic phosphate

Accepted Answer

ATP is negatively charged and can form

Question 7

The bond energies associated with noncovalent attractions in the cell are too weak to resist disruption by thermal motion. However, cellular macromolecules can interact specifically AND strongly with each other (or fold by themselves) merely via such interactions. How is this possible?

Accepted Answer

A)  The bond energies increase radically when two interacting molecules approach each other. 
B)  The interacting molecules also fortify their binding via covalent bonds to keep them from dissociation. 
C)  Many weak bonds together in a complementary geometry can afford a strong binding. 
D)  The cell lowers its internal temperature to reduce thermal motion of molecules and enhance the weak attractions. 
A)  The bond energies increase radically when two interacting molecules approach each other. 
B)  The interacting molecules also fortify their binding via covalent bonds to keep them from dissociation. 
C)  Many weak bonds together in a complementary geometry can afford a strong binding. 
D)  The cell lowers its internal temperature to reduce thermal motion of molecules and enhance the weak attractions.

Question 8

The citric acid cycle is summarized in the following figure. Answer the following question(s) about this cycle.
  
-In the citric acid cycle shown above, which steps produce either NADH or FADH?? List all such steps by their number, from the smallest number to the largest. Your answer would be a number composed of digits 1 to 8 only, e.g. 258.

Accepted Answer

Steps 3, 4, and 8 p

Question 9

Enzymes are the cell's catalyst crew. They make the life of the cell possible by carrying out various reactions with astounding performance. Which of the following is NOT true regarding cellular enzymes?

Accepted Answer

A)  Enzymes lower the activation energy of the reactions that they catalyze. 
B)  Enzymes can specifically drive substrate along certain reaction pathways. 
C)  Enzymes can push energetically unfavorable reactions forward by coupling them to energetically favorable reactions. 
D)  Enzymes are proteins, but RNA catalysts, called ribozymes, also exist. 
E)  Enzymes can change the equilibrium point for reactions that they catalyze. 
A)  Enzymes lower the activation energy of the reactions that they catalyze. 
B)  Enzymes can specifically drive substrate along certain reaction pathways. 
C)  Enzymes can push energetically unfavorable reactions forward by coupling them to energetically favorable reactions. 
D)  Enzymes are proteins, but RNA catalysts, called ribozymes, also exist. 
E)  Enzymes can change the equilibrium point for reactions that they catalyze.

Question 10

Which of the following elements is not normally found in cells?

Accepted Answer

A)  Copper 
B)  Iron 
C)  Silver 
D)  Cobalt 
E)  Zinc 
A)  Copper 
B)  Iron 
C)  Silver 
D)  Cobalt 
E)  Zinc

Question 11

Which of the following is true regarding energy production and storage in plants and animals?

Accepted Answer

A)  Plant and animal cells make starch for long-term energy storage. 
B)  Most of the ATP in a plant cell has been generated in the chloroplast and transported to other parts of the cell. 
C)  Oxidation of one gram of starch releases more energy than oxidation of fat, but since starch absorbs a lot of water, it is not as efficient as fat in energy storage. 
D)  Animals, but not plants, can store fats in the form of triacylglycerol (triglyceride). 
E)  Plant seeds often contain large amounts of fats and starch. 
A)  Plant and animal cells make starch for long-term energy storage. 
B)  Most of the ATP in a plant cell has been generated in the chloroplast and transported to other parts of the cell. 
C)  Oxidation of one gram of starch releases more energy than oxidation of fat, but since starch absorbs a lot of water, it is not as efficient as fat in energy storage. 
D)  Animals, but not plants, can store fats in the form of triacylglycerol (triglyceride). 
E)  Plant seeds often contain large amounts of fats and starch.

Question 12

Which of the following chemicals do you NOT expect to be readily dissolved in water?

Accepted Answer

A)  Uric acid 
B)  Hexane 
C)  Glycerol 
D)  Ethanol 
E)  Potassium chloride 
A)  Uric acid 
B)  Hexane 
C)  Glycerol 
D)  Ethanol 
E)  Potassium chloride

Question 13

Indicate whether each of the following molecules is an intermediate in glycolysis (G) or in the tricarboxylic acid cycle (T). Your answer would be a four-letter string composed of letters G and T only, e.g. GGTT.
( )	Fumarate
( )	Malate
( )	Phosphoenolpyruvate
( )	Succinate

Accepted Answer

Phosphoenolpyruvate is converted to py

Question 14

The equilibrium constant for the reaction that breaks down each molecule of substrate A to one molecule of B and one molecule of C is equal to 0.5. Starting with a mixture containing only molecules A at 1 M concentration, what will be the concentration of molecule A after reaching equilibrium under these conditions?

Accepted Answer

A)  0.5 M 
B)  0.25 M 
C)  0.125 M 
D)  0.333 M 
E)  0.667 M 
A)  0.5 M 
B)  0.25 M 
C)  0.125 M 
D)  0.333 M 
E)  0.667 M

Steps 6 and 7 of glycolysis are catalyzed by the enzymes glyceraldehyde 3-phosphate dehydrogenase and phosphoglycerate kinase, respectively. Together, they ...

What is the end product of glycolysis in the cytoplasm of eukaryotic cells? How many carbon atoms does the molecule have?

The bond energies associated with noncovalent attractions in the cell are too weak to resist disruption by thermal motion. However, cellular macromolecules can interact specifically AND strongly with each other (or fold by themselves) merely via such interactions. How is this possible?

Enzymes are the cell's catalyst crew. They make the life of the cell possible by carrying out various reactions with astounding performance. Which of the following is NOT true regarding cellular enzymes?

Which of the following elements is not normally found in cells?

Which of the following is true regarding energy production and storage in plants and animals?

Which of the following chemicals do you NOT expect to be readily dissolved in water?

Indicate whether each of the following molecules is an intermediate in glycolysis (G) or in the tricarboxylic acid cycle (T). Your answer would be a four-letter string composed of letters G and T only, e.g. GGTT. ( ) Fumarate ( ) Malate ( ) Phosphoenolpyruvate ( ) Succinate

Cells and Genomes

Proteins

DNA, Chromosomes, and Genomes

DNA Replication, Repair, and Recombination

How Cells Read the Genome: From DNA to Protein

Control of Gene Expression

Analyzing Cells, Molecules, and Systems

Visualizing Cells

Membrane Structure

Membrane Transport of Small Molecules and the Electrical Properties of Membranes

Intracellular Compartments and Protein Sorting

Intracellular Membrane Traffic

Energy Conversion: Mitochondria and Chloroplasts

Cell Signaling

The Cytoskeleton

The Cell Cycle

Cell Death

Cell Junctions and the Extracellular Matrix

Cancer

Development of Multicellular Organisms

Stem Cells and Tissue Renewal

Pathogens and Infection

The Innate and Adaptive Immune Systems

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Exam 2: Cell Chemistry and Bioenergetics

Steps 6 and 7 of glycolysis are catalyzed by the enzymes glyceraldehyde 3-phosphate dehydrogenase and phosphoglycerate kinase, respectively. Together, they ...

What is the end product of glycolysis in the cytoplasm of eukaryotic cells? How many carbon atoms does the molecule have?

The bond energies associated with noncovalent attractions in the cell are too weak to resist disruption by thermal motion. However, cellular macromolecules can interact specifically AND strongly with each other (or fold by themselves) merely via such interactions. How is this possible?

Enzymes are the cell's catalyst crew. They make the life of the cell possible by carrying out various reactions with astounding performance. Which of the following is NOT true regarding cellular enzymes?

Which of the following elements is not normally found in cells?

Which of the following is true regarding energy production and storage in plants and animals?

Which of the following chemicals do you NOT expect to be readily dissolved in water?

Indicate whether each of the following molecules is an intermediate in glycolysis (G) or in the tricarboxylic acid cycle (T). Your answer would be a four-letter string composed of letters G and T only, e.g. GGTT. ( ) Fumarate ( ) Malate ( ) Phosphoenolpyruvate ( ) Succinate

Cells and Genomes

Proteins

DNA, Chromosomes, and Genomes

DNA Replication, Repair, and Recombination

How Cells Read the Genome: From DNA to Protein

Control of Gene Expression

Analyzing Cells, Molecules, and Systems

Visualizing Cells

Membrane Structure

Membrane Transport of Small Molecules and the Electrical Properties of Membranes

Intracellular Compartments and Protein Sorting

Intracellular Membrane Traffic

Energy Conversion: Mitochondria and Chloroplasts

Cell Signaling

The Cytoskeleton

The Cell Cycle

Cell Death

Cell Junctions and the Extracellular Matrix

Cancer

Development of Multicellular Organisms

Stem Cells and Tissue Renewal

Pathogens and Infection

The Innate and Adaptive Immune Systems

Filters