Question 1

Which of the following correctly identifies the proton pumping in the two-photosystem light reactions?

Accepted Answer

A) PSII: 4 protons;cytochrome b6f complex: 8 protons 
B) cytochrome b6f complex: 8 protons;PSI: 4 protons 
C) PSII: 4 protons;ferredoxin-NADP+ oxidoreductase: 4 protons 
D) PSII: 4 protons;PSI: 4 protons;ferredoxin-NADP+ oxidoreductase: 4 protons 
E) none of the above 
A) PSII: 4 protons;cytochrome b6f complex: 8 protons 
B) cytochrome b6f complex: 8 protons;PSI: 4 protons 
C) PSII: 4 protons;ferredoxin-NADP+ oxidoreductase: 4 protons 
D) PSII: 4 protons;PSI: 4 protons;ferredoxin-NADP+ oxidoreductase: 4 protons 
E) none of the above A

Question 2

Which of the following photosynthetic pigments would give rise to the yellow or red color of leaves seen during autumn?

Accepted Answer

A) chlorophyll a 
B) chlorophyll b 
C) $\beta$-carotene 
D) phycocyanin 
E) none of the above 
A) chlorophyll a 
B) chlorophyll b 
C) $\beta$-carotene 
D) phycocyanin 
E) none of the above C

Question 3

If light with an average wavelength of 660 nm is used to power the light reactions of  photosynthesis,what is the efficiency in terms of energy captured as NADPH and ATP based upon the following information?

2 H2O + 2 NADP+ $\to$ 2 H+ + O2 + 2 NADPH ES1U1P1$\circ$S1S1P0' = -0.50 V
the oxidation of 2 water molecules with production of 2 NADPH requires 8 photons
12 protons are transported to the thylakoid lumen for each oxygen produced

Accepted Answer

Energy of 2 NADPH production: (4)(96.5 kJ/V$\bullet$mol)(-0.50 V)= 193 kJ/2 NADPH

Energy of ATP production: 12 protons (1 ATP/3 protons)= 4 ATP
4 ATP (~50 kJ/mol)= 200 kJ/mol

Total energy required = 193 kJ + 200 kJ = 393 kJ

Energy of 8 einsteins of 660 nm light and calculation of efficiency:

Question 4

What range type(s)of electromagnetic radiation are absorbed by photosynthetic pigments to allow the reactions of photosynthesis to occur?

Accepted Answer

A) UV only 
B) visible only 
C) infrared only 
D) UV and visible 
E) visible and infrared 
A) UV only 
B) visible only 
C) infrared only 
D) UV and visible 
E) visible and infrared

Question 5

The energy available from the protonmotive force across the thylakoid membrane is about 20 kJ/mol of protons.How much energy per mole of photons absorbed by the two photosystems does this equal?

Accepted Answer

A) 13 kJ/mol 
B) 30 kJ/mol 
C) 40 kJ/mol 
D) 60 kJ/mol 
E) none of the above 
A) 13 kJ/mol 
B) 30 kJ/mol 
C) 40 kJ/mol 
D) 60 kJ/mol 
E) none of the above

Question 6

In the mechanism of Rubisco,what role does the Mg2+ play?

Accepted Answer

A) neutralizes negative charges of active site Asp and Glu,enabling ionization of CO2 
B) activates water molecule that hydrates the carboxy-$\beta$-keto intermediate 
C) complexes with the phosphate on C-1 to hold ribulose-1,5-bisphosphate in the active site 
D) repels the product,3-phosphoglycerate,allowing it to leave the active site more rapidly 
E) none of the above 
A) neutralizes negative charges of active site Asp and Glu,enabling ionization of CO2 
B) activates water molecule that hydrates the carboxy-$\beta$-keto intermediate 
C) complexes with the phosphate on C-1 to hold ribulose-1,5-bisphosphate in the active site 
D) repels the product,3-phosphoglycerate,allowing it to leave the active site more rapidly 
E) none of the above

Question 7

Which of the following carbohydrates is the most common molecule exported by photosynthetic cells for use in other parts of the plant?

Accepted Answer

A) amylose 
B) amylopectin 
C) glucose 
D) sucrose 
E) fructose 
A) amylose 
B) amylopectin 
C) glucose 
D) sucrose 
E) fructose

Question 8

What specific part of the chloroplast is responsible for the light reactions of photosynthesis?

Accepted Answer

A) thylakoid lumen 
B) thylakoid membrane 
C) stroma 
D) inner membrane of chloroplast 
E) outer membrane of chloroplast 
A) thylakoid lumen 
B) thylakoid membrane 
C) stroma 
D) inner membrane of chloroplast 
E) outer membrane of chloroplast

Question 9

If the following 14C labeled molecules served as substrates for rubisco (the labeled carbons are indicated with *),where would the 14C labels end up in the immediate product(s)of the reaction? Draw the product(s),clearly showing which atom(s)would be labeled.

Accepted Answer

Question 10

Which of the following explains why an electron will eventually travel to a chlorophyll molecule in the reaction center as opposed to just "wandering around" all of the antenna molecules?

Accepted Answer

A) antenna chlorophyll molecules are associated with proteins and have a higher excited state energy level 
B) antenna chlorophyll molecules are associated with proteins and have a lower excited state energy level 
C) reaction center chlorophyll molecules are associated with proteins and have a higher excited state energy level 
D) reaction center chlorophyll molecules are associated with proteins and have a lower excited state energy level 
E) none of the above 
A) antenna chlorophyll molecules are associated with proteins and have a higher excited state energy level 
B) antenna chlorophyll molecules are associated with proteins and have a lower excited state energy level 
C) reaction center chlorophyll molecules are associated with proteins and have a higher excited state energy level 
D) reaction center chlorophyll molecules are associated with proteins and have a lower excited state energy level 
E) none of the above

Question 11

Which of the following is required for the reaction catalyzed by rubisco in order to drive the reaction to completion?

Accepted Answer

A) NADH 
B) NADPH 
C) ATP $\to$ ADP + Pi 
D) ATP $\to$ AMP + PPi 
E) none of the above 
A) NADH 
B) NADPH 
C) ATP $\to$ ADP + Pi 
D) ATP $\to$ AMP + PPi 
E) none of the above

Question 12

Reaction of ribulose-1,5-bisphosphate with oxygen and then water results in the following intermediate.Show the resulting products from this reaction:

Accepted Answer

The answer of Reaction of ribulose-1,5-bisphosphate with oxygen and then...

Question 13

When photorespiration occurs and phosphoglycolate must be salvaged,which of the following occurs during the salvage reactions?

Accepted Answer

A) NADP+ is used in the oxidation of glycolate to glyoxylate 
B) NADPH is used in the reduction of hydroxypyruvate to glycerate 
C) carbon is lost in the form of CO2 
D) ATP is made during the conversion of phosphoglycolate to glycolate 
E) none of the above 
A) NADP+ is used in the oxidation of glycolate to glyoxylate 
B) NADPH is used in the reduction of hydroxypyruvate to glycerate 
C) carbon is lost in the form of CO2 
D) ATP is made during the conversion of phosphoglycolate to glycolate 
E) none of the above

Question 14

Which of the following describes the oxidation reactions for the two manganese ions that undergo oxidation in the oxygen-evolving complex?

Accepted Answer

A) a Mn2+ is oxidized to a Mn4+ and a Mn3+ is oxidized to a Mn5+ 
B) a Mn2+ is oxidized to a Mn5+ and a Mn3+ is oxidized to a Mn4+ 
C) a Mn2+ is oxidized to a Mn5+ and a Mn2+ is oxidized to a Mn3+ 
D) a Mn2+ is oxidized to a Mn5+ and a Mn4+ is oxidized to a Mn5+ 
E) two Mn2+ are oxidized to Mn4+ 
A) a Mn2+ is oxidized to a Mn4+ and a Mn3+ is oxidized to a Mn5+ 
B) a Mn2+ is oxidized to a Mn5+ and a Mn3+ is oxidized to a Mn4+ 
C) a Mn2+ is oxidized to a Mn5+ and a Mn2+ is oxidized to a Mn3+ 
D) a Mn2+ is oxidized to a Mn5+ and a Mn4+ is oxidized to a Mn5+ 
E) two Mn2+ are oxidized to Mn4+

Question 15

Which of the following best describes photosynthesis in purple photosynthetic bacteria?

Accepted Answer

A) a reaction center resembling PSI transfers electrons to plastocyanin 
B) a reaction center resembling PSII transfers electrons to plastoquinone 
C) water is split by the reaction center that resembles PSII 
D) NADPH is generated using electrons from a protein resembling ferredoxin 
E) the proton gradient is used for both ATP synthesis and NADPH generation 
A) a reaction center resembling PSI transfers electrons to plastocyanin 
B) a reaction center resembling PSII transfers electrons to plastoquinone 
C) water is split by the reaction center that resembles PSII 
D) NADPH is generated using electrons from a protein resembling ferredoxin 
E) the proton gradient is used for both ATP synthesis and NADPH generation

Question 16

Which of the following would have an inhibitory effect upon rubisco?

Accepted Answer

A) Mg2+ 
B) CO2 
C) H+ 
D) reduced thioredoxin 
E) none of the above 
A) Mg2+ 
B) CO2 
C) H+ 
D) reduced thioredoxin 
E) none of the above

Question 17

Which of the following acts as a corepressor for the transcription of chloroplast genes?

Accepted Answer

A) 3-phosphoglycerate 
B) fructose-1,6-bisphosphate 
C) CO2 
D) sucrose 
E) none of the above 
A) 3-phosphoglycerate 
B) fructose-1,6-bisphosphate 
C) CO2 
D) sucrose 
E) none of the above

Question 18

Which of the following depicts the general flow of electrons in the two-photosystem light reactions? (Q = plastoquinone,PC = plastocyanin,Fd = ferredoxin

Accepted Answer

A) PSI $\to$ Q $\to$ cytochrome b6f complex $\to$ PC $\to$ PSII $\to$ Fd $\to$ NADP+ 
B) PSI $\to$ cytochrome b6f complex $\to$ Q $\to$ PC $\to$ PSII $\to$ Fd $\to$ NADP+ 
C) PSII $\to$ Q $\to$ cytochrome b6f complex $\to$ PC $\to$ PSI $\to$ Fd $\to$ NADP+ 
D) PSII $\to$ PC $\to$ Q $\to$ Fd $\to$ PSI $\to$ cytochrome b6f complex $\to$ NADP+ 
E) PSII $\to$ Fd $\to$ PC $\to$ cytochrome b6f complex $\to$ PSI $\to$ Q $\to$ NADP+ 
A) PSI $\to$ Q $\to$ cytochrome b6f complex $\to$ PC $\to$ PSII $\to$ Fd $\to$ NADP+ 
B) PSI $\to$ cytochrome b6f complex $\to$ Q $\to$ PC $\to$ PSII $\to$ Fd $\to$ NADP+ 
C) PSII $\to$ Q $\to$ cytochrome b6f complex $\to$ PC $\to$ PSI $\to$ Fd $\to$ NADP+ 
D) PSII $\to$ PC $\to$ Q $\to$ Fd $\to$ PSI $\to$ cytochrome b6f complex $\to$ NADP+ 
E) PSII $\to$ Fd $\to$ PC $\to$ cytochrome b6f complex $\to$ PSI $\to$ Q $\to$ NADP+

Question 19

The following reaction would be catalyzed by which of the following enzymes?

Accepted Answer

A) ribulose-5-phosphate epimerase 
B) transaldolase 
C) transketolase 
D) triose phosphate isomerase 
E) pentose phosphate transferase 
A) ribulose-5-phosphate epimerase 
B) transaldolase 
C) transketolase 
D) triose phosphate isomerase 
E) pentose phosphate transferase

Question 20

What is the minimum number of photons that must be absorbed by PSII to reduce two molecules of water to one molecule of oxygen?

Accepted Answer

A) 1 
B) 2 
C) 4 
D) 8 
E) 16 
A) 1 
B) 2 
C) 4 
D) 8 
E) 16

Exam 16: Photosynthesis

Which of the following correctly identifies the proton pumping in the two-photosystem light reactions?

Which of the following photosynthetic pigments would give rise to the yellow or red color of leaves seen during autumn?

What range type(s)of electromagnetic radiation are absorbed by photosynthetic pigments to allow the reactions of photosynthesis to occur?

The energy available from the protonmotive force across the thylakoid membrane is about 20 kJ/mol of protons.How much energy per mole of photons absorbed by the two photosystems does this equal?

In the mechanism of Rubisco,what role does the Mg2+ play?

Which of the following carbohydrates is the most common molecule exported by photosynthetic cells for use in other parts of the plant?

What specific part of the chloroplast is responsible for the light reactions of photosynthesis?

If the following 14C labeled molecules served as substrates for rubisco (the labeled carbons are indicated with *),where would the 14C labels end up in the immediate product(s)of the reaction? Draw the product(s),clearly showing which atom(s)would be labeled.

Which of the following explains why an electron will eventually travel to a chlorophyll molecule in the reaction center as opposed to just "wandering around" all of the antenna molecules?

Which of the following is required for the reaction catalyzed by rubisco in order to drive the reaction to completion?

Reaction of ribulose-1,5-bisphosphate with oxygen and then water results in the following intermediate.Show the resulting products from this reaction:

When photorespiration occurs and phosphoglycolate must be salvaged,which of the following occurs during the salvage reactions?

Which of the following describes the oxidation reactions for the two manganese ions that undergo oxidation in the oxygen-evolving complex?

Which of the following best describes photosynthesis in purple photosynthetic bacteria?

Which of the following would have an inhibitory effect upon rubisco?

Which of the following acts as a corepressor for the transcription of chloroplast genes?

Which of the following depicts the general flow of electrons in the two-photosystem light reactions? (Q = plastoquinone,PC = plastocyanin,Fd = ferredoxin

The following reaction would be catalyzed by which of the following enzymes?

What is the minimum number of photons that must be absorbed by PSII to reduce two molecules of water to one molecule of oxygen?

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Contractile Proteins and Molecular Motors

Carbohydrates: Sugars,saccharides,glycans

Lipids,membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, oxidative Phosphorylation, and Oxygen Metabolism

Lipid Metabolism I: Fatty Acids,triacylglycerols,and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, steroids, isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, utilization, and Turnover

Metabolism of Nitogenous Compounds Ii: Amino Acids, porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes,genomes and Chromosomes

Dna Replication

Dna Restructuring: Repair,recombination,rearrangement,amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

In the mechanism of Rubisco,what role does the Mg²⁺ play?

If the following ¹⁴C labeled molecules served as substrates for rubisco (the labeled carbons are indicated with *),where would the ¹⁴C labels end up in the immediate product(s)of the reaction? Draw the product(s),clearly showing which atom(s)would be labeled.