Question 1

Which of the following is a photosynthetic light harvesting pigment?

Accepted Answer

A)  "FeS cluster" 
B)  "NADPH" 
C)  "plastoquinone" 
D)  "$\beta$-carotene" 
A)  "FeS cluster" 
B)  "NADPH" 
C)  "plastoquinone" 
D)  "$\beta$-carotene" D

Question 2

Why are Calvin cycle reactions also referred to as the dark reactions?

Accepted Answer

A)  They occur primarily at night. 
B)  They absorb, and do not reflect, the sunlight energy. 
C)  They do not absorb sunlight energy. 
D)  They do not require sunlight energy. 
A)  They occur primarily at night. 
B)  They absorb, and do not reflect, the sunlight energy. 
C)  They do not absorb sunlight energy. 
D)  They do not require sunlight energy. C

Question 3

In the five steps used by photosynthetic organisms to convert solar energy into chemical energy, which molecules store the solar energy before sugar synthesis?

Accepted Answer

A)  chlorophylls 
B)  NADH and FADH2 
C)  H2O and O2 
D)  ATP and NADPH 
A)  chlorophylls 
B)  NADH and FADH2 
C)  H2O and O2 
D)  ATP and NADPH D

Question 4

Trace the electron from plastocyanin to NADPH in the photosynthetic electron transport system.

Accepted Answer

See Figure 12.30 below. plastocyanin @#LAT-DLM& ph

Question 5

Which enzyme in the photosynthesis light reactions does NOT transfer electrons?

Accepted Answer

A)  ATP synthase 
B)  photosystem II 
C)  photosystem I 
D)  cytochrome b6f 
A)  ATP synthase 
B)  photosystem II 
C)  photosystem I 
D)  cytochrome b6f

Question 6

Which species from the light reactions keeps thioredoxin reduced so that it can activate enzymes in the Calvin cycle?

Accepted Answer

A)  ferredoxin 
B)  plastoquinone 
C)  P700 
D)  NADPH 
A)  ferredoxin 
B)  plastoquinone 
C)  P700 
D)  NADPH

Question 7

Write out the overall net Calvin cycle reaction assuming three CO2 molecules are the starting reactant.

Accepted Answer

3 CO₂ + 6 NADPH + 9

Question 8

Which statement regarding CAM plants is true?

Accepted Answer

A)  They use one cell type to absorb and store CO2 before utilizing it in the Calvin cycle in another cell type. 
B)  They are more efficient than C4 plants. 
C)  They absorb CO2 at night and release it to the Calvin cycle during the day. 
D)  They store CO2 in 3-phosphoglycerate before releasing it to the Calvin cycle. 
A)  They use one cell type to absorb and store CO2 before utilizing it in the Calvin cycle in another cell type. 
B)  They are more efficient than C4 plants. 
C)  They absorb CO2 at night and release it to the Calvin cycle during the day. 
D)  They store CO2 in 3-phosphoglycerate before releasing it to the Calvin cycle.

Question 9

During photophosphorylation, the protons are pumped into the __________, and the ATP is made in the _.

Accepted Answer

A)  thylakoid lumen; cytoplasm 
B)  thylakoid lumen; stroma 
C)  stroma; thylakoid lumen 
D)  cytoplasm; stroma 
A)  thylakoid lumen; cytoplasm 
B)  thylakoid lumen; stroma 
C)  stroma; thylakoid lumen 
D)  cytoplasm; stroma

Question 10

In the chloroplasts, photosystem I (PSI) and photosystem II (PSII) are known to localize in different regions. PSI generally localizes in the , whereas PSII localizes in the __________.

Accepted Answer

A)  thylakoid lumen; thylakoid grana 
B)  thylakoid lamellae; thylakoid grana 
C)  stroma; thylakoid lumen 
D)  thylakoid grana; thylakoid lamellae 
A)  thylakoid lumen; thylakoid grana 
B)  thylakoid lamellae; thylakoid grana 
C)  stroma; thylakoid lumen 
D)  thylakoid grana; thylakoid lamellae

Question 11

Approximately how many light-harvesting chromophores are found per photosystem enzyme, such as in PSI or PSII?

Accepted Answer

A)  2 
B)  about a dozen 
C)  about 100 to 200 
D)  about 1000 to 2000 
A)  2 
B)  about a dozen 
C)  about 100 to 200 
D)  about 1000 to 2000

Question 12

Heme and chlorophyll have similar overall structures. What is common between the two molecules?

Accepted Answer

A)  color 
B)  hydrophobic tail 
C)  polycyclic planar structure 
D)  metal ion found at their center 
A)  color 
B)  hydrophobic tail 
C)  polycyclic planar structure 
D)  metal ion found at their center

Question 13

Describe the arrangement of light-harvesting complexes relative to the reaction center in a plant's photosystem enzymes.

Accepted Answer

The reaction center is centrally located

Question 14

What group in photosystem II (PSII) directly reacts with H2O during its light-driven oxidation?

Accepted Answer

A)  oxygen evolving center 
B)  P680 
C)  tyrosine 
D)  pheophytin 
A)  oxygen evolving center 
B)  P680 
C)  tyrosine 
D)  pheophytin

Question 15

At what stage of plant growth is the glyoxylate cycle most common, and why?

Accepted Answer

The glyoxylate cycle is most c

Question 16

The five-step mechanism of ribulose bisphosphate carboxylase (rubisco)

Accepted Answer

A)  is an overall thermodynamically unstable reaction. 
B)  involves C1, C3, C4, C5, and C6 molecules in the enzyme mechanism intermediates. 
C)  adds a CO2 molecule to a C5 ribulose sugar, yielding an unstable C6 molecule that cleaves into two C3 molecules. 
D)  involves the incorporation of 3 CO2 molecules to yield one 3-phosphoglycerate molecule. 
A)  is an overall thermodynamically unstable reaction. 
B)  involves C1, C3, C4, C5, and C6 molecules in the enzyme mechanism intermediates. 
C)  adds a CO2 molecule to a C5 ribulose sugar, yielding an unstable C6 molecule that cleaves into two C3 molecules. 
D)  involves the incorporation of 3 CO2 molecules to yield one 3-phosphoglycerate molecule.

Question 17

Which enzyme in the photosynthetic Z scheme catalyzes the PQ cycle, which is analogous to Complex III and the Q cycle in the mitochondrial electron transport chain?

Accepted Answer

A)  photosystem II 
B)  plastocyanin 
C)  cytochrome b6f 
D)  photosystem I 
A)  photosystem II 
B)  plastocyanin 
C)  cytochrome b6f 
D)  photosystem I

Question 18

Regulation of photosystem II (PSII) enzyme activity is accomplished by phosphorylation. Higher levels of stimulates the phosphorylation and tuning down of PSII activity.

Accepted Answer

A)  oxidized NADP+ 
B)  reduced plastoquinone (PQH2) 
C)  reduced NADPH 
D)  ATP 
A)  oxidized NADP+ 
B)  reduced plastoquinone (PQH2) 
C)  reduced NADPH 
D)  ATP

Question 19

Identify the cell types of cells A and B below, and then identify the plant type in which the cell arrangements are found.

Accepted Answer

A is a mesophyll cel

Question 20

Which two proteins do electrons move between in the PQ cycle?

Accepted Answer

The PQ cycle moves e

Exam 12: Photosynthesis

Which of the following is a photosynthetic light harvesting pigment?

Why are Calvin cycle reactions also referred to as the dark reactions?

In the five steps used by photosynthetic organisms to convert solar energy into chemical energy, which molecules store the solar energy before sugar synthesis?

Trace the electron from plastocyanin to NADPH in the photosynthetic electron transport system.

Which enzyme in the photosynthesis light reactions does NOT transfer electrons?

Which species from the light reactions keeps thioredoxin reduced so that it can activate enzymes in the Calvin cycle?

Write out the overall net Calvin cycle reaction assuming three CO2 molecules are the starting reactant.

Which statement regarding CAM plants is true?

During photophosphorylation, the protons are pumped into the __________, and the ATP is made in the _.

In the chloroplasts, photosystem I (PSI) and photosystem II (PSII) are known to localize in different regions. PSI generally localizes in the , whereas PSII localizes in the __________.

Approximately how many light-harvesting chromophores are found per photosystem enzyme, such as in PSI or PSII?

Heme and chlorophyll have similar overall structures. What is common between the two molecules?

Describe the arrangement of light-harvesting complexes relative to the reaction center in a plant's photosystem enzymes.

What group in photosystem II (PSII) directly reacts with H2O during its light-driven oxidation?

At what stage of plant growth is the glyoxylate cycle most common, and why?

The five-step mechanism of ribulose bisphosphate carboxylase (rubisco)

Which enzyme in the photosynthetic Z scheme catalyzes the PQ cycle, which is analogous to Complex III and the Q cycle in the mitochondrial electron transport chain?

Regulation of photosystem II (PSII) enzyme activity is accomplished by phosphorylation. Higher levels of stimulates the phosphorylation and tuning down of PSII activity.

Identify the cell types of cells A and B below, and then identify the plant type in which the cell arrangements are found.

Which two proteins do electrons move between in the PQ cycle?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

DNA Replication, Repair, and Recombination

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

Filters

Write out the overall net Calvin cycle reaction assuming three CO₂ molecules are the starting reactant.

What group in photosystem II (PSII) directly reacts with H₂O during its light-driven oxidation?