Question 1

Why are plants unlikely to produce many carbohydrates at night?

Accepted Answer

A) Selected Calvin cycle enzymes are inactive in the dark because they are hydrogen-bound at night. 
B) Calvin cycle enzymes are denatured in the cold temperatures at night. 
C) Selected Calvin cycle enzymes are inactive in the dark because thioredoxin is oxidized and cannot reduce their disulfide linkages. 
D) Selected Calvin cycle enzymes are inactive in the dark because thioredoxin is reduced and can break their disulfide linkages. 
A) Selected Calvin cycle enzymes are inactive in the dark because they are hydrogen-bound at night. 
B) Calvin cycle enzymes are denatured in the cold temperatures at night. 
C) Selected Calvin cycle enzymes are inactive in the dark because thioredoxin is oxidized and cannot reduce their disulfide linkages. 
D) Selected Calvin cycle enzymes are inactive in the dark because thioredoxin is reduced and can break their disulfide linkages.

Question 2

Mercaptoethanol is a reagent that breaks disulfide linkages. If you were to treat Calvin cycle enzymes with this reagent, what is the likely effect?

Accepted Answer

A) It would competitively inhibit them. 
B) It would noncompetitively inhibit them. 
C) It would split them in two pieces. 
D) It would activate them. 
E) It would deactivate them. 
A) It would competitively inhibit them. 
B) It would noncompetitively inhibit them. 
C) It would split them in two pieces. 
D) It would activate them. 
E) It would deactivate them.

Question 3

Which statement about photodynamic therapy (PDT)is INCORRECT?

Accepted Answer

A) PDT treatments can use different light wavelengths 
B) treatments with different light wavelengths will all be of the same duration 
C) patients will endure pain during PDT 
D) red light wavelengths are more effective in deep tumor treatments 
A) PDT treatments can use different light wavelengths 
B) treatments with different light wavelengths will all be of the same duration 
C) patients will endure pain during PDT 
D) red light wavelengths are more effective in deep tumor treatments

Question 4

Why does Rubisco show relatively little preference for CO2 as a substrate over O2?

Accepted Answer

A) Rubisco's active site can bind to CO2 and O2 equally well. 
B) CO2 and O2 bind to RuBP which has roughly equal affinity for CO2 and O2. 
C) Ancient atmospheric conditions had high amounts of O2 which selected for Rubisco to bind to either molecule. 
D) CO2 and O2 bind to a regulatory site on Rubisco instead of the active site. 
A) Rubisco's active site can bind to CO2 and O2 equally well. 
B) CO2 and O2 bind to RuBP which has roughly equal affinity for CO2 and O2. 
C) Ancient atmospheric conditions had high amounts of O2 which selected for Rubisco to bind to either molecule. 
D) CO2 and O2 bind to a regulatory site on Rubisco instead of the active site.

Question 5

Which type of chlorophyll is only found in green and purple bacteria?

Accepted Answer

A) chlorophyll a 
B) chlorophyll b 
C) chlorophyll c 
D) bacteriochlorophyll 
E) carotenoids 
A) chlorophyll a 
B) chlorophyll b 
C) chlorophyll c 
D) bacteriochlorophyll 
E) carotenoids

Question 6

Why is CO2 split off of the C4 carriers once they get into the bundle sheath cells?

Accepted Answer

A) so that the CO2 can be used by Rubisco to initiate the Calvin cycle 
B) so that the CO2 can be used by PEP carboxylase to initiate the Calvin cycle 
C) so that the CO2 can be used by Rubisco to initiate the C4 pathway 
D) so that the CO2 can be used by PEP carboxylase to initiate the C4 pathway 
E) so that the O2 can be used by Rubisco to initiate the Calvin cycle 
A) so that the CO2 can be used by Rubisco to initiate the Calvin cycle 
B) so that the CO2 can be used by PEP carboxylase to initiate the Calvin cycle 
C) so that the CO2 can be used by Rubisco to initiate the C4 pathway 
D) so that the CO2 can be used by PEP carboxylase to initiate the C4 pathway 
E) so that the O2 can be used by Rubisco to initiate the Calvin cycle

Question 7

The shared properties of the two photosystems (I and II)with respect to protein composition and overall architecture suggest that __________.

Accepted Answer

A) both absorb exactly the same wavelength of light 
B) all photosynthetic reaction centers have evolved from a common ancestral structure that has been conserved for a long time (more than 3 billion years) 
C) all photosynthetic reaction centers have their own unique ancestor 
D) all photosynthetic reaction centers have evolved separately within the last 100,000 years 
E) all photosynthetic reaction centers evolved from unrelated structures 
A) both absorb exactly the same wavelength of light 
B) all photosynthetic reaction centers have evolved from a common ancestral structure that has been conserved for a long time (more than 3 billion years) 
C) all photosynthetic reaction centers have their own unique ancestor 
D) all photosynthetic reaction centers have evolved separately within the last 100,000 years 
E) all photosynthetic reaction centers evolved from unrelated structures

Question 8

How does high intensity light supposedly damage PSII?

Accepted Answer

A) If overexcited, PSII becomes highly acidic. 
B) If overexcited, PSII becomes highly basic. 
C) If overexcited, PSII can damage PSI. 
D) If overexcited, PSII can form toxic oxygen species. 
E) If overexcited, PSII dissociates. 
A) If overexcited, PSII becomes highly acidic. 
B) If overexcited, PSII becomes highly basic. 
C) If overexcited, PSII can damage PSI. 
D) If overexcited, PSII can form toxic oxygen species. 
E) If overexcited, PSII dissociates.

Question 9

The reduction of ________ is accomplished with electrons passed through ferredoxin; this substance then reduces certain _______ in selected Calvin cycle enzymes.

Accepted Answer

A) thioredoxin, disulfide bridges 
B) thioredoxin, sulfhydryl groups 
C) sulfhydryl groups, thioredoxin 
D) disulfide bridges, thioredoxin 
E) thioredoxin, hydrogen bonds 
A) thioredoxin, disulfide bridges 
B) thioredoxin, sulfhydryl groups 
C) sulfhydryl groups, thioredoxin 
D) disulfide bridges, thioredoxin 
E) thioredoxin, hydrogen bonds

Question 10

Which type of chlorophyll is only found in brown algae, diatoms and certain protozoa?

Accepted Answer

A) chlorophyll a 
B) chlorophyll b 
C) chlorophyll c 
D) bacteriochlorophyll 
E) carotenoids 
A) chlorophyll a 
B) chlorophyll b 
C) chlorophyll c 
D) bacteriochlorophyll 
E) carotenoids

Question 11

The initial product of carbon fixation contains ____ carbons, but it breaks down into two compounds containing _____ carbons.

Accepted Answer

A) 8, 4 
B) 6, 3 
C) 6, 6 
D) 10, 5 
E) 12, 6 
A) 8, 4 
B) 6, 3 
C) 6, 6 
D) 10, 5 
E) 12, 6

Question 12

What determines the direction of the Rubisco-catalyzed reactions?

Accepted Answer

A) the concentration of O2 alone 
B) the concentration of CO2 alone 
C) the CO2/O2 ratio available to the enzyme 
D) cofactors for Rubisco 
A) the concentration of O2 alone 
B) the concentration of CO2 alone 
C) the CO2/O2 ratio available to the enzyme 
D) cofactors for Rubisco

Question 13

Calvin originally thought that the acceptor molecule for carbon dioxide during carbon fixation contained how many carbons?

Accepted Answer

A) 2 
B) 1 
C) 3 
D) 4 
E) 6 
A) 2 
B) 1 
C) 3 
D) 4 
E) 6

Question 14

To what type of molecule does pheophytin pass its photo-excited electron?

Accepted Answer

A) theophyllin 
B) plastoquinone 
C) another pheophytin 
D) xanthophylls 
E) succinate dehydrogenase 
A) theophyllin 
B) plastoquinone 
C) another pheophytin 
D) xanthophylls 
E) succinate dehydrogenase

Question 15

What metal atom is part of the chlorophyll porphyrin ring?

Accepted Answer

A) magnesium 
B) manganese 
C) platinum 
D) iron 
E) aluminum 
A) magnesium 
B) manganese 
C) platinum 
D) iron 
E) aluminum

Question 16

In chloroplasts, a proton gradient is established with a higher concentration of protons found in the ______ and a lower concentration in the ______.

Accepted Answer

A) thylakoid lumen, intermembrane space 
B) intermembrane space, thylakoid lumen 
C) thylakoid lumen, stroma 
D) stroma, thylakoid lumen 
E) intermembrane space, matrix 
A) thylakoid lumen, intermembrane space 
B) intermembrane space, thylakoid lumen 
C) thylakoid lumen, stroma 
D) stroma, thylakoid lumen 
E) intermembrane space, matrix

Question 17

What part of PSII appears to suffer most of the damage from high intensity light?

Accepted Answer

A) the reaction center photopigment 
B) the D1 polypeptide of PSII 
C) the electrons 
D) NADPH 
E) both the D1 polypeptide of PSII and NADPH 
A) the reaction center photopigment 
B) the D1 polypeptide of PSII 
C) the electrons 
D) NADPH 
E) both the D1 polypeptide of PSII and NADPH

Question 18

The light-driven splitting of a water molecule is known as _______.

Accepted Answer

A) hydrolysis 
B) photonization 
C) photolysis 
D) condensation 
E) dehydration 
A) hydrolysis 
B) photonization 
C) photolysis 
D) condensation 
E) dehydration

Question 19

How does paraquat destroy human tissue?

Accepted Answer

A) It competes with ferredoxin for electrons from the PSI reaction center. 
B) It interferes with PSI function. 
C) Electrons attached to paraquat are used to reduce nitrogen, generating highly reactive nitrogen radicals. 
D) It leads to the production of substances that damage and kill the tissue. 
E) It generates oxygen radicals using electrons diverted from complex I of the respiratory chain. 
A) It competes with ferredoxin for electrons from the PSI reaction center. 
B) It interferes with PSI function. 
C) Electrons attached to paraquat are used to reduce nitrogen, generating highly reactive nitrogen radicals. 
D) It leads to the production of substances that damage and kill the tissue. 
E) It generates oxygen radicals using electrons diverted from complex I of the respiratory chain.

Question 20

Why is the process whereby O2 is added to RuBP called photorespiration?

Accepted Answer

A) because O2 is released and CO2 is taken up 
B) because CO2 is released and O2 is taken up 
C) because breathing is necessary 
D) because RuBP is released 
E) because it occurs in crop plants 
A) because O2 is released and CO2 is taken up 
B) because CO2 is released and O2 is taken up 
C) because breathing is necessary 
D) because RuBP is released 
E) because it occurs in crop plants

Why are plants unlikely to produce many carbohydrates at night?

Mercaptoethanol is a reagent that breaks disulfide linkages. If you were to treat Calvin cycle enzymes with this reagent, what is the likely effect?

Which statement about photodynamic therapy (PDT)is INCORRECT?

Why does Rubisco show relatively little preference for CO₂ as a substrate over O₂?

Which type of chlorophyll is only found in green and purple bacteria?

Why is CO₂ split off of the C₄ carriers once they get into the bundle sheath cells?

The shared properties of the two photosystems (I and II)with respect to protein composition and overall architecture suggest that __________.

How does high intensity light supposedly damage PSII?

The reduction of __ is accomplished with electrons passed through ferredoxin; this substance then reduces certain _ in selected Calvin cycle enzymes.

Which type of chlorophyll is only found in brown algae, diatoms and certain protozoa?

The initial product of carbon fixation contains carbons, but it breaks down into two compounds containing _ carbons.

What determines the direction of the Rubisco-catalyzed reactions?

Calvin originally thought that the acceptor molecule for carbon dioxide during carbon fixation contained how many carbons?

To what type of molecule does pheophytin pass its photo-excited electron?

What metal atom is part of the chlorophyll porphyrin ring?

In chloroplasts, a proton gradient is established with a higher concentration of protons found in the and a lower concentration in the .

What part of PSII appears to suffer most of the damage from high intensity light?

The light-driven splitting of a water molecule is known as _______.

How does paraquat destroy human tissue?

Why is the process whereby O₂ is added to RuBP called photorespiration?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 6: Photosynthesis and the Chloroplast

Why are plants unlikely to produce many carbohydrates at night?

Mercaptoethanol is a reagent that breaks disulfide linkages. If you were to treat Calvin cycle enzymes with this reagent, what is the likely effect?

Which statement about photodynamic therapy (PDT)is INCORRECT?

Why does Rubisco show relatively little preference for CO2 as a substrate over O2?

Which type of chlorophyll is only found in green and purple bacteria?

Why is CO2 split off of the C4 carriers once they get into the bundle sheath cells?

The shared properties of the two photosystems (I and II)with respect to protein composition and overall architecture suggest that __________.

How does high intensity light supposedly damage PSII?

The reduction of ________ is accomplished with electrons passed through ferredoxin; this substance then reduces certain _______ in selected Calvin cycle enzymes.

Which type of chlorophyll is only found in brown algae, diatoms and certain protozoa?

The initial product of carbon fixation contains ____ carbons, but it breaks down into two compounds containing _____ carbons.

What determines the direction of the Rubisco-catalyzed reactions?

Calvin originally thought that the acceptor molecule for carbon dioxide during carbon fixation contained how many carbons?

To what type of molecule does pheophytin pass its photo-excited electron?

What metal atom is part of the chlorophyll porphyrin ring?

In chloroplasts, a proton gradient is established with a higher concentration of protons found in the ______ and a lower concentration in the ______.

What part of PSII appears to suffer most of the damage from high intensity light?

The light-driven splitting of a water molecule is known as _______.

How does paraquat destroy human tissue?

Why is the process whereby O2 is added to RuBP called photorespiration?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Gene Expression: From Transcription to Translation

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Why does Rubisco show relatively little preference for CO₂ as a substrate over O₂?

Why is CO₂ split off of the C₄ carriers once they get into the bundle sheath cells?

The reduction of __ is accomplished with electrons passed through ferredoxin; this substance then reduces certain _ in selected Calvin cycle enzymes.

The initial product of carbon fixation contains carbons, but it breaks down into two compounds containing _ carbons.

In chloroplasts, a proton gradient is established with a higher concentration of protons found in the and a lower concentration in the .

Why is the process whereby O₂ is added to RuBP called photorespiration?