Question 1

Another investigator labels CO₂ with radiolabeled ¹⁸O.After exposure of a plant adapted to a hot,dry climate to the radiolabeled CO₂,in what molecule does the radiolabeled ¹⁸O appear?

Accepted Answer

The answer of Another investigator labels CO₂ with radiolabeled ¹⁸O.After...

Question 2

Why was the number of heterotrophs on primitive Earth likely to have initially been severely restricted?

Accepted Answer

A) The spontaneous production of organic molecules occurs very slowly. 
B) The spontaneous production of organic molecules occurs very quickly. 
C) The early heterotrophs could not reproduce. 
D) The early heterotrophs reproduced too quickly. 
E) Organic molecules spontaneously broke down keeping their amounts low.

Question 3

A direct advantage of using water as an electron source for photosynthesis was that _________.

Accepted Answer

A) organisms could live in fewer habitats than they could previously 
B) organisms could get larger 
C) organisms were able to live in a much more diverse array of habitats 
D) organisms could be smaller 
E) organisms could be rehydrated more readily

Question 4

You are studying mutant algal cells that lack carotenoids.You raise them in an aerobic environment.They do not survive.Why?

Accepted Answer

A) They cannot absorb any light. 
B) They reflect all colors of light. 
C) They dissipate aerobic environments. 
D) They transfer excess energy to O2 making ultrareactive singlet oxygen that can destroy biological molecules and cause cell death. 
E) The lack of carotenoids causes the chloroplast membranes to disintegrate.

Question 5

Which type of chlorophyll is found in red algae?

Accepted Answer

A) Chlorophyll a 
B) Chlorophyll b 
C) Chlorophyll c 
D) Chlorophyll d 
E) carotenoids

Question 6

Which molecule conveys protons from the chloroplast stroma into the thylakoid lumen?

Accepted Answer

A) cytochrome b6f 
B) plastocyanin 
C) phytochrome 
D) cytochrome c 
E) oxygen

Question 7

What metal atom is part of the chlorophyll porphyrin ring?

Accepted Answer

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

Question 8

What is the mechanism of action by which the herbicide paraquat kills plants?

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 oxygen,generating highly reactive oxygen radicals. 
D) It leads to the production of substances that damage the chloroplasts and kill the plant. 
E) All of these are correct.

Question 9

It is much _____ to pull electrons from water than hydrogen sulfide,since the sulfur atom in hydrogen sulfide has much ______ affinity for its electrons than the oxygen atom in water.

Accepted Answer

A) harder,lower 
B) harder,higher 
C) easier,lower 
D) easier,higher 
E) easier,more moderate

Question 10

______is a small,water-soluble,iron-sulfur protein that transfers electrons to NADP+ to form NADPH.

Accepted Answer

A) ferritin 
B) sulfotriene 
C) sulfate 
D) ferredoxin 
E) sulferritin

Question 11

Carotenoids ________.

Accepted Answer

A) absorb primarily blue light 
B) absorb primarily green light 
C) reflect orange and red light 
D) reflect yellow light 
E) All of these are correct.

Question 12

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

Accepted Answer

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

Question 13

What is the mechanism by which the herbicides diuron,atrazine and terbutryn are able to kill plants?

Accepted Answer

A) They bind to the manganese ions of chlorophyll. 
B) They block electron transport through PSII. 
C) They act as competitive inhibitors of reduced plastiquinone binding to chlorophyll a. 
D) They act as noncompetitive inhibitors of reduced plastiquinone binding to the D1 protein of PSII. 
E) They bind to hemoglobin.

Question 14

What is the reason that C3 plants must open their stomata even when the climate is hot and dry?

Accepted Answer

A) To take in CO 
B) To take in CO2 
C) To take in water 
D) To let CO2 out of the leaf 
E) To take in O2

Question 15

What is the plant cell's primary source of reducing power?

Accepted Answer

A) CO2 
B) ADP 
C) ATP 
D) NAD 
E) NADPH

Exam 6: Photosynthesis and the Chloroplast

Another investigator labels CO₂ with radiolabeled ¹⁸O.After exposure of a plant adapted to a hot,dry climate to the radiolabeled CO₂,in what molecule does the radiolabeled ¹⁸O appear?

Why was the number of heterotrophs on primitive Earth likely to have initially been severely restricted?

A direct advantage of using water as an electron source for photosynthesis was that _________.

You are studying mutant algal cells that lack carotenoids.You raise them in an aerobic environment.They do not survive.Why?

Which type of chlorophyll is found in red algae?

Which molecule conveys protons from the chloroplast stroma into the thylakoid lumen?

What metal atom is part of the chlorophyll porphyrin ring?

What is the mechanism of action by which the herbicide paraquat kills plants?

It is much _ to pull electrons from water than hydrogen sulfide,since the sulfur atom in hydrogen sulfide has much __ affinity for its electrons than the oxygen atom in water.

______is a small,water-soluble,iron-sulfur protein that transfers electrons to NADP⁺ to form NADPH.

Carotenoids ________.

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

What is the mechanism by which the herbicides diuron,atrazine and terbutryn are able to kill plants?

What is the reason that C₃ plants must open their stomata even when the climate is hot and dry?

What is the plant cell's primary source of reducing power?

Exam 6: Photosynthesis and the Chloroplast

Another investigator labels CO2 with radiolabeled 18O.After exposure of a plant adapted to a hot,dry climate to the radiolabeled CO2,in what molecule does the radiolabeled 18O appear?

Why was the number of heterotrophs on primitive Earth likely to have initially been severely restricted?

A direct advantage of using water as an electron source for photosynthesis was that _________.

You are studying mutant algal cells that lack carotenoids.You raise them in an aerobic environment.They do not survive.Why?

Which type of chlorophyll is found in red algae?

Which molecule conveys protons from the chloroplast stroma into the thylakoid lumen?

What metal atom is part of the chlorophyll porphyrin ring?

What is the mechanism of action by which the herbicide paraquat kills plants?

It is much _____ to pull electrons from water than hydrogen sulfide,since the sulfur atom in hydrogen sulfide has much ______ affinity for its electrons than the oxygen atom in water.

______is a small,water-soluble,iron-sulfur protein that transfers electrons to NADP+ to form NADPH.

Carotenoids ________.

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

What is the mechanism by which the herbicides diuron,atrazine and terbutryn are able to kill plants?

What is the reason that C3 plants must open their stomata even when the climate is hot and dry?

What is the plant cell's primary source of reducing power?

Another investigator labels CO₂ with radiolabeled ¹⁸O.After exposure of a plant adapted to a hot,dry climate to the radiolabeled CO₂,in what molecule does the radiolabeled ¹⁸O appear?

It is much _ to pull electrons from water than hydrogen sulfide,since the sulfur atom in hydrogen sulfide has much __ affinity for its electrons than the oxygen atom in water.

______is a small,water-soluble,iron-sulfur protein that transfers electrons to NADP⁺ to form NADPH.

What is the reason that C₃ plants must open their stomata even when the climate is hot and dry?