Question 1

The process of photosynthesis probably originated

Accepted Answer

A)  in plants. 
B)  three separate times. 
C)  in fungi. 
D)  in prokaryotes. 
A)  in plants. 
B)  three separate times. 
C)  in fungi. 
D)  in prokaryotes.

Question 2

Stomata, openings in the leaf, are important to photosynthesis for

Accepted Answer

A)  entry of oxygen that is used in the Calvin cycle. 
B)  removal of water and carbon dioxide, the end- products of photo- oxidation. 
C)  entry of carbon dioxide that is used in the Calvin cycle. 
D)  removal of nitrogen- containing waste products. 
A)  entry of oxygen that is used in the Calvin cycle. 
B)  removal of water and carbon dioxide, the end- products of photo- oxidation. 
C)  entry of carbon dioxide that is used in the Calvin cycle. 
D)  removal of nitrogen- containing waste products.

Question 3

Some photosynthetic organisms contain chloroplasts that lack photosystem II yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to

Accepted Answer

A)  test for CO2 fixation in the dark. 
B)  determine whether they have thylakoids in the chloroplasts. 
C)  do experiments to generate an action spectrum. 
D)  test for liberation of O2 in the light. 
E)  test for production of either sucrose or starch. 
A)  test for CO2 fixation in the dark. 
B)  determine whether they have thylakoids in the chloroplasts. 
C)  do experiments to generate an action spectrum. 
D)  test for liberation of O2 in the light. 
E)  test for production of either sucrose or starch.

Question 4

Purple photosynthetic bacteria do not contain chloroplasts. They have an antenna system that includes two light- harvesting protein complexes, both of which are integral membrane proteins. The bacteriochlorophyll a molecules contain Mg2+ and absorb light at 800 nm. Which of the following statements comparing photosynthesis in purple bacteria and plant chloroplasts is true?

Accepted Answer

A)  Because purple bacteria do not have chloroplasts, there is no electron transport associated with photosynthesis. 
B)  Plant chlorophyll a absorbs in the visible light range, whereas purple photosynthetic bacteriochlorophyll a absorbs light at a longer wavelength. 
C)  Bacteriochlorophyll a absorbs light most efficiently in the ultraviolet range, at a significantly shorter wavelength than that for chlorophyll a of chloroplasts. 
D)  Bacteriochlorophyll a is a molecule containing Mg2+, whereas chlorophyll a from chloroplasts contains Fe2+. 
A)  Because purple bacteria do not have chloroplasts, there is no electron transport associated with photosynthesis. 
B)  Plant chlorophyll a absorbs in the visible light range, whereas purple photosynthetic bacteriochlorophyll a absorbs light at a longer wavelength. 
C)  Bacteriochlorophyll a absorbs light most efficiently in the ultraviolet range, at a significantly shorter wavelength than that for chlorophyll a of chloroplasts. 
D)  Bacteriochlorophyll a is a molecule containing Mg2+, whereas chlorophyll a from chloroplasts contains Fe2+.

Question 5

Data suggest that rubisco ribulose- 1,5- bisphosphate carboxylase) makes up 10% of the total protein found in spinach leaves. Research elucidating the structure of rubisco shows that it has four active sites. Why, with four active sites, might there be such a large concentration of rubisco in plant matter?

Accepted Answer

A)  Rubisco is a very slow enzyme; what it lacks in speed, it makes up in numbers. 
B)  Rubisco catalyzes four of the six reactions found in the Calvin cycle. 
C)  Three of the four active sites bind carbon dioxide; only one binds ribulose- 1,5- bisphosphate. 
D)  All heterotrophic organisms depend on plants, either directly or indirectly, for their food supply. 
A)  Rubisco is a very slow enzyme; what it lacks in speed, it makes up in numbers. 
B)  Rubisco catalyzes four of the six reactions found in the Calvin cycle. 
C)  Three of the four active sites bind carbon dioxide; only one binds ribulose- 1,5- bisphosphate. 
D)  All heterotrophic organisms depend on plants, either directly or indirectly, for their food supply.

Question 6

Which of the following statements best describes the relationship between photosynthesis and respiration?

Accepted Answer

A)  Photosynthesis occurs only in plants; respiration occurs only in animals. 
B)  Respiration runs the biochemical pathways of photosynthesis in reverse. 
C)  ATP molecules are produced in photosynthesis but not in aerobic respiration. 
D)  Photosynthesis is catabolic; respiration is anabolic. 
E)  Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules. 
A)  Photosynthesis occurs only in plants; respiration occurs only in animals. 
B)  Respiration runs the biochemical pathways of photosynthesis in reverse. 
C)  ATP molecules are produced in photosynthesis but not in aerobic respiration. 
D)  Photosynthesis is catabolic; respiration is anabolic. 
E)  Photosynthesis stores energy in complex organic molecules; respiration releases energy from complex organic molecules.

Question 7

The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

Accepted Answer

A)  the electron carrier, plastocyanin 
B)  photosystem I 
C)  oxygen 
D)  water 
A)  the electron carrier, plastocyanin 
B)  photosystem I 
C)  oxygen 
D)  water

Question 8

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is the most believable result?

Accepted Answer

A)  The single band of pigment that is isolated is always some shade of green. 
B)  Paper chromatography would separate the pigments from a particular plant into several bands. 
C)  Paper chromatography isolates only the pigments that reflect green light. 
D)  Paper chromatography for the plant would isolate a single band of pigment that is characteristic of the particular plant. 
A)  The single band of pigment that is isolated is always some shade of green. 
B)  Paper chromatography would separate the pigments from a particular plant into several bands. 
C)  Paper chromatography isolates only the pigments that reflect green light. 
D)  Paper chromatography for the plant would isolate a single band of pigment that is characteristic of the particular plant.

Question 9

Energy from sunlight can excite electrons, kicking them out of their orbitals and creating free radicals. Free radicals are highly reactive atoms or molecules that have unpaired electrons. They degrade and destroy other compounds in their vicinity. Carotenoids, one of the pigments present in most chloroplasts, can stabilize these free radicals. This suggests that

Accepted Answer

A)  carotenoids probably have a protective function in the cell. 
B)  once chloroplasts are destroyed, the free radicals will destroy the cell. 
C)  other pigments besides carotenoids and chlorophyll) are essential for the health of a plant cell. 
D)  carotenoids communicate directly with the immune system of plants. 
A)  carotenoids probably have a protective function in the cell. 
B)  once chloroplasts are destroyed, the free radicals will destroy the cell. 
C)  other pigments besides carotenoids and chlorophyll) are essential for the health of a plant cell. 
D)  carotenoids communicate directly with the immune system of plants.

Question 10

The light- independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

Accepted Answer

A)  electrons from oxygen 
B)  ATP 
C)  NADPH 
D)  NADH 
A)  electrons from oxygen 
B)  ATP 
C)  NADPH 
D)  NADH

Question 11

Which of the following procedures would identify the enzyme that catalyzes the carboxylation of ribulose- 1,5- bisphosphate?

Accepted Answer

A)  differential sedimentation of a protein extract 
B)  introducing radiolabeled carbon dioxide into a plant extract and determining which molecules become radiolabeled 
C)  irradiating a leaf extract with red light 
D)  purifying a variety of proteins from plant extracts and testing each protein individually to see if it can carboxylate ribulose- 1,5- bisphosphate 
A)  differential sedimentation of a protein extract 
B)  introducing radiolabeled carbon dioxide into a plant extract and determining which molecules become radiolabeled 
C)  irradiating a leaf extract with red light 
D)  purifying a variety of proteins from plant extracts and testing each protein individually to see if it can carboxylate ribulose- 1,5- bisphosphate

Question 12

In autumn, the leaves of deciduous trees change colours. This is because the chlorophyll is degraded, and

Accepted Answer

A)  the carotenoids and other pigments are still present in the leaves. 
B)  water supply to the leaves has been reduced. 
C)  degraded chlorophyll becomes a pigment with different colours. 
D)  the cells of the leaves begin to die. 
A)  the carotenoids and other pigments are still present in the leaves. 
B)  water supply to the leaves has been reduced. 
C)  degraded chlorophyll becomes a pigment with different colours. 
D)  the cells of the leaves begin to die.

Question 13

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from

Accepted Answer

A)  H2S. 
B)  glucose. 
C)  water. 
D)  electrons from NADPH. 
A)  H2S. 
B)  glucose. 
C)  water. 
D)  electrons from NADPH.

Question 14

Photorespiration is

Accepted Answer

A)  not a problem, because oxygen is not available in the chloroplast where photorespiration takes place. 
B)  a process involving the carboxylation of ribulose- 1,5- bisphosphate. 
C)  a process involving addition of oxygen to ribulose- 1,5- bisphosphate and the formation of ribose- 1,5- diphosphate. 
D)  a process involving the addition of oxygen to ribulose- 1,5- bisphosphate and the formation of the products 3- phosphoglycerate and 2- phosphoglycolate. 
A)  not a problem, because oxygen is not available in the chloroplast where photorespiration takes place. 
B)  a process involving the carboxylation of ribulose- 1,5- bisphosphate. 
C)  a process involving addition of oxygen to ribulose- 1,5- bisphosphate and the formation of ribose- 1,5- diphosphate. 
D)  a process involving the addition of oxygen to ribulose- 1,5- bisphosphate and the formation of the products 3- phosphoglycerate and 2- phosphoglycolate.

Question 15

Plastoquinone PQ), an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

Accepted Answer

A)  mobile in the thylakoid membrane. 
B)  lipid soluble. 
C)  a molecule that serves as a shuttle between the electron transport chain and ATP synthase. 
D)  both A and B. 
A)  mobile in the thylakoid membrane. 
B)  lipid soluble. 
C)  a molecule that serves as a shuttle between the electron transport chain and ATP synthase. 
D)  both A and B.

Question 16

What is a difference between chlorophyll a and chlorophyll b?

Accepted Answer

A)  Chlorophyll a is a pigment, and chlorophyll b is the enzyme that transfers excited electrons from chlorophyll a to electron carriers of the thylakoid membrane. 
B)  Chlorophyll a and b absorb light energy at slightly different wavelengths. 
C)  Chlorophyll a absorbs yellow light, and chlorophyll b absorbs green. 
D)  Chlorophyll a contains Mg++ in a ring structure, whereas chlorophyll b contains iron. 
A)  Chlorophyll a is a pigment, and chlorophyll b is the enzyme that transfers excited electrons from chlorophyll a to electron carriers of the thylakoid membrane. 
B)  Chlorophyll a and b absorb light energy at slightly different wavelengths. 
C)  Chlorophyll a absorbs yellow light, and chlorophyll b absorbs green. 
D)  Chlorophyll a contains Mg++ in a ring structure, whereas chlorophyll b contains iron.

Question 17

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will most directly affect the

Accepted Answer

A)  splitting of water. 
B)  reduction of NADP+. 
C)  synthesis of ATP. 
D)  absorption of light energy by chlorophyll. 
E)  flow of electrons from photosystem II to photosystem I. 
A)  splitting of water. 
B)  reduction of NADP+. 
C)  synthesis of ATP. 
D)  absorption of light energy by chlorophyll. 
E)  flow of electrons from photosystem II to photosystem I.

Question 18

Besides proteins, thylakoid membranes must contain a large number of___________ molecules in the reaction centers in order to harvest light energy.

Accepted Answer

A)  pigment 
B)  electron carrier 
C)  oligosaccharide 
D)  phospholipid 
A)  pigment 
B)  electron carrier 
C)  oligosaccharide 
D)  phospholipid

Question 19

Most of the enzymes of the Calvin cycle also function in other metabolic pathways. This should not be a surprising finding, because

Accepted Answer

A)  the Calvin cycle probably evolved at the same time as did glycolysis. 
B)  the Calvin cycle is nearly ubiquitous in cells, as are metabolic pathways. 
C)  metabolic reactions are catalyzed by enzymes that have multiple functions. 
D)  there is a close relationship between carbohydrate synthesis and metabolic breakdown. 
A)  the Calvin cycle probably evolved at the same time as did glycolysis. 
B)  the Calvin cycle is nearly ubiquitous in cells, as are metabolic pathways. 
C)  metabolic reactions are catalyzed by enzymes that have multiple functions. 
D)  there is a close relationship between carbohydrate synthesis and metabolic breakdown.

Question 20

In photosynthesis, what is the role of water H2O)?

Accepted Answer

A)  It accepts electrons liberated from the reaction centre of photosystem I. 
B)  It provides O2, the terminal electron acceptor for the electron transport chain. 
C)  It allows cyclic photophosphorylation to occur when ATP levels are low in the stroma. 
D)  It donates electrons to replace lost electrons in the reaction centre of photosystem II. 
E)  It provides the necessary H+ ions needed to reduce glyceraldehyde- 3- phosphate G3P). 
A)  It accepts electrons liberated from the reaction centre of photosystem I. 
B)  It provides O2, the terminal electron acceptor for the electron transport chain. 
C)  It allows cyclic photophosphorylation to occur when ATP levels are low in the stroma. 
D)  It donates electrons to replace lost electrons in the reaction centre of photosystem II. 
E)  It provides the necessary H+ ions needed to reduce glyceraldehyde- 3- phosphate G3P).

Exam 10: Photosynthesis

The process of photosynthesis probably originated

Stomata, openings in the leaf, are important to photosynthesis for

Some photosynthetic organisms contain chloroplasts that lack photosystem II yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be to

Which of the following statements best describes the relationship between photosynthesis and respiration?

The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come?

If pigments from a particular species of plant are extracted and subjected to paper chromatography, which of the following is the most believable result?

The light- independent reactions of plants function to make organic molecules using carbon dioxide as a carbon source. What is the electron source that helps reduce carbon dioxide to sugars and other organic molecules?

Which of the following procedures would identify the enzyme that catalyzes the carboxylation of ribulose- 1,5- bisphosphate?

In autumn, the leaves of deciduous trees change colours. This is because the chlorophyll is degraded, and

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide. In fact, it comes from

Photorespiration is

Plastoquinone PQ), an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably

What is a difference between chlorophyll a and chlorophyll b?

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will most directly affect the

Besides proteins, thylakoid membranes must contain a large number of___________ molecules in the reaction centers in order to harvest light energy.

Most of the enzymes of the Calvin cycle also function in other metabolic pathways. This should not be a surprising finding, because

In photosynthesis, what is the role of water H2O)?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes

Cellular Respiration and Fermentation

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Gene Structure and Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

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