Mastering Biology Chapter 8

In a plant cell, where are ATP synthase complexes located? inner mitochondrial membranes only thylakoid membrane and inner mitochondrial membranes plasma membrane only thylakoid membranes only thylakoid membrane and plasma membranes

Thylakoid membranes and inner mitochondrial membranes

Which of the following products of the light reactions of photosynthesis is used during the Calvin cycle? Hints ADP + Pi water NADPH oxygen sugar

NADPH

What is the basic role of CO2 in photosynthesis? CO2 is a source of electrons in the formation of organic molecules. CO2 is taken in by plants as a form of inverse respiration, in which carbon dioxide is "breathed in" and oxygen is "breathed out." CO2 is fixed or incorporated into organic molecules.

CO2 is fixed or incorporated into organic molecules.

Which of these phosphorylates ADP to make ATP? The figure shows the membrane of the thylakoid. Letters from A to E indicate definite structures. Letter A indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. Letter B indicates the multiprotein complex between two photosystems. Letter C marks the second integral membrane protein complex of the light-dependent reactions. Letter D marks the substance inside thylakoid. Letter E indicates the flask-shaped structure, which has a canal for hydrogen ions. D E A C B

E

the figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. What colors of light are least effective in driving photosynthesis? green-yellow violet-blue orange-red yellow-orange

Green-Yellow

Plants are photoautotrophs. What does this mean? They are attracted to light. They generate oxygen. They are the primary consumers of the biosphere. They use light energy to drive the synthesis of organic molecules from inorganic materials. They synthesize their own food from inorganic materials.

They use light energy to drive the synthesis of organic molecules from inorganic materials.

In the thylakoid membranes, what is the main role of the pigment molecules in a light-harvesting complex? transfer electrons to NADPH split water and release oxygen to the reaction-center chlorophyll transfer light energy to the reaction-center chlorophyll synthesize ATP from ADP and ℗i

Transfer light energy to the reaction-center chlorophyll

Which of the following particles can pass through the ATP synthase channel? ADP ATP Protons Inorganic phosphate

Protons

The ultimate source of energy to support most life on Earth is _____. geothermal heat the carbon cycle chemosynthetic microbes sunlight photosynthetic plants

sunlight

Which process is most directly driven by light energy? reduction of NADP+ molecules creation of a pH gradient by pumping protons across the thylakoid membrane ATP synthesis removal of electrons from chlorophyll molecules

removal of electrons from chlorophyll molecules

How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose? 6 4 10 8 2

6

Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+. The figure shows the membrane of the thylakoid. Letters from A to E indicate definite structures. Letter A indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. Letter B indicates the multiprotein complex between two photosystems. Letter C marks the second integral membrane protein complex of the light-dependent reactions. Letter D marks the substance inside thylakoid. Letter E indicates the flask-shaped structure, which has a canal for hydrogen ions. B D E A C

C

In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells. thylakoids grana stomata stroma cytoplasm

Cytoplasm

Select the correct molecule that is the main product of the Calvin cycle. G3P Glucose NADPH

G3P

Photorespiration occurs when rubisco combines RuBP with NADPH. glyceraldehyde 3-phosphate. citrate. CO2. O2.

O2

Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose? Regneration of RuBP Production of 3-phosphoglycerate Production of G3P Carbon fixation

Regneration of RuBP

What is the biological significance of the light-independent reactions of photosynthesis? They convert carbon dioxide to sugar. They generate ATP and NADPH. They convert ATP to sugar. They make oxygen.

They convert carbon dioxide to sugar.

True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.

True

In C3 plants the conservation of water promotes _____. the opening of stomata photorespiration photosynthesis the light reactions a shift to C4 photosynthesis

photorespiration

Which of the following does NOT occur during the Calvin cycle? release of oxygen carbon fixation oxidation of NADPH regeneration of the CO2 acceptor

release of oxygen

Where does the Calvin cycle take place? outer membrane of the chloroplast interior of the thylakoid (thylakoid space) stroma of the chloroplast thylakoid membrane

stroma of the chloroplast

Where are the molecules of the electron transport chain associated with photophosphorylation located in plant cells? thylakoid membranes of chloroplasts stroma of chloroplasts matrix of mitochondria outer membrane of chloroplasts inner membrane of mitochondria

thylakoid membranes of chloroplasts

Carbon fixation involves the addition of carbon dioxide to _____. G3P NADPH Rubisco RuBP 3-PGA

RuBP

Which set of reactions uses H2O and produces O2? The light-independent reactions The light-dependent reactions

The light-dependent reactions

Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis? The light-independent reactions release energy, and the light-dependent reactions require energy. The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions. The light-dependent reactions produce carbon dioxide, which is then used by the light-independent reactions. The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.

The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they fix CO2 into organic acids in the bundle-sheath cells, which do not rely on stomata. fix CO2 into by combining it with RuBP in the Calvin cycle. fix CO2 into organic acids during the night when temperatures are cooler. obtain CO2 through their roots during the day. fix CO2 into organic acids in the mesophyll cells, which do not rely on stomata.

fix CO2 into organic acids during the night when temperatures are cooler.

Which of the following molecules is the primary product of photosystem I? ATP NADPH Oxygen Carbon dioxide

NADPH

Which term describes ATP production resulting from the capture of light energy by chlorophyll? Oxidative phosphorylation Substrate-level phosphorylation Dephosphorylation Photophosphorylation

Photophosphorylation

Which process produces oxygen? Cellular respiration Photosynthesis

Photosynthesis

Why are plants classified as producers? Plants are classified as producers because they produce oxygen. Plants are classified as producers because they are at the bottom of the food chain. Plants are classified as producers because they fix inorganic carbon into organic molecules.

Plants are classified as producers because they fix inorganic carbon into organic molecules.

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? ATP and NADPH ADP, i, and NADP+ CO2 and glucose electrons and H+ H2O and O2

ATP and NADPH

True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain. True False

False

Which of the following sequences correctly represents the flow of electrons during photosynthesis? NADPH → electron transport chain → O2 NADPH → O2 → CO2 H2O → photosystem I → photosystem II H2O → NADPH → Calvin cycle

H2O → NADPH → Calvin cycle

C4 plants occur more commonly in desert conditions because __________. Hints they store carbon by incorporating CO2 into organic acids that are later catabolized the stomata open at night and close in the day they produce carbon dioxide internally via photorespiration they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed they produce water as a product of their photosynthetic pathways

they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed

C4 plants differ from C3 and CAM plants in that C4 plants _____. use PEP carboxylase to fix carbon dioxide transfer fixed carbon dioxide to cells in which the Calvin cycle occurs open their stomata only at night are better adapted to wet conditions use malic acid to transfer carbon dioxide to the Calvin cycle

transfer fixed carbon dioxide to cells in which the Calvin cycle occurs

What compound provides the reducing power for the Calvin cycle reactions? CO2 FAD NADPH FADH2 ATP

NADPH

In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules? 3 2 5 4 1

3

_____ splits water into 1/2 O2, H+, and e- . The figure shows the membrane of the thylakoid. Letters from A to E indicate definite structures. Letter A indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. Letter B indicates the multiprotein complex between two photosystems. Letter C marks the second integral membrane protein complex of the light-dependent reactions. Letter D marks the substance inside thylakoid. Letter E indicates the flask-shaped structure, which has a canal for hydrogen ions. A C B E D

A

Chlorophyll can be found in _____. The figure shows the membrane of the thylakoid. Letters from A to E indicate definite structures. Letter A indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. Letter B indicates the multiprotein complex between two photosystems. Letter C marks the second integral membrane protein complex of the light-dependent reactions. Letter D marks the substance inside thylakoid. Letter E indicates the flask-shaped structure, which has a canal for hydrogen ions. A and B B and D B and E A and C B and C

A and C

Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5‎ . The solution is then adjusted to pH 8‎ . Which of the following conclusions can be drawn from these experimental conditions? ATP will be produced because the proton gradient favors proton movement through the ATP synthase channels. The change in the solution's pH results in a gradient across the chloroplast membranes such that there is a lower concentration of protons inside the vesicles and a higher concentration outside. Protons will not diffuse toward the outside of the vesicles. ATP will not be produced because there is no ADP and inorganic phosphate in the solution.

ATP will not be produced because there is no ADP and inorganic phosphate in the solution.

Which of the following statements is a correct distinction between autotrophs and heterotrophs? Only heterotrophs have mitochondria. Only heterotrophs require chemical compounds from the environment. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. Cellular respiration is unique to heterotrophs.

Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.

_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment. The figure shows the membrane of the thylakoid. Letters from A to E indicate definite structures. Letter A indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. Letter B indicates the multiprotein complex between two photosystems. Letter C marks the second integral membrane protein complex of the light-dependent reactions. Letter D marks the substance inside thylakoid. Letter E indicates the flask-shaped structure, which has a canal for hydrogen ions. D A B C E

B

Generation of proton gradients across membranes occurs during cellular respiration only. photosynthesis only. both photosynthesis and cellular respiration. neither photosynthesis nor cellular respiration.

Both photosynthesis an cellular respiration

Which of the following statements about the relationship between photosynthesis and cellular respiration is true? Cellular respiration is catabolic and photosynthesis is anabolic. Cellular respiration occurs only in animals and photosynthesis occurs only in plants. There is a net consumption of ATP in cellular respiration and a net production of ATP in photosynthesis. In photosynthesis the biochemical pathways of cellular respiration run in reverse. In cellular respiration the biochemical pathways of photosynthesis run in reverse.

Cellular respiration is cabloid and photosynthesis is anabolic

True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane. True False

False

How is photosynthesis similar in C4 plants and CAM plants? Both types of plants make most of their sugar in the dark. In both cases, rubisco is not used to fix carbon initially. Both types of plants make sugar without the Calvin cycle. In both cases, electron transport is not used.

In both cases, rubisco is not used to fix carbon initially.

Which of the following events occurs in the light reactions of photosynthesis? NADP+ is produced. ATP is consumed to yield ADP. Light is absorbed and funneled to reaction-center chlorophyll a. Carbon dioxide is fixed in organic molecules.

Light is absorbed and funneled to reaction-center

After 3-PGA is phosphorylated, it is reduced by _____. NADPH CO2 ATP NADP+ ADP

NADPH

According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis? Electrons Proton gradient Osmotic gradient Temperature gradient

Proton gradient

Which of the following is directly associated with photosystem I? generation of molecular oxygen extraction of hydrogen electrons from the splitting of water receiving electrons from the thylakoid membrane electron transport chain harvesting of light energy by ATP

Receiving electrons from the thylakoid membrane electron electron transport chain

_____ has a longer wavelength than _____. Red ... green Violet ... blue Yellow ... red Blue ... green Green ... yellow

Red....Green

Select the correct statement about the Calvin cycle. The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP. The Calvin cycle takes place primarily in the dark. The basic function of the Calvin cycle is the conversion of solar energy to chemical energy.

The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP.

Select the most accurate statement describing the basic function of the light reactions of photosynthesis. The basic function of the light reactions of photosynthesis is the production of glucose. The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy. The basic function of the light reactions of photosynthesis is the trapping of light energy.

The basic function of the light reactions of photosynthesis is the conversion of solar energy to chemical energy.

What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? The light-independent reactions turn glucose, a sugar, into CO2 gas. The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars. The light-independent reactions use CO2 to make ATP. The light-independent reactions turn sugar into ATP for energy.

The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.

Compared to C3 plants, C4 plants do not use rubisco for carbon fixation. grow better under cool, moist conditions. can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations. have higher rates of photorespiration.

can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations.

The overall function of the Calvin cycle is __________. Hints splitting water capturing sunlight making sugar oxidizing glucose producing carbon dioxide

making sugar

The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during respiration. neither photosynthesis nor respiration. photosynthesis. both photosynthesis and cellular respiration. photorespiration.

neither photosynthesis nor respiration

Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle. consumed...reduced reduced...reduced consumed...consumed reduced...oxidized oxidized...reduced

oxidized...reduced

In the process of carbon fixation, three molecules of RuBP combine with three molecules of CO2 to produce three six-carbon molecules, which are then split to produce 12 molecules of 3-phosphoglycerate. After phosphorylation and reduction produce 12 glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle? release of one G3P to make sugars and regeneration of RuBP release of two G3P to make sugars and regeneration of RuBP release of one G3P to make sugars and regeneration of citrate release of two G3P to make sugars and regeneration of ATP from ADP release of one G3P to make sugars and regeneration of NADPH

release of one G3P to make sugars and regeneration of RuBP