Mastering Biology 3

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? a) It is used to store energy as more ATP. b) It is used to generate ADP from nucleotide precursors. c) It is transported to specific organs such as the brain. d) It is used to power yet more cellular work. e) It is lost to the environment.

An enzyme is ________ when it loses its native conformation and its biological activity.

An enzyme is considered a ________ because it speeds up chemical reactions without being used up.

An enzyme is considered ________ because of its ability to recognize the shape of a particular molecule.

A _______, such as a vitamin, binds to an enzyme and plays a role in catalysis.

When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) ______.

A substrate binds to an enzyme at the __________, where the reaction occurs.

In a catalyzed reaction a reactant is often called a _______.

In general, enzymes are what kinds of molecules? a) carbohydrates b) lipids c) minerals d) proteins e) nucleic acids

Enzymes work by _____. a) adding energy to a reaction b) decreasing the potential energy difference between reactant and product c) reducing EA d) adding a phosphate group to a reactant e) increasing the potential energy difference between reactant and product

An enzyme _____. a) is an organic catalyst b) is a source of energy for endergonic reactions c) is a inorganic catalyst d) increases the EA of a reaction e) can bind to nearly any molecule

What name is given to the reactants in an enzymatically catalyzed reaction? a) active sites b) reactors c) EA d) products e) substrate

As a result of its involvement in a reaction, an enzyme _____. a) permanently alters its shape. b) loses energy c) is used up d) loses a phosphate group e) is unchanged

The active site of an enzyme is the region that a) binds the products of the catalytic reaction. b) is involved in the catalytic reaction of the enzyme. c) is inhibited by the presence of a coenzyme or a cofactor. d) binds allosteric regulators of the enzyme.

Where does glycolysis takes place? a) cytosol b) mitochondrial inner membrane c) mitochondrial matrix d) mitochondrial intermembrane space e) mitochondrial outer membrane

How many NADH are produced by glycolysis? a) 5 b) 4 c) 3 d) 1 e) 2

In glycolysis, ATP molecules are produced by _____. a) substrate-level phosphorylation b) photophosphorylation c) photosynthesis d) cellular respiration e) oxidative phosphorylation

Which of these is NOT a product of glycolysis? a) pyruvate b) FADH2 c) NADH d) ATP

In glycolysis, what starts the process of glucose oxidation? a) NADPH b) hexokinase c) FADH2 d) ADP e) ATP

In glycolysis there is a net gain of _____ ATP. a) 2 b) 3 c) 5 d) 1 e) 4

During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is a) transferred directly to ATP. b) used to phosphorylate fructose to form fructose-6-phosphate. c) retained in the pyruvate. d) transferred to ADP, forming ATP. e) stored in the NADH produced.

Starting with one molecule of glucose, the "net" products of glycolysis are a) 2 NAD+, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. b) 2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O. c) 6 CO2, 6 H2O, 2 ATP, and 2 pyruvate. d) 6 CO2, 6 H2O, 36 ATP, and 2 citrate. e) 2 FADH2, 2 pyruvate, 4 ATP, and 2 H2O.

In glycolysis, for each molecule of glucose oxidized to pyruvate a) 2 molecules of ATP are used and 2 molecules of ATP are produced. b) 6 molecules of ATP are used and 6 molecules of ATP are produced. c) 4 molecules of ATP are used and 2 molecules of ATP are produced. d) 2 molecules of ATP are used and 4 molecules of ATP are produced. e) 2 molecules of ATP are used and 6 molecules of ATP are produced.

During cellular respiration, acetyl CoA accumulates in which location? a) mitochondrial inner membrane b) mitochondrial outer membrane c) mitochondrial matrix d) cytosol e) mitochondrial intermembrane space

Energy released by the electron transport chain is used to pump H+ ions into which location? a) mitochondrial inner membrane b) mitochondrial outer membrane c) cytosol d) mitochondrial matrix e) mitochondrial intermembrane space

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the a) reduction of NAD+. b) restoration of the Na+/K+ balance across the membrane. c) formation of ATP. d) creation of a proton gradient. e) lowering of pH in the mitochondrial matrix.

Where is ATP synthase located in the mitochondrion? a) electron transport chain b) outer membrane c) cytosol d) inner membrane e) mitochondrial matrix

In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP? a) energy released from substrate-level phosphorylation b) energy released from movement of protons through ATP synthase c) No external source of energy is required because the reaction is exergonic. d) energy released from ATP synthase pumping hydrogen ions from the mitochondrial matrix e) energy released as electrons flow through the electron transport system

During oxidative phosphorylation, H2O is formed. Where does the oxygen for the synthesis of the water come from? a) lactate (C3H5O3-) b) glucose (C6H12O6) c) pyruvate (C3H3O3-) d) carbon dioxide (CO2) e) molecular oxygen (O2)

The primary role of oxygen in cellular respiration is to a) yield energy in the form of ATP as it is passed down the respiratory chain. b) act as an acceptor for electrons and hydrogen, forming water. c) combine with carbon, forming CO2. d) combine with lactate, forming pyruvate. e) catalyze the reactions of glycolysis.

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? a) fermentation and glycolysis b) oxidation of pyruvate to acetyl CoA and the citric acid cycle c) glycolysis and the oxidation of pyruvate to acetyl CoA d) the citric acid cycle and oxidative phosphorylation e) oxidative phosphorylation and fermentation

Where are the proteins of the electron transport chain located? a) mitochondrial intermembrane space b) mitochondrial matrix c) cytosol d) mitochondrial inner membrane e) mitochondrial outer membrane

Which metabolic pathway is common to both cellular respiration and fermentation? a) chemiosmosis b) the oxidation of pyruvate to acetyl CoA c) glycolysis d) the citric acid cycle e) oxidative phosphorylation

In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of a) ATP, CO2, and ethanol (ethyl alcohol). b) ATP, pyruvate, and acetyl CoA. c) ATP, pyruvate, and oxygen. d) ATP, CO2, and lactate. e) ATP, NADH, and pyruvate.

One function of both alcohol fermentation and lactic acid fermentation is to a) oxidize NADH to NAD+. b) reduce FADH2 to FAD+. c) reduce FAD+ to FADH2. d) reduce NAD+ to NADH. e) none of the above

The oxygen consumed during cellular respiration is involved directly in which process or event? a) the oxidation of pyruvate to acetyl CoA b) accepting electrons at the end of the electron transport chain c) the citric acid cycle d) the phosphorylation of ADP to form ATP e) glycolysis

Which of these equations best summarizes photosynthesis? a) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy b) H2O → 2 H+ + 1/2 O2 + 2e- c) 6 CO2 + 6 H2O → C6H12O6 + 6 O2 d) C6H12O6 + 6 O2 → 6 CO2 + 12 H2O e) 6 CO2 + 6 O2 → C6H12O6 + 6 H2O

Where does the Calvin Cycle occur? a) Stroma b) Chloroplasts c) Thylakoids

The light reactions of photosynthesis use _____ and produce _____. a) carbon dioxide ... oxygen b) carbon dioxide ... sugar c) NADPH ... NADP+ d) NADPH ... oxygen e) water ... NADPH

What phosphorylates ADP to make ATP?

_______ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.

_____ splits water into 1/2 O2, H+, and e- .

Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.

Chlorophyll can be found in _____.

Which of the following statements best describes the relationship between photosynthesis and respiration? a) ATP molecules are produced in photosynthesis and used up in respiration. b) Respiration is anabolic and photosynthesis is catabolic. c) Photosynthesis stores energy in complex organic molecules, while respiration releases it. d) Photosynthesis occurs only in plants and respiration occurs only in animals. e) Respiration is the reversal of the biochemical pathways of photosynthesis.

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? a) ATP and NADPH b) electrons and H+ c) ADP, Pi, and NADP+ d) H2O and O2 e) CO2 and glucose

In the thylakoid membranes, what is the main role of the antenna pigment molecules? a) transfer electrons to ferredoxin and then NADPH b) split water and release oxygen to the reaction-center chlorophyll c) synthesize ATP from ADP and Pi d) concentrate photons within the stroma e) harvest photons and transfer light energy to the reaction-center chlorophyll

Where does the Calvin cycle take place? a) chlorophyll molecule b) outer membrane of the chloroplast c) thylakoid membrane d) stroma of the chloroplast e) cytoplasm surrounding the chloroplast

Which of the events listed below occur in the light reactions of photosynthesis? a) carbon dioxide is incorporated into PGA. b) NADPH is reduced to NADP+ c) NADP is produced. d) ATP is phosphorylated to yield ADP. e) light is absorbed and funneled to reaction-center chlorophyll a.

In a plant cell, where are the ATP synthase complexes located? a) plasma membrane b) inner mitochondrial membrane c) thylakoid membrane and inner mitochondrial membrane d) thylakoid membrane, plasma membrane and inner mitochondrial membrane e) thylakoid membrane

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from a) the matrix to the stroma. b) the intermembrane space to the matrix. c) ATP synthase to NADP+ reductase. d) the stroma to the thylakoid space. e) the stroma to the photosystem II.

Synthesis of ATP by the chemiosmotic mechanism occurs during a) both photosynthesis and respiration. b) respiration. c) photorespiration. d) photosynthesis. e) neither photosynthesis nor respiration.

Generation of proton gradients across membranes occurs during a) respiration. b) photorespiration. c) neither photosynthesis nor respiration. d) both photosynthesis and respiration. e) photosynthesis.

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Produces molecular oxygen (O2) a) both the light reactions and the Calvin cycle b) neither the light reactions nor the Calvin cycle c) the Calvin cycle alone d) light reactions alone e) occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Produces NADPH a) neither the light reactions nor the Calvin cycle b) occurs in the chloroplast but is not part of photosynthesis c) both the light reactions and the Calvin cycle d) the Calvin cycle alone e) light reactions alone

Carbon fixation involves the addition of carbon dioxide to _____. a) Rubisco b) RuBP c) 3-PGA d) G3P e) NADPH

After 3-PGA is phosphorylated, it is reduced by _____. a) CO2 b) ADP c) NADP+ d) NADPH e) ATP

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

In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules? a) 1 b) 2 c) 4 d) 5 e) 3

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle? a) The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split. b) The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions. c) There is no relationship between the light reactions and the Calvin cycle. d) The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions. e) The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP.

Where do the enzymatic reactions of the Calvin cycle take place? a) thylakoid membranes b) outer membrane of the chloroplast c) electron transport chain d) thylakoid space e) stroma of the chloroplast

What is the primary function of the Calvin cycle? a) use ATP to release carbon dioxide b) split water and release oxygen c) transport RuBP out of the chloroplast d) synthesize simple sugars from carbon dioxide e) use NADPH to release carbon dioxide

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Requires ATP a) occurs in the chloroplast but is not part of photosynthesis b) light reactions alone c) neither the light reactions nor the Calvin cycle d) both the light reactions and the Calvin cycle e) the Calvin cycle alone

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Produces NADH a) neither the light reactions nor the Calvin cycle b) light reactions alone c) both the light reactions and the Calvin cycle d) occurs in the chloroplast but is not part of photosynthesis e) the Calvin cycle alone

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Produces three-carbon sugars a) neither the light reactions nor the Calvin cycle b) light reactions alone c) the Calvin cycle alone d) both the light reactions and the Calvin cycle e) occurs in the chloroplast but is not part of photosynthesis

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Requires CO2 a) both the light reactions and the Calvin cycle b) light reactions alone c) neither the light reactions nor the Calvin cycle d) occurs in the chloroplast but is not part of photosynthesis e) the Calvin cycle alone

For the following question, compare the light reactions with the Calvin cycle of photosynthesis in plants. Requires glucose a) neither the light reactions nor the Calvin cycle b) both the light reactions and the Calvin cycle c) the Calvin cycle alone d) occurs in the chloroplast but is not part of photosynthesis e) light reactions alone