55 terms

Biology Unit 3

The ATP made during glycolysis is generated by
A) oxidation of NADH to NADH+
B) photophosphorylation
C) chemiosmosis
D) electron transport
E) substrate-level phosphorylation
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
A) bioenergetic pathways
B) catabolic pathways
C) thermodynamic pathways
D) fermentaiton pathways
E) anabolic pathways
Which of the following statements describes the results of this reaction?
C6H12O6 + 6O2 --> 6CO2 + 6H2O + Energy
A) O2 is oxidized and H2O is reduced.
B) CO2 is reduced and O2 is oxidized.
C) C6H12O6 is oxidized and O2 is reduced.
D) C6H12O6 is reduced and CO2 is oxidized.
E) O2 is reduced and CO2 is oxidized.
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?
A) 0%
B) 38%
C) 10%
D) 100%
E) 2%
Where does glycolysis takes place?
A) cytosol
B) mitochondrial outer membrane
C) mitochondrial inner membrane
D) mitochondrial intermembrane space
E) mitochondrial matrix
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a hydrogen ion) the molecule becomes
A) redoxed.
B) hydrogenated.
C) oxidized.
D) reduced.
E) a reducing agent.
A molecule that is phosphorylated
A) has a decreased chemical reactivity; it is less likely to provide energy for cellular work.
B) has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate.
C) has less energy than before its phosphorylation and therefore less energy for cellular work.
D) has an increased chemical reactivity; it is primed to do cellular work.
E) has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
A) oxidative phosphorylation
B) chemiosmosis
C) electron transport
D) glycolysis
E) the citric acid cycle
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
These three steps result in the formation of
A) acetyl CoA, O2, and ATP.
B) acetyl CoA, NADH, H+, and CO2.
C) acetyl CoA, FAD, H2, and CO2.
D) acetyl CoA, FADH2, and CO2.
E) acetyl CoA, NADH+, ATP, and CO2
The oxygen consumed during cellular respiration is involved directly in which process or event?
A) the citric acid cycle
B) the phosphorylation of ADP to form ATP
C) accepting electrons at the end of the electron transport chain
D) glycolysis
E) the oxidation of pyruvate to acetyl CoA
During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is
A) transferred directly to ATP.
B) retained in the pyruvate.
C) used to phosphorylate fructose to form fructose-6-phosphate.
D) stored in the NADH produced.
E) transferred to ADP, forming ATP.
Starting with one molecule of glucose, the "net" products of glycolysis are
A) 2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O
B) 6 CO2, 6 H2O, 36 ATP, and 2 citrate
C) 2 NAD+, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O
D) 2 FADH2, 2 pyruvate, 4 ATP, and 2 H2O
E) 6 CO2, 6 H2O, 2 ATP, and 2 pyruvate
For each moleule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced?
A) 5
B) 12
C) 10
D) 6
E) 4
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
A) glycolysis and the oxidation of pyruvate to acetyl CoA
B) fermentation and glycolysis
C) oxidative phosphorylation and fermentation
D) oxidation of pyruvate to acetyl CoA and the citric acid cycle
E) the citric acid cycle and oxidative phosphoryation
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
A) 4
B) 10
C) 8
D) 6
E) 2
Cellular respiration harvests the most chemical energy from which of the following?
A) transferring electrons from organic molecules to pyruvate
B) substrate-level phosphorylation
C) generating carbon dioxide and oxygen in the electron transport chain
D) chemiosmotic phosphorylation
E) converting oxygen to ATP
Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate-level phosphorylation?
A) 1
B) 11
C) 24
D) 2
E) 12
During aerobic respiration, electrons travel downhill in which sequence?
A) food --> NADH --> electron transport chain --> oxygen
B) gluose --> ATP --> electron transport chain --> NADH
C) food --> citric acid cycle -->ATP --> NADH+
D) food --> glycolysis --> citric acid cycle --> NADH --> ATP
E) glucose --> pyruvate --> ATP --> oxygen
Where are the proteins of the electron transport chain located?
A) cytosol
B) mitochondrial matrix
C) mitochondrial inner membrane
D) mitochondrial intermembrane space
E) mitochondrial outer membrane
How many molecules of carbon dioxide (CO2) would be produced by five turns of the citric acid cycle?
A) 12
B) 2
C) 60
D) 5
E) 10
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 ATP synthase pumping hydrogen ions from the mitochondrial matrix
C) energy released from movement of protons through ATP synthase
D) energy released as electrons flow through the electron transport system
E) no external source of energy is required because the reaction is exergonic
Energy released by the electron transport chain is used to pump H+ ions into which location?
A) mitochondrial matrix
B) mitochondrial inner membrane
C) mitochondrial outer membrane
D) mitochondrial intermembrane space
E) cytosol
How many reduced dinucleotides would be produced with four turns of the citric acid cycle?
A) 1 FAD and 4 NAD+
B) 4 FAD+ and 12 NAD+
C) 2 FADH2 and 8 NADH
D) 1 FADH2 and 4 NADH
E) 4 FADH2 and 12 NADH
Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules (O2) are required?
A) 2
B) 1
C) 6
D) 38
E) 12
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in cellular respiration?
B) 76
C) 4
D) 2
E) 38
An organism is discovered that consumes a considerable amount of sugar, yet does not gain much weight when denied air. Curiously, the consumption of sugar increases as air is removed from the organism's environment, but the organism seems to thrive even in the absence of air. When returned to normal air, the organism does fine. Which of the following best describes the organism?
A) It must be a molecule other than oxygen to accept electrons from the electron transport chain.
B) It is a facultative anaerobe.
C) It is an anaerobic organism.
D) It is a normal eukaryotic organism.
E) The organism obviously lacks the citric acid cycle and electron transport chain.
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
A) ATP, pyruvate, and oxygen
B) ATP, pyruvate, and acetyl CoA
C) ATP, CO2, and ethanol (ethyl alcohol)
D) ATP, NADH, and pyruvate
E) ATP, CO2, and lactate
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
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
A) It produces much less ATP than does oxidative phosphorylation.
B) It is found in the cytosol, does not involve oxygen, and is present in most organisms.
C) It relies on chemiosmosis which is a metabolic mechanism present only in the first cells-prokaryotic cells.
D) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
E) It is found in prokaryotic cells but not in eukaryotic cells.
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
A) H2O and O2
B) ADP, Pi, and NADP+
C) electrons and H+
E) CO2 and glucose
A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?
A) blue, green, and red
B) red and yellow
C) green, blue, and yellow
D) blue and violet
E) green and yellow
Where does the Calvin cycle take place?
A) stroma of the chloroplast
B) outer membrane of the chloroplast
C) chlorophyll molecule
D) thylakoid membrane
E) cytoplasm surrounding the chloroplast
When oxygen is released as a result of photosynthesis, it is a by-product of which of the following?
A) the electron transfer system of photosystem II
B) splitting the water molecules
C) the electron transfer system of photosystem I
D) reducing NADP+
E) chemiosmosis
Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?
A) Oxygen giving off during photosynthesis interferes with the absorption of light.
B) Green and yellow wavelengths inhibit the absorption of red and blue wavelengths.
C) Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis.
D) Bright sunlight destroys photosynthetic pigments.
E) Other pigments absorb light in addition to chlorophyll a.
What wavelength of light in the figure is most effective in driving photosynthesis?
A) 625 mm
B) 420 mm
C) 730 mm
D) 475 mm
E) 575 mm
In the thylakoid membrane, what is the main role of the antenna pigment molecules?
A) transfer electrons to ferredoxin and then NADPH
B) harvest photons and transfer light energy to the reaction-center chlorophyll
C) concentrate photons within the stroma
D) split water and release oxygen to the reaction-center chlorophyll
E) synthesize ATP from ADP and Pi
What are the products of linear photophosphorylation?
A) heat and fluorescence
B) ATP and P700
D) P700 and P680
The reaction-center chlorophyll of photosystem I is known as P700 because
A) there are 700 photosystem I components to each chloroplast.
B) the plastoquinone reflects light with a wavelength of 700 nm
C) this pigment is best at absorbing light with a wavelength of 700 nm.
D) there are 700 chlorophyll molecule in the center.
E) it absorbs 700 photons per microsecond.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
A) the absorption of light energy by chlorophyll
B) the splitting of water
C) the flow of electrons from photosystem II to photosystem I
D) the synthesis of ATP
E) the reduction of NADP+
Which statement describes the functioning of photosystem II?
A) The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit.
B) The electron valence in P680 are filled by electrons derived from water.
C) The splitting of water yields molecular carbon dioxide as a by-product.
D) Light energy excites electrons in the electron transport chain in a photosynthetic unit.
E) The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+.
As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?
A) cyclic electron flow
B) chlorophyll
C) photosystem I
D) linear electron flow
E) photosystem II
In a plant cell, where are the ATP synthase complexes located?
A) thylakoid membrane
B) plasma membrane
C) inner mitochondrial membrane
D) A and C
E) A, B, and C
Which of the following statements best describes the relationship between photosynthesis and respiration?
A) Respiration is the reversal of the biochemical pathways of photosynthesis.
B) Respiration is anabolic and photosynthesis is catabolic.
C) ATP molecules are produced in photosynthesis and used up in repsiration.
D) Photosynthesis occurs only in plants and respiration occurs only in animals.
E) Photosynthesis stores energy in complex organic molecules, while respiration releases it.
Where are the molecules of the electron transport chain found in plant cells?
A) cytoplasm
B) stroma of chloroplasts
C) thylakoid membranes of chloroplasts
D) inner membrane of mitochondria
E) matrix of mitochondria
Synthesis of ATP by the chemiosmotic mechanism occurs during
A) photosynthesis.
B) neither photosynthesis nor respiration.
C) respiration.
D) photorespiration.
E) both photosynthesis and respiration.
What is the relationship between wavelength of light and the quantity of energy per photon?
A) They are logarithmically related.
B) They are separate phenomena.
C) They are only related in certain parts to the spectrum.
D) They have a direct, linear relationship.
E) They are inversely related.
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
A) There is no relationship between the light reactions and the Calvin cycle.
B) The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.
C) 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.
D) the light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle to provides the light reactions with water to split.
E) 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.
Where do enzymatic reactions of the Calvin cycle take place?
A) thylakoid membranes
B) stroma of the chloroplast
C) outer membrane of the chloroplast
D) electron transport chain
E) thylakoid space
What is the primary function of the Calvin cycle?
A) synthesize simple sugars from carbon dioxide
B) use NADPH to release carbon dioxide
C) split water and release oxygen
D) transport RuBP out of the chloroplast
E) use ATP to release carbon dioxide
In the process of carbon fixation, RuBP attaches a CO2 to produce a 6 carbon molecule, which is then split in two. After phosphorylation and reduction, what more needs to happen in the Calvin cycle?
A) regeneration of RuBP
B) addition of a pair of electrons from NADPH
C) inactivation of RuBP carboxylase enzyme
D) regeneration of ATP from ADP
E) a gain of NADPH
Requires glucose
A) both the light reactions and the Calvin cycle
B) the Calvin cycle alone
C) light reactions alone
D) occurs in the chloroplast but is not part of photosynthesis
E) neither the light reactions nor the Calvin cycle
Produces molecular oxygen (O2)
A) occurs int eh 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
Which of the following statements is true concerning Figure 10.3? (two types of cells)
A) It represents a relationship between plant cells that photosynthesize and those that cannot.
B) It represents cell processes involved in C4 photosynthesis.
C) It represents a C3 photosynthetic system.
D) It represents the type of cell structures found in CAM plants.
E) It represents an adaptation that maximizes photorespiration.
The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?
A) The pH of the thylakoid space is higher than that anywhere else in the cell.
B) The pH of the stroma is higher than that of the other two measurements.
C) The pH within the thylakoid is less than that of the stroma.
D) The pH of the stroma is higher than that of the thylakoid space but lower than that of the cytosol.
E) There is no consistent repationship
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
A) use photosystems I and II at night.
B) fix CO2 into organic acids during the night.
C) fix CO2 into pyruvate int eh mesophyll cells.
D) fix CO2 into sugars in the bundle-sheath cells.
E) use the enzyme phosphofructokinase, which outcompetes rubisco for CO2.