Bio Exam 3
In mitochondrial electron transport, what is the direct role of O2? The definition of "direct role" The electron transport chain
to function as the final electron acceptor in the electron transport chain participates in reaction
C4 plants differ from C3 and CAM plants in that C4 plants _____.
transfer fixed carbon dioxide to cells in which the Calvin cycle occurs
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
For each molecule of CO2 that enters the Calvin cycle, which equation correctly represents what happens to its carbon (C) as the next intermediate is produced?
1 C + 5 C → 3 C + 3 C
How many NADH are produced by glycolysis?
2
In glycolysis there is a net gain of _____ ATP.
2
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
Approximately what wavelength of light is best absorbed by chlorophyll a, the pigment that participates directly in the light reactions?
435 nm
Which wavelength of light is best absorbed by chlorophyll b?
455nm
How many Pi are released in Phase 3? For the net conversion of 3 molecules of CO2 into 1 molecule of G3P by the Calvin cycle, which of the following equations correctly accounts for the inputs and outputs of phosphate groups in Phase 3?
5 P (in G3P) → 3 P (in R5P) + 2 Pi
Hint 2. How many carbon atoms are in the molecules from which CO2 is released in the citric acid cycle? How many carbon atoms are present in the intermediates from which CO2 is removed?
5 or 6
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
Assuming that the y-axis tick marks will be separated by 1.0 (0.0, 1.0, 2.0, and so on), what is the largest value that should appear on the y-axis?
9.0
Identify the chloroplast.
A
_____ splits water into 1/2 O2, H+, and e- .
A
Chlorophyll can be found in _____.
A and C
Which of the following statements is not true of most cellular redox reactions? What happens to the electrons and bonds during a redox reaction?
A hydrogen atom is transferred to the atom that loses an electron.
In which of the following plants would Photosystem II be most efficient?
A plant that produces few hydroxyl radicals and superoxides.
Which product or products of the Calvin cycle is/are returned as input(s) to the light reactions?' Which of the following outputs from the Calvin cycle are also inputs to the light reactions?
ADP NADP+
In glycolysis, what starts the process of glucose oxidation?
ATP
Which energy sources produced in the light reactions will be used by the Calvin cycle? Which of the following transfer energy from the light reactions to the Calvin cycle?
ATP NADPH
Which statement correctly describes how this increased demand would lead to an increased rate of ATP production? What happens to the amount of ATP in your muscle cells in that first second, as you leap out of the room, slamming the door behind you?
ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production. The cellular ATP level decreases.
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 not be produced because there is no ADP and inorganic phosphate in the solution.
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other? How does the electrical state of each atom change?
Anion and cation.
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
B
How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.) The role of O2 in electron transport What is the link between electron transport and ATP synthesis in oxidative phosphorylation?
Both electron transport and ATP synthesis would stop. O2 is the final electron acceptor Without electron transport from NADH and FADH2 to O2, the pumping of protons across the inner mitochondrial membrane ceases.
Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.
C
What is the basic role of CO2 in photosynthesis?
CO2 is fixed or incorporated into organic molecules.
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration? The metabolism of the carbon atoms in glucose is completed during the Krebs cycle.
Carbon dioxide
Select the correct statement about cellular respiration.
Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level.
Identify a thylakoid.
D
Identify the stroma.
E
Where does the Calvin cycle occur?
E
Which of these phosphorylates ADP to make ATP? https://session.masteringbiology.com/problemAsset/1100529/5/1008q.jpg
E
Which stage of glucose metabolism produces the most ATP? This stage of cellular respiration is highly dependent on the presence of oxygen.
Electron transport and chemiosmosis
How would gramicidin affect electron transport and proton pumping? What would happen to the proton gradient in the presence of gramicidin?
Electron transport would continue to pump protons across the inner mitochondrial membrane, but gramicidin would allow the protons to leak back across the membrane.
Which term describes the degree to which an element attracts electrons? Which is a property of atoms?
Electronegativity.
What are the electron carriers in acetyl CoA formation and the citric acid cycle? What is the second pair of electron carriers in the citric acid cycle?
FAD (the oxidized form) and FADH2 (the reduced form)
Which of these is NOT a product of glycolysis?
FADH2
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.
False
True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
False
Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell? Which process does not have the same requirements as those in the cellular respiration pathway?
Fermentation
Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2? How does the number of protons pumped across the membrane per NADH and FADH2 compare?
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. NADH contributes more H+ ions than FADH2.
Select the correct molecule that is the main product of the Calvin cycle.
G3P
What is the product of the Calvin cycle that contains "fixed" carbon? What is the product of the Calvin cycle that contains this fixed carbon?
G3P
Which molecule is metabolized in a cell to produce energy "currency" in the form of ATP? Which molecule is the source of a cell's "currency" for performing work?
Glucose
What would happen to the cell's rate of glucose utilization? Glucose utilization would increase a lot. How much ATP is made during fermentation compared to during aerobic respiration?
Glucose utilization would increase a lot. Fermentation produces less than 10% of the amount of ATP produced by aerobic respiration.
Which step of the cellular respiration pathway can take place in the absence of oxygen?
Glycolysis
What is the original electron donor in photosynthesis? What is the original source of the electrons that are eventually used to reduce CO2 to sugar in photosynthesis?
H2O
In the light reactions, light energy is used to oxidize --- to --. The electrons derived from this oxidation reaction in the light reactions are used to reduce ------ to ---------. The Calvin cycle oxidizes the light-reactions product -------- to -------. The electrons derived from this oxidation reaction in the Calvin cycle are used to reduce ---- to ----.
H2O O2 NADP+ NADPH NADPH NADP+ CO2 G3P
Gaseous hydrogen burns in the presence of oxygen to form water: 2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed? How are the electrons transferred?
Hydrogen, polar.
Which of these statements is the correct explanation for this observation?
In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration.
Inputs and outputs of the Calvin cycle
Input ATP NADPH CO2 Output ADP NADP+ glucose neither Light O2 G3P
Acetyl CoA
Input NAD+ CoA pyru Output Nadh Acetyl CO2 neither O2 ATP ADP Glucose
Citric Acid
Input NAD+ O2 ADP Output NADH Atp Water neither Glucose CO2 Pyru Acetyl ,CoA
Glycolysis
Input Nad+ Adp Glucose Output ATP Nadh Pyruvate neither o2, co2, acetyl, coenzyme
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride? Consider the electrons in the outermost shell of each atom.
Ionic
What is Rubisco's role in photosynthesis? What does the location of the enzyme Rubisco reveal about where processes occur in the chloroplast?
It catalyzes a reaction in the Calvin cycle.
Why is the citric acid cycle a cyclic pathway rather than a linear pathway?
It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.
What is the role of light in the light reactions? Which of the following statements correctly describes light's role?
Light supplies the energy to remove electrons from water and to transport those electrons to NADP+.
You apply this research to the world's number one food crop, rice. Which of the following are you looking for using mass spectrometry?
Modified amino acid residues
Hint 3. What are the electron carriers in glycolysis? In glycolysis, which molecule picks up the electrons released by the oxidation of glucose?
NAD+
What compound couples oxidative phosphorylation (the stage directly affected by the lack of oxygen) to acetyl CoA formation? What compound couples oxidative phosphorylation to acetyl CoA formation?
NAD+
What are the electron carriers in glycolysis?
NAD+ and NADH are a common pair of electron carriers in cells
What is the reduced form of nicotinamide adenine dinucleotide? Which of the following molecules is the reduced form of nicotinamide adenine dinucleotide?
NADH
Which of the following statements about the electron transport chain is true? Think about how molecules move through the electron transport chain.
NADH and FADH2 donate their electrons to the chain.
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
How is redox energy transferred from the light reactions to the Calvin cycle? Which of the following molecules shuttles electrons from the light reactions to the Calvin cycle?
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
Can you tell from these absorption spectra whether red light is effective in driving photosynthesis?
One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.
What molecule is indicated by the letter D?
Oxygen
Which of the following is the product of the electron transport system in Photosystem II?
Oxygen
Which of the following statements is true of the bonds in a water molecule?
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Which term describes ATP production resulting from the capture of light energy by chlorophyll? Which ATP-producing process uses light energy?
Photophosphorylation
What process occurs in structure H? https://session.masteringbiology.com/problemAsset/1100520/6/0901q.jpg
Photosynthesis
What is the role of the alga in this experiment? What was the role of the algal cells in Engelmann's experiment? Select the two that apply.
Photosynthetic pigments in the alga absorbed specific wavelengths of light. The alga photosynthesized, producing oxygen that attracted the bacteria.
Why are plants classified as producers?
Plants are classified as producers because they fix inorganic carbon into organic molecules.
Which component of the light reactions is involved in pumping protons across the thylakoid membrane?
Pq (plastoquinone) as it transfers electrons from PS II to the cytochrome complex
According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis? What is the chemiosmotic hypothesis?
Proton gradient
How many carbon atoms are in pyruvate and acetyl CoA? Which statement is true about the number of carbon atoms in the compounds involved in acetyl CoA formation?
Pyruvate is a three-carbon molecule, while acetyl CoA is a two-carbon molecule. One molecule of CO2 is released. 6c 6c 5c 2c 4c 4c 4c 4c 4c
Based on what you know about mitochondrial electron transport and heat production, predict which rats had the highest body temperature, and which had the lowest body temperature.
Rats with elevated thyroid hormone had the highest body temperature; rats with low thyroid hormone had the lowest.
Reactants and products of lactic acid fermentation
Reactants NADH pyru products NAD+ Lactate
_____ has a longer wavelength than _____.
Red ... green
Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose?
Regneration of RuBP
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups. How does the structure of ATP contribute to its high-energy state?
T
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria. Remember that the reactions that generate the most ATP during cellular respiration occur in the presence of oxygen.
T
Select the correct statement about the Calvin cycle.
The Calvin cycle has three phases: carbon fixation, reduction, and regeneration of RuBP.
What happens to the remainder of the G3P produced in Phase 2 of the Calvin cycle?
The G3Ps are used in Phase 3 to regenerate the RuBP molecules used in Phase 1.
In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain?
The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.
If plants could be genetically altered to improve Photosystem II, which of the following would occur?
The altered plants would release more oxygen.
What is the role of the bacteria in this experiment? Which statement best describes the role of the bacteria in Engelmann's experiment?
The bacteria were attracted to oxygen produced by photosynthesis in the alga.
Identify all correct statements about the basic function of fermentation.
The basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis.
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 conversion of solar energy to chemical energy.
What assumptions did Engelmann make in order to conclude that red and violet-blue light were more effective than green light in driving photosynthesis? Select the two that apply.
The distribution of chloroplasts within each algal cell was approximately the same. The number of bacteria clustered at each wavelength (color) was approximately proportional to the amount of oxygen being produced by that portion of the alga.
How is the energy of the excited state of P680 chlorophyll used in Photosystem II?
The excited state of P680 donates an electron to the primary electron acceptor.
Which of the following statements accurately describes the function of a metabolic pathway involved in cellular respiration?
The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP.
If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm) be effective in driving photosynthesis?
The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective.
How will a healthy individual's ATP production change during an eight-hour fast?
The individual's ATP production will not change significantly.
Which set of reactions uses H2O and produces O2? What happens to the hydrogen atoms?
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-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? In plants, if carbon dioxide goes in, what comes out?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
How does the oxidation of water contribute to the proton gradient across the thylakoid membrane?
The oxidation of water by PS II releases protons in the thylakoid space.
Which of the following must also occur when compound X is added to chloroplasts in order to account for the observed reduction of NADP+ to NADPH in the dark?
The primary electron acceptor of PS I must be reduced.
Which statement correctly describes how O2 production would be affected? (Assume that the light intensity does not change.)
The rate of O2 production would decrease because the rate of ADP and NADP+ production by the Calvin cycle would decrease.
Is there a net input or net output of ATP in glycolysis?
There is a net output of ATP.
An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of about 490 nm is effective in driving photosynthesis. Based on this information and the absorption spectra shown at left, what role may chlorophyll b and carotenoids play in photosynthesis?
These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.
You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?
They absorb blue/green light and reflect yellow and red wavelengths of light.
What is the fate of carbon atoms entering the citric acid cycle? What happens to the other two carbon atoms?
They are released as two CO2 molecules.
What is the biological significance of the light-independent reactions of photosynthesis? The light-independent reactions are also known as the Calvin cycle.
They convert carbon dioxide to sugar.
Why are reactive oxygen species problematic in Photosystem II?
They damage proteins.
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True
Do the results in the graph support the researchers' hypothesis?
Yes; cells that were exposed to elevated thyroid hormone levels showed increased oxygen consumption, indicating that the efficiency of the electron transport chain was reduced.
Which of these enters the citric acid cycle?
acetyl CoA
Which of these is NOT a product of the citric acid cycle?
acetyl CoA
What products are generated in mitochondria? Which two of the following molecules are products of mitochondria?
carbon dioxide ATP
What molecules belong in spaces E and F?
carbon dioxide and water
Which cell type(s) had the highest rate of oxygen consumption?
cells from rats with elevated thyroid hormone
Which cell type(s) had the lowest rate of oxygen consumption?
cells from rats with low thyroid hormone
ATP synthesis in glycolysis: substrate-level phosphorylation
correct An enzyme is required in order for the reaction to occur. One of the substrates is a molecule derived from the breakdown of glucose. A bond must be broken between an organic molecule and phosphate before ATP can form. incorrect The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions
In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.
cytoplasm
glycolysis acetyl citric oxidative
cytosol mitochondrial matrix mitochondrial matrix inner mitochondrial membrane
What molecules belong in space A and B?
glucose and O2
What process occurs in Box A? https://session.masteringbiology.com/problemAsset/1100521/5/0905q.jpg
glycolysis in the cytosol
Oxidative Phosphorylation
input NADH O2 ADP FADH2 Output Nad+ Atp water FADH neither glucose CO2 pyru Acetyl CoA
Inputs and outputs of the light reactions
input- light water NADP+ output- Nadph ATP O2 neither- CO2 G3P Glucose
In this reaction, the electron donor is __________ and the electron acceptor is __________.
isocitrate/NAD+
In muscle cells, fermentation produces _____.
lactate and NAD+
Assuming that the x-axis tick marks will be used to identify the thyroid hormone level of each type of rat, what bars should appear on the x-axis?
low normal elevated
What organelle is indicated by the letter C?
mitochondrion
What is the role of P680+ in the light reactions?
oxidation of water to O2
When a compound donates (loses) electrons, that compound becomes -------Such a compound is often referred to as an electron donor. 2. When a compound accepts (gains) electrons, that compound becomes -------Such a compound is often referred to as an electron acceptor. 3. In glycolysis, the carbon-containing compound that functions as the electron donor is ------ 4. Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called -------- 5. NAD+ is the compound that functions as the electron acceptor in glycolysis. 6. The reduced form of the electron acceptor in glycolysis is-------
oxidized. reduced. glucose. pyruvate. NADH.
What variable responded to thyroid hormone level (the independent variable), and what are the units for this variable?
oxygen consumption rate of liver cells, in nmol O2/min • mg cells
In C3 plants the conservation of water promotes _____.
photorespiration
Where does oxygen come from? Which process produces oxygen?
photosynthesis
Which of the following particles can pass through the ATP synthase channel?
protons
Can you identify a compound that couples two processes? What compound couples glycolysis to acetyl CoA formation?
pyruvate
In fermentation _____ is reduced and _____ is oxidized.
pyruvate ... NADH
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? What is the fate of NADH produced by glycolysis? Is the NADH produced in glycolysis used in any other reactions of cellular respiration where ATP is produced?
pyruvate, ATP, and NADH Yes, NADH is an input to oxidative phosphorylation, where more ATP is produced.
What is the role of the reduced PS I primary electron acceptor in the light reactions?
reduction of NADP+ to NADPH
The effect of gramicidin on oxidative phosphorylation
same proton pumping rate electron transport rate rate of oxygen uptake decrease rate of ATP synthesis size of the proton gradient
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
What products are generated in chloroplasts? Which two of the following molecules are products of chloroplasts?
sugar oxygen gas
What process occurs within Box B?
the citric acid cycle transfers electrons to NADH and FADH2.
Can you trace the net movement of phosphate groups in the Calvin cycle? Phosphate is output from the Calvin cycle in all of the following ways except
the output of 5 G3P from Phase 2 to Phase 3 of the Calvin cycle.
Where are NADPH and ATP produced? Where in the chloroplast are ATP and NADPH produced?
thylakoid membrane
What variable did the researchers intentionally vary in the experiment, and what are the units for this variable?
thyroid hormone level of the rats chosen for the experiment, in relative units
