ch7-8
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the electron transport chain?
0%
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
100%
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
2
Starting with one molecule of glucose, the energy-containing products of glycolysis are
2 NADH, 2 pyruvate, and 2 ATP
What fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle, if glucose is the sole energy source?
2/3
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
Approximately how many molecules of ATP are produced by substrate-level phosphorylation during the complete oxidation of a molecule of glucose (C6H12O6) in aerobic cellular respiration?
4
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
What are the products of linear electron flow?
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
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 of the following activities is associated with photosystem II?
Electrons released from the P680 chlorophyll are replaced by electrons derived from water.
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
Select the correct molecule that is the main product of the Calvin cycle.
G3P
In the combined processes of glycolysis and cellular respiration, what is consumed, and what is produced?
Glucose is consumed, and carbon dioxide is produced.
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?
It increases the surface area for oxidative phosphorylation.
A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?
It is stored in NADH and FADH2
When an individual is exercising heavily and the muscle becomes oxygen-deprived, muscle cells convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells?
It is taken to the liver and converted back to pyruvate.
Which of the following statements about NAD+ is true?
NAD+ is reduced to NADH during glycolysis
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the highest energy level?
NADH
In addition to ATP, what are the end products of glycolysis?
NADH and pyruvate
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
What compound provides the reducing power for the Calvin cycle reactions?
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
Which of the following products of the light reactions of photosynthesis is used during the Calvin cycle?
NADPH
Which term describes ATP production resulting from the capture of light energy by chlorophyll?
Photophosphorylation
Which process produces oxygen?
Photosynthesis
According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?
Proton gradient
Which of the following particles can pass through the ATP synthase channel?
Protons
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
RuBP
In most cells, not all of the carbon compounds that participate in glycolysis and the citric acid cycle are converted to carbon dioxide by cellular respiration. What happens to the carbon in these compounds that does not end up as CO2?
The carbon compounds are removed from these processes to serve as building blocks for other complex molecules.
Which of the following statements about the chemiosmotic synthesis of ATP is correct?
The chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane.
Which statement about the citric acid cycle is correct?
The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns ADP, i, and NADP+ to the light 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?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
Which one of the following statements about the redox reactions of the electron transport chain is correct?
The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane.
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
Why are C4 plants able to photosynthesize with no apparent photorespiration?
They do not use rubisco to fix CO2.
Why are carbohydrates and fats considered high-energy foods?
They have a large number of electrons associated with hydrogen
Where does the Calvin cycle occur?
Thylakoid
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
True
In the complete reactions of aerobic respiration, the energy for the majority of ATP synthesis is provided by
a proton gradient across a membrane.
The oxygen consumed during cellular respiration is involved directly in which process or event?
accepting electrons at the end of the electron transport chain
Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate?
acetyl CoA
The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of
an endergonic reaction coupled to an exergonic reaction.
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?
blue and violet
In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during
both photosynthesis and cellular respiration
Generation of proton gradients across membranes occurs during
both photosynthesis and cellular respiration.
Metabolic pathways that release stored energy by breaking down complex molecules are known as
catabolic pathways.
The photosynthetic membranes are found in the _____ in plant cells.
chloroplasts
In animal cells, glycolysis occurs in the
cytosol
When light strikes chlorophyll molecules of PS II, they lose electrons, which are ultimately replaced by _____.
electrons released by splitting water
In chemiosmosis, what is the most direct source of energy that is used to convert ADP + i to ATP?
energy released from movement of protons down their electrochemical gradient through ATP synthase
What does the chemiosmotic process in chloroplasts involve?
establishment of a proton gradient across the thylakoid membrane
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
fix CO2 into organic acids during the night when temperatures are cooler
As a result of an oxidation-reduction reaction the oxidizing agent
gains electrons and gains potential energy
What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions?
glucose
Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration
glucose → NADH → electron transport chain → oxygen
The complete oxidation of glucose in aerobic respiration occurs through which of the following sequence of metabolic reactions?
glucose → glycolysis → pyruvate oxidation → citric acid cycle → electron transport chain
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
glycolysis
Which of the following occur(s) in the cytosol of a eukaryotic cell?
glycolysis and fermentation
A molecule that is phosphorylated
has increased chemical potential energy that may be used to do cellular work.
A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells?
he mutant yeast will be unable to grow anaerobically.
In autotrophic bacteria, where are chlorophyll-like pigments located?
in infolded regions of the plasma membrane
Where in mitochondria is the enzyme ATP synthase localized?
inner membrane
When an electron is transferred to a more electronegative atom
it loses potential energy.
Which set of reactions uses H2O and produces O2?
light dependent reactions
In an oxidation-reduction reaction, the reducing agent
loses electrons and loses potential energy.
The overall function of the Calvin cycle is __________.
making sugar
Where are the proteins of the electron transport chain located?
mitochondrial inner membrane
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
mitochondrial intermembrane space
What is the source of the oxygen used to form water in the complete reactions of cellular respiration?
molecular oxygen (O2)
The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy) result in which of the following?
oxidation of C6H12O6 and reduction of O2
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
oxidation of pyruvate to acetyl CoA and the citric acid cycle
Which of the following occur(s) in mitochondria?
oxidation of pyruvate to acetyl CoA and the citric acid cycle
When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the glucose molecule becomes
oxidized.
Photosynthesis is a redox reaction. This means that H2O is _____ during the light reactions and CO2 is _____ during the Calvin cycle.
oxidized...reduced
Which of the following is(are) a product(s) of the light reactions of photosynthesis?
oxygen, ATP, and NADPH
In bacteria, ATP synthase is located
plasma membrane
What is the primary function of the Calvin cycle?
produce simple sugars from carbon dioxide
Which of the following is directly associated with photosystem I?
receiving electrons from the thylakoid membrane electron transport chain
_____ has a longer wavelength than _____.
red and green
The energy used to pump hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space is derived from
redox reactions in the electron transport chain
The primary role of oxygen in cellular respiration is to
serve as an acceptor for electrons and hydrogen, forming water.
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules.
Where do the enzymatic reactions of the Calvin cycle take place?
stroma of the chloroplast
Where does the Calvin cycle take place?
stroma of the chloroplast
The ATP produced in glycolysis is generated by
substrate-level phosphorylation
The ATP produced in the citric acid cycle is generated by
substrate-level phosphorylation
The ultimate source of energy to support most life on Earth is _____.
sunlight
In C3 photosynthesis, the reactions that require ATP take place in
the Calvin cycle alone.
Which metabolic pathway generates a proton gradient?
the electron transport chain
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is
the proton-motive force across the inner mitochondrial membrane
Electron transport chains associated with ATP production in plant cells are located in
the thylakoid and mitochondrial inner membranes
In chemiosmosis in mitochondria, protons flow from the intermembrane space into the matrix, whereas in chemiosmosis in chloroplasts, protons flow from
the thylakoid space to into the stroma.
C4 plants occur more commonly in desert conditions because __________.
they can fix carbon at the lower CO2 concentrations that develop when the stomata are closed
In a plant cell, where are ATP synthase complexes located?
thylakoid membrane and inner mitochondrial membranes
Where are the molecules of the electron transport chain associated with photophosphorylation located in plant cells?
thylakoid membranes of chloroplasts
In the thylakoid membranes, what is the main role of the pigment molecules in a light-harvesting complex?
transfer light energy to the reaction-center chlorophyll
Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?
transforming the energy in glucose and related molecules in a chemical form that cells can use for work
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
two ATP
In the electromagnetic spectrum, the type of radiation that we call visible light occurs between _____.
ultraviolet radiation and infrared radiation
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
