ap bio unit 3 pt 1 Flashcards
What does the chemiosmotic process in chloroplasts involve?
establishment of a proton gradient
In glycolysis, for each molecule of glucose oxidized to pyruvate
2 molecules of ATP are used and 4 molecules of ATP are produced.
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?
energy released from movement of protons through ATP synthase
Which statement describes the functioning of photosystem II?
The electron vacancies in P680 are filled by electrons derived from water.
The primary role of oxygen in cellular respiration is to
act as an acceptor for electrons and hydrogen, forming water.
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?
FADH2
Which of the following is likely to lead to an increase in the concentration of ATP in a cell?
an increase in a cell’s catabolic activity
What wavelength of light in the figure is most effective in driving photosynthesis?
420 mm
Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for
photosynthesis. Why are they different?
Other pigments absorb light in addition to chlorophyll a.
The oxygen consumed during cellular respiration is involved directly in which process or event?
accepting electrons at the end of the electron transport chain
In a plant cell, where are the ATP synthase complexes located?
thylakoid membrane & plasma membrane
Where does the Calvin cycle take place?
stroma of the chloroplast
Photorespiration lowers the efficiency of photosynthesis by preventing the formation of
3-phosphoglycerate molecules
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
Why are C4 plants able to photosynthesize with no apparent photorespiration?
They use PEP carboxylase to initially fix CO2 .
What are the products of linear photophosphorylation?
ATP and NADPH
The ATP made during glycolysis is generated by
substrate-level phosphorylation.
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
loses electrons and loses energy.
Which of the following is an example of potential rather than kinetic energy?
a food molecule made up of energy-rich macromolecules
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a hydrogen ion) the molecule becomes
reduced
What is proton-motive force?
the transmembrane proton concentration gradient
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.
A molecule that is phosphorylated
has an increased chemical reactivity; it is primed to do cellular work
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
glycolysis
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
ATP, CO2 , and ethanol (ethyl alcohol).
The ATP made during fermentation is generated by which of the following?
substrate-level phosphorylation
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?
cyclic electron flow
Where are the molecules of the electron transport chain found in plant cells?
thylakoid membranes of chloroplasts
Generation of proton gradients across membranes occurs during
both photosynthesis and respiration.
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
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H2O → NADPH → Calvin cycle
Which of the following statements best describes the relationship between photosynthesis and
respiration?
Photosynthesis stores energy in complex organic molecules, while respiration
releases it.
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of
pyruvate?
2
Synthesis of ATP by the chemiosmotic mechanism occurs during
both photosynthesis and respiration.
Inside an active mitochondrion, most electrons follow which pathway?
citric acid cycle → NADH → electron transport chain → oxygen
