Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: Why are components of electron transport chains embedded in membranes?
Electron
Answer:
transport chains must occur in the membrane because their primary function is to
produce a
proton motive force, which is the concentration of protons across a membrane
Q: Why the cell might not always want to break glucose all the way down to CO2
through
Answer:
glycolysis and the TCA cycle/respiration? The intermediate of glycolysis can also be
used for
nucleotide synthesis, amino acid synthesis and lipid synthesis. If the cell senses that
enough
energy is being made then some of the intermediates can be used to make other
important
cellular components. For example, if there is a lot of ATP in the cell
glyceraldehyde-3-phosphate
can be used to make lipids for more permanent energy storage
,Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: How does ATP regulate phosphofructokinase's activity? ATP can bind PFK at
two locations
Answer:
the active site and the allosteric site. When ATP binds in PFK's allosteric site it
induces a
CONFORMATIONAL change that decreases its kinase activity. This is an example
of feedback
inhibition
,Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: ATP can be synthesized by substrate-level phosphorylation and by ATP
synthase. Explain
Answer:
these two mechanisms of ATP synthesis, and indicate when they each occur during
carbon
catabolism - In substrate level phosphorylation (glycolysis), ATP is formed by
donation of a
high energy phosphate bond from another organic molecule to ADP:
Organic molecule-P + ADP → Organic molecule + ATP
In contrast, ATP synthase generates ATP by driving the reaction ADP + Pi → ATP
during
oxidative phosphorylation, using the energy from PMF
, Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: Components of the electron transport chain pump protons across the
mitochondrial inner
Answer:
membrane. Where does the energy required to do this come from? What is this
energy later
used for? The energy comes from the high energy electrons that were donated to the
ETC
by NADH and FADH2. By the end of the ETC, when they are donated to O2, the
electrons are
low energy. The energy stored in the PMF is later used by ATP synthase to make
ATP
Q: How can eukaryotic cells solve the NAD+ pool depletion problem in the absence
of O2. How
Answer:
would they solve this problem in the presence of O2? Which is more efficient and
why? - In
2026 Update
Q: Why are components of electron transport chains embedded in membranes?
Electron
Answer:
transport chains must occur in the membrane because their primary function is to
produce a
proton motive force, which is the concentration of protons across a membrane
Q: Why the cell might not always want to break glucose all the way down to CO2
through
Answer:
glycolysis and the TCA cycle/respiration? The intermediate of glycolysis can also be
used for
nucleotide synthesis, amino acid synthesis and lipid synthesis. If the cell senses that
enough
energy is being made then some of the intermediates can be used to make other
important
cellular components. For example, if there is a lot of ATP in the cell
glyceraldehyde-3-phosphate
can be used to make lipids for more permanent energy storage
,Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: How does ATP regulate phosphofructokinase's activity? ATP can bind PFK at
two locations
Answer:
the active site and the allosteric site. When ATP binds in PFK's allosteric site it
induces a
CONFORMATIONAL change that decreases its kinase activity. This is an example
of feedback
inhibition
,Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: ATP can be synthesized by substrate-level phosphorylation and by ATP
synthase. Explain
Answer:
these two mechanisms of ATP synthesis, and indicate when they each occur during
carbon
catabolism - In substrate level phosphorylation (glycolysis), ATP is formed by
donation of a
high energy phosphate bond from another organic molecule to ADP:
Organic molecule-P + ADP → Organic molecule + ATP
In contrast, ATP synthase generates ATP by driving the reaction ADP + Pi → ATP
during
oxidative phosphorylation, using the energy from PMF
, Bio 230 Exam 4 Questions and Answers with Verified Solutions | Latest
2026 Update
Q: Components of the electron transport chain pump protons across the
mitochondrial inner
Answer:
membrane. Where does the energy required to do this come from? What is this
energy later
used for? The energy comes from the high energy electrons that were donated to the
ETC
by NADH and FADH2. By the end of the ETC, when they are donated to O2, the
electrons are
low energy. The energy stored in the PMF is later used by ATP synthase to make
ATP
Q: How can eukaryotic cells solve the NAD+ pool depletion problem in the absence
of O2. How
Answer:
would they solve this problem in the presence of O2? Which is more efficient and
why? - In
