BIO 2600 CH. 14 QUESTIONS WITH
COMPLETE ANSWERS { GRADED A+}
The link between bond-forming reactions and membrane transport processes in the
mitochondria is called __________________.✔✔
Choice (a) is correct. Choices (b), (c), and (d) are individual parts of the overall
process of chemiosmotic coupling.
(a) chemiosmotic coupling.
(b) proton pumping.
(c) electron transfer.
(d) ATP synthesis.
Describe how a standard flashlight battery can convert energy into useful work and
explain how this is similar to the energy conversions in the mitochondria.
,- ✔✔A battery contains chemicals that generate negatively charged ions at one
pole, and it is able to cause the continuous transfer of electrons along a metal wire
if that pole is connected to the other end of the battery. The energy released by the
electron-transfer process driven by the battery can be harnessed to do useful work,
as when it is used to run an electric motor. Likewise, the energy released by the
electron transfers that occur between the protein complexes in the electron-
transport chain does useful work when it drives the movement of protons to one
side of the membrane, since the resulting proton gradient is then used to generate
chemical energy in the form of ATP
Based upon what you know about metabolism, explain how electrons are stripped
from food molecules and used to drive the electron-transport chain. ✔✔
Food molecules are ultimately converted into acetyl CoA,. Electrons removed
during the generation of acetyl CoA are added to the cofactors NAD+ and FAD to
generate the reduced cofactors NADH and FADH2, respectively. The two carbon
atoms in the acetyl group of acetyl CoA are then fed into the citric acid cycle,
where they are oxidized to two molecules of CO2. The electrons removed during
this oxidation are also captured by the activated carriers NADH and FADH2. The
high-energy electrons in all of these activated carriers, which derived from carbons
,that were formerly part of food molecules are now transferred to the proteins in the
electron-transport chain.
Which of the following is not part of the process known as oxidative
phosphorylation?
- ✔✔ (d) During glycolysis, ATP generation occurs simultaneously with two of
the key reactions that convert glucose to pyruvate in the cytosol. This production
of ATP in the absence of oxygen is not part of oxidative phosphorylation; it is
referred to as substrate-level phosphorylation.
(a) Molecular oxygen serves as a final electron acceptor.
(b) FADH2 and NADH become oxidized as they transfer a pair of electrons to the
electron-transport chain.
(c) The electron carriers in the electron-transport chain toggle between reduced and
oxidized states as electrons are passed along.
(d) ATP molecules are produced in the cytosol as glucose is converted into
pyruvate.
, (a) - ✔✔Which of the following statements describes the phosphorylation event
that occurs during the process known as oxidative phosphorylation?
(a) A phosphate group is added to ADP.
(b) ATP is hydrolyzed in order to add phosphate groups to protein substrates.
(c) A phosphate group is added to molecular oxygen.
(d) Inorganic phosphate is transported into the mitochondrial matrix, increasing the
local phosphate concentration.
Choice (a) is correct. Glycolysis of a single glucose molecule generates 2 ATP
molecules. Oxidative phosphorylation in the mitochondria generates an additional
28 ATP molecules, making a total of 30 ATP molecules for each glucose molecule.
- ✔✔Modern eukaryotes depend on mitochondria to generate most of the cell's
ATP. How many molecules of ATP can a single molecule of glucose generate?
(a) 30
(b) 2
(c) 20
(d) 36
COMPLETE ANSWERS { GRADED A+}
The link between bond-forming reactions and membrane transport processes in the
mitochondria is called __________________.✔✔
Choice (a) is correct. Choices (b), (c), and (d) are individual parts of the overall
process of chemiosmotic coupling.
(a) chemiosmotic coupling.
(b) proton pumping.
(c) electron transfer.
(d) ATP synthesis.
Describe how a standard flashlight battery can convert energy into useful work and
explain how this is similar to the energy conversions in the mitochondria.
,- ✔✔A battery contains chemicals that generate negatively charged ions at one
pole, and it is able to cause the continuous transfer of electrons along a metal wire
if that pole is connected to the other end of the battery. The energy released by the
electron-transfer process driven by the battery can be harnessed to do useful work,
as when it is used to run an electric motor. Likewise, the energy released by the
electron transfers that occur between the protein complexes in the electron-
transport chain does useful work when it drives the movement of protons to one
side of the membrane, since the resulting proton gradient is then used to generate
chemical energy in the form of ATP
Based upon what you know about metabolism, explain how electrons are stripped
from food molecules and used to drive the electron-transport chain. ✔✔
Food molecules are ultimately converted into acetyl CoA,. Electrons removed
during the generation of acetyl CoA are added to the cofactors NAD+ and FAD to
generate the reduced cofactors NADH and FADH2, respectively. The two carbon
atoms in the acetyl group of acetyl CoA are then fed into the citric acid cycle,
where they are oxidized to two molecules of CO2. The electrons removed during
this oxidation are also captured by the activated carriers NADH and FADH2. The
high-energy electrons in all of these activated carriers, which derived from carbons
,that were formerly part of food molecules are now transferred to the proteins in the
electron-transport chain.
Which of the following is not part of the process known as oxidative
phosphorylation?
- ✔✔ (d) During glycolysis, ATP generation occurs simultaneously with two of
the key reactions that convert glucose to pyruvate in the cytosol. This production
of ATP in the absence of oxygen is not part of oxidative phosphorylation; it is
referred to as substrate-level phosphorylation.
(a) Molecular oxygen serves as a final electron acceptor.
(b) FADH2 and NADH become oxidized as they transfer a pair of electrons to the
electron-transport chain.
(c) The electron carriers in the electron-transport chain toggle between reduced and
oxidized states as electrons are passed along.
(d) ATP molecules are produced in the cytosol as glucose is converted into
pyruvate.
, (a) - ✔✔Which of the following statements describes the phosphorylation event
that occurs during the process known as oxidative phosphorylation?
(a) A phosphate group is added to ADP.
(b) ATP is hydrolyzed in order to add phosphate groups to protein substrates.
(c) A phosphate group is added to molecular oxygen.
(d) Inorganic phosphate is transported into the mitochondrial matrix, increasing the
local phosphate concentration.
Choice (a) is correct. Glycolysis of a single glucose molecule generates 2 ATP
molecules. Oxidative phosphorylation in the mitochondria generates an additional
28 ATP molecules, making a total of 30 ATP molecules for each glucose molecule.
- ✔✔Modern eukaryotes depend on mitochondria to generate most of the cell's
ATP. How many molecules of ATP can a single molecule of glucose generate?
(a) 30
(b) 2
(c) 20
(d) 36
