mastering biology chp 9
high levels of ATP inhibit phosphofructokinase (PFK), an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP production,___. ___ enables cells to adjust their rate of cellular respiration to match their demand for ATP.
decreases;Feedback inhibition
2. When a compound accepts (gains) electrons, that compound becomes reduced. Such a compound is often referred to as an
electron acceptor
When a compound donates (loses) electrons, that compound becomes oxidized. Such a compound is often referred to as an__
electron donor
Which term describes the degree to which an element attracts electrons?
electronegaitivty
for substrate-level phosphorylation in glycolysis ___ is required in order for the reaction to occur
enzyme
What process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?
fermentation
which is used by many cells in the absence of oxygen.
fermentation,
Which molecule is metabolized in a cell to produce energy "currency" in the form of ATP?
glucose
for substrate-level phosphorylation in glycolysis one of the substrates is a molecule derived from the breakdown of
glucose
Photosynthesis produces ___ and releases___ into the atmosphere.
glucose, oxygen
In glycolysis, the carbon-containing compound that functions as the electron donor is
glucose.
Under anaerobic conditions,____ continues in most cells despite the fact that oxidative phosphorylation stops, and its production of NAD+ also stops.
glycolysis
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?
hydrogen, polar
where does Oxidative phosphorylation occur
inner mitochondrial membrane
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?
ionic bond
In muscle cells, fermentation produces _____.
lactate and NAD+
In the oxidation of pyruvate to acetyl CoA,___ atom is released as ___.
one carbon ;CO2,
for substrate-level phosphorylation in glycolysis bond must be broken between an__ and a ___ before ATP can form
organic molecule and phosphate
When a compound donates (loses) electrons, that compound becomes ____. Such a compound is often referred to as an electron donor.
oxidized
is the final electron acceptor of cellular respiration.
oxygen
high levels of ATP inhibit ___, an early enzyme in glycolysis. As a result, the rate of cellular respiration, and thus ATP production, decreases. Feedback inhibition enables cells to adjust their rate of cellular respiration to match their demand for ATP.
phosphofructokinase (PFK)
In the sequential reactions of acetyl CoA formation and the citric acid cycle,___ is completely oxidized, and the electrons produced from this oxidation are passed on to two types of electron acceptors.
pyruvate (the output from glycolysis);
In glycolysis, the six-carbon sugar glucose is converted to two molecules of ___), with the net production of 2 ATP and 2 NADH per glucose molecule. There is no O2 uptake or CO2 release in glycolysis.
pyruvate (three carbons each
In fermentation _____ is reduced and _____ is oxidized.
pyruvate ... NADH
All of the carbon atoms in glucose are incorporated into carbon dioxide: Two molecules are formed as___, and four molecules are formed during the ___
pyruvate is converted to acetyl CoA ;Krebs cycle.
Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called
pyruvate.
. When a compound accepts (gains) electrons, that compound becomes ___. Such a compound is often referred to as an electron acceptor.
reduced
The complete transfer of an electron from lithium to fluorine results in a
stable compound in which both atoms have full outermost shells.
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation
The ATP that is generated in glycolysis is produced by
substrate-level phosphorylation
__ and ___ , which generate the largest amounts of ATP during cellular respiration, take place in the mitochondria.
the Krebs cycle and the electron transport chain
Phosphorylation reactions involve
the addition of a phosphate group to another molecule.
the oxidation of the remaining two carbon atoms—in acetate—to CO2 requires a complex, eight-step pathway—___.on.
the citric acid cycle
True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.
true
is the compound that functions as the electron acceptor in glycolysis.
NAD+
is needed as an input to glycolysis)
NAD+ (
The main coupling among the stages of cellular respiration is accomplished by
NAD+ and NADH.
As in glycolysis, the electrons removed from carbon-containing intermediates during acetyl CoA formation and the citric acid cycle are passed to the electron carrier ___, reducing it to ___. The citric acid cycle also uses a second electron carrier, ___, the oxidized form, and ___, the reduced form.
NAD+,NADH,FAD ,FADH2
In the first three stages, ___ accepts electrons from the oxidation of glucose, ___, and acetyl CoA. The ___ produced in these redox reactions then gets oxidized during oxidative phosphorylation, regenerating the ___ needed for the earlier stages.
NAD+;pyruvate;NADH.NAD+
donates electrons to the electron transport chain.
NADH
In fermentation, the ___produced by glycolysis is used to reduce the ___ produced by glycolysis to either lactate or ethanol.
NADH ;pyruvate
Which of the following statements about the electron transport chain is true? The electron transport chain is the first step in cellular respiration. Water is the last electron acceptor. Electrons gain energy as they move down the chain. NADH and FADH2 donate their electrons to the chain.
NADH and FADH2 donate their electrons to the chain.
The citric acid cycle transfers electrons to
NADH and FADH2.
which compounds are the net inputs of oxidative phosphorylation.(3)
NADH, ADP, O₂
which compounds involved in cellular respiration, are the net outputs of acetyl CoA formation.(3)
NADH, acetyl CoA, CO₂
The reduced form of the electron acceptor in glycolysis is
NADH.
which compounds are the net outputs of oxidative phosphorylation.(3)
NAD⁺, ATP, and Water
which compounds involved in cellular respiration, are the net inputs of acetyl CoA formation. (3)
NAD⁺, coenzyme A, pyruvate
During strenuous exercise, anaerobic conditions can result if the cardiovascular system cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a muscle cell's demand for ATP under anaerobic conditions remains the same as it was under aerobic conditions. What would happen to the cell's rate of glucose utilization?
What would happen to the cell's rate of glucose utilization? Glucose utilization would increase a lot.
What is the correct order of electron transport compounds from least electronegative to most electronegative?
a) NADH -- Fe-S of Complex I -- Q -- Fe-S of Complex III -- Cyt c-- Cyt a of Complex IV -- O2
Which of these enters the citric acid cycle? glucose pyruvate acetyl CoA NADH + H+ G3P
acetyl CoA
Which of these is NOT a product of the citric acid cycle? NADH + H+ ATP CO2 acetyl CoA FADH2
acetyl CoA
Although it is possible to oxidize the two-carbon acetyl group of acetyl CoA to two molecules of CO2, it is much more difficult than
adding the acetyl group to a four-carbon acid to form a six-carbon acid (citrate).
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?
anion and cation
Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?
carbon dioxide
Glycolysis takes place in the
cytoplasm,
Glycolysis occurs in the
cytosol
are by-products of cellular respiration.
Carbon dioxide and water
can then be oxidized sequentially to release two molecules of CO2.
Citrate
what compounds involved in cellular respiration are the net outputs of the citric acid cycle.(4)
Coenzyme A, CO₂, NADH, ATP
is a multi-protein complex within the electron transport chain.
Complex III
what stage of glucose metabolism produces the most ATP?
Electron transport and chemiosmosis
what is the order of electron transport compounds from the one containing electrons with the highest free energy to the one containing electrons with the lowest free energy?
FADH2 -- FMN of Complex I -- Fe-S of Complex II -- Q -- Fe-S of Complex III -- Cyt c -- Cyt a of Complex IV -- O2
Which of these is NOT a product of glycolysis?
FAHD2
is a prosthetic group present in several components of the electron transport chain.
Fe-S
what step of the cellular respiration pathway can take place in the absence of oxygen?
Glycolysis
what are 4 stages of cellular respiration
Glycolysis - Acetyl CoA - citric acid cycle Oxidative phosphorylation
can take place in the absence of oxygen; its product, __, enters the cellular respiration pathway or undergoes fermentation depending on the availability of oxygen.
Glycolysis;pyruvate
Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. what is the correct observation for this
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.
why are the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction?
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.
is a reactant in the citric acid cycle.
Acetyl CoA
what compounds involved in cellular respiration are the net inputs of the citric acid cycle.(3)
Acetyl CoA, NAD⁺, ADP
anaerobic conditions
(a lack of oxygen
FAD
(flavin adenine dinucleotide)
where does Glycolysis occur
- Cytosol
where does Acetyl CoA occur
- Mitochondrial matrix
where does the Citric acid cycle occur
- Mitochondrial matrix
How many NADH are produced by glycolysis?
2
In glycolysis there is a net gain of _____ ATP.
2
In glycolysis, the six-carbon sugar glucose is converted to two molecules of pyruvate (three carbons each), with the net production of__ and -__ per glucose molecule. There is no O2 uptake or CO2 release in glycolysis.
2 ATP and 2 NADH
Fermentation results in a net production of
2 ATP per glucose molecule.
Electron transport and chemiosmosis (oxidative phosphorylation) can yield around
26 molecules of ATP.
Approximately how much more free energy is supplied to the electron transport chain by NADH than by FADH2?
8 kcal/mol
is often transferred to the atom that gains an electron.
A hydrogen atom (proton, or H+)
Which of the following statements is not true of most cellular redox reactions? A hydrogen atom is transferred to the atom that loses an electron. The reactant that is oxidized loses electrons. Changes in potential energy can be released as heat. The electron acceptor is reduced.
A hydrogen atom is transferred to the atom that loses an electron.
what compounds involved in cellular respiration are net inputs of glycolysis. (3)
ADP, NAD⁺, Glucose
In glycolysis, what starts the process of glucose oxidation?
ATP
The rate of cellular respiration is regulated by its major product,___, via feedback inhibition.
ATP
what correctly describes how this increased demand would lead to an increased rate of ATP production?
ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production.
what compounds involved in cellular respiration are net outputs of glycolysis.(3)
ATP, NADH and Pyruvate,
is the final electron acceptor of the electron transport chain.
O2 (molecular oxygen
In glycolysis, the six-carbon sugar glucose is converted to two molecules of pyruvate (three carbons each), with the net production of 2 ATP and 2 NADH per glucose molecule. There is no __ or ___ in glycolysis.
O2 uptake or CO2 release
Which of the following statements is true of the bonds in a water molecule? Oxygen acts as the electron acceptor and is oxidized. The electron in each hydrogen atom is completely transferred to the oxygen atom, and each hydrogen atom has a net charge of +1. There is equal sharing of the electrons between the oxygen atom and the two hydrogen atoms, and the net charge is zero. Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Given what you know about glycolysis and regulation of metabolism by PFK, what is the likely mechanism by which PFK activity differs depending on ATP concentration?
PFK is an allosteric enzyme that is inhibited by ATP and stimulated by AMP.
Based on the graph, is PFK more active at low or high ATP concentration?
PFK is more active at low ATP concentration.
is an enzyme that acts on fructose 6-phosphate at an early step in glucose breakdown. Regulation of this enzyme controls whether the sugar will continue on in the glycolytic pathway.
Phosphofructokinase (PFK)
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?
Pyruvate, ATP and NADH
is a nonprotein organic electron carrier within the electron transport chain.
Q (ubiquinone)
True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.
True
