Cellular respiration
Based on a total yield of 32 ATP from one glucose, what fraction of the ATP comes from glycolysis?
1/16
The _____ stage of cellular respiration generates the most NADH, which will be used in oxidative phosphorylation to produce _____ (proportion) of the total ATP yield from glucose.
citric acid cycle, 15/32
During what phase of glycolysis is NADH formed?
during phase 3, when glyceraldehyde 3-phosphate is phosphorylated
During glycolysis, pyruvate oxidation, and the citric acid cycle, the chemical energy in glucose is transferred to:
electron carriers and ATP
The majority of the energy captured in the citric acid cycle is in the form of:
electrons donated to NAD+ and FAD
The first phase of glycolysis requires the input of two ATP molecules. It is therefore:
endergonic
Fermentation occurs only in anaerobic conditions
false
Fermentation produces nearly twice as much ATP as aerobic respiration, which explains why it is a preferred pathway for bacteria.
false
Malate is both the starting and ending product of the citric acid cycle.
false
Oxidation is the gain of electrons.
false
Pyruvate oxidation produces a large amount of ATP through substrate-level phosphorylation.
false
The glycolysis stage is responsible for producing most of the ATP during cellular respiration.
false
The majority of cells within the human body have a very high baseline amount of ATP, so cells are always prepared for any long-term activity.
false
In eukaryotes, fermentation takes place:
in the cytoplasm
The chemical bonds of carbohydrates and lipids have high potential energy because:
many of these bonds are C—C and C—H bonds, in which electrons are shared equally between atoms
In eukaryotes, pyruvate oxidation takes place in the:
mitochondrial matrix
The citric acid cycle takes place in the:
mitochondrial matrix
In what organelle is pyruvate oxidation carried out in a cell?
mitochondrion
The citric acid cycle is a cycle because the starting molecule, _____, is regenerated at the end.
oxaloacetate
The mitochondrial electron transport chain is part of:
oxidative phosphorylation
Which stages of cellular respiration use O2 as an input?
oxidative phosphorylation
In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.
oxidized, reduced
The final (terminal) electron acceptor of the electron transport chain is:
oxygen
A simplified overall equation for respiration is as follows: C6H12O6 + 6O2 →6CO2+ 6H2O + energy In this reaction, we can say that _____ is reduced and _____ is oxidized.
oxygen, glucose
During which phase(s) of glycolysis do we observe pyruvate production, ATP synthesis, and reduction of NAD+?
payoff phase
Acetyl-CoA synthesis occurs during:
pyruvate oxidation
Which stage of cellular respiration occurs following production of pyruvate?
pyruvate oxidation
Which stages of cellular respiration produce CO2 as a waste product?
pyruvate oxidation and the citric acid cycle
In pyruvate oxidation, the electron donor is _____ and the electron acceptor is _____.
pyruvate, NAD+
During lactic acid fermentation, pyruvate is:
reduced
The _____ forms of the electron carriers NAD+/NADH and FAD/FADH2 have high potential energy.
reduced
In glycolysis, ATP is synthesized by:
substrate-level phosphorylation
In eukaryotic cells, glycolysis occurs in:
the cytoplasm
During the pyruvate oxidation stage of cellular respiration, which of the following occurs?
the formation of CO2 the formation of NADH the oxidation of pyruvate the formation of acetyl-CoA
We can tell from their structure that fatty acids are a good source of energy because of:
the large number of carbon-carbon and carbon-hydrogen bonds they contain
Coenzyme Q and cytochrome c:
transfer electrons between protein complexes of the electron transport chain
In addition to destabilizing glucose for subsequent breakdown, what else does phosphorylation of glucose do?
traps glucose inside the cell
Cellular respiration is a series of _____ reactions.
catabolic
Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of glycolysis?
0
Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of the pyruvate oxidation stage?
2
Which of the following is a net product of glycolysis?
2 pyruvate
Tracing the metabolism of one glucose molecule, how many carbon atoms are available for further oxidation at the completion of the pyruvate oxidation stage?
4
Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of aerobic respiration?
6
Which of the following is required for the preparatory phase of glycolysis and then produced during the payoff phase?
ATP
During the citric acid cycle:
ATP is synthesized by substrate-level phosphorylation
The conversion of the potential energy of a proton gradient to a form more useful to the cell is achieved by coupling the movement of protons down their electrochemical gradient with the synthesis of ATP. This coupling is made possible by:
ATP synthase
Each molecule of acetyl-CoA that enters the citric acid cycle carries two of the carbon atoms from the original starting glucose molecule. These carbon atoms will ultimately leave the citric acid cycle as carbon atoms in which of the following?
CO2
The ethanol resulting from fermentation of glucose only accounts for four of the six starting carbon atoms. In which of the following are the other two carbon atoms found?
CO2
What is the fully oxidized product that results from the pyruvate oxidation stage of cellular respiration?
CO2
We consume a variety of carbohydrates that are digested into a variety of different monosaccharides. How do these different sugars enter glycolysis?
Different sugars can be modified to form different intermediates of glycolysis
ATP is not generated directly in the citric acid cycle. Instead, an intermediate is first generated by substrate-level phosphorylation. The intermediate is:
GTP
What happens when glucose is phosphorylated during phase 1 of glycolysis?
Glucose is destabilized so that it can be broken apart in phase 2
Which of the following is one explanation for why glycolysis is believed to have arisen very early in the evolution of life?
It does not require oxygen
During the citric acid cycle, which is shown, what happens to the coenzyme A that is part of acetyl-CoA?
It is recycled for use in other reactions
Which correctly characterizes the F1 subunit of ATP synthase?
It is the catalytic unit that synthesizes ATP
One of the enzymatic results of the pyruvate oxidation stage of cellular respiration is the reduction of _____ to _____.
NAD+, NADH
Which of the following is an electron carrier in its reduced form?
NADH
When a single pyruvate is converted to acetyl-CoA during pyruvate oxidation, the other products of the reaction are:
NADH and CO2
A researcher is comparing the amount of protein contained in inner and outer mitochondrial membranes. What do you predict they will find?
The amount of proteins will be greater in the inner membrane
Glycolysis is:
anaerobic
Lactic acid fermentation occurs in:
bacteria and animals
The breakdown of fatty acids takes place by a process called:
beta-oxidation
How did the earliest organisms on Earth most likely produce ATP?
by glycolysis
In cellular respiration, oxygen:
gains electrons and is reduced
Which of the following are inputs, but not outputs, of glycolysis?
glucose
Excess glucose is stored in large branched molecules of:
glycogen in animals
The storage carbohydrate in animals is ___________ and in plants is __________.
glycogen, starch
Proteins can be broken down to extract energy. They are typically broken down into amino acids, which then enter cellular respiration via:
glycolysis or the citric acid cycle
Pyruvate oxidation is an important stage in cellular respiration because:
it links glycolysis with the citric acid cycle
When a substance in a reaction is oxidized, it:
loses electrons
Both NAD+ and molecular oxygen serve as electron acceptors in cellular respiration.
true
The ATP produced during glycolysis is the result of substrate-level phosphorylation.
true
Although glycolysis produces four molecules of ATP by substrate-level phosphorylation, the net gain of ATP for the cell is two molecules. This is because:
two molecules are used in the initial stage
Which of the following summarizes the net final products of glycolysis?
two molecules of pyruvate, two molecules of ATP, and two molecules of NADH
At the end of glycolysis, the carbon originally found in the starting glucose molecule is now present in:
two pyruvate molecules
Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation, _____ carbons are fully oxidized to _____, while _____ carbons remain in _____.
two, CO2, four, acetyl groups
Which of the following is a product (as opposed to a substrate) of at least one of the processes of cellular respiration?
water
