Ch 6 Flashcards
Glycolysis involves the breakdown of one molecule of glucose into:
two molecules of pyruvate
Arrange the three phases of glycolysis in the correct order. Begin with the initial phase at the top of the list.
- energy investment phase
- Cleavages phase
- Energy libration
The net products of glycolysis are
2 pyruvate, 2 NADH,
2 H+, 2 H2O,
2 ATP
glycolysis is regulated primarily by the availability of substrates such as _______ and by the process of ______ inhibition
glucose; feedback
After glucose is broken down into pyruvate by glycolysis, the pyruvate must be transported into the
mitochondrion
During glycolysis, one molecule of _______ is broken down into two molecules of pyruvate, driving the synthesis of ATP.
glucose
During cellular respiration, acetyl-CoA is formed during a reaction that also removes ____
CO2 from pyruvate
The reactions of glycolysis can be grouped into three phases. Match each phase with the key biochemical event that occurs.
energy investment phase = ATP is hydrolyzed, and phosphate groups are attached to glucose
- cleavage phase = 6-carbon molecule is broken down into two 3-carbon molecules
- energy liberation phase = ATP and NADH are synthesized
The products of the breakdown of pyruvate are
acetyl CoA, CO2 and NADH.
Which of the following serve as REACTANTS in the net reaction of glycolysis?
2 NAD+
2 ADP2-
2 Pi2-
During a(n) ___ cycle, some molecules enter a pathway, and others leave. Ultimately, some molecules are regenerated and can be used again.
metabolic
Which of the following factors regulate the rate of glycolysis?
Feedback inhibition
Availability of glucose
In the first reaction of the citric acid cycle, oxaloacetate, which contains ______ carbons, is combined with acetyl-CoA, which contains ______ carbons in its acetyl group, to produce citric acid, which contains ______ carbons.
4; 2; 6
In order for cellular respiration to continue, the pyruvate produced in glycolysis must be transported into the
mitochondrion
In order for cellular respiration to continue, the pyruvate produced in glycolysis must be transported into the
mitochondrion
What are the products of the citric acid cycle?
2 FADH2 2 (ATP) GTP 4 CO2 2NADH + H+ 2 CoA
When a carbon dioxide is removed from pyruvate, the product is a(n)
acetyl
What are the products of the chemical reaction that breaks down pyruvate oxidation?
Acetyl-CoA
NADH
CO2
The first three stages of the oxidation of one molecule of glucose (glycolysis, pyruvate breakdown, and the citric acid cycle) produce:
6 CO2, 10 NADH, 2 FADH2, and 4 ATP
What is a metabolic cycle?
A series of reactions that regenerates organic molecules
As a result of the reactions of the citric acid cycle, the carbons from acetyl CoA are released as:
CO2
During oxidative phosphorylation, the molecules _____ and ____ are oxidized by the electron transport chain.
NADH and FADH2
What reactants are required for the citric acid cycle?
FAD
GDP2-
NAD+
Acetyl-CoA
During cellular respiration, acetyl-CoA is formed during a reaction that also
removes a CO2 from pyruvate
The structural components of the electron transport chain include:
protein complexes
small organic molecules
For one molecule of glucose, the steps preceding oxidative phosphorylation produce a net total of ____ molecules of CO2, ___ molecules of ATP, ___ molecules of NADH, and ____ molecules of FADH2
6, 4, 10, 2
The electron transport chain involves a series of ______ reactions.
redox
During a(n) cycle, some molecules enter a pathway, and others leave. Ultimately, some molecules are regenerated and can be used again.
citric acid or metabolic
When electrons are transferred to oxygen in the final step of the electron transport chain, a molecule form ____
water
What molecules become oxidized during oxidative phosphorylation?
FADH2
NADH
In eukaryotic cells, the electron transport chain is located in the
inner mitochondrial membrane.
The final electron acceptor in the electron transport chain is:
oxygen
A series of redox reactions make up the ____ transport chain.
electron
As electrons travel through the electron transport chain, _____ are pumped across the cristae into the space between the inner and outer mitochondrial membranes.
protons
In the last step of the electron transport chain, electrons are transferred to oxygen. This results in the production of:
water
During oxidative phosphorylation, ATP is produced by the enzyme:
ATP synthase
During chemiosmosis, energy stored in a proton gradient is
converted to chemical bond energy in ATP
The yield of ATP per molecule of glucose is often lower than the maximum possible value because:
- the H+ gradient is also used to transport pyruvate into the matrix
- some of the NADH is used in other biochemical pathways
During aerobic respiration, the final electron acceptor in the electron transport chain is
oxygen
during the complete oxidation of a glucose molecule during aerobic cellular respiration, glycolysis produces ________ ATP(net), citric acid cycle produces ___________, And oxidative phosphorylation produces between ___________ and ___________ ATP
2, 2, 30, and 34
The enzymes of the electron transport chain use the energy released during the transfer of electrons to _________
pump protons across the inner mitochondrial membrane
The second event in oxidative phosphorylation is the production of ATP by the enzyme ATP
synthase
ATP synthase functions like a
rotary machine
During chemiosmosis, the energy in the form of a proton gradient is converted to chemical potential energy in
ATP
Amino acids can be broken down or modified so that they can enter:
glycolysis
the citric acid cycle
Which of the following are reasons that the maximum amount of ATP may not always be produced through oxidative phosphorylation?
The mitochondrion may use some of the H+ gradient for other purposes.
Some NADH might be used to synthesize organic molecules.
The breakdown of fatty acids results in the production of:
acetyl-CoA
The majority of ATP produced during aerobic cellular respiration is during
oxidative phosphorylation
What type of motion is coupled to the synthesis of ATP by the enzyme ATP synthase?
Spinning
Which term is used to describe an environment that lacks oxygen?
Anaerobic
True or false: Amino acids can be used for cellular respiration only after they are converted to glucose.
False
Fatty acids can be broken down to acetyl groups, which bind to CoA and enter the ____ ____ _____
citric acid cycle
two types of metabolic pathways that enable organisms to metabolize organic molecules in the absence of _____ are anaerobic respiration and fermentation
oxygen
Some species of bacteria that live in _________ conditions have evolved specialized enzymes that work like cytochrome c to pass electrons to molecules other than O2
anaerobic
An environment where oxygen is absent is termed
anaerobic
Which of the following statements are true regarding the generation of an electrochemical gradient during the conversion of nitrate to nitrite when nitrate serves as a final electron acceptor?
- NADH dehydrogenase pumps H+ out of the cytoplasm.
- Ubiquinone picks up H+ in the cytoplasm and carries it to the other side of the membrane.
- The reduction of nitrate to nitrite consumes H+ in the cytoplasm.
Organisms that can use only oxygen as a final electron acceptor can generate ATP via ___ during anaerobic conditions.
glycolysis
Which of the following mechanisms have evolved to allow the metabolism of organic molecules in the absence of oxygen?
Anaerobic respiration
Fermentation
Under anaerobic conditions, high levels of ______ may cause the production of free radicals.
NADH
Bacterial species that live in anaerobic conditions can carry out anaerobic respiration using an electron transport chain that donates electrons to a molecule other than
O2 or oxygen
Muscle cells overcome the buildup of NADH and decrease of NAD+ under anaerobic conditions by
reducing pyruvate to lactate
In E. coli, under anaerobic conditions, the production of a proton gradient is coupled to:
the reduction of nitrate to nitrite
If an organism can use only O2 as a final electron acceptor, can it generate ATP under anaerobic conditions?
Yes, it can generate ATP through glycolysis.
What problem results from the buildup of NADH and decrease of NAD+ under anaerobic conditions?
High concentrations of NADH can lead to the release of free radicals, which can damage DNA and proteins.
What molecule is produced during fermentation in muscle cells?
Lactate
Yeast cells can metabolize sugar under anaerobic conditions by breaking down pyruvate. Which of these are the end products of fermentation in yeast?
Ethanol
NAD+
CO2
What organic molecules can be produced during fermentation reactions?
Ethanol
Lactate
The anaerobic breakdown of glucose to lactate or ethanol yield
2
