Unit 3- Ch 7
In eukaryotes, pyruvate oxidation takes place in the:
mitochondrial matrix
The citric acid cycle takes place in the:
mitochondrial matrix
Where is CO2 produced?
mitochondrial matrix
During the citric acid cycle, the production of CO2 is the result of the _____ of intermediate compounds of the citric acid cycle coupled to the production of _____.
oxidation; NADH
In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.
oxidized; reduced
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
Proton gradient provides ______ energy
potential
During the action of ATP synthase, the _____ energy of the proton gradient is transformed into _____ energy of the F1 subunit, and this is converted into _____ energy of chemical bonds in ATP.
potential; kinetic; potential
Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of:
proton gradient
During lactic acid fermentation, pyruvate is:
reduced
In the citric acid cycle, after the acetyl-group (2C) from acetyl-CoA is transferred to oxaloacetate (4C) to produce citrate (6C), subsequent reactions eventually result in 4C intermediates that are rearranged to regenerate oxaloacetate. What happens to the other two carbons?
released as CO2 byproducts
Which of the following summarizes the net final products of glycolysis?
two molecules of pyruvate, two molecules of ATP, and two molecules of NADH
Oxidative Phosphorylation Uses: [4]
- O2 - ADP+Pi - NADH - FADH2
Glycolysis Uses: [4]
- glucose - some ATP (net is negative) - ADP +Pi - NAD+
The citric acid cycle produces _____ and _____ which serve as ________ source for the ________
The citric acid cycle produces [electron donors NADH and FADH2] which serve as an [electron] source for the [electron transport chain]
How is the rate of O2 disappearance a measure of electron transport?
O2 is used to become water in ETC so less oxygen indicates this is occurring
In which order does one molecule of glucose undergoing cellular respiration go through processes?
Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation
What stages of glucose metabolism convert NAD+ to NADH?
Glydolysis, conversion of pyruvate to acetyl CoA, citric acid cycle
The reaction of iron with oxygen to form iron oxide is an example of an oxidation-reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction ______ gains electrons and is _________.
O2; reduced
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. [T/F]
false
Which is the only reaction in the citric acid cycle that produces ATP by substrate-level phosphorylation?
formation of succinate
In cellular respiration, oxygen:
gains electrons and is reduced.
Which of the following are inputs, but not outputs, of glycolysis?
glucose
The storage carbohydrate in animals is ___________ and in plants is __________.
glycogen; starch
During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is:
less energetic than the acetyl group.
Acetate is the starting point for synthesis of a cell's:
lipids
The reaction of iron with oxygen to form iron oxide is an example of an oxidation-reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction each iron atom will:
lose 3 electrons.
Oxidation is the ____ of electrons
loss
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.
Oxidative Phosphorylation Produces: [4]
- H2O - ATP - NAD+ - FAD
What is a net product of glycolysis?
2 pyruvate, 2 ATP, 2 NADH
Citric Acid Cycle Uses: [4]
- ADP + Pi - NAD+ - FAD - H2O (used to rearrange citrate and fumarate)
Citric Acid Cycle Produces: [4]
- CO2 - ATP - NADH - FADH2
Formation of Acetyl CoA Produces: [2]
- CO2 - NADH
What conditions in a cell would result in all NAD+ being converted to NADH? What would be the consequences on the steps of glucose metabolism?
- if the ETC were shut down none of the NADH would be used and NAD+ would continue= all NAD+ - glycolysis would stop without NAD+ so everything stops
Glycolysis Produces: [3]
- pyruvate - ATP - NADH
Formation of Acetyl CoA Uses: [2]
- pyruvate - NAD+
The coronary arteries supply oxygenated blood to heart muscle. Following a heart attack, what would occur in heart tissue due to a block in the coronary arteries?
-Phosphofructokinase, an intermediary enzyme of glycolysis, would be activated. -The production of ATP would decrease. -Lactic acid would accumulate in the tissue due to glycolysis and fermentation.
Pyruvate oxidation:
-occurs twice for each glucose oxidized. -occurs in the mitochondrial matrix. -shows synthesis of the substrate that enters the citric acid cycle.
Earth's earliest organisms...
.... likely carried out fermentation and may have had rudimentary proton pumps.
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
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 _____.
2 carbons; to CO2; 4 carbons; acetyl groups
Nicotinamide adenine dinucleotide is an electron carrier in many important cellular reactions. It exists in an oxidized form (NAD+) and a reduced form (NADH). What is the missing component in the reaction: NAD+ + ____ + H+ → NADH?
2e-
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
What is the hypothesis for Racker and Stoeckenius's experiment?
A proton gradient is required for ATP synthase to synthesize ATP. - Peter Mitchell's hypothesis suggested that the proton gradient generated in the electron transport chain provides the potential energy to drive ATP synthesis.
chemiosmotic theory
A theory stating that the products of oxidative metabolism store their energy in an electrochemical gradient that can drive cell processes such as ATP synthesis.
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.
During a long bout of sustained exercise, in which order will your body's energy stores/sources be used?
ATP stored in muscle, glycogen stored in muscle, glycogen stored in the liver, fatty acids
Some drugs allow protons [H+] to diffuse across the mitochondrial inner membrane. When such a drug is added, what will happen to ATP synthase?
ATP synthesis will decrease; because the diffusion of protons decreases the concentration gradient that powers ATP synthase
ADP increases the phosphofructokinase-mediated reaction by binding at a distinct binding site. This is an example of _______
Allosteric inhibition
Why is pyruvate imported from the cytoplasm into the mitochondrial matrix?
Although pyruvate is made in the cytoplasm, the product of its oxidation, acetyl-CoA, is a substrate for the citric acid cycle, which is located in the mitochondrial matrix.
Overall reactions of cellular respiration [equation]
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
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
During exercise, as muscles go into anaerobiosis, the body will increase its consumption of ______
Carbohydrates
CO2 is produced during _____
Citric Acid Cycle and Acetyl CoA production
Where is water produced?
ETC in the inner membrane
Why does the CAC shut down without oxygen?
ETC stops so the e- produced by the CAC have nowhere to go and the cycle stops
Without O2, what do you predict will happen to the electron transport chain?
Electron transfer will
O2 is used during ____
Electron transport
Where is O2 used?
Electron transport chain in the inner membrane of mitochondrion
When oxygen is depleted, the citric acid cycle stops. What would you need to add to the system to restore activity?
FAD & NAD+
The reaction of iron with oxygen to form iron oxide is an example of an oxidation-reduction reaction: 4Fe + 3O2 → 2Fe2O3. In this reaction ______ loses electrons and is _________.
Fe; oxidized
The energy required to drive the synthesis of the majority of the ATP generated during aerobic respiration comes most directly from:
Flow of protons through an ATP synthase complex. - The flow of electrons and stepwise lowering of the energy level of those electrons by the electron transport chain drives formation of a proton gradient between the matrix and the intermembrane space. The potential energy of this gradient drives ATP formation as the protons flow back to the matrix through ATP synthase.
The first stage in the production of ATP via the oxidation of glucose molecules is referred to as:
Glycolysis
Through beta-oxidation, fatty acids are converted to acetyl-CoA. Entering the pathway as acetyl-CoA bypasses which part of aerobic respiration?
Glycolysis
Where is glucose used?
Glycolysis in the cytosol
Protons in a mitochondrion flow through an ATP synthase from the:
Intermembrane space to the matrix. - The electron transport chain transforms the energy from the high energy electrons of FADH2 and NADH into an electrochemical gradient by pumping protons from the mitochondrial matrix into the intermembrane space. Those protons flow back into the matrix by passing through a special enzyme embedded in the membrane called ATP synthase.
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.
If the researchers added a transmembrane protein channel that allows protons to freely pass through it, what result would you predict?
Less ATP would be produced when the light is on because protons would bypass the ATP synthase. - In order for ATP to be generated, there must be a proton concentration and electrical gradient. If there was a new protein that freely allowed the protons to flow through the membrane, then eventually the protons would reach equilibrium and there would not be a gradient to drive the synthesis of ATP.
The oxidation of pyruvate occurs in the:
Mitochondrial matrix
One of the enzymatic results of the pyruvate oxidation stage of cellular respiration is the reduction of _____ to _____.
NAD+; NADH
Which molecule(s) serve as electron donors for the mitochondrial electron transport chain?
NADH & FADH2
When a single pyruvate is converted to acetyl-CoA during pyruvate oxidation, the other products of the reaction are:
NADH and CO2.
Some drugs allow protons to diffuse across the mitochondrial inner membrane. When such a drug is added, what will happen to O2 consumption?
Oxygen consumption will not change because it creates the gradient and is not powered by the gradient like ATP synthase is
The terminal electron acceptor of a mitochondrial electron transport chain is:
Oxygen. - Once the available energy of the electrons passing along the electron transport chain has been extracted and used to pump protons into the intermembrane space, they are passed to O2 as the final step
Regarding pyruvate and glucose:
Pyruvate can be transported across both membranes of the mitochondrion to be further metabolized, but glucose cannot.
____ is the end product of glycolysis. It is oxidized into ____, which enters the citric acid cycle.
Pyruvate; acetyl CoA
When electrons move closer to oxygen during cellular respiration energy is _____.
Released
Cytochrome c
The enzyme to which electrons are transferred in complex III of the electron transport chain.
substrate-level phosphorylation: definition
The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.
How will a healthy individual's ATP production change during an eight-hour fast? (assuming daily activity is not changed)
The individual's ATP production will not change significantly although they haven't eaten. Production will use storage to power the same usage.
pH is a measure of the acidity of a solution and equals the negative logarithm of the proton concentration. If the proton concentration decreased on the inside of the vesicle, what would happen to the pH measured on the outside of the vesicle?
The pH would decrease outside of the vesicle. - As the proton concentration decreases on the inside of the cell, they are increasing on the outside of the vesicle. Increased proton concentration makes the pH lower (more acidic).
If ATP concentration in the cell is high, what do you predict will happen to the rate of glucose oxidation?
There is already a lot of ATP, so oxidation of glucose will slow down
Conditions that reduce the strength of the proton gradient across the inner mitochondrial membrane slow the production of ATP by ATP synthase. [T/F]
True
When glucose is broken down in a cell, all of the energy it stores is not released simultaneously but is instead released in a stepwise process. [T/F]
True
Glycolysis is a series of chemical reactions (endergonic and exergonic) by which the cell can obtain ATP. NAD+ plays a crucial role in the reactions of glycolysis by:
accepting electrons during glycolysis, with the overall result that glucose is partially oxidized to pyruvate.
Coenzyme Q (Ubiquinone)
accepts electrons from both complexes I and II - accepts 2 e- and 2 protons= CoQH2
Beta-oxidation does not produce any ATP directly, but it does produce:
acetyl CoA, NADH, FADH2
Lactic acid fermentation occurs in:
bacteria and animals
How did the earliest organisms on Earth most likely produce ATP?
by glycolysis
ATP houses ______ energy
chemical
pH is a measure of the acidity of a solution and equals the negative logarithm of the proton concentration. When the light is on and the proton pump is activated, the pH:
decreases inside the vesicle and increases outside of the vesicle. - When protons increase on the inside of the cell, they are decreasing on the outside of the cell. A decreased proton concentration makes the pH higher (more basic) on the outside of the vesicles.
During glycolysis, pyruvate oxidation, and the citric acid cycle, the chemical energy in glucose is transferred to:
electron carriers and ATP.
The outer surface of the Fo subunit of ATP synthase must be _____ to be embedded in the membrane.
hydrophobic
Where are protein complexes I through IV of the electron transport chain located?
inner mitochondrial matrix
On completion of either ethanol or lactic acid fermentation, the yield is only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in:
lactic acid and ethanol
Red blood cells in the human bloodstream do not have mitochondria. What metabolic process would you predict these cells use to provide cellular energy/ATP?
lactic acid fermentation
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 on the inner membrane
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.
In addition to destabilizing glucose for subsequent breakdown, what else does phosphorylation of glucose do?
traps glucose inside the cell
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.
What is a product (as opposed to a substrate) of at least one of the processes of cellular respiration?
water
