BSC2010 Modules 16-18
products of citric acid cycle
6 NADH, 2 FADH2, 2 ATP, 4 CO2
Reduced
Because it's gaining electrons, NAD+ has become _____________
products of pyruvate oxidation per pyruvate
CO2, NADH, Acetyl CoA
ATP
Cellular respiration takes chemical energy and converts it to a different form in order to convert it back to chemical energy in the form of _____
Dehydrogenase
Enzymes that do redox reactions
Allosteric regulation
High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location than the active site. This is an example of which of the following?
From movement of protons through ATP synthase, down they electrochemical gradient
In chemiosmosis, the most direct source of energy used to convert ADP + Pi to ATP is released
Pyruvate...NADH
In fermentation _____ is reduced and _____ is oxidized.
2
In glycolysis there is a net gain of ______ ATP
substrate-level phosphorylation
In glycolysis, ATP molecules are produced by _____.
Glucose
In glycolysis, the carbon-containing compound that functions as the electron donor is ___________
ATP
In glycolysis, what starts the process of glucose oxidation?
Oxidative phosphorylation
In liver cells, the inner mitochondrial membranes contain about five times the surface areas of the outer mitochondrial membranes, which allows for increased rates of which of the processes below?
to function as the final electron acceptor in the electron transport chain
In mitochondrial electron transport, what is the direct role of O2?
2 electrons and 1 proton
NAD+ becomes reduced during glycolysis to become NADH by binding to _____________
Two electrons, two protons
NAD+ is the oxidized form of electron carrier, which will pick up __________ and _____________ from the molecule that was oxidized
Proton motive force
Once ATP synthèse allows electrons to go down their concentration gradient, ________________ is lost
Pyruvate
Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called______
Glucose
One of the substrates is a molecule derived from the breakdown of _____________
Kinetic energy that is released as hydrogen ions diffuse down their concentration gradient
The proximate (immediate) source of energy for oxidative phosphorylation is _____.
NADH
The reduced form of the electron acceptor in glycolysis is _____
Coupling of an endergonic reaction to an exergonic reaction
The synthesis of ATP by oxidative phosphorylation is an example of which of the following processes?
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
What types of cells carry out ATP synthesis by chemiosmosis?
The electron transport chain
When a cell is deprived of oxygen, which of the following processes will be inhibited first?
Electron acceptor
When a compound accepts (gains) electrons, that compound becomes reduced. Such a compound is often referred to as an _______________
Electron donor
When a compound donates (loses) electrons, that compound becomes oxidized. Such a compound is often referred to as an ______________
Mitochondrial inner membrane
Where are the protein complexes of the electron transport chain located?
Cytosol
Where do fermentation reactions take place in a eukaryotic cell?
Mitochondrial matrix
Where does pyruvate oxidation take place?
Mitochondrial matrix
Where does the citric acid cycle take place?
Mitochondrial intermembrane space
Where is the proton motive force located?
products of alcoholic fermentation
2 ATP, 2 NAD+, 2 CO2, 2 ethyl alcohol molecules
products of lactic acid fermentation
2 ATP, 2 NAD+, 2 lactic acid molecules
reactants of citric acid cycle
2 Acetyl CoA
Products of pyruvate oxidation per glucose
2 CO2, 2 NADH, 2 Acetyl CoA
It represents the first stage in the chemical oxidation of glucose by a cell.
Which of the following describes the process of glycolysis?
CO2
Which of the following is a product of pyruvate oxidation?
Acetyl CoA
Which of the following is one of the molecules formed by the removal of a carboxyl group (as CO2) from a molecule of pyruvate?
Products of Glycolysis
2 pyruvate, 2 ATP, 2 NADH
glycolysis and fermentation
Which of the following occurs in the cytosol of a eukaryotic cell?
NADH and CO2
Which of the following products result from the oxidation of pyruvate to acetyl CoA?
The citric acid cycle
Which of the following reactions produces the majority of the CO2 released by the complete oxidation of glucose?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
Which of the following statements about NAD+ is true?
It consists of a series of redox reactions
Which of the following statements best describes the electron transport chain?
It serves as the final acceptor for electrons from the electron transport chain
Which of the following statements best describes the primary role played by oxygen in cellular respiration?
Oxidation of NADH to NAD+
Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation?
C6H12O6 is oxidized and O2 is reduced
Which of the listed statements describes the results of the following reaction? C6H12O6 + 6O2 —-> 6CO2 + 6H2O + Energy
Acetyl CoA
Which of these is not a product of glycolysis?
FADH2
Which of these is not a product of glycolysis?
Acetyl CoA
Which of this is NOT a product of the citric acid cycle?
Fewer proteins are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor
Which statement best explains why more ATP is made per molecule in NADH than per molecule of FADH2
Glucose
Yeast cells with defective mitochondria that are incapable of performing cellular respiration will be able to survive by using which of the following muscles for energy?
2
____ATP are formed during substrate-level phosphorylation
Complex 4
_______ collects electrons and uses oxygen to combine electrons, protons, and oxygen to form water as a byproduct
Hydride ion
______________ converts NAD+ to NADH
Electron carriers
_____________cycle between being oxidized and being reduced
NAD+
________is the compound that functions as the electron acceptor in glycolysis
2 ATP
fermentation produces
Glucose
Remaining carbohydrates from Acetyl CoA become fully oxidized to ___________
Electron transport chain lost
ATP synthase can work, as long as a proton gradient is present
The proton motive force
ATP synthesis is an endergonic reaction where does the energy come from for ATP synthase to synthesize ATP?
-7.3 kcal/mole
ATP ——-> ADP + Pi
26 or 28
About ______________ ATP are made during oxidative phosphorylation
32 ATP
Aerobic respiration
Cytochrome C
Electrons are shuttled through ______________, which delivers electrons to complex 4
CO2
Electrons flow through a system that will convert ____
-Required for cellular respiration to take place -Used in last step of cellular respiration
Role of oxygen
100%
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
I'm both glycolysis and the citric acid cycle
Substrate-level phosphorylation occurs ______________
-5.5 kcal/mole
Sucrose ——>glucose + fructose
ATP levels would fall first, decreasing the inhibition of PFK and increasing the rate of ATP production
Suppose that a cell's demand for ATP suddenly exceeds is supply of ATP from cellular respiration. Which statement correctly describes how this increased demand would lead to an increased rate of ATP production?
Carrier molecules
Take electrons from sugar molecules and carry them to reactions
Oxidative Phosphorylation
Takes energy in electron carriers and converts it to the rest of the ATP
Substrate-level phosphorylation
-10% ATP -Found in glycolysis and citric acid cycle -Phosphotransferase reaction -Energy stored in electron carriers
Oxidative phosphorylation
-90% ATP -Electron transport powers the synthesis of ATP -Two ADP and Pi free-floating molecules and squeezing them close together so they synthesis ATP
ATP synthase
-A channel and a mechanical wheel -Allows protons to flow down their concentration gradient
Citric Acid Cycle
-A series of enzymatic reactions that produce more NADH and FAD2 -Produces ATP -Produces most of the CO2 -Glucose is being fully oxidized to CO2 -Energy is converted either directly to ATP or to electron carriers
Fermentation
-Anaerobic respiration -No O2 -Substrate-level phosphorylation only -Allows glycolysis to continue to make ATP -Alcohol -Do not make their own ATP -Lactic acid
Location of Glycolysis
-Cytoplasm -Prokaryotes and eukaryotes all contain cytosol -Prokaryotes do not contain mitochondria as opposed to eukaryotes -All cells regardless of domain perform glycolysis
Alcohol fermentation
-Done by yeast or other plants -Takes pyruvate and oxidizes it into 2 Acetaldehyde and then to 2 ethanol -Redox reaction -Acetaldehyde is reduced, NAD+ is oxidized
Lactic acid fermentation
-Done in several animals -Produces ATP to allow glycolysis to continue -Glycolysis produces 2 pyruvate and reduced further into 2 lactate
Pyruvate Oxidation
-Pyruvate molecule is turner into a molecule called Acetyl CoA -NADH produced
Glycolysis
-Takes glucose and converts it to pyruvate -Obtain two ATP molecules -Stores energy in NADH
ATP synthase lost
-The concentration gradient can be created, but protons have nowhere to go -Matrix will run out of protons
Reactants of Glycolysis
-The starting reactant is glucose (sugar) -A series of 10 steps that splits sugar -Glucose is a 6 ring sugar
Mitochondrial inner membrane space
Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic cells?
Organic molecule, phosphate
A bond must be broken between an ____________ and _____________ before ATP can form
Products of Electron Transport Chain
ATP and water
Pyruvate, ATP, and NADH
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?
Enzyme
An _________ is required in order for the reaction to occur
30-32
Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?
NAD+
Depletion is which of the following molecules from the mitochondria will most directly inhibit the citric acid cycle?
Substrate-level phosphorylation
During anaerobic fermentation, ATP is synthesized through _________________
NADH2 and FADH2...mitochondrial matrix
During electron transport energy from ________ is used to pump hydrogen ions into the ________
Glucose utilization would increase a lot
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?
6
For each glucose that enters glycolysis, ______ NADH + H+ are produced by the citric acid cycle
2
For each glucose that enters glycolysis, _____acetyl CoA enter the citric acid cycle
-1.7 kcal/mole
Glucose 1-P ——-> glucose 6-P
Potential energies
Glycolysis is rearranging the locations of the atoms into different forms that change their ________________
2 NADH, 2 pyruvate, and 2 ATP
Glycolysis results in a net production of which of the following from each molecule of glucose?
2
How many NADH are produced by glycolysis?
Both electron transport and ATP synthesis would stop
How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.)
NAD+
If a sugar molecule becomes oxidized, the electrons will go to ____________
NADH
If there is a lack of oxygen in cellular respiration, you would expect an increase in the concentration of ____________
Mitochondria, pyruvate oxidation
If there is enough oxygen, pyruvate will move to the ________________ and go through ________________
Oxidative phosphorylation
In cellular respiration, most ATP molecules are produced by _____
Lactate and NAD+
In muscle cells, fermentation produces _____.
Two ATP
In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?
ATP, CO2, and ethanol
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
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
In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. However, the oxidation of the remaining two carbon atoms—in acetate—to CO2 requires a complex, eight-step pathway—the citric acid cycle. Consider four possible explanations for why the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction.
In both glycolysis and the citric acid cycle
In which reactions of cellular respiration does substrate-level phosphorylation occur?
Pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the inter membrane space
Inhibition of which of the following processes would reduce or eliminate generation of a proton-motive force in mitochondria?
Reactants of Electron Transport Chain
NADH and FADH2
reactants of pyruvate oxidation
Pyruvate
Matric
Pyruvate moves through both membranes of the mitochondria and into the ___________
NADH
Reduced form of NAD+
ATP, citrate
The enzyme phosphofructokinase (PFK) catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?
ATP and citrate
The enzyme phosphofructokinase catalyzes a key step in glycolysis and is inhibited by high levels of which of the following molecules?
Oxygen
The final electron acceptor of cellular respiration is _______
A chemical concentration gradient, a pH gradient, and an electrical gradient
The proton motive force is what type of gradient?
Lactate, ATP, NAD+
The products of glucose metabolism using fermentation in anaerobic conditions from animals are ______________
CO2, ethanol, ATP, and NAD+
The products of glucose metabolism using fermentation in anaerobic conditions from yeast are_______________
ATP, inorganic phosphate
Through rotation of the mechanical wheel, enzymes take ______ and _______ and brings them closer together that they catalyze a covalent bond and form ATP
In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three steps if cellular respiration
Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Which of these statements is the correct explanation for this observation?
NADH
Upon completion of the citric acid cycle, most of the energy originally stored in each glucose molecule catabolized by cellular respiration stored in which of the following molecules?
2 ATP, 2 NADH, 2 Pyruvate
What are the net products of glycolysis from one molecule of glucose?
Allows glycolysis to continue to produce ATP for energy, by reducing the oxidized NAD+
What is the goal of fermentation?
-Extract electrons from NADH and FADH2 -Generate NAD+ and FAD
What is the goal of the electron transport chain?
O2 is the final electron acceptor to form H2O go allow the flow of electrons through the ETC
What is the role of oxygen (O2) in oxidative phosphorylation?
It involves and enzyme that catalyzes a phosphotransferase reaction
What makes substrate-level phosphorylation different than oxidative phosphorylation?
-686 kcal/mole
glucose + 6O2 ——> 6CO2 + 6H2O
location of electron transport chain
inner mitochondrial membrane
location of citric acid cycle
mitochondrial matrix
location of pyruvate oxidation
mitochondrial matrix
Ubiquinone
soluble electron transporter in the electron transport chain that connects the first or second complex to the third