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