Biochem, Unit 3, HWK

Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? View Available Hint(s) Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? ATP and NADH only ATP only pyruvate, ATP, and NADH CO2 only O2 only pyruvate and ATP only NADH only

ATP is the main product of cellular respiration that contains energy that can be used by other cellular processes. Some ATP is made in glycolysis. In addition, the NADH and pyruvate produced in glycolysis are used in subsequent steps of cellular respiration to make even more ATP.

activation of pyruvate dehydrogenase phosphatase by Ca2+ activation of pyruvate dehydrogenase phosphatase by Ca2+ activates PDH through interaction with an active site of enzyme, when huge amount of ATP molecules is needed for protein synthesis activation. Ca2+ interacts with active sites of four proteins which participate in contraction of vertebrate muscle, which places a huge demand on ATP production. Ca2+ mediates stimulation of PDH activity during muscle contraction, which can produce a huge amound of ATP molecules. Ca2+ is a critical signaling molecule for contraction in vertebrate muscle, which places a huge demand on ATP production.

Ca2+ is a critical signaling molecule for contraction in vertebrate muscle, which places a huge demand on ATP production.

The ATP that is generated in glycolysis is produced by substrate-level phosphorylation, a very different mechanism than the one used to produce ATP during oxidative phosphorylation. Phosphorylation reactions involve the addition of a phosphate group to another molecule.

Correct: -One of the substrates is a molecule derived from the breakdown of glucose -An enzyme is required in order for the reaction to occur -A bond must be broken between an organic molecule and phosphate before ATP can form. Incorrect: -The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions. -The enyzmes involved in ATP synthesis must be attached to a membrane to produce ATP. In substrate-level phosphorylation, an enzyme transfers a phosphate group from one molecule (an intermediate in the breakdown of glucose to pyruvate) to ADP to form ATP. This is very different from the mechanism of ATP synthesis that takes place in oxidative phosphorylation.

Predict which one of the five steps of the α-ketoglutarate dehydrogenase complex reaction is metabolically irreversible under physiological conditions. Predict which one of the five steps of the -ketoglutarate dehydrogenase complex reaction is metabolically irreversible under physiological conditions. Step 1. Decarboxylation. Step 2. Oxidation of 4-carbon group, reduction of lipoamide disulfide. Step 3. Transacylation. Step 4. Dihydrolipoyl dehydrogenase. Step 5. FADH2 enzymatically reoxidized by NAD+ to form NADH. why?

Decarboxylation The CO2 product diffuses away from the enzyme, and does not rebind to any significant extent.

Glucose is one of the major sources of energy in the body. The oxidation of glucose produces energy in the form of ATP.

Glucose is physically broken apart during glycolysis to form pyruvate. Then pyruvate is converted to acetyl CoA. Acetyl CoA goes through the citric acid cycle, and this cycle produces many NADH and FADH2 molecules. NADH and FADH2 enter the electron transport chain, which oxidizes them and uses the energy to pump protons out of the matrix of the mitochondrion. These protons drive ATP synthase to produce ATP.

In glycolysis, the first stage of cellular respiration, one molecule of glucose is oxidized to two molecules of pyruvate, with the production of ATP and NADH. As you watch the Glycolysis animation, pay attention to the reactions involved in the production of NADH. These reactions, called redox (oxidation-reduction) reactions, play a key role in cellular respiration. Also pay attention to the mechanism by which ATP is synthesized. Think about how ATP synthesis at this stage differs from ATP synthesis during oxidative phosphorylation, where most of the ATP in cellular respiration is made. Part A - Redox (oxidation-reduction) reactions in glycolysis Part complete In glycolysis, as in all the stages of cellular respiration, the transfer of electrons from electron donors to electron acceptors plays a critical role in the overall conversion of the energy in foods to energy in ATP. These reactions involving electron transfers are known as oxidation-reduction, or redox, reactions. Drag the words on the left to the appropriate blanks on the right to complete the sentences. View Available Hint(s) ResetHelp oxygen water 1. When a compound donates (loses) electrons, that compound becomes oxidized. Such a compound is often referred to as an electron donor. 2. When a compound accepts (gains) electrons, that compound becomes reduced. Such a compound is often referred to as an electron acceptor. 3. In glycolysis, the carbon-containing compound that functions as the electron donor is glucose. 4. Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called pyruvate. 5. NAD+ is the compound that functions as the electron acceptor in glycolysis. 6. The reduced form of the electron acceptor in glycolysis isNADH.

In the net reaction for glycolysis, glucose (the electron donor) is oxidized to pyruvate. The electrons removed from glucose are transferred to the electron acceptor, NAD+, creating NADH.

One or more of the following molecules are substrates or products in the glycolytic pathway. Identify them. Check all that apply. View Available Hint(s) Check all that apply. glucose pyruvate arachidonic acid ATP NADH

One or more of the following molecules are substrates or products in the glycolytic pathway. Identify them. Check all that apply. View Available Hint(s) Check all that apply. glucose pyruvate arachidonic acid ATP NADH Previous Answers Correct The glycolytic pathway is a quite extensive metabolic pathway with 10 enzymatic steps. There are many substrates and products along the way. The most important products in the pathway are ATP and NADH, which can be reduced to produce more ATP in a separate process.

Part complete Rank the following molecules by the number of ATP molecules they produce.

Pyruvate can be oxidized to produce 12.5 ATP molecules. Acetyl CoA can likewise be oxidized to produce 10 ATP molecules. The electron carriers NADH and FADH2 have enough energy to produce 2.5 and 1 ATP molecules, respectively. GTP carries the same amount of energy as ATP.

Cellular respiration breaks down glucose and releases carbon dioxide and water. Which step in the oxidation of pyruvate produces carbon dioxide? Cellular respiration breaks down glucose and releases carbon dioxide and water. Which step in the oxidation of pyruvate produces carbon dioxide? Removal of an acetyl group from pyruvate releases carbon dioxide. The pyruvate dehydrogenase complex comes into play. Removal of a carbonyl group from pyruvate releases carbon dioxide. The pyruvate dehydrogenase complex comes into play. Removal of an acetyl group from pyruvate releases carbon dioxide. The pyruvate decarboxylase complex comes into play. Removal of a carboxyl group from pyruvate releases carbon dioxide. The pyruvate dehydrogenase complex comes into play.

Removal of a carboxyl group from pyruvate releases carbon dioxide. The pyruvate dehydrogenase complex comes into play.

Put the enzymes of the second half of the citric acid cycle in order from left to right.

The final product of the citric acid cycle is oxaloacetate, which is a substrate for another round of the cycle.

Put the structures of glycolysis in the order in which they appear in the first five reactions in the glycolytic pathway. Start with glucose, and end with glyceraldehyde-3-phosphate. Rank from first to last. To rank items as equivalent, overlap them.

The first five reactions of the glycolytic pathway are considered the "energy investment" segment of glycolysis. The initial investment is two ATP molecules. This ATP investment is regained later in the pathway.

The citric acid cycle is the central oxidative pathway for biological organisms to produce ATP under aerobic conditions. The cycle has several intermediates that it shares with the metabolism of proteins, fats, as well as carbohydrates. The enzymes used in each step of the pathway are often named after the type of reaction and either the product formed or the substrate acted upon. For example, oxidation and decarboxylation of the substrate isocitrate to form α-ketoglutarate is conducted by isocitrate dehydrogenase. Isocitrate is the substrate and the reaction involves the transfer of a hydride, H−, to an electron acceptor. One enzyme of the citric acid cycle that does not utilize such a naming practice is aconitase, sometimes called aconitate hydratase. This enzyme catalyses isomerizations of citric acid substrates. Part A Put the enzymes of the first half of the citric acid cycle in order from left to right. Rank the items from first to last. To rank items as equivalent, overlap them.

The first four reactions of the citric acid cycle release two carbon dioxide molecules and result in succinyl CoA.

Part complete activation of pyruvate carboxylase by acetyl-CoA activation of pyruvate carboxylase by acetyl-CoA This is a signal that pyruvate can be oxidized in the citric acid cycle instead of shunted into gluconeogenesis. In addition, it is a signal of activation carbohydrate metabolism. This is a signal that pyruvate can be oxidized in the citric acid cycle as well as can be shunted into gluconeogenesis. In addition, it is a signal of activation fat metabolism. This is a signal that part of available pyruvate can be metabolized into oxaloacetate, when the energy charge is low and production of additional ATP through the citric acid cycle is required. This is a signal that pyruvate can be shunted into gluconeogenesis instead of being oxidized in the citric acid cycle. In addition, it is a signal of unbalanced fat and carbohydrate metabolism.

This is a signal that pyruvate can be oxidized in the citric acid cycle instead of shunted into gluconeogenesis. In addition, it is a signal of activation carbohydrate metabolism.

inhibition of isocitrate dehydrogenase by NADH inhibition of isocitrate dehydrogenase by This is a signal to reduce flux through the citric acid cycle when metabolism of acetyl-CoA through glyoxylate pathway is more preferred. This is a signal to reduce flux through the citric acid cycle when additional amount of acetyl-CoA is needed for lipid biosynthesis. This is a signal to increase flux through the citric acid cycle when metabolism of acetyl-CoA through glyoxylate pathway is less preferred. This is a signal to reduce flux through the citric acid cycle when levels of reduced electron carriers are adequate for energy generation.

This is a signal to reduce flux through the citric acid cycle when levels of reduced electron carriers are adequate for energy generation.

inhibition of α-ketoglutarate dehydrogenase by succinyl-CoA inhibition of -ketoglutarate dehydrogenase by succinyl-CoA This serves as a signal that there is insufficient amount of NAD+, FAD, flux through the electron transport should be increased. This allows to increase α-ketoglutarate accumulation and thereby to increase the rate of amino acids transamination. This allows to turn back reversible stages of the citric acid cycle, to produce additional pyruvate which can be used in gluconeogenesis at high glucose level in the blood. This serves as a general indicator that when an energy-rich substrate (succinyl-CoA) is abundant, flux through the citric acid cycle can be reduced.

This serves as a general indicator that when an energy-rich substrate (succinyl-CoA) is abundant, flux through the citric acid cycle can be reduced.

ation of pyruvate dehydrogenase kinase by NADH activation of pyruvate dehydrogenase kinase by This tends to inactivate pyruvate dehydrogenase and to activate pyruvate carboxylase and to increase the oxaloacetate production and, hence, to activate gluconeogenesis. This tends to inactivate pyruvate dehydrogenase when level of NADH is sufficient for ATP production via the respiratory chain and, hence, to make pyruvate available for other purposes. This tends to activate pyruvate dehydrogenase when level of NADH is sufficient for ATP production via the cytric acid cycle and, hence, to increase the oxidation of the lipids and carbonhydrates. This tends to activate pyruvate dehydrogenase when level of NADH is sufficient for ATP production via the respiratory chain and, hence, to make pyruvate unavailable for other purposes.

This tends to inactivate pyruvate dehydrogenase when level of NADH is sufficient for ATP production via the respiratory chain and, hence, to make pyruvate available for other purposes.

activation of isocitrate dehydrogenase by ADP activation of isocitrate dehydrogenase by When the energy charge is low, the accumulation of ADP provides a signal to activate the citric acid cycle and thereby increase the oxidation of nutrients for ATP production. The accumulation of ADP provides a signal to activate the isocitrate dehydrogenase and thereby increase \alpha-ketoglutarate level in organism preventing ATP consumption in the process of glutamine desamination. When the energy charge is high, the accumulation of ADP provides a signal to activate the citric acid cycle and thereby increase the oxidation of nutrients for proteins production. When the energy charge is high, the accumulation of ADP provides a signal to activate the citric acid cycle and thereby increase the succinate production for electron transport chain.

When the energy charge is low, the accumulation of ADP provides a signal to activate the citric acid cycle and thereby increase the oxidation of nutrients for ATP production.

The two carbon atoms that are lost as CO2 in the third and fourth steps of the citric acid cycle are the same as the two carbon atoms of acetyl CoA because of the stereochemistry of the isocitrate dehydrogenase reaction.

false

Given what you know about the function of the glyoxylate cycle and the regulation of the citric acid cycle, propose control mechanisms that might regulate the glyoxylate cycle. Check all that apply. Check all that apply. substrate-level control of citrate synthase increasing the availability of glucose as the carbon source substrate-level control of succinyl-CoA synthetase activation of succinic dehydrogenase inhibition of isocitrate lyase by succinate increasing fatty acids level in a cell activation of citrate lyase by acetyl-CoA or fatty acids

inhibition by isocitrate by succinate substralte level control of citrate synthase activation of strate lyase by acetal coae

Avidin is a protein that binds extremely tightly to biotin, so avidin is a potent inhibitor of biotin-requiring enzyme reactions.Consider glucose biosynthesis from each of the following substrates and predict which of these pathways would be inhibited by avidin. Check all that apply. Check all that apply. oxaloacetate phosphoenolpyruvate lactate malate fructose-6-phosphate

lactate

In the pyruvate dehydrogenase complex, the swinging arm responsible for channeling metabolic intermediates between successive enzymes is which cofactor? In the pyruvate dehydrogenase complex, the swinging arm responsible for channeling metabolic intermediates between successive enzymes is which cofactor? biotin coenzyme A lipoic acid thiamine pyrophospate FAD

lipoic acid http://kitto.cm.utexas.edu/courses/ch395g/fall2009/secure/docs/Old%20Exams/Exam3-04.pdf

Which of the following cannot be metabolized to make molecules that can enter the citric acid cycle? View Available Hint(s) Which of the following cannot be metabolized to make molecules that can enter the citric acid cycle? carbohydrates lipids proteins metal ions Previous Answers Correct Every one of the nutrient group's fats, carbohydrates, and proteins can be metabolized to a precursor that can be used in the citric acid cycle. Metal ions, however, are already in their elemental state and cannot be altered enzymatically.

metal ions

Which of the following enzymes is NOT part of gluconeogenesis? Which of the following enzymes is NOT part of gluconeogenesis? fructose-1,6-bisphosphatase phosphoenolpyruvate carboxykinase phosphofructokinase pyruvate carboxylase

phosphofructokinase PFK is part of glycolysis

The glyoxylate cycle in plants and bacteria can be used for net carbohydrate synthesis from fat because isocitrate lyase yields glyoxylate and ________ without the loss of two carbons as occurs in the citric acid cycle.⁸

succinate

Constants | Periodic Table In plants and animals, there are four major polysaccharides composed of glyucose monomers: amylose, cellulose, glycogen, and starch. Both amylose and cellulose are linear polysaccharides. Cellulose form sheets because the beta-1,4 glycosidic linkages form an elongated polymer. Both glycogen and starch form branched polymers. Glycogen is found in animals and is more highly branched than starch, which is found in plants. Part A - Select the figure that best illustrates the structure of glycogen.

the first

Arrange the sequence of events for the conversion of succinyl-CoA to succinate and ATP (or GTP) in the correct order: 1) The phosphate group is transferred from a histidine residue of the phosphorylated enzyme intermediate to the nucleotide. 2) Inorganic phosphate reacts at the thioester of succinyl-CoA to yield a mixed phosphoanhydride. 3) A His residue from the protein is phosphorylated by succinyl phosphate.

this is a reaction that is catalyzed by the enzyme Succinyl CoA synthetase. This enzyme converts the succinyl CoA to succinate. The events should be 2, 3 and 1. I will make structures to show it to you. Remember, all of the reactions are reversible in this reaction and the histidine residue that the protein utilized for this reaction is His246.

Glycogen is a major energy source for skeletal muscle contraction. true/false

true http://www.chegg.com/homework-help/questions-and-answers/phosphorylases-phosphatases-catalyze-reaction-removal-phosphate-group-glycogen-major-energ-q16130005