MODULE 3- BIO PROBLEM SETS

Match the following descriptions to the appropriate term. -an intermediate in an enzyme-catalyzed reaction that consists of the enzyme bound to its substrate -the molecule or molecules on which an enzyme exerts catalytic action -the region on the surface of an enzyme where the substrate binds and catalysis occurs -protein catalyst -any substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change -a high-energy intermediate state of the reactants during a chemical reaction that must be overcome for the reaction to proceed -the amount of kinetic energy required to initiate a chemical reaction (achieve the transition state -activation energy -transition state -catalyst -enzyme -active site -substrate -enzyme complex substrate

-an intermediate in an enzyme-catalyzed reaction that consists of the enzyme bound to its substrate with enzyme complex substrate -the molecule or molecules on which an enzyme exerts catalytic action with substrate -the region on the surface of an enzyme where the substrate binds and catalysis occurs with active site -protein catalyst with enzyme -any substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change with catalyst -a high-energy intermediate state of the reactants during a chemical reaction that must be overcome for the reaction to proceed with transition state) -the amount of kinetic energy required to initiate a chemical reaction (achieve the transition state) with activation energy

Match each of the following descriptions to the correct term -the molecule or molecules on which an enzyme exerts catalytic action -the region on the surface of an enzyme where the substrate binds and catalysis occurs -a protein that increases the rate of a chemical reaction without itself undergoing any permanent chemical change -a high-energy intermediate state of the reactants during a chemical reaction that must be overcome for the reaction to proceed - the amount of energy required to initiate a chemical reaction (achieve the transition state) --enzyme --transition state --activation energy --active site --substrate

-the molecule or molecules on which an enzyme exerts catalytic action with substrate -the region on the surface of an enzyme where the substrate binds and catalysis occurs with active site -a protein that increases the rate of a chemical reaction without itself undergoing any permanent chemical change with enzyme -a high-energy intermediate state of the reactants during a chemical reaction that must be overcome for the reaction to proceed with transition state - the amount of energy required to initiate a chemical reaction (achieve the transition state) with activation energy

Match each scenario below with the spontaneity of the reaction. Note: "> 0" indicates "greater than zero" and "< 0" indicates "less than zero" -ΔS > 0 and ΔH > 0 -ΔS < 0 and ΔH < 0 -ΔS > 0 and ΔH < 0 -ΔS < 0 and ΔH > 0 -Spontaneous only at high temperatures (when TΔS is large) -Spontaneous only at low temperatures (when TΔS is small). -Spontaneous at all temperatures. -Non-spontaneous at all temperatures

-ΔS > 0 and ΔH > 0 (entropy is greater than 0 and enthalpy is greater than 0) with spontaneous at only high temperatures -ΔS < 0 and ΔH < 0 (entropy is less than 0 and enthalpy is less than 0) with spontaneous only at low temperatures -ΔS > 0 and ΔH < 0 (entropy is greater than 0 and enthalpy is less than 0) with spontaneous at all temperatures -ΔS < 0 and ΔH > 0 (entropy is less than 0 and enthalpy is greater than 0) with non-spontaneous at all temperatures

What is the standard free energy of the reactant of glycolysis, glucose, in kcal/mol?

0 look at glucose step 1, it matches with 0 on the y axis

The hydrolysis of ATP has a ΔG'° = -30.5 kJ/mol. Using the table above, identify the Gibbs Free Energy for step 1 in Glycolysis if ATP was NOT present. Hint: Your answer will be a ΔG'° value and in units of kJ/mol, and report your answer to onedecimal.

13.8 (-16.7-(-30.5)=13.8

The hydrolysis of ATP has a ΔG'° = -30.5 kJ/mol. Using the table above, identify the Gibbs Free Energy for step 3 in Glycolysis if ATP was NOT present. Hint: Your answer will be a ΔG'° value and in units of kJ/mol, and report your answer to one decimal.

16.3 (14.2-(-30.5)=16.3

How many electrons are transferred in Reaction 1?

2

How many electrons are transferred in Reaction 2?

2

The hydrolysis of ATP has a ΔG of -7.3 kcal/mol. The phosphorylation of creatine to creatine phosphate has a ΔG of 10.3 kcal/mol. What is the free energy change when these two equations are coupled together? Give your answer as a number only in units of kcal/mol.

3

If the following two reactions: Reaction 1: A → B ΔG = −5 kcal/mol Reaction 2: B → C + D ΔG = 8 kcal/mol were coupled to yield the equation:A → C + D What is ΔG (in kcal/mol) for the coupled reaction? Give your answer as a number only. Would the coupled reaction be spontaneous?

3.0 (add the two G values) the coupled reaction would not be spontaneous because the G value is positive

What is the Gibbs free energy change in units of kcal/mol of a reaction at 37°C (310 K) that has an enthalpy change of 250 kcal/mol and an entropy change of 2 kcal/mol•K? Give your answer as a number only.

370.0

What is the net change in standard Gibbs free energy?

-140 take 0 and -140, net change is -140

What is the estimated standard free energy of the product of glycolysis, pyruvate, in kcal/mol?

-140 look at pyruvate in the last step

What is the change in free energy for a reaction with an enthalpy change of 725 kJ/mol and an entropy change of 3 kJ/mol⋅K at physiological temperature of 37°C? Give your answer as a numeral only in units of kJ/mol.

-205 -remember that you need to convert celsius into kelvin, which is celsius +273

The temperature term in the Gibb's free energy equation is always given in Kelvin (K). You can convert °C to K by adding 273, so 25 °C = 298 K. At 25°C, what is the change in Gibb's free energy (ΔG) in kJ/mol if the change in enthalpy is 500 kJ/mol, and the change in entropy is 10 kJ/mol•K. Give your answer as a numeral only.

-2480

Using the information below, calculate the standard Gibb's free energy change for the synthesis of sucrose from glucose, fructose, and ATP in kJ/mol. Give your answer as a number only. sucrose + H2O --> fructose + glucose ΔG° = −27 kJ/molATP + H2O --> ADP +Pi ΔG° = −30 kJ/mol

-3.0 (-30+27)

If the reactions below were coupled as shown, what would be the net ΔG in kcal/mol? Give your answer as a number only. ATP → ADP + Pi ΔG = −7.3 kcal/molA + B → C ΔG = 4.2 kcal/molA + B + ATP → C + ADP + Pi

-3.1 (-7.3+4.2)= -3.1

PKA is a tetrameric protein consisting of two catalytic subunits and two regulatory subunits. When PKA is in its inactive form, the regulatory subunits block the active sites on the catalytic subunits. Cyclic AMP binds to the regulatory subunits, which exposes the active sites on the catalytic subunits. Both the substrate, ATP, and two Mg2+ ions form intensive contacts with the catalytic subunit of PKA. You are a scientist and you want to set up a protein phosphorylation reaction using PKA (protein kinase A). You purchase PKA from a biotech company, and the data sheet tells you that PKA requires ATP, cAMP and Mg2+. Match the molecules to its role in the reaction of PKA. -ATP -MG2+ -cAMP -uncompetitive inhibitor -substrate -allosteric activator -allosteric inhibitor -cofactor -competitive inhibitor

-ATP with substrate -MG2+ with cofactor -cAMP with allosteric activator ATP is the substrate that the catalytic subunit binds to MG2+ is the small inorganic molecule that assists in enzyme activity and cAMP as the allosteric activator binds to the enzyme away from the active site and makes the active site more available for substrate binding

FILL IN THE BLANKS A reaction in which a molecule loses an electron is a(n) ___________ reaction, and a reaction in which a molecule gains an electron is a(n) _________ reaction.

A reaction in which a molecule loses an electron is a oxidation reaction, and a reaction in which a molecule gains an electron is a reduction reaction

FILL IN THE BLANKS Consider the two-step metabolic pathway: A —(enzyme 1)—> B —(enzyme 2)—> C How would inactivating enzyme 1 affect the concentrations of molecules A, B, and C relative to what they would be if the pathway were fully functional? Write the word "increase" or "decrease" in each of the blanks below: A would _________ B would _________ C would ___________

A would increase B would decrease C would decrease A would increase because enzyme 1 comes after it, but B would decrease because enzyme 1 comes before it and C would decrease because B decreased

Match each of the labels in the image to the correct subcellular location or structure. Intermembrane Space Mitochondrial Inner Membrane Mitochondrial Matrix Complex I Coenzyme Q Complex II Complex III Cytochrome C Complex IV ATP Synthase

A- inter membrane space B- mitochondrial inner membrane C- mitochondrial matrix D- Complex 1 E- Coenzyme Q (Ubiquinone) F- Complex 2 G- Complex 3 H- Cytochrome C I- Complex IV J- ATP Synthase

The pH of pure water is 7 Acids have a pH _______ than 7 Bases have a pH _________ than 7

Acids have a pH less than 7 Bases have a pH greater than 7

PFK-1 binds ATP at two different sites (with differing affinities). Low levels of ATP binding stimulate PFK activity (in the presence of fructose 6-phosphate) and high levels of ATP inhibit PFK activity by stabilizing the inactive state. Considering PFK has only one active site, what type of regulation does ATP have on PFK?

Allosteric Regulation Allosteric Inhibition Allosteric

Where does the oxidation of NADH occur?

D NADH enters through complex 1 and gets oxidized (loses electrons, specifically H+ions to contribute to the gradient in the inter membrane space)

Which of the following ETC components couple the energy released from electron transfers to the pumping of protons against their gradient? Select all that apply. D E F G H I J

D (Complex 1 ) G (Complex 3) I (Complex 4) These all contribute to forming the high H+ion concentration in the inter membrane space which encourages the pumping of protons against their gradient

Many of the metabolic disorders we see in this acute-care unit arise from disruptions in glucose homeostasis. For example, diabetics either have cells that don't respond to insulin properly (Type II diabetes) or don't have functional insulin produced (Type I diabetes). This sugar balance, however, isn't the only thing we worry about here in the metabolic disorders ward. There are genetic disorders where a person is missing an enzyme required to break down the glucose (or other sugar) once it gets into its target cell. Once glucose enters the cell, hexokinase will add a phosphate group to the glucose. This gives the glucose a negative charge and traps it within the cell. This addition of a phosphate group is the beginning of glycolysis. Some of the disorders you encounter are caused by enzyme deficiencies in glycolysis. It is not uncommon for patients with glycolytic disorders to be anemic (deficient in red blood cells). Since they lack mitochondria, mammalian red blood cells rely solely on glycolysis to generate ATP. If red blood cells are deficient in one or more enzymes required to complete glycolysis, they will have a short half-life in vivo. This shortened half-life will lead to anemia since there will be fewer red blood cells circulating at any given time. Patients may compensate for these short-lived red blood cells by making more; however, this is not always the case and some people affected by these deficiency diseases may suffer from life threatening anemia." After his mini-lecture, Dr. Saccharo asks if anybody has questions. One of the other interns, asks, "If glycolysis is needed to use glucose, how can a person live without all the enzymes needed for glycolysis?" Dr. Saccharo responds with one word, "Isoenzymes." Isoenzymes Isoenzymes are different forms of an enzyme that catalyze the same reaction. They use the same substrates and produce the same products. However, they are often encoded for by different genes. They may be found in different tissues, and they may be produced at different stages of development. Isoenzymes usually have slightly different affinities for their substrates. Different isoenzymes often represent different gene products and patients are often deficient in one isoform, but not the others. So a patient suffering from anemia will likely have a deficiency in an isoenzyme found in red blood cells, but not the isoenzyme that is normally found in the liver or the intestines. In most cells, hexokinase catalyzes the first step in glycolysis. However in liver cells, hexokinase is not present. Instead, the first step of glycolysis is catalyzed by glucokinase in the liver. Hexokinase and glucokinase are isoenzymes that both use _______ as a substrate.

In most cells, hexokinase catalyzes the first step in glycolysis. However in liver cells, hexokinase is not present. Instead, the first step of glycolysis is catalyzed by glucokinase in the liver. Hexokinase and glucokinase are isoenzymes that both use glucose as a substrate, this is because isoenzymes are different forms of a n enzyme that catalyze the same reaction and have the same substrates and produce the same products

Another glycolysis enzyme that has isoenzymes is phosphofructokinase (PFK). There are three different isoenzymes and each is encode by a different gene: PFK - L is expressed in the liver and the gene for this isoenzyme is found on chromosome 21 PFK - M is expressed in the muscle and the gene is found on chromosome 12 PFK - P is expressed in platelets and the gene is found on chromosome 10 Which step in glycolysis is catalyzed by phosphofructokinase? Answer with a number only (refer to the figure way above for numbering in the Scenario (glycolysis)).

Step 3

Describe the difference between oxidative phosphorylation and substrate-level phosphorylation

Substrate-level phosphorylation is when ADP is phosphorylated by a substrate to produce ATP, occurs in glycolysis and Krebs cycle, in oxidative phosphorylation, electrons derived from NADH and FADH2 combine with O2, and the energy released from these oxidation/ reduction reactions is used to drive the synthesis of ATP from ADP, so substrate level phosphorylation does happen in glycolysis but earlier, whereas oxidative phosphorylation is strictly in the ETC

FILL IN THE BLANKS: The process of ____________ is the breakdown of glucose by enzymes to release energy and generate____________. ___________ is then converted to _____________ to be further metabolized in the _________ _______ ________ to generate molecules of ___________ and ____________ that are further oxidized to produce __________

The process of glycolysis is the breakdown of glucose by enzymes to release energy and generate pyruvate or pyruvic acid. Pyruvate is then converted to Acetyl CoA to be further metabolized in the Citric Acid Cycle to generate molecules of NADH and FADH2 that are further oxidized to produce ATP.

Vitamin Water Energy Tropical Citrus has a pH of 3.15. Would this be considered a base, an acid, or neutral? a base b acid c neutral

This would be considered an acid because the pH is less than 7

FILL IN THE BLANKS: ________ inhibitors binds to only the enzyme-substrate complex, whereas _______ inhibitors can bind to free enzyme or to the enzyme-substrate complex

Uncompetitive inhibitors binds to only the enzyme-substrate complex, whereas noncompetitive inhibitors can bind to free enzyme or to the enzyme-substrate complex

The graph shows energy changes associated with a reaction that goes forward without an enzyme present. Which statement correctly describes the graph and what happens when an enzyme is added to catalyze the reaction? Select all that apply. a A decreases and B does not change. b C represents the ΔG of the reaction and A represents the activation energy required for the catalyzed reaction. c A is related to the rate of the reaction and B is related to the spontaneity of the reaction. d Both A and B decrease. e A does not change and B decreases. f As for the reverse reaction; B decreases and A stays the same. g As for the reverse reaction; both B and C decrease. h As for the reverse reaction; B represents the ΔG of the reaction and C represents the activation energy required for the uncatalyzed reaction.

a A decreases and B does not change, the enzyme will decrease the activation energy needed but it does not affect Gibbs free energy (B) c A is related to the rate of the reaction and B is related to the spontaneity of the reaction. The enzyme can speed up the rate of the reaction with its activation energy, and because B represents Gibbs free energy, it also represents the spontaneity of the reaction, remember enzymes do not affect Gibbs free energy or the spontaneity, only the rate of the reaction h As for the reverse reaction; B represents the ΔG of the reaction and C represents the activation energy required for the uncatalyzed reaction.

Enzymes within metabolic pathways can be regulated by SELECT ALL THAT APPLY a Allosteric activators b Alloseteric inhibitors c Reversible inhibitors d Covalent modification e Gene expression

a Allosteric activators b Alloseteric inhibitors c Reversible inhibitors d Covalent modification (enzyme-substrate complexes are held together by covalent bonds)n e Gene expression

Which substrate will be oxidized in the reaction catalyzed by glyceraldeyde 3-phosphate dehydrogenase? a Glyceraldehyde 3-phosphate b NAD+ c NADH d 1,3-bisphosphoglycerate

a Glyceraldehyde 3-phosphate

Glycerol is a 3-carbon molecule that can be oxidized by your cells by a two-step pathway that converts glycerol to the glycolytic intermediate dihydroxyacetone phosphate (DHAP). This two-step pathway is pictured below. The DHAP generated from glycerol feeds into the remaining steps of glycolysis (the payoff phase). Metabolic disorders often arise from enzyme deficiencies in which a key metabolic enzyme is produced in lower levels than usual. Many of these metabolic disorders have similar symptoms because of the connections between pathways. For example, Lactate dehydrogenase deficiency and phosphofructokinase (PFK) deficiency in muscle both have symptoms of exercise intolerance, including fatigue and muscle pain during strenuous exercise. Both deficiencies can also result in reduced lactate levels during exercise. Treatment for both individuals includes avoidance of high-intensity exercise. In order to distinguish between these two disorders, a physician could test the patient's lactate levels during exercise before and after administering glycerol. What would be the expected results if this test were performed? Select all that apply. a Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase. b Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in muscle PFK. c Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in muscle PFK. d Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase.

a Lactate levels would be low after intense exercise and would not increase after glycerol was administered if the patient has a deficiency in lactate dehydrogenase. b Lactate levels would be low after intense exercise and would increase after glycerol was administered if the patient has a deficiency in muscle PFK.

For the following two reactions: Reaction 1: A → B ΔG = −5 kcal/mol Reaction 2: B → C + D ΔG = 8 kcal/mol Which reaction is exergonic? a Reaction 1 b Reaction 2 c Both reactions d Neither reaction

a Reaction 1 this is because it's overall G value is negative, and therefore spontaneous and exergonic (energy is released)

For the two energy diagrams shown, which represents a reaction that is endergonic? a The energy diagram on the left b The energy diagram on the right c Both energy diagrams d Neither energy diagram

a The energy diagram on the left energy is being absorbed

Changing pH moves buffering systems away from equilibrium. How will the reaction in the figure be altered if the concentration of H+ increases? a The equation will be driven to the left (towards reactants). b The equation will be driven to the right (towards products).

a The equation will be driven to the left (towards reactants).

Enthalpy of a reaction is defined as the heat energy change (ΔH) that takes place when reactants go to products. If heat is absorbedduring the reaction, ΔH is positive; if heat is released, then ΔH is negative. Which of the following is true regarding the spontaneity of cellular respiration? Use the equation for ΔG (ΔG = ΔH - TΔS) to assess spontaneity. Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a The reaction is spontaneous at all temperatures b The reaction is non-spontaneous at all temperatures. c The reaction is only spontaneous at high temperatures. d The reaction is only spontaneous at low temperatures. Provide your reasoning about your answer above. ΔG? ΔH? ΔS?

a The reaction is spontaneous at all temperatures Cellular respiration is breaking down glucose, it is therefore catabolic and exergonic (energy is released) which means it is spontaneous The overall Gibbs free energy would be negative because cellular respiration is an exothermic and spontaneous reaction. Again, because it is releasing energy, the enthalpy would be negative, and because of its spontaneity, it will be more disordered and have a positive entropy. So, negative G, negative H, positive S

Is the overall process of cellular respiration spontaneous? a Yes b No

a Yes cellular respiration is exergonic and therefore spontaneous

When FAD becomes FADH2, the coenzyme has been a reduced. b oxidized. c metabolized. d hydrolyzed.

a reduced it is gaining electrons

Catabolic pathways a supply energy, primarily in the form of ATP, for the cell's work. b are endergonic. c are spontaneous and do not need enzyme catalysis. d combine molecules into more energy-rich molecules. e build up complex molecules such as protein from simpler compounds.

a supply energy, primarily in the form of ATP, for the cell's work. Catabolic pathways involve the breakdown of larger molecules into simpler ones. For example, in cellular respiration, glucose is broken down into energy, specifically ATP which then the cell can use for its own purpose

Assess the entropy changes that occur as ice melts to water. Which of the following would you expect to be true? Select all that apply. a the entropy change is favorable. b the entropy change is unfavorable. c the reaction creates more order. d the reaction creates more disorder. e ΔS is a positive number. f ΔS is a negative number.

a the entropy change is favorable. d the reaction creates more disorder. e ΔS is a positive number. the entropy change is favorable because as the ice melts, there is more disorder aka entropy, and so S is a positive number due to the high amount of disorder

The rate of an enzymatic reaction can be affected by a pH b Temperature c Concentration

a, b and c each enzyme has an optimum pH range, so changing the pH outside of this range will slow enzymatic activity raising temperatures generally speeds up a reaction where lowering temperatures generally slows down a reaction increasing substrate or enzyme concentration will generally speed up a reaction

Identify which steps in glycolysis shows reaction coupling in which ATP hydrolysis is involved? a 1->2 b 2->3 c 3->4 d 4->5 e 5->6 f 6->7 g 7->8 h 8->9 i 9->10

a- 1->2 c- 3->4 Endergonic reactions are those that are non-spontaneous. Therefore, they require an input of energy from ATP. The energy-investment phase requires two molecules of ATP at steps 1->2 and 3->4.

Cellular respiration uses glucose and oxygen, which have high levels of free energy, and releases CO2 and water, which have low levels of free energy. Which of the following statements correctly describe this process. a Cellular respiration is spontaneous. b Cellular respiration is not spontaneous. c Cellular respiration is endergonic. d Cellular respiration is exergonic. e Cellular respiration has an overall positive Gibbs free energy change. f Cellular respiration has an overall negative Gibbs free energy change.

a- Cellular respiration is spontaneous. d- Cellular respiration is exergonic. f- Cellular respiration has an overall negative Gibbs free energy change. Spontaneous reactions occur if the free energy of the products is lower than that of the reactants, as is the case in cellular respiration. Spontaneous reactions occur without the input of energy (are exergonic) and have a negative ΔG.

Which complexes use the energy from electron transfer to move protons? a Complex I b Complex II c Complex III d Complex IV

a- Complex I c- Complex III d- Complex IV

Select all of the statements that correctly describe the exergonic reacction above. a Reaction 1 is an oxidation reaction b Reaction 1 is a reduction reaction c Reaction 2 is an oxidation reaction d Reaction 2 is a reduction reaction e AH2 has the highest energy electrons. f B+ has the highest energy electrons. g A has the highest energy electrons. h BH has the highest energy electrons.

a- Reaction 1 is an oxidation reaction, this is because oxidation reactions are always coupled with reduction reactions, and when oxidized, an atom loses one or more electrons, in this case it lost an H electron d- Reaction 2 is a reduction reaction, this is because again, oxidation and reduction reactions are always coupled with eachother, and when reduced, an atoms gains one or more electrons, and in this case, it gained an H electron e- AH2 has the highest energy electrons.

Photosynthesis is a ------ process. a anabolic b catabolic

a- anabolic In photosynthesis, it requires energy to build up large molecules like glucose from C02 and H20

Reversible inhibitors are reversible because they bind to the enzyme through weak interactions. Which of the following types of interactions would you expect to find between an enzyme and an inhibitor? a hydrogen bonds b ionic (charge/charge) interactions c disulfide bonds d hydrophobic interactions e van der Waals interactions f peptide bonds

a- hydrogen bonds b- ionic (charge/charge) interactions d- hydrophobic interactions e- van der Waals interactions

What levels of protein structure would an allosteric enzyme like PKA have? a primary b secondary c tertiary d quaternary

a- primary b- secondary c- tertiary d- quaternary allosteric enzymes are multi-subunit proteins

If the respiratory chain is working properly, how does the pH of the mitochondrial matrix differ from the pH in the intermembrane space (IMS)? a The pH of the matrix is lower than the pH of the IMS. b The pH of the matrix is higher than the pH of the IMS. c The pH of the matrix is the same as the pH of the IMS>

b The pH of the matrix is higher than the pH of the IMS. The matrix has a lower concentration of H+ions so it is higher on the pH scale (base, greater than 7) , where the inter membrane space has a higher concentration of h+ ions and is lower on the pH scale (acid, less than 7)

Enthalpy of a reaction is defined as the heat energy change (ΔH) that takes place when reactants go to products. If heat is absorbedduring the reaction, ΔH is positive; if heat is released, then ΔH is negative. Which of the following is true regarding the spontaneity of photosynthesis? Use the equation for ΔG (ΔG = ΔH - TΔS) to assess spontaneity. a The reaction is spontaneous at all temperatures. b The reaction is non-spontaneous at all temperatures. c The reaction is only spontaneous at high temperatures. d The reaction is only spontaneous at low temperatures.

b The reaction is non-spontaneous at all temperatures Photosynthesis is a anabolic reaction of building up glucose from smaller molecules, so it requires energy input. Due to the energy absorbing, this would be an endergonic reaction and therefore non spontaneous. Provide your reasoning about your answer above. ΔG? ΔH? ΔS? The overall Gibbs free energy would be positive due to the fact that this is an energy absorbing endothermic reaction and therefore non-spontaneous. Again, because it is absorbing energy, the enthalpy value will be positive, and because of the non-spontaneity, the entropy value (disorder) will be negative. So, positive G, positive H, and negative S

In competitive inhibition, the competitor binds to a The substrate b The substrate binding site c Distant from the substrate binding site d The active site e An allosteric site

b The substrate binding site d The active site

Which statement most accurately explains why ATP hydrolysis is highly exergonic? a ATP contains the carbohydrate ribose which stores a large amount of chemical energy. b There is a large drop in potential energy because charge repulsion is reduced. c There is a large increase in potential energy because charge repulsion is reduced. d Energy is released when a phosphate group is added.

b There is a large drop in potential energy because charge repulsion is reduced. Potential energy drops because ATP's four negative charges become spread between two molecules.

Which of the following is true about enzymes? Select all that apply a They increase ΔG of reactions b They are usually made of amino acids c They lower the activation energy of chemical reactions d Each one is specific to the particular substrate(s) to which it binds

b They are usually made of amino acids- enzymes are proteins so they would be made of amino acids c They lower the activation energy of chemical reactions- they up the rate of a reaction by lowering the activation energy d Each one is specific to the particular substrate(s) to which it binds- enzymes are like lock and keys, the enzyme is the lock and the substrate is the key, it is all very specific and personalized

Cellular respiration is a ----- process. a anabolic b catabolic

b catabolic Glucose is being broken down, so it is a catabolic process

The overall process of photosynthesis is a exergonic b endergonic

b endergonic this is because in photosynthesis, more complex molecules like glucose are made from simpler ones like CO2 and H2O, which requires an input of energy (the sunlight)

The overall process of cellular respiration is a endergonic. b exergonic.

b exergonic this is because in cellular respiration, glucose is broken down, so energy is released

Step 1 and Step 3 require ATP. This is an example of . . . a reaction coupling: using a highly endergonic reaction to provide energy. b reaction coupling: using a highly exergonic reaction to provide energy. c substrate-level phosphorylation. ATP is condensed and donates a Pi group to the substrate. d substrate-level phosphorylation. ATP is hydrolyzed and the substrate is phosphorylated in the active site.

b reaction coupling: using a highly exergonic reaction to provide energy. the hydrolysis of ATP a thermodynamically favorable and spontaneous reaction is coupled with an unfavorable non spontaneous reaction that can't proceed without energy, so ATP is put with the endergonic reaction in step 1 and 3 for reaction coupling

Enthalpy of a reaction is defined as the heat energy change (ΔH) that takes place when reactants go to products. If heat is absorbed during the reaction, ΔH is positive; if heat is released, then ΔH is negative. Assess the enthalpy changes that occur as ice melts to water. Which of the following would you expect to be true? Select all that apply. a the enthalpy change is favorable. b the enthalpy change is unfavorable. c the reaction produces products that are less stable (higher potential energy) than the reactants. d the reaction produces products that are more stable (lower potential energy) than the reactants. e ΔH is a positive number. f ΔH is a negative number.

b the enthalpy change is unfavorable. c the reaction produces products that are less stable (higher potential energy) than the reactants. e ΔH is a positive number. the enthalpy change is unfavorable because ice is melting, so heat is being absorbed. The reaction is producing a more disordered product, hence the ice melting into water, and enthalpy is positive because heat is being absorbed in order for the ice to melt, so there is more overall energy

Enthalpy of a reaction is defined as the heat energy change (ΔH) that takes place when reactants go to products. If heat is absorbed during the reaction, ΔH is positive; if heat is released, then ΔH is negative. Assess the enthalpy changes that occur as two single strands of DNA base pair to form a double helix. Which of the following would you expect to be true? Select all that apply. a the enthalpy change is favorable. b the enthalpy change is unfavorable. c the reaction produces products that are less stable (higher potential energy) than the reactants. d the reaction produces products that are more stable (lower potential energy) than the reactants. e ΔH is a positive number. f ΔH is a negative number.

b the enthalpy change is unfavorable. d the reaction produces products that are more stable (lower potential energy) than the reactants. f ΔH is a negative number. the enthalpy change is unfavorable because this process is releasing energy to form the double helix which is more stable. this release of energy would cause H (enthalpy) to be negative

Assess the entropy changes that occur as two single strands of DNA base pair to form a double helix. Which of the following would you expect to be true? Select all that apply. a the entropy change is favorable. b the entropy change is unfavorable. c the reaction creates more order. d the reaction creates more disorder. e ΔS is a positive number. f ΔS is a negative number.

b the entropy change is unfavorable. c the reaction creates more order. f ΔS is a negative number. the entropy change is unfavorable because the forming of a double helix is creating more order, and decreasing disorder which is entropy. The amount of order and little to no amount of disorder would cause the entropy value to be negative

Which portion of ATP synthase catalyzes the formation of ATP from ADP and Pi? a F0 b F1

b- F1 The protons flow through F0, spinning the rotor. As the F1unit spins, its subunits change shape and catalyze the phosphorylation of ADP to ATP.

Two energy diagrams for two different reactions are shown in the image. Which statement accurately describes the reactants and products in these reactions? a Labels A and D represent reactants; labels B and C represent products. b Labels A and C represent reactants; labels B and D represent products. c Labels A and D represent products; labels B and C represent reactants. d Labels A and C represent products; labels B and D represent reactanats.

b- Labels A and C represent reactants; labels B and D represent products. the reactants come before the products

Is the overall process of photosynthesis spontaneous? a Yes b No

b- No Due to the reaction being endergonic, it is not a spontaneous reaction

Which of the following amino acids in a protein could be phosphorylated? a Arg b Ser c Glu d Phe e Tyr f Thr

b- Ser e- Tyr f- Thr

Is glycolysis an anabolic or a catabolic process? a anabolic b catabolic

b- catabolic Glucose is broken down into simpler compounds and ATP is produced. This indicates that glycolysis is a catabolic process

When energy is converted from one form to another, only some of the energy is usable. The unusable energy is released to a form associated with disorder. A measure of this disorder is referred to as a free energy. b entropy. c enthalpy. d thermodynamics

b- entropy, its the measure of disorder in a thermodynamic system

Can an enzyme make a non-spontaneous reaction spontaneous? a Yes b No

b- no. again, enzymes can not affect Gibbs free energy and therefore can not affect the spontaneity of the reaction

If a person would be deficient in all 3 forms of PFK, this person would a Have lower than normal glycogen stores. b Have more mitochondrial activity than normal. c Be dead. d Produce more energy per glucose molecule because glycolysis would be unregulated.

c Be dead. If PFK itself is not functioning, and it's three "back-up" iso-enzymes are not working, there is no source of PFK in the body and therefore the body can not function properly and is completely deficient in PFK

An allosteric inhibitor does which of the following? a Binds to an enzyme away from the active site and changes the conformation of the active site, increasing its affinity for substrate binding b Binds to the active site and blocks it from binding substrate c Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate d Binds directly to the active site and mimics the substrate

c Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate decreasing its affinity for the substrate is an allosteric inhibitor where increasing its affinity for substrate binding is allosteric activator

The energy source that most directly drives ATP synthesis by ATP synthase during oxidative phosphorylation is the a transfer of phosphate to ADP. b affinity of oxygen for electrons. c H+ movement down a concentration gradient. d oxidation of glucose and other organic molecules. e flow of electrons down the electron transport chain.

c H+ movement down a concentration gradient. The proton (H+) gradient generated by the electron transport in the respiratory chain is used to make ATP by ATP synthase. ATP synthase makes ATP using the proton gradient established by the respiratory chain.

Which of the following enzymes catalyzes a reaction that produces ATP during glycolysis? Select an answer and submit. a Hexokinase b Phosphoglucoisomerase c Pyruvate Kinase d Phosphofructokinase e Enolase

c Pyruvate Kinase Pyruvate kinase catalyzes the reaction in step 10 which creates 2 ATP,. this.is a release of ATP rather than investment of ATP in the energy-investing phase in step 1 with hexokinase

The reaction diagrams below depict two reactions (the conversion of A-->B and the conversion of C-->D), each of which requires multiple steps. Which of the following is a correct comparison between the series of reactions that convert A-->B versus the series of reactions that convert C-->D? Select all that apply. a Reaction C-->D is more spontaneous than reaction A-->B. b As for the reverse reaction: reaction B-->A is exergonic but reaction D-->C is endergonic. c Reaction C-->D will happen faster than reaction A-->B. d An enzyme can make reaction C-->D more exergonic than reaction A-->B. e More free energy will be released from the conversion of A-->B than the conversion of C-->D. f As for the reverse reaction: both reaction D-->C and reaction B-->A are not spontaneous.

c Reaction C-->D will happen faster than reaction A-->B. e More free energy will be released from the conversion of A-->B than the conversion of C-->D. f As for the reverse reaction: both reaction D-->C and reaction B-->A are not spontaneous.

The overall chemical reaction of cellular respiration is: C6H12O6+6O2--- 6CO2+6H20+Energy Please analyze this reaction carefully, and choose the description which describes it best. a This is a reduction, because oxygen is reduced to water. b This is an oxidation, because glucose is oxidized to carbon dioxide. c This is a redox reaction, wherein oxygen is the electron acceptor and carbon and hydrogen atoms are the electron donors. d This is oxidation, because oxygen atom can be found in at least one of the reactant molecules.

c This is a redox reaction, wherein oxygen is the electron acceptor and carbon and hydrogen atoms are the electron donors.

Below is the conversion of ubiquinone to ubiquinol. This reaction takes place in the inner mitochondrial membrane, and ubiquinone and ubiquinol are two forms of coenzyme Q in the electron transport chain. Please analyze the following reaction carefully, and choose the statement which describes it best. a This is an addition reaction, because electrons and protons are added to ubiquinone to form ubiquinol. b This is an addition reaction, because hydrogen atoms are added to ubiquinone to form ubiquinol. c This is a redox reaction, wherein ubiquinone is reduced to ubiquinol and ubiquinone is the oxidizing agent. d This is a redox reaction, wherein ubiquinone is reduced to ubiquinol and ubiquinone is the reducing agent.

c This is a redox reaction, wherein ubiquinone is reduced to ubiquinol and ubiquinone is the oxidizing agent.

If ATP were not present for the energy investment phase, step 1 and step 3 would . . . a occur spontaneously because the Gibbs Free Energy for both reactions would be less than zero. b occur spontaneously because hexokinase catalyzes PFK are enzymes that catalyze the reaction. c not occur because the Gibbs Free Energy for both reactions would be greater than zero. d not occur because both reactions are non-spontaneous and do not require ATP. e occur spontaneously because Glycolysis is an overall exergonic process.

c not occur because the Gibbs Free Energy for both reactions would be greater than zero. without ATP there would be no reaction coupling, and because this is an endergonic solution it requires energy and cannot happen spontaneously, so without energy from ATP it can not occur

To which of the following does a competitive inhibitor most structurally resemble? a the active site b the allosteric site c the substrate d a coenzyme

c the substrate

On the energy diagram below, the blue line indicates the uncatalyzed reaction, and the red line is the enzyme catalyzed reaction. How has ΔG changed in the presence of an enzyme? a ΔG is lower. b ΔG is higher. c ΔG remains the same.

c- G remains the same. This is because even with the presence of an enzyme, Gibbs free energy is not affected

What happens to the rate of the catalyzed reaction at high substrate concentrations? a It increases. b It decreases. c It does not change.

c- it does not change because active sites cannot accept substrates any faster, no matter how large the concentration of substrates gets.

Is the reaction depicted here spontaneous, and how do you know? a Yes; ΔG is positive b No; ΔG is positive c Yes; ΔG is negative d No; ΔG is negative

c- yes G is negative, when G aka Gibbs free energy is negative, the reaction is spontaneous and exergonic

Which of the following enzymes breaks one 6-carbon sugar into two 3-carbon sugars? a Hexokinase b Phosphoglucoisomerase c Phosphofructokinase d Aldolase e Enolase

d Aldolase This is visible in step 4 when aldolase splits the 6 carbon fructose into 2 3 carbon sugars

Select the following TRUE statement(s) about the steps of glycolysis. a The energy investment phase is exergonic and requires ATP to generate glyceraldehyde-3-phosphate. b The energy payoff phase is exergonic and requires ATP to release energy. c The process of glycolysis is exergonic: the reactants have lower free energy than the products. d Approximately 100 kcal/mol is released between the molecules: 5 and 6, and is highly exergonic. e The free energy of the glycolysis intermediates decreases at first, then increases to produce usable energy in the form of ATP.

d Approximately 100 kcal/mol is released between the molecules: 5 and 6, and is highly exergonic.

Which of the following comparisons or contrasts between endergonic and exergonicreactions is FALSE? a Endergonic reactions have a positive ΔG and exergonic reactions have a negative ΔG b Endergonic reactions consume energy and exergonic reactions release energy c Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier d Endergonic reactions take place slowly and exergonic reactions take place quickly

d Endergonic reactions take place slowly and exergonic reactions take place quickly The rate of a reaction has nothing to do with Gibbs free energy or spontaneity

Which of the following terms best describes the reaction depicted in the figure? a Endergonic, ∆G > 0 b Endergonic, ∆G < 0 c Exergonic, ∆G > 0 d Exergonic, ∆G < 0

d Exergonic, ∆G < 0 it is exergonic because the products are less than the reactants, and the result is a negative G value which solidifies that its an exergonic reaction

In which direction do the protons move through the protein complexes of the respiratory (electron transport) chain? a From the mitochondrial matrix to the cytosol. b From the intermembrane space to the mitochondrial matrix. c From the cytosol to the intermembrane space of the mitochondria. d From the mitochondrial matrix to the intermembrane space. e From the intermembrane space of the mitochondria to the cytosol

d From the mitochondrial matrix to the intermembrane space. there is a high concentration of H+ in the inter membrane space

Where do NADH and FADH2 enter the respiratory (electron transport) chain? a Both enter at Complex I. b Both can enter at either Complex I or Complex II. c NADH enters at Complex II and FADH2 enters at Complex I. d NADH enters at Complex I and FADH2 enters at Complex II. e NADH enters at Complex I unless there is no FADH2, then NADH enters at Complex II.

d NADH enters at Complex I and FADH2 enters at Complex II.

Select the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ------ is to ------. a free energy; entropy b exergonic; spontaneous c entropy; enthalpy d exergonic; endergonic e work; energy

d exergonic; endergonic Catabolism is the breaking down of larger molecules into simpler molecules which releases energy like a exergonic reaction, anabolism builds up larger molecules from simpler molecules which absorbs energy like a endergonic reaction

If enzyme 3 was inhibited, what would happen to the concentration of C and D? a C would decrease; D would decrease b C would decrease; D would increase c C would increase; D would increase d C would increase; D would decrease e C would stay the same; D would increase f C would stay the same; D would decrease g C would stay the same; D would stay the same

d- C would increase; D would decrease If enzyme 3 is inhibited, the reaction from C → D cannot occur. Therefore the concentration of D would decrease, and there would be an increase in concentration of C.

Which steps of glycolysis are substrate level phosphorylations? a Step 1 b Step 3 c Step 6 d Step 7 e Step 10

d- Step 7 e- Step 10 In Glycolysis, ATP is produced through substrate level phosphorylation. Step 7 and 10 show the enzyme-catalyzed transfer of a phosphate group from an intermediate substrate to ADP to form ATP

If intermediate B was being used up by another pathway, what would happen to the rates of reaction 1 and reaction 2? a Reaction 1 rate will decrease; reaction 2 rate will decrease b Reaction 1 rate will decrease; reaction 2 rate will stay the same c Reaction 1 rate will decrease; reaction 2 rate will increase d Reaction 1 rate will increase; reaction 2 rate will increase e Reaction 1 rate will increase; reaction 2 rate will decrease f Reaction 1 rate will stay the same; reaction 2 rate will increase

e Reaction 1 rate will increase; reaction 2 rate will decrease If B is removed from the pathway, it cannot be converted to C and reaction 2 will slow down (or stop if all B is removed). The rate of reaction 1 will increase to replace the B that is removed from the cell.

Using the figure above, is the overall process of glycolysis exergonic or endergonic?Report your answers as either "endergonic" or "exergonic."

exergonic glycolysis is the process of breaking down glucose, and when we break things down, we release energy

FILL IN THE BLANK The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as __________ inhibition

feedback inhibition

When you have gone without food for several hours, your pancreas will release ------, which triggers the liver to release glucose from glycogen stores.

glucagon

When you eat, your blood glucose levels will temporarily rise, signaling the pancreas to release ------.

insulin

Drugs that inhibit enzymes are usually ________ inhibitors

irreversible inhibitors: A substance that permanently blocks the action of an enzyme.

When looking at only the energy-investment phase of glycolysis (steps for the conversion of molecules from 1 to 5), what would be the overall change in standard free energy? Report your answer as either "positive" or "negative."

positive the change is increasing (going up) and therefore positive

The equation for Gibb's free energy above has a number of symbols. Match each symbol in the equation with what it represents. Δ G H S T Gibbs free energy enthalpy entropy "change in" temperature

Δ- "change in" G- Gibbs free energy H- enthalpy S- entropy T- temperature