EXAM 2 for C&M
Base your answers to Questions 19 - 21 on the following information: For a particular cell at 25∘C, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+) is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is -150 mV. Constants: R=1.987cal/mol⋅K;T=25∘C=298K;F=23,062cal/mol⋅V What is the ΔG for the inward transport of sucrose? - 1.774 kcal/mol; an exergonic reaction +1.774 kcal/mol; an endergonic reaction - 1.774 kcal/mol; an endergonic reaction +1.774 kcal/mol; an exergonic reaction None of the above are correct.
+1.774 kcal/mol; an endergonic reaction
Base your answers to Questions 19 - 21 on the following information: For a particular cell at 25∘C, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+) is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is -150 mV. Constants: R = 1.987 cal/mol⋅K; T = 25∘C = 298 K; F = 23,062 cal/mole⋅V What would be the net ΔG for the coupling of these two reactions? - 7.007 kcal/mol +3.459 kcal/mol - 3.459 kcal/mol +7.007 kcal/mol - 1.774 kcal/mol
- 3.459 kcal/mol
Base your answers to Questions 19 - 21 on the following information: For a particular cell at 25∘C, the concentration of sucrose is 10 mM on the inside of the cell and 0.5 mM on the outside, whereas the concentration of sodium ions (Na+) is 0.5 mM on the inside of the cell and 10 mM on the outside. The membrane potential is -150 mV. Constants: R = 1.987 cal/mol⋅K; T = 25∘C = 298 K; F = 23,062 cal/mole⋅V What is the ΔG for the inward transport of sodium ions? - 5.233 kcal/mol; an endergonic reaction +5.233 kcal/mol; an endergonic reaction - 5.233 kcal/mol; an exergonic reaction +5.233 kcal/mol; an exergonic reaction None of the above are correct.
- 5.233 kcal/mol; an exergonic reaction
Base your answers to Questions 22 - 23 on the following information: A cell biologist interested in the transport of calcium ions (Ca2+) across the plasma membrane of bacterial cells made the following measurements on bacterial cells at 25∘C: Vm =- 150 mV[Ca2+] outside = 20 mM [Ca2+] inside = 0.4 mM Assuming no change in either the internal or external calcium ion concentration, at what membrane potential would there be no net movement of calcium across the membrane? +50 mV +25 mV - 25 mV 0 mV - 50 mV
- 50 mV
Base your answers to Questions 22 - 23 on the following information: A cell biologist interested in the transport of calcium ions (Ca2+) across the plasma membrane of bacterial cells made the following measurements on bacterial cells at 25∘C: Vm =- 150 mV[Ca2+] outside = 20 mM [Ca2+] inside = 0.4 mM What is the free energy change for the inward movement of calcium ions into the bacterial cell? +4.6 kcal/mol; an endergonic reaction - 9.2 kcal/mol; an endergonic reaction +9.2 kcal/mol; an exergonic reaction - 9.2 kcal/mol; an exergonic reaction +4.6 kcal/mol; an exergonic reaction
- 9.2 kcal/mol; an exergonic reaction
Select all that apply for Channels ONLY. 1: Provide a continuous path across the membrane 2: Undergo a change in shape to transport solutes across the membrane 3: Are integral membrane proteins 4: Allow water molecules and small ions to flow quickly across the membrane. 5: Transport primarily small polar organic molecules. 6: Provide a hydrophilic path across the membrane. 7: Transport solutes down a concentration or electrochemical gradient
1: Provide a continuous path across the membrane 4: Allow water molecules and small ions to flow quickly across the membrane.
Most of the cells of your body pump potassium ions inward to maintain an internal K+ concentration that is many times the internal concentration. Specifically the internal concentration is 140 mM and the external concentration is about 5 mM. If the membrane potential is 0 mV, what would the ΔG be for inward transport of potassium ions at 37 deg. C (310 K) ? Do not enter units, only integer to nearest tenth. Use constants and equation at the front of the classroom.
2,052.5
Select all that apply for Carriers ONLY. 1: Provide a continuous path across the membrane 2: Undergo a change in shape to transport solutes across the membrane 3: Are integral membrane proteins 4: Allow water molecules and small ions to flow quickly across the membrane. 5: Transport primarily small polar organic molecules. 6: Provide a hydrophilic path across the membrane. 7: Transport solutes down a concentration or electrochemical gradient
2: Undergo a change in shape to transport solutes across the membrane 5: Transport primarily small polar organic molecules.
Select all that apply to BOTH Channels and Carriers ONLY 1: Provide a continuous path across the membrane 2: Undergo a change in shape to transport solutes across the membrane 3: Are integral membrane proteins 4: Allow water molecules and small ions to flow quickly across the membrane. 5: Transport primarily small polar organic molecules. 6: Provide a hydrophilic path across the membrane. 7: Transport solutes down a concentration or electrochemical gradient
3: Are integral membrane proteins 6: Provide a hydrophilic path across the membrane. 7: Transport solutes down a concentration or electrochemical gradient
Most of the cells of your body pump potassium ions inward to maintain an internal K+ concentration that is many times the internal concentration. Specifically the internal concentration is 140 mM and the external concentration is about 5 mM. If the membrane potential is -70 mV, what would the ΔG be for inward transport of potassium ions at 37 deg. C (310 K) ? Do not enter units, only integer to nearest tenth. Use constants and equation at the front of the classroom. Hint: Convert mV to Volts (divide by 1000)!
438.16
See Ch. 9 HW, Q: 9 for graphs. NOT SURE IF THIS IS ON THE TEST
?
Which of the following statements is not true of most cellular redox reactions? The reactant that is oxidized loses electrons. The electron acceptor is reduced. A hydrogen atom is transferred to the atom that loses an electron. Changes in potential energy can be released as heat.
A hydrogen atom is transferred to the atom that loses an electron.
Which of the following is an example of a prosthetic group? a zinc ion carboxypeptidase A a nickel catalyst a polypeptide chain a glycine residue
A zinc ion
Some solutes are able to pass directly through the lipid bilayer of a plasma membrane, whereas other solutes require a transport protein or other mechanism to cross between the inside and the outside of a cell. The fact that the plasma membrane is permeable to some solutes but not others is what is referred to as selective permeability. Q: Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism? Select all that apply sucrose lipids proteins water carbon dioxide oxygen ions
A: Lipids, Water, Carbon Dioxide, Oxygen Some solutes pass readily through the lipid bilayer of a cell membrane, whereas others pass through much more slowly, or not at all. Small nonpolar (hydrophobic) molecules, such as dissolved gases (O2, CO2, N2) and small lipids, can pass directly through the membrane. They do so by interacting directly with the hydrophobic interior of the lipid bilayer. Very small polar molecules such as water and glycerol can pass directly through the membrane, but much more slowly than small nonpolar molecules. The mechanism that permits small polar molecules to cross the hydrophobic interior of the lipid bilayer is not completely understood, but it must involve the molecules squeezing between the hydrophobic tails of the lipids that make up the bilayer. Polar molecules such as glucose and sucrose have very limited permeability. Large molecules such as proteins cannot pass through the lipid bilayer. Ions and charged molecules of any size are essentially impermeable to the lipid bilayer because they are much more soluble in water than in the interior of the membrane.
What is neither an INput or an OUTput for Acetyl-CoA formation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
ADP, ATP, glucose, O2
What are the net INputs for oxidative phosphorylation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
ADP, O2, NADH
What are the net OUTputs for oxidative phosphorylation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
ATP, H2O, NAD+
Most of the unpleasant effects of hangovers result from an accumulation of acetaldehyde and its metabolites. Where does the acetaldehyde come from? Acetaldehyde is the immediate product of ethanol oxidation. Ethanol+NADH+H+→acetaldehyde+NAD+ Acetaldehyde is the immediate product of ethanol reduction. Ethanol+NAD+→acetaldehyde+NADH+H+ Acetaldehyde is the immediate product of ethanol oxidation. Ethanol+NAD+→acetaldehyde+NADH+H+ Acetaldehyde is the immediate product of ethanol reduction. Ethanol+NADH+H+→acetaldehyde+NAD+
Acetaldehyde is the immediate product of ethanol oxidation. Ethanol+NAD+→acetaldehyde+NADH+H+
Which of these enters the citric acid cycle? G3P NADH + H+ acetyl CoA pyruvate glucose
Acetyl-CoA
Which of these is NOT a product of the citric acid cycle? FADH2 acetyl CoA NADH + H+ CO2 ATP
Acetyl-CoA
What are the INputs for the Citric Acid Cycle? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
Acetyl-CoA, NAD+, ADP
What is not an INput or an OUTput for glycolysis? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
Acetyl-CoA, O2, coenzyme A, CO2
Which enzyme in the TCA cycle do you suspect is affected by fluorocitrate? malate dehydrogenase succinyl CoA synthetase succinate dehydrogenase fumarate hydratase α-ketoglutarate dehydrogenase aconitase isocitrate dehydrogenase citrate synthase
Aconitase
6. A substrate binds to an enzyme at the __________, where the reaction occurs.
Active site
The site on an enzyme that will bind the substrate is called the metastable site. active site. prosthetic group. activation site. catalyst.
Active site
Q36-40 All molecules have energy that causes thermal motion. One result of thermal motion is diffusion: the tendency of substances to spread out evenly in the available space. Although the motion of each individual molecule is random, there can be directional motion of an entire population of molecules. Consider a chamber containing two different types of dye molecules, purple and orange. The chamber is divided into two compartments (A and B) by a membrane that is permeable to both types of dye. Initially (left image), the concentration of the orange dye is greater on side A, and the concentration of the purple dye is greater on side B. With time, the dye molecules diffuse to a final, equilibrium state (right image) where they are evenly distributed throughout the chamber. Q: Orange dye moves independently of purple dye Never Always Only before equilibrium is reached Only at equilibrium
Always
ATP synthesis in glycolysis: substrate-level phosphorylation 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. Sort the statements into the appropriate bin depending on whether or not they correctly describe some aspect of substrate-level phosphorylation in glycolysis. Q: Correct Statements An enzyme is required in order for the reaction to occur. The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions A bond must be broken between an organic molecule and phosphate before ATP can form. 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. One of the substrates is a molecule derived from the breakdown of glucose.
Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other? Hints Proton and electron. Anion and cation. Ionic and covalent. Polar and nonpolar.
Anion and Cation
In some cells, it was noted that water moved faster than could be accounted for by simple diffusion. From this information, which of the following were identified and characterized? a. facilitator porins. b. glycoporins. c. aquaporins. d. hydroporins. e. lipoporins.
Aquaporins
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.) Hints Neither electron transport nor ATP synthesis would be affected. Electron transport would stop but ATP synthesis would be unaffected. Electron transport would be unaffected but ATP synthesis would stop. Both electron transport and ATP synthesis would stop.
Both electron transport and ATP synthesis would stop
A plot of enzyme velocity against temperature for an enzyme indicates little activity at 0 degrees Celsius and 40 degrees Celsius, with peak activity at 35 degrees Celsius. The most reasonable explanation for the low velocity at 0 degrees Celsius is that __________. substrate binding at the active site is thermodynamically unfavorable at low temperature the enzyme was denatured at this temperature both the frequency and energy of enzyme-substrate collisions are low the hydrogen bonds that define the enzyme's active site are broken as temperature increases
Both the frequency and energy of enzyme-substrate collisions are low
2. An enzyme is considered a _________ because it speeds up chemical reactions without being used up.
Catalyst
Which of the following structures serves the same purpose as the inner membrane and matrix of the mitochondrion with regard to their roles in aerobic respiration? cell membrane nuceloid ribosomes cytoplasm cell membrane and cytoplasm
Cell membrane and cytoplasm
Cystic fibrosis is the result of a malfunction of a cellular ABC transporter that transports a hydrophobic drug. vitamin B12. glucose. amino acids. Cl -.
Cl-
Cystic fibrosis is the result of a malfunction of the cell in transporting which of the following ions? a. glucose b. Na+ c. K+ d. OH- e. Cl-
Cl-
What are the net OUTputs for the Citric Acid Cycle? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
Coenzyme A, CO2, NADH, ATP
4. A ___________, such as a vitamin, binds to an enzyme and plays a role in catalysis.
Cofactor
Glycolysis occurs in the ?
Cytosol of the cell
1. An enzyme is _________________when it loses its native conformation and its biological activity.
Denatured
Which term describes the degree to which an element attracts electrons? Hints Reduction. Electronegativity. Polarity. Oxidation.
Electronegativity
What is the correct label for "A"? The figure shows the graph of the potential energy of the reactants and products in the reaction. The potential energy of the reactants is higher than the potential energy of products. For initiation of this reaction, it is necessary to add definite amount of energy. This amount is labeled A. ATP uphill enzyme energy energy of activation substrate energy
Energy of activation. The energy of activation must be overcome in order for a reaction to proceed.
View Pre Cls 3 (Ch.6) Question Part A for graph and multiple choice
Enzymes lower the activation energy of a chemical reaction. This means that a catalyzed reaction is more likely to proceed than an uncatalyzed reaction, and it forms products more rapidly than an uncatalyzed reaction.
Fill in the blank Ethanol catabolism in the body begins with its _______ (dehydrogenation), with NAD+ as the electron _______. The more ethanol is consumed, the greater the demand is for NAD+ and the more serious is the _______ in NAD+ concentration. The supply of NAD+ may be inadequate for _______ respiration of glucose. Donor Oxidation Aerobic Anaerobic Reduction Acceptor
Ethanol catabolism in the body begins with its oxidation (dehydrogenation), with NAD+ as the electron acceptor. The more ethanol is consumed, the greater the demand is for NAD+ and the more serious is the reduction in NAD+ concentration. The supply of NAD+ may be inadequate for aerobic respiration of glucose.
The number of ATPs per NADH generated by the electron transport system is higher than the number generated per FADH2 because __________. NADH is converted to NAD+, which increases the charge gradient for ATP synthesis FADH2 has a lower (less negative) redox potential than NADH does electrons from FADH2 are not oxidized all the way to water FADH2 has a higher (more negative) redox potential than NADH does
FADH2 has a lower (less negative) redox potential than NADH does
NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O2 to water in the final step of electron transport. However, the amount of ATP made by electrons from an NADH molecule is greater than the amount made by electrons from an FADH2 molecule. Q: Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2? The H+ gradient made from electron transport using NADH is located in a different part of the mitochondrion than the H+ gradient made using FADH2. Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor. FADH2 is made only in the citric acid cycle while NADH is made in glycolysis, acetyl CoA formation, and the citric acid cycle. There is more NADH than FADH2 made for every glucose that enters cellular respiration. It takes more energy to make ATP from ADP and Pi using FADH2 than using NADH.
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.
How could fluoroacetate be converted to fluorocitrate? Fluoroacetate is probably activated to fluoroacetyl CoA and condensed onto isocitrate by citrate synthase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoA and condensed onto oxaloacetate by aconitase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoA and condensed onto oxaloacetate by citrate synthase to generate fluorocitrate. Fluoroacetate is probably activated to fluoroacetyl CoA and condensed onto isocitrate by aconitase to generate fluorocitrate.
Fluoroacetate is probably activated to fluoroacetyl CoA and condensed onto oxaloacetate by citrate synthase to generate fluorocitrate.
Why might you expect fluorocitrate to have an inhibitory effect on one or more of the TCA cycle enzymes if incubated with the purified enzymes in vitro, even though fluoroacetate has no effect? Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a reduction of at least one of the TCA cycle intermediates. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a conversion of at least one of the TCA cycle intermediates into inactive form. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is an oxidation of at least one of the TCA cycle intermediates. Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a buildup of at least one of the TCA cycle intermediates.
Fluorocitrate has been characterized as the actual poison in the tissues of the animal, and one of the most pronounced of its effects is a buildup of at least one of the TCA cycle intermediates.
The process of glucose synthesis is called gluconeogenesis. aglycolysis. glycolysis. glucogenesis. gluconeogenesis and glucogenesis.
Gluconeogenesis
3. In glycolysis, the carbon-containing compound that functions as the electron donor is _______. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
Glucose
Each of the following molecules move across membranes by simple diffusion except a. fatty acids. b. glucose. c. carbon dioxide. d. oxygen. e. water
Glucose
Each of the following molecules move across membranes by simple diffusion except glucose. fatty acids. carbon dioxide. water. oxygen.
Glucose
Glucose is transported in the bloodstream to cells in all parts of your body. In cells, glucose has four main fates. Which of the following is not one of those fates? Glucose is converted to acetyl CoA to make body fat. Glucose is catabolized to carbon dioxide and water. Glucose is converted to lactate. Glucose is used to synthesize glycogen. Glucose is transformed into sucrose.
Glucose is transformed into sucrose.
What is neither an INput or an OUTput for oxidative phosphorylation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
Glucose, CO2, Pyruvate, Acetyl-CoA, Coenzyme A
What is the net INput for Glycolysis? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
Glucose, NAD+, ADP
A competitive inhibitor will affect the ________ of an enzymatic reaction. Km Vmax S P both Km and Vmax
Km
Gaseous hydrogen burns in the presence of oxygen to form water: 2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed? Hydrogen, nonpolar. Oxygen, polar. Hydrogen, polar. Oxygen, nonpolar.
Hydrogen, Polar
Consider a nerve cell with an internal Cl− concentration of 50 mM, a membrane potential of 60 mV and an external Cl− concentration of 100 mM. Each of the following is true for Cl− import into the cell except import ΔG is positive. import is down an electrochemical concentration gradient. import requires energy input. import is down a concentration gradient. All are true.
Import is down an electrochemical concentration gradient
Thermogenin in the inner membrane of brown fat cell mitochondria does all of the following except uncouple ATP synthesis from electron transport. generate heat. increase ATP synthesis. decrease the proton gradient. decrease ATP synthesis.
Increase ATP synthesis
Electron transport and oxidative phosphorylation are metabolic functions of the __________ of the mitochondrion. matrix outer membrane inner membrane intermembrane space
Inner membrane
Oxidative phosphorylation occurs in the ?
Inner mitochondrial membrane
What kind of bond is formed when lithium and fluorine combine to form lithium fluoride? Redox. Polar covalent. Ionic. Nonpolar covalent.
Ionic
An enzyme _____. increases the EA of a reaction is a source of energy for endergonic reactions is a inorganic catalyst can bind to nearly any molecule is an organic catalyst
Is an organic catalyst. Enzymes are proteins that behave as Catalyst.
As a result of its involvement in a reaction, an enzyme _____. permanently alters its shape. is unchanged is used up loses energy loses a phosphate group
Is unchanged
Involves proteins called ATPases. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of active transport
Work is done during the transport process. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of active transport
Requires the presence of an integral membrane protein. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of facilitated diffusion it is true of active transport
A Michaelis constant (Km) can be calculated. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of facilitated diffusion. It is true of active transport.
Applies only to small, nonpolar solutes. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of simple diffusion
Depends primarily on solubility properties of the solute. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of simple diffusion
Doubling the concentration gradient of the molecule to be transported will double the rate of transport over a broad range of concentrations. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of simple diffusion
Transport can occur in either direction across the membrane, depending on the prevailing concentration gradient. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of simple diffusion it is true of facilitated diffusion
ΔG∘=0. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport.
Match: Lactate, Ethanol, and Acetyl CoA with the correct statment. Fermentation in human muscle Fermentation in yeast and bacteria aerobic oxidation
Lactate - fermentation in human muscle Ethanol - fermentation in yeast and bacteria acetyl CoA - aerobic oxidation
Vmax Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
Maxiumum velocity
The medical treatment for methanol poisoning usually involves administration of large doses of ethanol. Why is this treatment effective? Methanol and ethanol are both substrates of the enzyme alcohol dehydrogenase.The body is flooded with a large amount of ethanol to provide an effective competitor of methanol, thereby minimizing the production of formaldehyde. Methanol and ethanol are both substrates of the enzyme alcohol peroxidase.The body is flooded with a large amount of ethanol to provide an effective competitor of methanol, thereby minimizing the production of formaldehyde. Methanol and ethanol are both substrates of the enzyme alcohol dehydrogenase.The body is flooded with a large amount of ethanol to provide an effective competitor of methanol, thereby minimizing the production of acetaldehyde. Methanol and ethanol are both substrates of the enzyme alcohol peroxidase.The body is flooded with a large amount of ethanol to provide an effective competitor of methanol, thereby minimizing the production of acetaldehyde.
Methanol and ethanol are both substrates of the enzyme alcohol dehydrogenase.The body is flooded with a large amount of ethanol to provide an effective competitor of methanol, thereby minimizing the production of formaldehyde.
Km Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
Michaelis-Menten constant
Citric Acid cycle occurs in the ?
Mitochondrial Matrix
Acetyl-CoA formation occurs in the?
Mitochondrial matrix
5. _______is the compound that functions as the electron acceptor in glycolysis. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
NAD+
Which of the following statements best describes the role of NAD+/NADH in glycolysis and / or aerobic metabolic pathways? a.NADH is used to produce energy by directly creating the phosphoanhydride bonds in ATP. b.NAD+ is used to carry electrons. c.NADH is capable of pumping ions during glycolysis. d.NADH is used primarily in substrate-level phosphorylation. e.all of these
NAD+ is used to carry electrons.
6. The reduced form of the electron acceptor in glycolysis is _______. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
NADH
What is the net OUTput for Glycolysis? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
NADH, ATP, pyruvate
What is the net OUTput for Acetyl-CoA formation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
NADH, CO2, acetyl CoA
Applies only to ions. Select all that apply. It is true of simple diffusion. It is true of facilitated diffusion. It is true of active transport. None of the above.
NONE of the above
Purple dye moves only from side B to side A Never Always Only before equilibrium is reached Only at equilibrium
Never
What is neither an INput or an OUTput for the citric Acid Cycle Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
O2, glucose, pyruvate
There is no net movement of purple dye
Only at equilibrium
Concentration gradients exist that drive diffusion of both dyes Never Always Only before equilibrium is reached Only at equilibrium
Only before equilibrium is reached
There is a net movement of orange dye from side A to side B. Never Always Only before equilibrium is reached Only at equilibrium
Only before equilibrium is reached
What name is given to the process by which water crosses a selectively permeable membrane? a. phagocytosis b. osmosis c. pinocytosis d. diffusion e. passive transport
Osmosis
1. When a compound donates (loses) electrons, that compound becomes ___________. Such a compound is often referred to as an electron donor. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
Oxidized
Which of the following statements is true of the bonds in a water molecule? Hints The electron in each hydrogen atom is completely transferred to the oxygen atom, and each hydrogen atom has a net charge of +1. Oxygen acts as the electron acceptor and is oxidized. There is equal sharing of the electrons between the oxygen atom and the two hydrogen atoms, and the net charge is zero. Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
Oxygen holds electrons more tightly than hydrogen does, and the net charge is zero.
in general, enzymes are what kinds of molecules? nucleic acids carbohydrates proteins lipids minerals
Proteins
4. Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called _______. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
Pyruvate
Sort the following items according to whether they are reactants or products in the anaerobic reduction of pyruvate during lactic acid fermentation. Reactants: Products: Lactate NADH NAD+ pyruvate
Reactants: NADH, pyruvate Products: lactate, NAD+
2. When a compound accepts (gains) electrons, that compound becomes _______. Such a compound is often referred to as an electron acceptor. Water Oxygen Oxidized NADH Reduced NAD+ Glucose Pyruvate
Reduced
Enzymes work by _____. increasing the potential energy difference between reactant and product adding energy to a reaction adding a phosphate group to a reactant reducing EA decreasing the potential energy difference between reactant and product
Reducing the EA
When the protein gramicidin is integrated into a membrane, an H+ channel forms and the membrane becomes very permeable to protons (H+ ions). If gramicidin is added to an actively respiring muscle cell, how would it affect the rates of electron transport, proton pumping, and ATP synthesis in oxidative phosphorylation? (Assume that gramicidin does not affect the production of NADH and FADH2 during the early stages of cellular respiration.) Q: Sort the labels into the correct bin according to the effect that gramicidin would have on each process. Remains the Same: Decreases (or goes to zero): Increases: rate of ATP synthesis rate of oxygen uptake size of the proton gradient proton pumping rate electron transport rate
Remains the same: Electron transport rate, proton pumping rate, rate of oxygen uptake Decreases (or goes to zero): rate of ATP synthesis, Size of the proton gradient Increases: NONE
See in class 3 Ch6 question 7 for graph and math equations A-F
See above
Km/Vmax Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
Slope of a michaelis-mente plot
3. An enzyme is considered ___________ because of its ability to recognize the shape of a particular molecule.
Specific
What name is given to the reactants in an enzymatically catalyzed reaction? active sites reactors substrate EA products
Substrate
[S] Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
Substrate concentration
In the citric acid cycle, ATP molecules are produced by _____. photosynthesis oxidative phosphorylation photophosphorylation cellular respiration substrate-level phosphorylation
Substrate-level phosphorylation
7. In a catalyzed reaction a reactant is often called a __________.
Substrate. A substrate binds at an enzyme's active site; the enzyme typically recognizes the specific shape of its substrate. A cofactor, such as an inorganic ion or vitamin, may bind to the enzyme and assist in catalyzing the reaction. The reaction environment must be appropriate for catalysis to proceed. An enzyme will denature, or change its shape and lose its biological activity, at too high a temperature or at a pH outside the enzyme's optimal range.
An enzyme reduces the free energy of which of the following? substrate product intermediate product cofactor transition state
Transition state
Which of the following accurately summarizes how the discovery of aquaporins has changed the definition of osmosis across the plasma membranes of cells? The discovery of aquaporins suggests that water osmotically crosses biological membranes by endocytosis. The discovery of aquaporins suggests that water osmotically crosses biological membranes by both simple diffusion and facilitated diffusion. The discovery of aquaporins suggests that water osmotically crosses biological membranes by facilitated diffusion only. The discovery of aquaporins suggests that water osmotically crosses biological membranes by active transport.
The discovery of aquaporins suggests that water osmotically crosses biological membranes by both simple diffusion and facilitated diffusion.
ATP synthesis in glycolysis: substrate-level phosphorylation 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. Sort the statements into the appropriate bin depending on whether or not they correctly describe some aspect of substrate-level phosphorylation in glycolysis. Q: Incorrect statements An enzyme is required in order for the reaction to occur. The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions A bond must be broken between an organic molecule and phosphate before ATP can form. One of the substrates is a molecule derived from the breakdown of glucose.
The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP. The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions
Phosphoenolpyruvate (PEP) is considered an unstable molecule, whereas ATP is considered a metastable molecule. Which of the following is likely true about the nonenzymatic hydrolysis of PEP and the hydrolysis of ATP? The hydrolysis of ATP will be spontaneous and fast, whereas the hydrolysis of PEP will be nonspontaneous. The hydrolysis of ATP and PEP will be spontaneous, but the hydrolysis of ATP will be much slower than the hydrolysis of PEP. The hydrolysis of ATP and PEP will occur spontaneously and quickly. The hydrolysis of ATP and PEP will be nonspontaneous.
The hydrolysis of ATP and PEP will be spontaneous, but the hydrolysis of ATP will be much slower than the hydrolysis of PEP.
Why is this phenomenon referred to as lethal synthesis? The ingested compound is itself not toxic, but it catalyzes the formation of lethal metabolites. The ingested compound disrupts intermolecular bonds between TCA intermediates. The ingested compound forms covalent bonds with TCA intermediates and enzymes, inactivating them. The ingested compound is itself not toxic, but it is converted into a lethal metabolite in vivo.
The ingested compound is itself not toxic, but it is converted into a lethal metabolite in vivo.
How do cells use ATP to raise the energy level of reaction substrates? a. The terminal phosphate of ATP is transferred (forms a new bond) to the substrate. b.ATP is hydrolyzed to release its energy. c.All of the above d. The ADP part of ATP is bound to the substrate.
The terminal phosphate of ATP is transferred (forms a new bond) to the substrate.
In mitochondrial electron transport, what is the direct role of O2? Hints to provide the driving force for the synthesis of ATP from ADP and Pi to function as the final electron acceptor in the electron transport chain to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle to provide the driving force for the production of a proton gradient
To function as the final electron acceptor in the electron transport chain
Kcat Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
Turnover Number
A noncompetitive inhibitor will affect the ________ of an enzymatic reaction. Km Vmax S P both Km and Vmax
Vmax
Because NADH generated in the cytosol cannot enter the mitochondrion, electrons and protons from NADH are transferred in by __________. a proton pump cytochromes lactate an electron shuttle system
an Electron shuttle system
Because NADH generated in the cytosol cannot enter the mitochondrion, electrons and protons from NADH are transferred in by __________. a proton pump cytochromes lactate an electron shuttle system
an electron shuttle system
Most cells have a negative plasma membrane potential (Vm) because they have an excess of positively charged solute molecules inside the cell. an excess of water molecules inside the cell. an excess of negatively charged solute molecules inside the cell. equal concentrations of ions on both sides of the membrane. an excess of negatively charged solute molecules outside the cell.
an excess of negatively charged solute molecules inside the cell.
What distinguishes facilitated diffusion from simple diffusion? a. No energy is used to move molecules across the membrane. b. Molecules move from a region of lower concentration to a region of higher concentration. c.Membrane protiens help move molecules across the membrane. d.Molecules move from a region of higher concentration to a region of lower concentration.
c.Membrane protiens help move molecules across the membrane.
5. When properly aligned, the enzyme and substrate form an enzyme-substrate (ES)___________.
complex
A sick person often has a fever, which can inhibit the growth of bacteria because the higher temperature increases the activity of lyases. bacteria reproduce more rapidly at higher body temperature. sweating removes prosthetic groups from biological enzymes. fever blocks synthesis of proteins in the bacterial nucleus. enzymes do not function as well at temperatures other than the optimal temperature.
enzymes do not function as well at temperatures other than the optimal temperature.
A sick person often has a fever, which can inhibit the growth of bacteria because? enzymes do not function as well at temperatures other than the optimal temperature. the higher temperature increases the activity of lyases. sweating removes prosthetic groups from biological enzymes. fever blocks synthesis of proteins in the bacterial nucleus. bacteria reproduce more rapidly at higher body temperature.
enzymes do not function as well at temperatures other than the optimal temperature.
Consider a nerve cell with an internal Cl− concentration of 50 mM, a membrane potential of -60 mV and an external Cl− concentration of 100 mM. Each of the following is true for Cl− import into the cell except a. import requires energy input. b. import ΔG is positive. c. import is down an electrochemical (charge) gradient. d.All are true. e. import is down a concentration gradient.
import is down an electrochemical (charge) gradient.
Feedback inhibition prevents cells from accumulating unnecessary proteins. destroying enzymes by proteolytic cleavage when they are needed in biosynthetic pathways. irreversibly inhibiting critical enzymes. the harmful effects of enzyme activation by covalent modification of unneeded enzymes. making products that are not needed by inhibiting the activity of enzymes in biosynthetic pathways allosterically.
making products that are not needed by inhibiting the activity of enzymes in biosynthetic pathways allosterically.
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions? ATP and NADH only CO2 only pyruvate and ATP only ATP only O2 only pyruvate, ATP, and NADH NADH only
pyruvate, ATP, and NADH
What is the net INput for Acetyl-CoA formation? Acetyl-CoA O2 ATP NAD+ Glucose CO2 Coenzyme A pyruvate NADH + H+ ADP
pyruvate, NAD+, coenzyme A
The purpose of the fermentation process is the? a. regeneration of NAD+. b. generation of additional energy in the form of ATP. c. generation of additional reducing equivalents. d. production of novel compounds, such as inorganic acids. e. all of these
regeneration of NAD+.
Look at and understand IN CLASS 4, CH 10 Q: 1A-D
see above
See Ch. 9 HW Q 1 part A for Image
see above
See Ch.8 HW Question 16 for part A-C
see above
See Ch.8 HW Question 5 for graph
see above
See in class 3 Ch6 question 6 for graph and matching
see above
See in class 3 Ch6 question 8 for graph and math equations A-H
see above
An enzyme is active in the stomach of an animal but quickly loses its activity when it leaves the stomach. This example illustrates that enzymes are digested in the small intestine. sensitive to changes in pH. specific to the organs in which they are produced. consumed by the quantities of substrate in the small intestine. inactivated by movement.
sensitive to changes in pH.
The Michaelis constant, Km, refers to the __________ at which a reaction proceeds at __________ of the maximum velocity. This constant most accurately reflects __________. substrate concentration; one-half; the affinity of the substrate-enzyme interaction enzyme concentration; one-half; temperature optimum of the enzyme product concentration; one-half; structure of the substrate substrate concentration; one-fourth; pH optimum of the enzyme
substrate concentration; one-half; the affinity of the substrate-enzyme interaction
Both the phosphorylation of intermediates and the formation of ATP in glycolysis and/or aerobic metabolic pathways are examples of a. substrate-level phosphorylation. b.product-level phosphorylation. c.oxidative phosphorylation. d.anabolic phosphorylation. e.aerobic phosphorylation.
substrate-level phosphorylation.
The cycle in which lactate is removed from muscle tissue and returned to the liver to produce glucose is called fermentation. the Cori cycle. the Calvin cycle. the pyruvate recovery cycle. glycolysis.
the Cori Cycle
The primary difference between active transport and facilitated diffusion is that active transport is the only one of the two in which a. the direction of transport is [S]high → [S]low. b. transporter proteins are required. c. the S concentration gradient provides the energy necessary for S transport. d. the direction of transport is [S]low → [S]high. e. the mechanism is not saturable.
the direction of transport is [S]low → [S]high.
The primary difference between active transport and facilitated diffusion is that active transport is the only one of the two in which transporter proteins are required. the direction of transport is [S]low → [S]high. the mechanism is not saturable. the direction of transport is [S]high → [S]low. the S concentration gradient provides the energy necessary for S transport.
the direction of transport is [S]low → [S]high.
Frog oocytes are a useful experimental system for studying transporters, because frog oocytes possess all of the following characteristics except they express all transporters known. they are relatively inexpensive and easy to obtain. they express injected heterologous mRNAs. they can be maintained in little more than pure water. they are large, easily injected cells.
they express all transporters known.
1/Vmax Maximum velocity substrate concentration slope of a michaelis-menten plot turnover number michaelis-menten constant y-intercept of a lineweaver-burk plot
y-intercept of a lineweaver-burk plot
Which part of the adenosine triphosphate molecule is released when it is hydrolyzed to provide energy for biological reactions? Hints α -phosphate (the phosphate closest to ribose) β-phosphate (the middle phosphate) γ-phosphate (the terminal phosphate) adenine group ribose sugar
γ-phosphate (the terminal phosphate)
