Lecture 10: Cellular Respiration

glycolysis energy payoff phase

1 PGAL to 1 pyruvate 1 PGAL to 1 pyruvate 1 NAD+ to 1 NADH 1 NAD+ to 1 NADH 1 ADP to 1ATP 1 ADP to 1 ATP

glycolysis energy investment phase

2 ATP are used to create 2 ADP glucose transforms to fructose bisphosphate which transforms to 2 PGALs

Vesicles from portions of the inner mitochondrial membrane have all the necessary components for what metabolic pathway?

Oxidative phosphorylations its components are all part of the inner membrane of the mitochondrion

What happens to electrons as they move to atoms that are more electronegative?

They lose potential energy

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the: a. H+ concentration across the membrane holding ATP synthase b. flow of electrons down the electron transport chain c. oxidation of glucose and other organic compounds d. affinity of oxygen for electrons

a. H+ concentration across the membrane holding ATP synthase

A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? a. The mutant yeast will be unable to grow anaerobically. b. The mutant yeast will grow anaerobically only when given glucose. c. The mutant yeast will die because they cannot regenerate NAD+ from NAD. d. The mutant yeast will be unable to metabolize glucose.

a. The mutant yeast will be unable to grow anaerobically.

A molecule that is phosphorylated: a. has an increased chemical reactivity, it is primed to do cellular work b. has a decreased chemical reactivity, it is less likely to provide energy for cellular work c. is unchanged in its capacity to do cellular work d. has less energy than before its phosphorylation and therefore less energy for cellular work

a. has an increased chemical reactivity, it is primed to do cellular work

You have a friend who lost 7kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave her body? a. it was released as CO2 and H2O b. it was converted to heat and then released c. it was converted to urine and eliminate from the body d. it was converted to ATP, which weighs much less than fat

a. it was released as CO2 and H2O

It is possible to prepare vesicles from portions of the inner mitochondrial membrane. Which one of the following processes could still be carried on by this isolated inner membrane? a. oxidative phosphorylation b. both the citric acid cycle and oxidative phosphorylation c. reduction of NAD+ d. glycolysis and fermentation

a. oxidative phosphorylation

an electron loses potential energy when it: a. shifts to a more electronegative atom b. increases its kinetic energy c. shifts to a less electronegative atom d. moves further away from the nucleus of the atom

a. shifts to a more electronegative atom

A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? a. the mutant yeast will be unable to grow anaerobically b. the mutant yeast will be unable to metabolize glucose c. the mutant yeast will die because they cannot regenerate NAD+ from NAD d. the mutant yeast will grow anaerobically only when given glucose

a. the mutant yeast will be unable to grow anaerobically they will not be able to regenerate NAD+ from NADH so they won't be able to produce any energy from glycolysis in the absence of oxygen. These mutant yeast cells will only be able to grow aerobically

When electrons flow along the electron transport chain in mitochondria, which of the following changes occurs? a. the pH of the matrix increases b. ATP synthase pumps protons by active transport c. the electrons gain free energy d. NAD+ is oxidized

a. the pH of the matrix increases

The purpose of fermentation reactions is to: a. to regenerate NAD+ so glycolysis can continue b. to make alcohol or lactic acid that cells can metabolize for energy under anaerobic conditions c. to make additional ATP when respiration can't make ATP fast enough d. to slow down cellular oxygen consumption when oxygen is scare

a. to regenerate NAD+ so glycolysis can continue

types of fermentation

alcohol and lactic acid fermentation

Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected to: a. inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle b. inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle c. activate the enzyme and increase the rates of glycolysis and the citric acid cycle d. activates the enzyme and thus slow the rates of glycolysis and the citric acid cycle

b. inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle

What is proton-motive force? a. the force that moves hydrogen into the intermembrane space b. the force exerted on a proton by a transmembrane proton concentration gradient c. the force required to remove an electron from hydrogen d. the force that moves hydrogen to NAD+

b. the force exerted on a proton by a transmembrane proton concentration gradient

Drugs known as uncouplers facilitate diffusion of protons across the membrane. When such a drug is added, what will happen to ATP synthesis and oxygen consumption, if the rates of glycolysis and the citric acid cycle stay the same? a. ATP synthesis will increase; oxygen consumption will decrease b. Both ATP synthesis and oxygen consumption will increase c. ATP synthesis will decrease; oxygen consumption will stay the same d. Both ATP synthesis and oxygen consumption will decrease

c. ATP synthesis will decrease; oxygen consumption will stay the same Protons will be able to move down the electrochemical gradient without powering ATP synthase so less ATP is produced and if the rates of glycolysis and citric acid cycle stay the same then the amount of oxygen consumed will as well

In addition to ATP, what are the end products of glycolysis? a. CO2 and H2O b. CO2 and pyruvate c. NADH and pyruvate d. CO2 and NADH

c. NADH and pyruvate

In the process known as substrate-level phosphorylation: a. a phosphate group is transferred from a substrate molecule to ATP b. a phosphate group is transferred from ATP to a substrate molecule c. a phosphate group is transferred from a substrate molecule to ADP d. all of these answers are correct

c. a phosphate group is transferred from a substrate molecule to ADP

the primary role of oxygen in cellular respiration is to: a. combine with carbon, forming CO2. b. yield energy in the form of ATP as it is passed down the respiratory chain c. act as an acceptor for electrons and hydrogen, forming water d. combine with lactate, forming pyruvate

c. act as an acceptor for electrons and hydrogen, forming water

High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of: a. an enzyme requiring a cofactor b. the specificity of enzymes for their substrates c. allosteric regulation d. competitive inhiition

c. allosteric regulation

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient is an example of: a. active transport b. a reaction with a positive ΔG c. an endergonic reaction coupled to an exergonic reaction d. allosteric regulation

c. an endergonic reaction coupled to an exergonic reaction

during aerobic respiration, electrons travel downhill in which sequence? a. food to glycolysis to citric acid cycle to NADH to ATP b. glucose to ATP to electron transport chain to NADH c. food to NADH to electron transport chain to oxygen d. food to citric acid cycle to ATP to NAD+

c. food to NADH to electron transport chain to oxygen

Carbon dioxide (CO2) is released during which of the following stages of cellular respiration? a. the citric acid cycle and oxidative phosphorylation b. fermentation and glycolysis c. oxidation of pyruvate to acetyl CoA and the citric acid cycle d. glycolysis and the oxidation of pyruvate to acetyl CoA

c. oxidation of pyruvate to acetyl CoA and the citric acid cycle

In mitochondria, exergonic redox reactions: a. reduce carbon atoms to carbon dioxide b. are the source of energy driving prokaryotic ATP synthesis c. provide the energy that establishes the proton gradient d. are directly coupled to substrate-level phosphorylation

c. provide the energy that establishes the proton gradient

In vertebrate animals, brown fat tissue's color is due to abundant blood vessels and capillaries. White fat tissue, on the other hand, is specialized for fat storage and contains relatively few blood vessels or capillaries. Brown fat cells have a specialized protein that dissipates the proton-motive force across the mitochondrial membranes. Which of the following might be the function of the brown fat tissue? a. to increase the production of ATP b. to allow the animals to regulate their metabolic rate when it is especially hot c. to regulate temperature by converting most of the energy from NADH oxidation to heat d. to allow other membranes of the cell to perform mitochondrial functions

c. to regulate temperature by converting most of the energy from NADH oxidation to heat

Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out". These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. These inside-out membrane vesicles: a. will make ATP from ADP and Pi if transferred to a pH 4 buffered solution after incubation in a pH 7 buffered solution. b. will hydrolyze ATP to pump protons out of the interior of the vesicle to the exterior c. will become acidic inside the vesicles when NADH is added d. will become alkaline inside the vesicles when NADH is added

c. will become acidic inside the vesicles when NADH is added

is cellular respiration a catabolic or anabolic process?

catabolic

a molecule that is phosphorylated has and increased ______________ ______________ and it is _____________ to do cellular ___________.

chemical reactivity, primed, work

Where does glycolysis take place?

cytosol

In cellular respiration, the energy for most ATP synthesis is supplied by a. high energy phosphate bonds inorganic molecules. b. transferring electrons from organic molecules to pyruvate. c. converting oxygen to ATP. d. a proton gradient across a membrane

d. a proton gradient across a membrane

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space the direct result is the: a. lowering of pH in the mitochondrial matrix b. formation of ATP c. reduction of NAD+ d. creation of a proton-motive force

d. creation of a proton-motive force

Which of the following most accurately describes what happens along the electron transport chain? a. molecules in the chain give up some of their potential energy b. ATP is generated at each step c. energy of the electrons increases at each step d. each electron carrier alternates between being reduced and being oxidized

d. each electron carrier alternates between being reduced and being oxidized

In prokaryotes, the respiratory electron transport chain is located: a. in the mitochondrial outer membrane b. in the cytoplasm c. in the mitochondrial inner membrane d. in the plasma membrane

d. in the plasma membrane

During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from? a. pyruvate (C3H3O3-) b. glucose (C6H1206) c. carbon dioxide (CO2) d. molecular oxygen (O2)

d. molecular oxygen (O2)

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes: a. hydrogenated b. hydrolyzed c. reduced d. oxidized

d. oxidized

What is the oxidizing agent in the following reaction? Pyruvate + NADH + (H+) --> Lactate +NAD+ a. lactate b. NAD+ c. NADH d. pyruvate

d. pyruvate

To sustain high rates of glycolysis under anaerobic conditions, cells require: a. all of these answers are correct b. regeneration of NADH c. oxidative phosphorylation of ATP d. regeneration of NAD+

d. regeneration of NAD+

is catabolism endergonic or exergonic?

exergonic

proton-motive force

force exerted on a proton by a transmembrane protein concentration gradient

NADH

generated by glycolysis and the citric acid cycle electron carrier

Steps of alcohol fermentation

glucose + 2 ADP + 2 Pi + 2 NAD+ --> 2 pyruvate + 2 NADH + 2 CO2 --> 2 Acetaldehyde --> 2 NAD+ + 2 ethanol

Steps of lactic acid fermentation

glucose + 2NAD+ + 2ADP + 2 Pi --> 2 pyruvate + 2 ATP + 2 NADH --> 2 lactate + 2 NAD+ then glycolysis happens again with the 2 NAD+

path of energy during cellular respiration

glucose --> NADH --> electron transport chain --> proton-motive force -->

metabolic pathways of anaerobic respiration

glycolysis citric acid cycle oxidative phosphorylation - electron transport chain with different final electron acceptor - chemiosmosis

steps of fermentaion

glycolysis and reactions that regenerate NAD+

During cellular respiration, acetyl CoA accumulates in which location? a. mitochondrial intermembrane space b. mitochondrial matix c. mitochondrial inner membrane d. cytosol

mitochondrial matrix

Where does citric acid cycle take place?

mitochondrial matrix

phosphorylated

molecules has gained a phosphate group - gained a high-energy bond that increases its potential energy in the phosphorylated molecule, increasing its capacity to do work

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction the molecule becomes.......

oxidized

Where does most of the free energy from the oxidation of glucose remain?

pyruvate

the purpose of fermentation reactions

regenerate NAD+ so glycolysis can continue

anaerobic respiration

respiration without O2

cellular respiration

set of metabolic reactions that convert biochemical energy from nutrients to ATP and waste products

Difference between aerobic respiration and anaerobic respiration

something other than O2 is used as the final electron acceptor for the electron transport chain that is less electronegative than O2 so less energy is released and less ATP are made

How is ATP produced in fermentation?

substrate-level phosphorylation

What happens to electrons as they move closer to the nucleus of an atom?

they lose potential energy

aerobic respiration

using oxygen