Chapter 9: Pathways That Harvest Chemical Energy
How many reaction steps are involved in the citric acid cycle? One Three Five Eight Ten
Eight
OPP
Electron transport + Chemiosmosis
Reduction
Gain of electrons
What is an example of anabolic interconversion? Gluconeogenesis Lipids broken down into their constituents, glycerol and fatty acids Proteins hydrolyzed to amino acids Pyruvate oxidation Glycolysis
Gluconeogenesis
Cells get energy from ______ in a series of metabolic pathways.
Glucose
Cells harvest energy from ______.
Glucose
During cellular respiration, most energy flows in this sequence
Glucose - NADH/FADH2 - Electron Transport Chain - Proton-Motive Force - ATP
Glyconeogenesis
Glucose formed from citric acid cycle and glycolysis
During cellular respiration, fuel such as _____ is ______ and ______ is released.
Glucose, Oxidized, O2
Glycolysis and fermentation steps
Glycolsis-Pyruvate (O2 absent) - Fermentation - Lactate or Alcohol
Glycolysis is both an energy ____/____ phase.
Requiring and Releasing
Eukaryotes (Inner membrane)
Respiratory change
The reactions of lactic acid fermentation are ________.
Reversible
How are steps 1-3 of glycolysis different from steps 6-10? Steps 1-3 catalyze reactions that require ATP, while steps 6-10 catalyze changes that require NADH. Steps 1-3 catalyze reactions that require ATP, while steps 6-10 catalyze changes that produce NADH and ATP. Steps 1-3 catalyze changes in a six-carbon molecule, while steps 6-10 catalyze changes in a four-carbon molecule. Steps 1-3 occur in the cytoplasm, while steps 6-10 occur in the mitochondrial matrix. Steps 1-3 catalyze reactions that require ATP, while steps 6-10 catalyze changes that produce NADH and GTP.
Steps 1-3 catalyze reactions that require ATP, while steps 6-10 catalyze changes that produce NADH and ATP.
How many enzymatic steps are involved in glycolysis in animals? One Three Five Eight Ten
Ten
Energy production occurs in different locations in prokaryotic and eukaryotic cells. Which statement is true for eukaryotes? The conversion of pyruvate to CO2 and H2O occurs in the mitochondria. The citric acid cycle enzymes are found in the cytoplasm. The conversion of pyruvate to lactate occurs in the mitochondria. The conversion of glucose to pyruvate occurs in the mitochondria. The respiratory chain enzymes are found at the plasma membrane.
The conversion of pyruvate to CO2 and H2O occurs in the mitochondria
If the regeneration of NAD+ were inhibited during lactic acid fermentation, which of the following would likely occur? The rate of glucose converted to pyruvate would increase. The rate of lactic acid production would decrease. The concentration of NAD+ would increase. The rate of pyruvate production would remain the same. The concentration of ATP would increase.
The rate of lactic acid production would decrease.
Energy production occurs in different locations in prokaryotic and eukaryotic cells. Which statement is true for prokaryotes? The conversion of pyruvate to lactate occurs on the cell membrane. The respiratory chain enzymes are found on the cell membrane. The conversion of glucose to pyruvate occurs on the cell membrane. The conversion of pyruvate to CO2 and H2O occurs in the mitochondria. The citric acid cycle enzymes are found in the mitochondria.
The respiratory chain enzymes are found on the cell membrane.
Oxidation-Reduction (Redox) reactions
Transfer of electrons during chemical reactions release energy stored in organic molecule
Glycolysis can occur ____ or _____ oxygen.
With ; without
Which is required for wine production? Yeast and a source of glucose Plant cells devoid of sugar Lactic acid fermentation from glucose Purified chloroplasts only An aerobic environment
Yeast and a source of glucose
Alcoholic fermentation occurs in what type of organisms?
Yeast and some plant cells
If 0.5 mole of glucose is oxidized by lactic acid fermentation, the amount of ATP generated in the cytoplasm will be 0.1 mole. 0.5 mole. 1.0 mole. 2.0 moles. 5.0 moles.
1.0 mole.
Glycolysis produces ....
2 ATP and 2 NADH
What is the net free energy captured by 32 moles of ATP? 7.3 kcal 52.4 kcal 234 kcal 686 kcal 730 kcal
234 kcal
Glycolysis is a series of reactions that extract energy by splitting it into 2 _________ molecules called _________.
3-carbon ; Pyruvates
Approximately how many more ATP molecules per glucose molecule are produced via glycolysis and cellular respiration than via glycolysis and fermentation? 2 4 6 14 30
30
Some poisons are compounds that interfere with metabolic pathways. Which poison would interfere with the citric acid cycle but not affect glycolysis? A compound that accelerates pyruvate oxidation A compound that accelerates coenzyme A synthesis A compound that inhibits regeneration of NAD+ from NADH A compound that accelerates ATP hydrolysis A compound that inhibits pyruvate dehydrogenase
A compound that inhibits pyruvate dehydrogenase
Glycolysis
A series of reactions that ultimately splits glucose into pyruvate. Occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration
Which reaction is not an example of an oxidation-reduction reaction? NADH + H+ + ½ O2 → NAD+ + H2O CH4 + ½ O2 → CH3OH + H+ ADP + Pi → ATP + H2O C2H5OH + NAD+ → C2H4O + NADH + H+ C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
ADP + Pi → ATP + H2O
oxidative phosphorylation
ATP is synthesized by reoxidation of electron carriers in the presence of O2
What is used to produce alcoholic drinks?
Alcoholic fermentation
Catabolism / _______ are linked.
Anabolism
Some prokaryotes can harvest change by __________.
Anaerobic respiration
Oxidative phosphorylation has two major components: _______ and _______. electron transport; chemical reduction electron transport; osmosis proton transport; chemiosmosis electron transport; chemiosmosis proton transport; energy coupling
electron transport; chemiosmosis
Energy is transferred as ______ move from 1 molecule to another via _______________________.
electrons ; oxidation-reduction reactions.
Pyruvate oxidation is a ______ reaction.
exergonic
Metabolism of glucose is highly ______ and _______.
exergonic and catabolic
Lactic acid/alcoholic fermentation are pathways that allow _____ to be oxidized in the _______ of oxygen by regenerating oxidized electron carriers.
glucose ; absence
Eukaryotes (in cytoplasm) -
glycolysis and fermentation
Prokaryotes (In cytoplasm) -
glycolysis, fermentation, citric acid cycle
The chemiosmotic mechanism explains how ATP is produced in the cytoplasm. how a proton gradient is coupled to ATP production. the coupling of glycolysis to the citric acid cycle. why membranes are not needed for ATP production. how water flows in and out of the mitochondria.
how a proton gradient is coupled to ATP production.
Cellular respiration refers to the metabolic process that involves the oxidation of glucose to pyruvate. starts with sucrose. involves the oxidation of pyruvate to carbon dioxide. produces 30 ATP. releases less usable energy for a cell than fermentation.
involves the oxidation of pyruvate to carbon dioxide.
Under anaerobic conditions, pyruvate is reduced to lactate. enters the citric acid cycle. is fermented to lactate or alcohol. is converted to lactate or tricarboxylic acids. is broken down on the cell membrane.
is fermented to lactate or alcohol
Pyruvate oxidation to acetyl CoA is a complex reaction because it involves the transfer of acetyl CoA to oxaloacetate. it is a multistep chemical reaction catalyzed by a pyruvate dehydrogenase complex made up of three enzymes, carrying out multiple intermediate steps in the process. it requires the input of energy. one pyruvate molecule is oxidized to another three-carbon compound. it is located in the mitochondrial matrix.
it is a multistep chemical reaction catalyzed by a pyruvate dehydrogenase complex made up of three enzymes, carrying out multiple intermediate steps in the process.
When a person runs for an extended period of time, the main source of glucose for muscle cells comes from the breakdown of glycogen in the skeletal muscle. liver. lungs. electron transport chain. heart muscle.
liver.
Pyruvate oxidation occurs in the ....
mitochondrial matrix
Electron transfer in the electron transport chain causes _____ to pump _____ across the membrane.
proteins ; H+
The H+ gradient is referred to as
proton motive force
In alcoholic fermentation, ______ is converted to _____ in 2 steps.
pyruvate ; ethanol
Several mechanisms _______ the rate of each step in a ____________.
regulate ; biochemical pathway
ATP molecules are important in metabolism because ATP can release chemical energy, which drives endergonic reactions. release chemical energy, which drives exergonic reactions. absorb chemical energy from another reaction as it is hydrolyzed. substitute for glucose as an energy source for cells. store chemical energy for long periods of time in the body.
release chemical energy, which drives endergonic reactions.
ATP is the _____ in all living organisms.
same
Glucose is broken down in a ____________.
series of steps
Proteins are built from carbons that can come directly from electron transport. the citric acid cycle. pyruvate oxidation. pyruvate. acetyl CoA.
the citric acid cycle.
burning/metabolism of glucose
C6H12O6 + 6O2 = 6CO2 + 6 H2O + free energy Change in G= 686 kcal/mol
Bubbles in beer and champagne are caused by?
CO2 from action of pyruvate decarboxylase
Which statement about metabolic pathways is correct? Chemical transformations occur in a series of separate chemical reactions. One enzyme usually catalyzes all of the transformational steps.In eukaryotes, all metabolic reactions occur in the cytoplasm. Activators that target some key enzymes in a pathway have no effect on the rate of reaction. Inhibitors that target some key enzymes in a pathway increase the rate of reaction.
Chemical transformations occur in a series of separate chemical reactions.
Eukaryotes (In mitochondrial matrix) -
Citric Acid Cycle, Pyruvate Oxidation
Acetyol CoA serves as fuel for the ______.
Citric acid cycle
Electron carrier molecules functions as ______ to pick up/donate electrons during ____________.
Coenzymes ; Biological Redox Reactions
______________ is a key electron carrier in redox reactions.
Coenzymes NAD+
Synthesis and breakdown of macromolecules in a cell are linked through ____________.
Common metabolic pathways.
Which component of the respiratory chain is a peripheral protein? Complex III Complex IV Complex II Cytochrome c Complex I
Cytochrome c
Glycolysis takes place in the _______.
Cytosol
If you were making beer, you would combine water, a starch source such as malted barley that becomes a sugar source during fermentation, and brewer's yeast, which is responsible for the fermentation. As the process proceeds, what is a good indication that your mixture is producing alcohol? Bubbles of carbon dioxide are rising in the mixture. The mixture contains lactic acid. The mixture tastes sweeter than it did initially. There are more yeast cells at the top of the mixture where oxygen levels are higher than at the bottom of the mixture. The yeast cells are not growing.
Bubbles of carbon dioxide are rising in the mixture.
Chemiosmosis
Electrons flow back across the membrane through a channel protein, ATP synthase, which couples the diffusion with ATP synthesis. Diffusion of proton back across the membrane is coupled to ATP synthesis.
Electron transport
Electrons from NADH and FADH2 pass through the respiratory chain and result in a proton concentration gradient across their inner mitochondrial membrane
Metabolic pathways are regulated to ...
Ensure efficiency and proper functioning of the cell.
Pathways are regulated by _______.
Enzyme inhibitors
ATP synthase used _______ flow of H+ to drive ____________ of ATP.
Exergonic ; Phosphorylation
Electrons are shuttled from glycolysis and the citric acid cycle to the respiratory chain via ATP. FADH2 only. GTP. NADH only. FADH2 and NADH.
FADH2 and NADH.
Products from the citric acid cycle include NAD+. ATP. FADH2. GDP. acetyl CoA.
FADH2.
Which describes how the components of the respiratory chain are ordered? From low to high free energy relative to oxygen From low to high ability to pass electrons to oxygen From high to low ability to pump protons across the inner membrane From high to low reduction potential relative to oxygen From large to small mass
From high to low reduction potential relative to oxygen
In eukaryotes, the proton-motive force allows protons to move passively through ATP synthase in which direction? From the cytoplasm to the mitochondrial inner membrane space From the mitochondrial matrix to the inner mitochondrial membrane space From the mitochondrial inner membrane space to the mitochondrial matrix From the cytoplasm to the mitochondrial matrix From the outside of the cell to the cytoplasm
From the mitochondrial inner membrane space to the mitochondrial matrix
3 catabolic processes that harvest energy from glucose
Glycolysis, Cellular Respiration, Fermentation
Cellular respiration cycle steps
Glycosis-Pyruvate (O2 present)- Pyruvate Oxidation - Citric Acid Cycle - Electron transport/ATP synthesis- CO2 + H2O
At key steps of breaking down glucose, electrons are stripped from glucose, in the form of a ___________.
Hydrogen atom
Metabolic pathways do not operate ________.
In isolation
Oxidation
Loss of electrons
Lactic acid fermentation occurs in
Microorganisms and complex organisms, including higher plants and vegetables
By recycling ____________, fermentation allows glycolysis to continue, thus producing small amounts of ATP through substrate-level phosphorylation.
NAD+
In lactic acid fermentation, pyruvate is reduced by _______, forming lactate as an end product.
NADH
Which statement best describes how key molecules are regenerated to allow continued metabolism in a cell? NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue. ATP can donate its electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue. GTP, NADH, and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue. FADH2 can donate its electrons to the electron transport chain and be regenerated to allow glycolysis to continue. GTP can donate its electrons to the electron transport chain and be regenerated to allow pyruvate oxidation to continue.
NADH and FADH2 can donate their electrons to the electron transport chain and be regenerated to allow the citric acid cycle to continue.
What causes muscle pain during active exercise?
O2 can not be delivered to muscle cells fats enough, there is a breakdown of glycogen, lactic acid fermentation occurs, increase of H+ lowers pH
Reduction and Oxidation always ....
Occur together
Malate dehydrogenase is responsible for catalyzing which reaction? Oxidation of malate to oxaloacetate Reduction of malate to oxaloacetate Oxidation of NADH to NAD+ Decarboxylation of a five-carbon molecule to a four-carbon molecule Substrate phosphorylation of ADP to ATP
Oxidation of malate to oxaloacetate
Which statement regarding glycolysis is true? Glucose is not catabolized. NADH is not formed. ATP is not formed. Oxygen is not required. Pyruvate is not formed.
Oxygen is not required.
Chemiosmosis converts the _________ of a proton concentration gradient to __________ ATP.
Potential energy ; Chemical Energy
glycolysis converts glucose into two molecules of
Pyruvate
Prokaryotes (On cell membrane)
Pyruvate Oxidation and Respiratory Chain
Cellular respiration is
aerobic
Fermentation is
anaerobic
Glycolysis is
anaerobic
