Exam 3, Chapter 10,11,12 & 16

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What reactions capture energy from the organisms energy source?
_____ is the total of all chemical reactions occurring in the cell
________ reactions build new organic molecules from smaller inorganic and organic compounds
In thermodynamic studies, energy changes are analyzed in a collection of matter called a _____. All other matter in the universe is called the _____
system; surroundings
________ is the science that analyzes energy changes in a collection of matter
A rxn in which the forward rate is equal to the reverse rate is said to be at ______
Cells must efficiently transfer energy from their energy-trapping systems to the systems actually carrying our work and also use various metabolic processes to replace the energy used in doing work. This is called the ______ _______
Energy cycle
In order for the cell to be able to input energy into necessary endergonic reactions, energy-generating processes such as photosynthesis, fermentation, and respiration are used to produce _____
A molecule that binds to an enzyme at a location other than active site and thereby alters the enzyme's shape, making it inactive or less active is a _______ inhibitor
The molecules formed by an enzyme-catalyzed
The reacting molecules in an enzyme-catalyzed reaction are called _______
The _______ ________ is the substrate concentration needed for an enzyme to achieve half maximal velocity
Michaelis constant (Km)
A complex formed during a reaction that resembles both the substrate and the product is called the _____ state complex
RNA molecules that have catalytic activity are known as ______
Cells carry out three major types of work; which of the following involves the synthesis of macromolecules as well as the breakdown of substances for their energy?
Chemical work
Cells carry out three major types of work; which of the following involves nutrient uptake and waste elimination?
Transport work
Cells carry out three major types of work. Which of the following involves energy for cell motility and the movement of structures within cells?
Mechanical work
T/F Energy can be redistributed within a collection of matter (called a system) or can be redistributed between the system and its surroundings
______ is a measure of randomness or disorder of a system
The _____ law of thermodynamic states that energy can be neither created nor destroyed
The _____ law of thermodynamics states that physical and chemical processes occur in such a way that randomness increases to a maximum.
The amount of heat energy needed to raise 1 gram of water from 14.5 to 15.5 is called a ______
T/F The numerical value of the free energy change indicates how fast a reaction will reach equilibrium
_____ is the total energy change that accompanies a chemical reaction
For the reaction A + B ---- C + D, the equilibrium constant is expressed as _______
The change in _____ _____ is the amount of energy in a system that is available to do work.
free energy
T/F The most commonly used practical form of energy used in cells is adenosine diphosphate
A reaction that releases energy is ______
T/F Some energonic reactions can be made to proceed forward if they are coupled to hydrolysis of one or more oh the phosphates of ATP
A chemical reaction that requires an input of energy in order to proceed is _____
The _____ is the electron acceptor in a redox reaction
The ____ is the electron donor in a redox reaction
The standard reduction potential of a redox reaction is a measure of the tendency of the _____ to _____ electrons
Reductant, lose
T/F The equilibrium constant for a redox reaction is called the standard reduction potential
Which of the following is used as an electron carrier by a living organisms?
NAD+ NADP+ Ubiquinone
T/F The ETC is based on the principle that redox couples with more positive reduction potentils will donate electrons to couples with more negative potentials
T/F One of the components used during photosythetic electron transport is ferredoxin, a nonheme iron protein
ETC molecules that only transfer electrons includes _______
Which of the follow is/are true about enzymes?
All of the choices are correct
T/F Each enzyme normally has a specific pH and temperature optima at which they function best.
T/F The Michaelis constant (Km) of an enzyme is the substrate concentration that produces maximum velocity
T/F Enzyme activity can be greatly affected by the pH and the temperature of the environment in which the enzyme must function
T/F When the amount of enzyme present is held constant, the rate of reaction will continue to increase as long as the substrate concentration increases.
T/F Enzymes increase the rate of reaction but do not alter equilibrium constants
T/F Enzymes increase the rate of reaction by increasing molecular motion, thereby providing kinetic energy to drive the reaction
Enzymes are usually named based on _____
The substrated they act on and the type of reaction they catalyze
The most specific term used to describe a substance in a biological system that increases the rate of a reaction without being permanently changed by the reaction is a ______
The substrate of an enzyme binds at the ______
active site
A complete enzyme that consists of a protein component and a nonprotein component is called a _____
A nonprotein component of an enzyme that is loosely attached to the protein component is referred to as a _____
The nonprotein component of an enzyme that is firmly attached to the protein is called _____
prosthetic group
If an enzyme consists of a protein component and a nonprotein component, the protein component is referred as the _____
If all available enzyme molecules are binding substrate and converting it to product as rapidly as possible, the reaction is said to be proceeding at __________ velocity.
A _____ increases the rate of reaction without being permanently altered by the reaction
Enzymes function as catalysts by ______
concentrating the substrates and correctly orienting them at the active site
Enzymes catalyze a reaction by _____
decreasing the activation energy of the reaction
The energy required to bring the substrated of a reaction together in the correct way to reach the T.S. is called ______
activation energy
T/F One important ribozyme responsible for catalyzing peptide bond formation during protein synthesis is located in the mitochondria
Which of the following is a reason for metabolic regulation?
All of the choices are correct
In metabolic channeling, the regulation of metabolic pathways is controlled by the ____ of metabolites and enzymes involved in the pathway
Metabolic channeling involves the localization of ___ in different parts of a cell in order to influence the activity of metabolic pathways
Susbstrates and enzymes
When the end product of a pathway inhibits the catalysis of the first step of that pathway, this phenomenon is called _____
Feedback inhibition
Enzyme activity can be controlled by _____
All of the choices are correct
In allosteric regulation, effector molecules usually bind ______
Reversible and non-covalently
In a branched pathway with many end products, an abundance of on of the end products will usually inhibit ______
The first committed step in the branch of the pathway leading to the production of that particular product
T/F Isoenzymes are different enzymes that catalyze the same reaction but can be regulated independently of one another
Which of the following are components of the ATP molecule?
Adenine RIbose Three phosphate
T/F In an ATP molecule, the phosphates are bonded to the adenine ring
Based on phosphate transfer potential, which is more likely to happen
Phosphoenolpyruvate will transfer phosphate to ADP
ATP has a phosphate transfer potential of 30.5, whereas glucose-6-phosphate has a phosphate transfer potential of 13.8. Based on these differences, which of the following will happen?
ATP will transfer phosphate to glucose-6-phosphate
The energy made available during cell respiration and fermentation is used to make ____, which is then available to provide energy for cellular work
What nucleoside triphosphate, other than ATP, provides some of the energy for protein synthesis?
What nucleoside trisphosphate provides energy for lipid synthesis?
As the difference in reduction potential between a redox pair increases, the amount of free energy made available _____
In a redox reaction involving NAD/NADH and pyruvate, ___ will be the electron donor and ___ will be the electron acceptor
NADH, pyruvate
Standard reduction potentials go in order from ____ to ____
least, greatest
Where is the ETC located in bacterial cells?
Plasma Membrane
In bacterial and archaeal cells, the ETC is located in the ____ whereas in eukaryotic cells, the ETC is located in the _____
Plasma membrane; inner mitochondiral membrane
T/F Enzymes decrease the overall free energy change in a chemical reaction
Until the discovery of ______, enzymes were the only recognized biological molecules that were catalytic
Catalytic proteins are known as ____ whereas catalytic RNA molecules are known as ______
Enzymes; ribozymes
Which of the following reactions is catalyzed by a ribozyme?
Peptide bond formation during protein synthesis
Which strategy can be used for regulation of metabolism?
All of the strategies may be used
Feedback inhibition, covalent modification, and allosteric regulation are all examples of _____
Posttranslational regulation
T/F The regulatory site in an allosteric enzyme is found within the catalytic site
How does the binding of a regulatory molecule to the allosteric site affect the activity of an enzyme? A) It causes the enzyme to denature and become inactive. B) It may change the affinity of the enzyme for its substrate. C) It may cause the active site to disappear altogether. D) It may change the maximum velocity of the enzyme. E) It may decrease the activity of the enzyme. F) It may increase the activity of the enzyme. G) It may change the shape of the enzyme
B, D, E, F, G
A positive allosteric effector will ______ the activity of an enzyme while a negative effector will ____ the activity
Increase, decrease
The binding of a positive allosteric regulator molecule will _____
increase the ability of the substrate to bind to the catalytic site
Which three of the following groups are most commonly used to covalently modify an enzyme and its activity? A) Phosphoryl group B) Hydroxyl group C) Methyl group D) Adenyl group
A, C, D
T/F Covalent modification of enzymes most commonly uses phosphoryl, methyl, and adenyl groups
Consider a biochemical pathway with five steps that lead to the production of product Q. If there is an abundance of product Q, the most efficient way to slow down the entire pathway would be to regulate ______
The first enzyme in the pathway
A bacterial biosynthetic pathway synthesizes an amino acid in a series of steps, each catalyzed by a different enzyme. The bacteria is transferred to fresh media where the amino acid is present in abundance. The amino acid binds to a regulatory site on the first enzyme in the pathway, effectively shutting down the entire process. This is an example of ________.
Feedback inhibition
the total of all chemical reactions occurring in a cell is called ______
T/F Although most metabolic reactions are freely reversible, a few irreversible catabolic steps are bypassed during biosynthesis with special enzymes that catalyze the reverse reaction in order to allow for independent regulation of catabolic and anabolic pathways.
T/F Metabolic pathways can be either catabolic or anabolic but not both
_____ pathways are those that function both catabolically and anabolically
T/F The catabolism of glucose begins with one or more of the glycolytic pathways that yield pyruvate
____ ___ is a process that can completely catabolize an organic energy source to CO2 using the glycolytic pathways and TCA cycle with O2 as the terminal electron acceptor for an ETC
Aerobic respiration
T/F Very few gram positive bacteria utilize the Entner-Doudoroff glycolytic pathway.
T/F Some aerobic bacteria lack the Entner-Doudoroff and Embden-Meyerhoff pathways and instead use the pentose phosphate pathway for glycolysis.
T/F An organism may use glycolysis and the petnose phosphate pathway simultaneously
The net gain of ATP per molecule of glucose metabolized anaerobically via the Embden-Meyerhof pathway in prokaryotes is ______
The net gain of ATP per molecule of glucose metabolized to pyruvate using Entner-Doudoroff pathway is ______
The pentose phosphate pathway produces _____
CO2 NADPH glyceraldehye 3-phosphate
The synthesis of ATP from ADP and Pi, when coupled with an exergonic chemical reaction is called _______ phosphorylation
The most common pathway for conversion of glucose to pyruvate is ______
The TCA cycle generates all of the following from each acetyl-CoA molecule oxidized except ______
two ATP or GTP molecules
The pyruvate dehydrogenase complex oxidizes and cleaves pyruvate to form one CO2 and _____
After glycolysis, pyruvate is oxidize to oneCO2 and the two-carbon molecule acetyl-CoA by a multienzyme system called the ____ _____ complex
pyruvate dehydrogenase
TCA cycle enzymes are found in the ____ _____ of eukaryotic cells
Mitochondrial matrix
In the TCA cycles, two carbons are removed from citric acid in the form of ____ thereby regenerating oxaloacetate to complete the cycle
Carbon dioxide
In the TCA cycle, two carbons in the form of ______ are added to oxaloacetate at the start of the cycle
The major function of the TCA cycle is _____
energy production and provision of carbon skeletons for biosynthesis of cell components
When mitochondria pass electrons donated by NADH through the electron transport chain to molecular oxygen, a theoretical max of ______ molecules of ATP can be made per oxygen molecule reduced
The hypothesis that proton motive force drives ATP synthesis is called the ____ hypothesis
The most commonly accepted hypothesis for the production of ATP that results from electron transport system is called the ____ hypothesis
T/F Bacterial ETC may be comprised of fewer components and have lower phosphate to oxygen ratios than mitochondrial transport chains
T/F The electron transport systems in eukaryotes and prokaryotes use different electron carriers
T/F In addition to being used in the making of ATP, a proton motive force is used directly to power the rotation of bacterial flagella
Differences between mitochondrial and E. Coli electron transport chains include which of the following?
The E. Coli chain contains a different array of cytochromes
Which of the following is NOT true regarding ATP synthases?
The proton flow is outward during ATP synthesis
The theoretical max net gain of ATP per molecule of glucose metabolized aerobically in eukaryotes is _____
Production of ATP using the energy liberated when electrons from reduced chemical bonds are passed through the electron transport system is generally referred to as ______
Mitochondrial electron transport takes place ______
On the inner mitochondrial membrane
In higher eukaryotes, most aerobically generated ATP is produced by _____
A membrane-bound proton translocating ATP synthase during oxidative phosphorylation
The number of ATP molecules generated per atom of oxygen that is reduced when electrons are passed from NADH or reduced FAD to O2 is called ______
P/O ratio
In aerobic conditions, it takes ______ sugar to produce the same amount of ATP when compared to anaerobic conditions
T/F Prokaryotes may use several different terminal oxidases for the electron transport system
T/F Reduction of nitrate to nitrite by Paracoccus denitrificans is an example of anaerobic respiration
When cells of a facultative anaerobe such as Paracoccus denitrificans are growing under anaerobic conditions and using nitrate as the terminal electron acceptor, ______________ nitrate reduction is occurring.
Which of the following can be used as electron acceptors during anaerobic respiration?
All of the choices are correct
Organisms that form lactate, ethanol, and CO2 as end products of glucose metabolism are called ____ fermenters
T/F Fermentation involves the use of pyruvate and/or other organic molecules as electron acceptors
T/F In the process of fermentation an organic substrate, such as glucose, is reduced and an intermediate of the pathway, such as pyruvate, is oxidized
Organisms that directly reduce almost all of their pyruvate to lactate are called _____ fermenters
T/F Oxygen is always required for the regeneration of NAD from NADH
Large external polysaccharides are degraded by bacteria and archaea using ________ ________, which secrete these substances outside the cell.
hydrolytic enzymes
Disaccharides and polysaccharides can be processed as nutrients after first being cleaved to monosaccharides by either ______ or _____
hydrolysis, phosphorolysis
Fatty acids are metabolized by the ____ pathway
beta oxidation
During breakdown of fatty acids, carbons are removed ______ at a time with each turn of the cycles, and two carbon units are released as ______
two, acetyl-CoA
Proteins are catabolized by hydrolytic cleavage to amino acids by the action of enzymes called ______
Amino acids are processed first by the removal of the amino group through ______
T/F Nitrification of ammonia occurs when ammonia is first converted to nitrite and then is converted to nitrate by the nitrogen-fixing bacteria.
______ is a two-step process that depends on the activity of at least two genera to carry out the oxidation of ammonia to nitrate
Which of the following may be used as sources of energy by chemolithotrophs?
Hydrogen gas - reduced nitrogen compounds -reduced sulfur compounds
How many molecules of ATP are needed to reduce one molecule of Co2 to carbohydrate by oxygenic phototrophs during the dark reactions of photosynthesis
How many molecules of NADH are produced during glycolysis?
How many quanta of light are needed to reduce one molecule of CO2 to carbohydrate during photosynthesis
T/F All prokaryotic photosynthesizers are anoxygenic
T/F Photosynthetic organisms serve as the base for most food chains in the biosphere
T/F All eukaryotic photosynthesizers are oxygenic
In the process of noncyclic photophosphorylation, _____ A) water is split to form oxygen gas B) electrons from water flow through electron transport chains resulting in synthesis of ATP and NADPH C) photosystems I and II are both required D) All of the choices are correct.
D) All of the choices are correct
In the process of ____, ATP is synthesized when excited electrons from chlorophyll P700 pass through a series of electron carriers then return to chlorophyll P700
Cyclic photophosphorylation
Photosynthetic electron transport in cyanobacteria takes place _____
on the thylakoid membranes
Select the terms that describe an organism's carbon source A) Heterotroph B) Lithotroph C) Chemotroph D) Autotroph E) Organotroph
A, D
The terms phototroph and chemotroph refer to an organism's source of ______
A newly described bacterial species has been shown to use CO2 as its carbon source. Its energy source and its source of reducing power (electrons) are inorganic chemicals. Which term would best describe this nutritional type?
Which nutritional classification would you predict to fit most of the well-known members of the human microbiome?
Processes that supply ATP, reducing power, and precursor metabolites are collectively referred to as ____ reaction
In most cases, fueling reaction are _____ reactions
T/F An organism can it into only one nutritional patter, such as photoheterotrophy, and cannot change if the environmental conditions change
T/F An organism can take advantage of energy available from both light and from organic molecules and exhibit both phototrophy and chemoorganotrophy
Indicated the processes below that represent the basic types of chemoorganotrophic metabolism A) Photosynthesis B) Aerobic respiration C) Fermentation D) Oxidation-reduction E) Anaerobic respiration
B, C, E
Aerobic respiration, anaerobic respiration, and fermentation are the three basic types of ________
Chemoorganoheterotrophic metabolism
T/F Glycolysis and the TCA cycle are two of the most important catabolic pathways in chemoorganotrophs
What distinguishing feature characterizes aerobic and anaerobic respiration but does not play a role in fermentation pathways?
The presence of an ETC
The six carbons of the glucose molecule that enter the cell respiration pathway end up in/as _____ _____ by the end of the process
carbon dioxide
Indicate the products of aerobic respiration.
Water, CO2, ATP
Which of the following produces the most ATP during aerobic respiration?
ETC and chemiosmosis
During glycolysis, ATP is produced when 1, 3, bisphosphoglycerate transfers a phosphate to ADP forming ATP. This is an example of _____
Substrate-level phosphorylation
In order for a substance to transfer a phosphate to ADP in substrate-level phosphorylation reaction , which of the following must be true?
The phosphate donor may have a high phosphate transfer potential than ATP
Where the embden-Meyerhof pathway produces two molecules of pyruvate for each glucose, the Entner-Doudoroff pathway produces one molecule each of ____ and _____
pyruvate, glyceraldehyde
Which of the following is the major glycolytic pathway used by plants and animals?
Embden-Meyerhof pathway
T/F The pentose phosphate pathway is the major glycolytic pathway used by archaea?
Which of the following names refer to the tricarboxlic acid cycle?
Krebs cycle, citric acid cycle
Which of the following is produced in largest numbers by the TCA cycle?
The TCA cycle is located in the ____ of bacteria, and in the _____ of eukaryotes
cytoplasm; mitochondrial matrix
T/F The major difference between aerobic and anaerobic respiration is the final electron acceptor at the end of the ETC
When nitrate is used as a final acceptor by bacteria growing in anoxic soils, the nitrogen is no longer available for the construction of precursor metabolites. This Is referred to as ______
dissimilatory nitrate reduction
The amount of ATP produced during anaerobic respiration is _____ that produced during aerobic respiration, because the difference in the standard reduction potential between NADH and the final electron acceptor is ________
Less than; smaller
Which of the following are consequences of anaerobic respiration? A) Some bacteria are able to readily survive in both well-oxygenated as well as anoxic environments. B) Some bacteria may cause denitrification. C) Some bacteria are able to perform nitrogen fixation. D) Bacteria are able to reduce the levels of NO3− in sewage plant effluents
A, B, D
How is ATP produced during fermentation?
Substrate-level phosphorylation
How does a fermenter generate PMF to drive active transport?
Fermenters can reverse the direction of the ATP synthase to generate PMF
How does the phosphorylation of galactose differ from the phosphorylation of glucose, mannose, and fructose prior to catabolism?
Phosphorylation of galactose requires UTP to phosphorylate galactose-1-phosphate
Complete catabolism of lactose requires ______
ATP, UTP, NAD, and appropriate enzymes
What enzymes hydrolyze proteins, releasing amino acids?
A ______ hydrolyzes a protein into its constituent amino acid monomers and a ______ enzyme removes amino groups from the amino acids
Protease; deaminase
______ refers to the removal of an amino group from an amino acid. One mechanism for this removal is ______, in which the amino group is transferred to an acceptor molecule
Deamination; transamination
The substance that donate electrons to the electron transport chains of chemolithotrophs are _____
inorganic compounds
T/F Most chemolithotrophs have ETC that terminate with O2 as the final electron acceptor
T/F Many chemolithotrophs are able to produce more ATP from oxidation of their inorganic energy source than chemoheterotrophs produce from the aerobic oxidation of glucose
Chemolithotrophs generally derive ____ ATP from oxidation of inorganic substrates because the reduction potentials of those substrates are much more _____ than the reduction potential of organic substrates
less; positive
________ is an aerobic chemolithotrophic process that ultimately oxidizes ammonia to nitrate, whereas ________ is a form of anaerobic respiration involving the oxidation of an organic compound using an oxidized nitrogenous compound, such as nitrate, as the terminal electron acceptor.
Nitrification; denitrification
T/F All forms of phototropy "harvest" light energy to fix carbon, producing sugar
Photoheterotrophs that use light to generate ATP, but do not fix CO2______
would be best described as phototropic and would use light reactions but not Calvin cycle
Chlorophyll a and chlorophyll b as well as the accessory pigments are arranged in an antenna array with a reaction center chlorophyll. These antenna arrays with the reaction center chlorophyll are known as _______
Which of the following described roles attributed to accessory pigments such as carotenes and phycobiliproteins? A) These pigments absorb light in ranges not absorbed by chlorophylls and transfer the energy to chlorophylls. B) These pigments extend the spectrum of wavelengths that will drive photosynthesis. C) The accessory pigments are involved in maintaining the Calvin cycle. D) Accessory pigments protect organisms from potentially damaging intense sunlight.
A, B, D
In what ways are oxidative phosphorylation and photophosphorylation similar? A) The source of energy is highly reduced organic compounds B) An electron transport chain is used C) Proton motive force is generated D) Water is split to provide electrons E) ATP synthase enzyme phosphorylates ADP to make ATP
B, C, E
Consider the metabolism of a chlorophyll-based phototroph. In oxidative phosphorylation during cell respiration, the source of energy is _____ whereas in photophosphorylation the source of energy is ______
Highly reduced organic compounds; light
The Embden-Meyerhof, Entner-Doudoroff and pentose phosphate pathways all bring about the reduction of coenzymes. The reduced coenzymes
provide reducing power to fuel subsequent reactions
The TCA cycle _____
Provides reducing power in the form of NADH and FADH2
The TCA cycles begins when _____
Pyruvate from the glycolytic pathway is oxidized to acetyl-CoA
T/F Oxidative decarboxylation takes place when pyruvate from the glycolytic pathway is oxidized, producing acetyl-CoA along with one CO2 and one NADH
Which of the following statements is true regarding the effect of electron transport chain length on energy production?
As electrons are passed from carrier to carrier, each oxidation releases enough energy to actively transport protons across a membrane, thus, the more carriers, the greater the proton motive force produced.
The oxidation of glucose to CO2 and H2O with the subsequent production of energy is best reflected in which of the following statements?
Glucose is oxidized in a stepwise fashion beginning with a glycolytic pathway and continuing with the TCA cycle where the remainder of the energy from the glucose is harnessed in reduced coenzymes
T/F The catabolism of glucose through a glycolytic pathway, followed by the TCA cycle and culminating in ATP production via the formation of a proton motive force in the electron transport chain, represents the overall reduction of glucose
The energy source for substrate-level phosphorylation differs from that of oxidative phosphorylation in that ________
OP is driven using energy provided by a proton motive force, whereas the energy to add a phosphate group to ADP during SLP comes from the direct transfer of a phosphate group from a molecule with a higher phosphate transfer potential than ATP
Chemolithotrophs obtain their energy from_____
inorganic molecules that are oxidized, providing electrons to create a proton motive force that drives oxidative phosphorylation