Chapter 8 Textbook Q's Metabolism Flashcards
______ speed up the rate of the reaction without changing the ΔG for the reaction.
Enzymes speed up the rate of the reaction without changing the ΔG for the reaction.
______ is a macromolecule that acts as a catalyst, a chemical agent that speeds up a reaction without being consumed by the reaction.
enzyme
An enzyme _____change the ΔG for a reaction; it cannot make an endergonic reaction exergonic.
cannot
______ are very specific for the reactions they catalyze, they determine which chemical processes will be going on in the cell at any particular time.
enzymes
Instead of heat, organisms use _____ to speed up reactions.
enzymes
In general, the hydrolysis of ATP drives cellular work by __________.
releasing free energy that can be coupled to other reactions
_________ is key feature in the way cells manage their energy resources to do work, which is the use of an exergonic process to drive an endergonic one.
Energy coupling
______is responsible for mediating most energy coupling in cells, and in most cases it acts as the immediate source of energy (not a catalyst) that powers cellular work.
ATP
______ reaction absorbs free energy from its surroundings.
An endergonic reaction
____ reaction proceeds with a net release of free energy.
An exergonic reaction
the use of an exergonic process to drive an endergonic one.
energy coupling
______ reactions typically drive anabolic reactions.
Catabolic reactions typically drive anabolic reactions.
Catabolic: breaking down large substances into small
Anabolic: building large substances from smaller ones
______ reactions drive endergonic reactions.
Exergonic reactions drive endergonic reactions.
If chemical reactions in cells are at equilibrium, _______
the cell is dead
Endergonic and exergonic reactions
often occur together.
Metabolic pathways can be
both anabolic and catabolic.
ATP allosterically inhibits enzymes in ATP-producing pathways. The result of this is called __________.
feedback inhibition
Allosterically means relating to a change in a protein’s shape and activity that occurs when it binds with a substance at a site other than its active site.
_______ thereby prevents the cell from making more product than is necessary and thus wasting chemical resources.
Feedback inhibition
In _________, a metabolic pathway is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway.
feedback inhibition
the breakdown in structure of an enzyme
Denaturing
The energy in an ATP molecule is released through_______ of one of the _______ groups.
The energy in an ATP molecule is released through hydrolysis of one of the phosphate groups.
Excess ATP acts as an ________. It deactivates enzymes by reversibly changing their shape.
Excess ATP acts as an allosteric inhibitor. It deactivates enzymes by reversibly changing their shape.
In general, the hydrolysis of ATP drives cellular work by __________.
releasing free energy that can be coupled to other reactions
_____ pathways synthesize more complex organic molecules using the energy derived from ______pathways.
Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
metabolic pathways release energy by breaking down complex molecules to simpler compounds.
These degradative processes are called catabolic pathways, or breakdown pathways
A major pathway of catabolism is _______, in which the sugar glucose and other organic fuels are broken down in the presence of oxygen to carbon dioxide and water.
cellular respiration
___pathways: Energy that was stored in the organic molecules becomes available to do the work of the cell, such as membrane transport.
catabolic pathways
consume energy to build complicated molecules from simpler ones; they are sometimes called biosynthetic pathways.
Anabolic pathway
the synthesis of an amino acid from simpler molecules and the synthesis of a protein from amino acids.
anabolism
Energy released from the downhill reactions of _____ pathways can be stored and then used to drive the uphill reactions of _____ pathways.
Energy released from the downhill reactions of catabolic pathways can be stored and then used to drive the uphill reactions of anabolic pathways.
An exergonic (spontaneous) reaction is a chemical reaction that __________.
releases energy when proceeding in the forward direction
An exergonic reaction proceeds with a net release of
free energy (ΔG < 0)
every spontaneous process _____ the system’s free energy, and processes that have a positive or zero ΔG are never spontaneous.
decreases
An exergonic reaction __________ free energy, and an endergonic reaction __________ free energy.
releases; absorbs
The second law of thermodynamics states that ______ processes, those requiring no outside input of energy, increase the _______of the universe.
The second law of thermodynamics states that spontaneous processes, those requiring no outside input of energy, increase the entropy (disorder) of the universe.
Enzyme activity is affected by pH because __________.
high or low pH may disrupt hydrogen bonding or ionic interactions and thus change the shape of the active site
The activation energy is changed by the presence of an _____ in a reaction.
enzyme
The active site of an enzyme may resemble a groove or pocket in the surface of a protein into which the
substrate fits or binds for reactions
By converting sunlight to ________, a plant acts as an energy transformer, not an energy producer.
chemical energy
The first law of thermodynamics, the energy of the universe is constant:
Energy can be transferred and transformed, but it cannot be created or destroyed.
the first law of thermodynamics to biology: Energy can be freely transformed among different forms as long as
the total energy is conserved.
The role of ATP in cellular metabolism can best be characterized as the ______ released by ATP hydrolysis that may be coupled to an ______ process via the formation of a phosphorylated intermediate.
The role of ATP in cellular metabolism can best be characterized as the free energy released by ATP hydrolysis that may be coupled to an endergonic process via the formation of a phosphorylated intermediate.
Endergonic absorbs free energy from its surrounding
with the help of specific _______, the cell is able to use the energy released by ATP hydrolysis directly to drive chemical reactions that, by themselves, are ______.
enzymes, endergonic.
Endergonic absorbs free energy from its surrounding
If the ΔG of an endergonic reaction is less than the amount of energy released by ATP hydrolysis, then the two reactions can be coupled so that, overall, the coupled reactions are
exergonic.
reaction proceeds with a net release of free energy.
ATP adds _______ to chemical reactions.
free energy
ATP adds a _____ to a transport protein for this kind of work
phosphate
Chemical work is driven by ____ providing free energy to facilitate the formation of polymers from monomers.
ATP
Mechanical work is driven by ATP binding to
motor proteins.
True or False: If the entropy of a living organism is decreasing, then energy input into the organism must be occurring to drive the decrease in entropy.
T
A logical consequence of the loss of usable energy during energy transfer or transformation is that each such event makes the universe more ______.Called ______
disordered, entropy
The more randomly arranged a collection of matter is, the greater its ______. The second law of thermodynamics states that every energy transfer or transformation increases the _____ of the universe.
entropy
The depletion of chemical energy is accounted for by ____ generated during metabolism. On a larger scale, energy flows into most ecosystems in the form of light and exits in the form of _____.
heat
Competitive inhibitors bind to ________, while noncompetitive inhibitors bind to _________.
Competitive inhibitors bind to the active site of an enzyme while noncompetitive inhibitors bind to an enzyme away from the active site.
Which of the following is NOT a form of kinetic energy?
a) When the temperature of a substance rises causing the molecules of that substance to move faster.
b) When a hockey puck slides across the ice after being hit by a player.
c) When glucose molecules are broken down to create energy for cellular work.
d) When the molecules of the air vibrate transmitting soundwaves.
c) When glucose molecules are broken down to create energy for cellular work.
This is not a form of kinetic energy because it refers to the chemical potential energy stored in glucose molecules, which is released through metabolic processes like cellular respiration.
On the other hand:
(a) describes thermal energy, which is a form of kinetic energy. (b) describes mechanical energy, which is also kinetic. (d) describes sound energy, which involves the movement (vibration) of air molecules, making it kinetic energy.
Which of the following is an example of potential energy?
a) Water rushing over a water fall.
b) A glucose molecule.
c) A spring being released and expanding rapidly.
d) An ant foraging (moving around) for food.
b) A glucose molecule.
A glucose molecule stores chemical potential energy in its bonds, which can be released during cellular respiration to power biological processes.
The other options describe kinetic energy:
(a) Water rushing over a waterfall – This is mechanical kinetic energy due to the movement of water. (c) A spring being released and expanding rapidly – The stored potential energy is converted into kinetic energy when the spring moves. (d) An ant foraging for food – This involves kinetic energy because the ant is in motion.
Which of the following is NOT an example of a biological system?
a) A human eating a cheeseburger.
b) A coral reef where energy and mass both enter and exit.
c) The digestive system of an organism absorbing food energy and discarding food waste.
d) The universe where the amount of energy and mass is constant.
d) The universe where the amount of energy and mass is constant.
The universe is considered a closed system in which energy and mass are conserved, but it is not typically classified as a biological system because it encompasses all physical and non-biological phenomena.
The other options are biological systems because they involve the transfer and transformation of energy and matter within living organisms or ecosystems:
(a) A human eating a cheeseburger involves energy intake and metabolism. (b) A coral reef is an ecosystem where organisms exchange energy and matter. (c) The digestive system processes food, absorbs nutrients, and eliminates waste.
Your room getting messier is a
spontaneous process.
cleaning up your room, putting it back into order, that requires energy and work and that is a ______ process.
non-spontaneous
Spontaneous processes (messiness)_____ entropy naturally; non-spontaneous processes (cleaning) _____ entropy but need energy.
Spontaneous processes (messiness) increase entropy naturally; non-spontaneous processes (cleaning) decrease entropy but need energy.
Cleaning (_______ Process): To restore order (low entropy), you must expend energy and work to clean the room again. This is_______, requiring effort to decrease entropy.
Cleaning (Non-Spontaneous Process): To restore order (low entropy), you must expend energy and work to clean the room again. This is non-spontaneous, requiring effort to decrease entropy.
Clean Room (Low Entropy): Imagine cleaning your room on a weekend (e.g., Saturday or Sunday) to start the school week organized. This represents a highly ordered state with low entropy—everything is in place (e.g., bed made, clothes folded).
Clean Room (Low Entropy): Imagine cleaning your room on a weekend (e.g., Saturday or Sunday) to start the school week organized. This represents a highly ordered state with low entropy—everything is in place (e.g., bed made, clothes folded).
Natural Disorder (________ Process): Over the week (Monday to Thursday), the room naturally becomes messier without effort—clothes pile up, books scatter, etc. This is a _______ process that increases entropy (disorder) because it happens without energy input.
Natural Disorder (Spontaneous Process): Over the week (Monday to Thursday), the room naturally becomes messier without effort—clothes pile up, books scatter, etc. This is a spontaneous process that increases entropy (disorder) because it happens without energy input.
First Law of Thermodynamics
● “Energy ____ be transferred and transformed, but it ____ be created or destroyed.”
□ AKA: The Principle of _____ of Energy.
□ The TOTAL amount of energy in the universe does ____ change.
First Law of Thermodynamics
● “Energy can be transferred and transformed, but it cannot be created or destroyed.”
□ AKA: The Principle of Conservation of Energy.
□ The TOTAL amount of energy in the universe does not change.
Entropy
●A measure of ____________, or randomness; the greater the disorder, the __________ the entropy.
●The “natural tendency” of reactions is to move the Universe toward a state of ___________________ entropy (disorder).
□ Reactions can decrease entropy of a system with an ______________ input
● A measure of disorder, or randomness; the greater the disorder, the higher the entropy.
● The “natural tendency” of reactions is to move the Universe toward a state of increased entropy (disorder).
□ Reactions can decrease entropy of a system with an energy input.
Second Law of Thermodynamics
●2nd law: 100% efficient energy conversion is impossible since ___________ energy is lost, increasing universal entropy.
□ Heat: form of _________________ energy that is transferred between two objects with different temperatures
● 2nd law: 100% efficient energy conversion is impossible since some energy is lost, increasing universal entropy.
□ Heat: form of kinetic energy that is transferred between two objects with different temperatures.
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
a) It is used to power yet more cellular work in the surroundings.
b) It is captured to store energy as more heat in the system.
c) It is used to generate ADP.
d) It is lost to the environment
d) It is lost to the environment.
When chemical, transport, or mechanical work is done by an organism, the energy that is not used for these processes is often released as heat, which is then lost to the environment. This is consistent with the Second Law of Thermodynamics, where energy conversions are never 100% efficient, and some energy is always dissipated as heat.
Which of the following statements is true regarding how energy moves up the food chain?
a) All of the energy is not transferred from producer to consumer because some of the energy is destroyed.
b) All of the energy is transfer from producer to consumer.
c) All of the energy is not transferred from producer to consume because some of the energy is lost as heat.
d) None of the above
c) All of the energy is not transferred from producer to consumer because some of the energy is lost as heat.
As energy moves up the food chain, not all of the energy from producers (plants) is transferred to consumers (herbivores, carnivores). Some energy is lost as heat due to metabolic processes, as described by the Second Law of Thermodynamics. This explains why only a small portion of the energy is passed on to higher trophic levels.
●Chemical reactions consist of the making and/or breaking of ________________ bonds leading to changes in matter.
□ Reactants: the ______________ material in a chemical reaction.
□ Products: the ________________ material in a chemical reaction.
● Chemical reactions consist of the making and/or breaking of chemical bonds leading to changes in matter.
□ Reactants: the starting material in a chemical reaction.
□ Products: the ending material in a chemical reaction.
●Chemical Reactions are categorized into 2 groups based on ________________ requirement:
1) _____dergonic Reactions: requires an input of energy (energy ENters the reaction).
2) _____ergonic Reactions: releases energy (energy EXits the reaction).
Chemical reactions are categorized into 2 groups based on energy requirement:
Endergonic Reactions: requires an input of energy (energy enters the reaction). Exergonic Reactions: releases energy (energy exits the reaction).
Which of the following statements is true for all exergonic reactions?
a) The products have more total energy than the reactants.
b) The reaction proceeds with a net loss of free energy.
c) The reaction goes only in a forward direction: all reactants will be converted to products.
d) A net input of energy from the surroundings is required for the reactions to proceed
b) The reaction proceeds with a net loss of free energy.
Exergonic reactions are characterized by a release of energy, meaning the products have less free energy than the reactants. This results in a net loss of free energy during the reaction.
Recall: Adenosine Triphosphate (________): a ____________ energy molecule used to “power” cellular activities.
●There are 3 primary components of an ATP molecule:
1) Chain of ____ phosphate groups 2) __________ sugar 3) ________________ nitrogenous base
Recall: Adenosine Triphosphate (ATP): a high-energy molecule used to “power” cellular activities.
● There are 3 primary components of an ATP molecule:
Chain of 3 phosphate groups Ribose sugar Adenine nitrogenous base
ATP Hydrolysis: process of breaking bonds between ___________________ groups generating chemical energy & ADP.
□ Sometimes ADP can be hydrolyzed to form AMP
ATP Hydrolysis: process of breaking bonds between phosphate groups, generating chemical energy & ADP.
□ Sometimes ADP can be hydrolyzed to form AMP.
Which of the following statements is true?
a) ADP contains more potential energy than ATP.
b) Following hydrolysis, ATP can give off one phosphate group and usable energy, whereas ADP cannot.
c) The energy produced by ATP comes from the breaking of the bond between two phosphate groups.
d) AMP and ADP contain the same amount of potential energy.
c) The energy produced by ATP comes from the breaking of the bond between two phosphate groups.
When ATP is hydrolyzed, the bond between the second and third phosphate groups is broken, releasing energy that the cell can use. This is the primary source of energy in many biological processes.
ATP (Adenosine Triphosphate) is the primary energy carrier in cells. It stores energy in the high-energy bonds between its phosphate groups and releases this energy when the bonds are broken (usually between the second and third phosphate groups). ADP and inorganic phosphate (Pi) are products after ATP is used for energy, and they can be recharged to form ATP again in the cellular processes.
ATP (Adenosine Triphosphate) is the primary energy carrier in cells. It stores energy in the high-energy bonds between its phosphate groups and releases this energy when the bonds are broken (usually between the second and third phosphate groups). ADP and inorganic phosphate (Pi) are products after ATP is used for energy, and they can be recharged to form ATP again in the cellular processes.
How does ATP participate in energy-coupling reactions?
a) Hydrolysis of ATP fuels endergonic reactions.
b) Hydrolysis of ADP fuels endergonic reactions.
c) Synthesis of ATP fuels exergonic reactions.
d) Synthesis of ADP fuels exergonic reactions
a) Hydrolysis of ATP fuels endergonic reactions.
ATP hydrolysis (breaking down ATP into ADP and inorganic phosphate) releases energy, which can then be used to drive endergonic (energy-requiring) reactions in the cell. This process is a key example of energy coupling, where the energy released from an exergonic reaction (ATP hydrolysis) is used to power an endergonic reaction.
Energy Coupling
●When energy released by an _________________ reaction is used to power/drive an endergonic reaction.
□ ATP _______________ is coupled to endergonic reactions to provide the energy input they need to proceed
Energy Coupling
● When energy released by an exergonic reaction is used to power/drive an endergonic reaction.
□ ATP hydrolysis is coupled to endergonic reactions to provide the energy input they need to proceed.
___is
●The transfer of a phosphate group from ATP to another molecule to provide energy.
●____ by ATP hydrolysis can have a wide range of effects:
1) Activates a target molecule to react. 2) Changes the conformation of a target protein.
Phosphorylation
● The transfer of a phosphate group from ATP to another molecule to provide energy.
● Phosphorylation by ATP hydrolysis can have a wide range of effects:
Activates a target molecule to react. Changes the conformation of a target protein.
Enzyme: molecule that catalyzes (or “___________-_____”) a chemical reaction _____________ being consumed.
□ Substrates: the reactants of a chemical reaction that is catalyzed by an enzyme.
Enzyme: molecule that catalyzes (or “speeds up”) a chemical reaction without being consumed.
□ Substrates: the reactants of a chemical reaction that is catalyzed by an enzyme.
Enzymes have a variety of functions in living cells including:
1) Building ____________ ; Copying ________ ; ________________ food.
Building molecules; Copying DNA; Breaking down food.
Which of the following are examples of the functions of enzymes?
a) A lactase enzyme breaking down lactose sugar in the small intestine.
b) A DNA polymerase enzyme synthesizing new strands of DNA.
c) A lipase enzyme breaking down fats (lipids) in the small intestine.
d) A helicase enzyme unraveling DNA so it can be replicated.
e) All of the above.
e) All of the above.
●Enzyme Activity: a measure of the amount of ______________ an enzyme can produce in a certain amount of time.
●Many environmental factors affect an enzyme’s activity:
1) ____________________ 2) ______ 3) __________________ of reactants
Enzyme Activity: a measure of the amount of product an enzyme can produce in a certain amount of time.
● Many environmental factors affect an enzyme’s activity:
Temperature pH Concentration of reactants
Several environmental factors (ex. high temp. or acidity) can cause a protein or enzyme to ________________.
□ Denatured enzymes lose their shape & would therefore have ___________________ activity
Several environmental factors (ex. high temp. or acidity) can cause a protein or enzyme to denature.
□ Denatured enzymes lose their shape & would therefore have reduced or no activity.
Certain species of bacteria are able to perform metabolic reactions (involving enzymes) in hot springs because:
a) They are able to maintain a lower internal temperature.
b) High temperatures make catalysis unnecessary.
c) Their enzymes have high optimal temperatures.
d) Their enzymes are completely insensitive to temperature
c) Their enzymes have high optimal temperatures.
Certain species of bacteria, such as thermophiles, have enzymes that are adapted to function at high temperatures, making them capable of performing metabolic reactions in hot springs. These enzymes are stable and active at elevated temperatures, which would denature enzymes from other organisms.
Enzyme-Substrate Complex
●A substrate binds an enzyme at the active site, forming the Enzyme-Substrate _________________ (______).
□ Active Site: specific region of an enzyme that ___________ substrates.
□ After catalysis, _______________ are released from the active site but the enzyme is unchanged.
● A substrate binds an enzyme at the active site, forming the Enzyme-Substrate complex (ESC).
□ Active Site: specific region of an enzyme that binds substrates.
□ After catalysis, products are released from the active site but the enzyme is unchanged.
Cofactors
●Some enzymes require _________________: non-protein substances required for catalysis to occur (ex. metal ions).
□ Cofactors are NOT consumed in the reaction.
□ Coenzyme: an organic molecule cofactor derived from vitamins.
EXAMPLE: Cofactors can assist in substrate binding
Cofactors
● Some enzymes require cofactors: non-protein substances required for catalysis to occur (ex. metal ions).
□ Cofactors are NOT consumed in the reaction.
□ Coenzyme: an organic molecule cofactor derived from vitamins.
EXAMPLE: Cofactors can assist in substrate binding.
The organic non-protein components that aid in enzyme catalysis are called:
a) Reactants. b) Cofactors. c) Coenzymes. d) Substrates. e) Products
c) Coenzymes.
Coenzymes are organic non-protein molecules that assist enzymes in catalyzing reactions. They often help in the transfer of chemical groups or electrons during enzymatic processes.
CONCEPT: ENZYME INHIBITION
●Enzyme Inhibitors: compounds that interfere with & selectively ______________ the catalysis of specific enzymes.
1) Competitive Inhibitors: compete with the substrate for a position in the free enzyme’s ______________ site.
□ Can only bind when the active site is ______________.
2) Noncompetitive Inhibitor: does not compete with the substrate & binds at an _________________ site on the enzyme.
□ Allosteric site: an alternative site for inhibitor binding that is _______ in the active site.
● Enzyme Inhibitors: compounds that interfere with & selectively block the catalysis of specific enzymes.
Competitive Inhibitors: compete with the substrate for a position in the free enzyme’s active site. □ Can only bind when the active site is unoccupied. Noncompetitive Inhibitor: does not compete with the substrate & binds at an allosteric site on the enzyme. □ Allosteric site: an alternative site for inhibitor binding that is distinct from the active site.
Which of the following statements correctly describes competitive inhibition?
a) A competitive inhibitor binds to the substrate and inhibits it from binding to the active site of the enzyme.
b) A competitive inhibitor binds to a site other than the active site and inhibits the substrate from binding.
c) A competitive inhibitor binds to the active site and degrades the enzyme.
d) A competitive inhibitor binds to the active site of an enzyme and inhibits the substrate to bind.
d) A competitive inhibitor binds to the active site of an enzyme and inhibits the substrate from binding.
In competitive inhibition, the inhibitor competes with the substrate for binding to the enzyme’s active site, preventing the substrate from binding and thus inhibiting the enzyme’s activity.
How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?
a) By binding to the active site of the enzyme, thus preventing binding of the normal substrate.
b) By binding to an allosteric site, thus changing the shape of the active site of the enzyme.
c) By decreasing the free-energy change of the reaction catalyzed by the enzyme.
d) By binding to the substrate, thus changing its shape so that it no longer binds to the active site of the enzyme.
b) By binding to an allosteric site, thus changing the shape of the active site of the enzyme.
Noncompetitive inhibitors bind to an allosteric site (a site other than the active site) on the enzyme. This binding changes the shape of the enzyme, including the shape of the active site, making it less effective at catalyzing the reaction, even though the substrate can still bind.
Which of the following types of enzyme inhibition is overcome by increasing the substrate concentration?
a) The need for a coenzyme. c) Competitive inhibition.
b) Noncompetitive inhibition. d) None of the above
c) Competitive inhibition.
In competitive inhibition, increasing the substrate concentration can overcome the inhibition because the higher concentration of substrate increases the likelihood of the substrate binding to the active site, rather than the inhibitor. This is not the case with noncompetitive inhibition, where the inhibitor binds to a different site on the enzyme and changes its shape, making it less effective regardless of substrate concentration.
Which of the following statements is TRUE regarding anabolic pathways?
a) They are used for digesting sugars.
b) They consume energy to build up polymers from monomers.
c) They release energy by breaking down polymers into monomers.
d) They increase the entropy of the organism
b) They consume energy to build up polymers from monomers.
Anabolic pathways are constructive metabolic processes that require energy to build complex molecules (polymers) from simpler ones (monomers). These pathways are typically endergonic, meaning they absorb energy, such as in the synthesis of proteins, nucleic acids, and other macromolecules.
Which of the following terms specifically describes the metabolic process of breaking down large molecules?
a) Catabolism. b) Metabolism. c) Anabolism. d) Dehydration
a) Catabolism.
Catabolism refers to the metabolic process of breaking down large molecules into smaller ones, often releasing energy in the process. This is the opposite of anabolism, which is the process of building complex molecules from simpler ones.
●There are _______ types of metabolic pathways:
1) _______abolic Pathways (Catabolism): releases energy by breaking-__________ molecules into smaller ones.
2) Anabolic Pathways (Anabolism): spends energy to build-_______ larger molecules (like DNA & proteins)
There are two types of metabolic pathways:
Catabolic Pathways (Catabolism): releases energy by breaking down molecules into smaller ones. Anabolic Pathways (Anabolism): spends energy to build up larger molecules (like DNA & proteins).
●Metabolism: _________ of an organism’s chemical reactions.
□ Metabolic _____________: series of reactions that alters a substrate multiple times before the final product
● Metabolism: the sum of an organism’s chemical reactions.
□ Metabolic pathway: series of reactions that alters a substrate multiple times before the final product.
Which of the following is TRUE about feedback inhibition?
a) Feedback inhibition has no physiological importance.
b) Multiple products are required for feedback inhibition.
c) Feedback inhibition of a pathway can only be accomplished by the products of that pathway.
d) Feedback inhibition involves products binding to the active site to prevent enzyme activity.
c) Feedback inhibition of a pathway can only be accomplished by the products of that pathway is the most accurate answer, as it highlights that feedback inhibition relies on the end products of the pathway, which act to regulate the pathway itself.
________ is when the product of a biochemical pathway activates the production of itself.
a) Negative feedback inhibition. c) Substrate feedback inhibition.
b) Positive feedback. d) Product feedback inhibition.
b) Positive feedback.
Positive feedback occurs when the product of a biochemical pathway activates the production of more of itself, amplifying the process rather than inhibiting it. This is in contrast to negative feedback, which inhibits the process to maintain homeostasis.
Negative Feedback
●When the final product of a metabolic pathway ______________ an earlier step in the same pathway.
EXAMPLE: Negative Feedback acts like the “red light” to inhibit (-) metabolic pathways.
Negative Feedback
● When the final product of a metabolic pathway inhibits an earlier step in the same pathway.
EXAMPLE: Negative Feedback acts like the “red light” to inhibit (-) metabolic pathways, helping maintain balance and prevent overproduction.
Positive Feedback
●When the final product of a metabolic pathway ________________ an earlier step in the same pathway.
EXAMPLE: Positive Feedback acts like the “green light” to further stimulate (+) metabolic pathways.
Positive Feedback
● When the final product of a metabolic pathway stimulates an earlier step in the same pathway.
EXAMPLE: Positive Feedback acts like the “green light” to further stimulate (+) metabolic pathways, often amplifying the process.
