Energía de Activación y Estados Metaestables

Podcast

Play an AI-generated podcast conversation about this lesson

Download our mobile app to listen on the go

Get App

Questions and Answers

Match the descriptions to the appropriate states of molecules in a chemical reaction:

Reactants = Molecules that are thermodynamically unstable but lack sufficient energy to overcome the activation energy barrier. Transition state = The intermediate chemical stage that reactants must pass through, possessing higher free energy than initial reactants. Metastable state = Describes molecules that do not react at an appreciable rate on their own due to lack of sufficient energy. Products = The result of a chemical reaction between reactants.

Match the processes with how they overcome the activation energy barrier:

Catalysis = Provides a reactive surface that lowers the activation energy, enhancing reaction rate without being permanently changed or consumed. Thermal Activation = Increases the kinetic energy of molecules to overcome the activation energy barrier by simply increasing the temperature of the system. Quantum Tunneling = Matter behaves as both, particle-like and wave-like properties. In dehydrogenation reactions, hydrogen atoms tunnel through the barrier effectively without exceeding it. Without intervention = Reactions do not proceed at an appreciable rate unless the energy barrier is bypassed.

Match the terms to the biological catalyst:

Enzymes = Typically proteins that enhance the rate of a reaction by lowering the activation energy requirement. Active site = A specific region within an enzyme that substrates bind to and facilitates the catalytic event. Prosthetic groups = Cofactors, metal ions, or small organic molecules that are necessary for catalytic property. Ribozymes = RNA molecules with catalytic activity.

Connect the term to the proper function regarding enzyme specificity:

Substrate specificity = The ability of a certain enzyme to bind and react with only one or a few molecules. Lock-and-key model = Early mode that assumes, the enzyme is a rigid structure where the substrate fits. Induced-fit model = Substrate bindings at the active site distorts substrate and the enzyme to ensure a better fit. Group specificity = Some enzymes will act on a number of closely related molecules as long as they possess some common structural feature. Signup and view all the answers

Match the enzymes with the temperature dependence:

Homeotherms = Regulation of body temperature that is independet from environment temperature. Thermophilic bacterium = Enzyme temperature maximum reaction in about 75°C. Human enzyme = Enzyme temperature maximum reaction in about 37°C. Psychrophilic bacteria = Functions well in the temperature at low temperatures. Signup and view all the answers

Match the enzymes with its pH optima:

Pepsin = Protein-degrading enzymes in human that function in about 2 pH. Trypsin = Protein-degrading enzymes in human that function in a pH between 7 and 8. Enzymes = Most are active only within range of about 3-4 pH units. Activity = Dependent on having such groups present in a specific, either charged or uncharged form. Signup and view all the answers

Match the terms related to enzyme function to its correct definition:

Substrate binding = The interaction between the active site of an enzyme and a potential substrate through collisions that position substrate to catalyze the reaction. Bond distortion = The change in enzyme configuration, induced by initial substrate binding, that causes a tighter fit and weakens the substrates bonds. Proton transfer = The process by which an enzyme may accept or donate protons, modifying the chemical reactivity of the substrate due to the charged amino acids. Electron transfer = The process by which an enzyme may accept or donate electrons, forming temporary covalent bonds between the enzyme and its substrate. Signup and view all the answers

Match the terms related to active site to its best description:

Ribozyme = Catalytic RNA molecules. Ribosomal RNA = the catalytic activity was destroyed by treatment with ribonuclease but not by proteinase. Tetrahymena RNA = the removal of a internal segment if RNA from a specific ribosomal RNA precursor proceeds without protein. Ribonuclease = cleaves transfer RNA precursors to yield functional RNA molecules. Signup and view all the answers

Match each term to the definition:

Enzyme kinetics = The aspects of enzyme catalysis and rate of substrate conversions. Initial reaction velocity = Measurement of change in product concentration per unit. Vmax = Value that depends on the level of enzyme molecules. Satuation = Catalisyed reactions always become saturated at high substrate concentrations. Signup and view all the answers

Match the description, with the formula:

v = (Vmax [S]) / (Km + [S]) = Equation is known as the Michaelis–Menten equation, a central relationship of enzyme kinetics. v = (Vmax [S]) / Km = Describes what happens at very low substrate concentration. =Vmax = Describes what happens at very high substrate concentration. v = Vmax/ 2 = Describes what happens when Special case where [S] = Km. Signup and view all the answers

What is the meaning of ?max and Km??

Value = allows to estimate where along the Michaelis-Menten plot of an enzyme is functioning in a cell providing that the normal substrate concentration in the cell is known. value = estimate at what fraction of the maximum velocity the enzyme-catalyzed reaction is likely to be proceeding in the cell. Turnover number = expresses the rate at which substrate molecules are converted to product by a single enzyme molecule when the enzyme is operating at its maximum velocity. Constant = is the quotient of Vmax divided by [E], the concentration of the enzyme. Signup and view all the answers

Match the terms with the correct description:

Inhibitors = Substances in cells that can affect enzyme activity. Substrate analogues = These are compounds that resemble the usual substrate or the transition state closely enough to bind to the active site. Irreversible inhibitor = Binds to the enzyme covalently, causing permanent loss of catalytic activity. Reversible inhibitor = Binds to an enzyme in a noncovalent, dissociable manner. Signup and view all the answers

Match the best definition to allosteric:

Allosteric regulation = Important control whereby the rates of enzyme-catalyzed reactions are adjusted to meet cellular needs is. Allosteric enzymes = All can exist in two different forms. Allosteric effector = Regulation depends on the cellular concentration. Active form = Enzyme has a high affinity for its substrate leading to high activity. Signup and view all the answers

Match the descriptions to the appropriate states of molecules in a multistep enzyme reaction:

Substrate-Level Regulation = Regulation depends directly on interactions of substrates and products with its enzymes. Allosteric Regulation = Enzymes regulate with other mechanisms. Allosteric effector = Small organic molecule that regulates the activity of an enzymes. Feedback inhibition = Common mechanisms used by the cell for best interest. Signup and view all the answers

Classify the following as instances of positive cooperativity, negative cooperativity, or no cooperativity:

Positive cooperativity = binding of a substrate molecule to one subunit increases the affinity of other subunits for substrate. Negative cooperativity = substrate binding to one subunit reduces the affinity of the other sites for substrate. Allosteric = the substrate binds to the allosteric sites. No cooperativity = the binding of a substrate does not significantly affects the affinity of other subunits for subsequent binding. Signup and view all the answers

Connect the term to the description:

Covalent modification = Form of regulation affected by the addition o Removal of specific chemical groups through covalent bonding. Phosphorylation = Common process that occurs to hydroxyl groups of certain residues in the protein. Dephosphorylation = Removes a phosphoryl group from a phosphatased protein. Protein Kinases = Catalyze the phosphorylation of other enzymes. Signup and view all the answers

Put the enzyme in the correct catagory:

Catalyze phosphorylations = protein kinases. Removes phosphoryl groups = protein phosphatases. Liver glycogen phosphorylase, an allosteric enzyme = inhibited by glucose and ATP and activated by AMP Enzyme = most highly regulated catalyzes the initial step of a multistep sequence Signup and view all the answers

Match the definition:

Regulation = Often controlled by 2 are more regulatory mechanisms. Enzymes = Enzymes that are synthesized to create larger, catalytically inactive molecule called a zymogen. Proteolytic = kind of activation of involves the one-time, irreversible removal of a portion of the polypeptide chain by an appropriate proteolytic. Trypsin = Activates other zymogens by specific proteolytic cleavages . Signup and view all the answers

Match the term associated with 'ACE Inhibitors':

ACE inhibitors = Help lowering blood pressure by controlling the amount of angiotensin II and bradykinin in the blood. ACE = Inactivates bradykinin and, at the same time, increases the amount of angiotensin II, and these combined effects lead to a rise in blood pressure. Captopril = compound like captopril allows for treatments that decrease high blood pressure and prevent secondary heart attacks, congestive heart failure, and complications from diabetes. Brazilian pit = Used for analysis of chemical and discovery if ACE inhibitors. Signup and view all the answers

Relate to allosteric inhibition:

Allosteric control = is based on the binding of some modulator which is usually a small molecule to a site on the enzyme separate from the catalytic or substrate binding site-the allosteric site. Regulatory subunits = the binding of effector molecules to the allosteric sites affects the shape of the catalytic subunits as well. Positive Cooperatively = the binding of a substrate molecule to one subunit increases the affinity of other subunits for substrate. Negative cooperativity = substrate binding to one subunit reduces the affinity of the other sites for substrate. Signup and view all the answers

Match the enzymatic changes:

Add phosphoryl groups = phosphorylation. Remove phosphoryl groups = dephosphorylation. Changes in primary structure = proteolytic cleavage. Active = requires 2 interconvertible forms . Signup and view all the answers

Match the enzyme to the step in the reaction:

Kinase enzymes = catalyze phosphorylation of other enzymes (or proteins). Phosphatases enzymes = catalyze dephosphorylation of proteins. Reversible = is an important cellular regulatory mechanism. Most used = ATP for glucose. Signup and view all the answers

Flashcards

¿Qué es ΔG'?

Cambio en la energía libre que indica la posibilidad y magnitud de una reacción.

¿Qué son las enzimas?

Proteínas que actúan como catalizadores en las reacciones celulares.