Enzymes Flashcards
What is an Oxidoreductase?
Enzyme that transfers electrons in redox reactions.
What is a Dehydrogenase?
Transfers hydrogen atoms in a reaction.
What is a Transferase?
Transfers functional groups between molecules.
What is a Hydrolase?
Breaks bonds using water (hydrolysis).
What is a Lyase?
Cleaves bonds without hydrolysis or oxidation.
What is a Ligase?
Joins molecules together using ATP.
What is an Isomerase?
Changes substrates into their isomeric forms.
What is a Competitive Inhibitor?
Molecule that mimics substrate and blocks enzyme activity.
What is a Noncompetitive Inhibitor?
Molecule that binds to an enzyme at a different site, altering its function.
What is Enzyme Repression?
Regulatory mechanism where excess product stops enzyme production.
What is NAD?
Most common electron carrier in metabolic reactions.
What is Aerobic Metabolism?
Oxygen is the final electron acceptor, producing 36-38 ATP.
What is Anaerobic Metabolism?
Final electron acceptor is an organic or inorganic compound, producing 2-36 ATP.
What is Fermentation?
Uses organic compounds as electron acceptors, producing ATP, alcohols, and acids.
What is Alcoholic Fermentation?
Converts pyruvate into ethanol and CO2.
What is Homolactic Fermentation?
Reduces pyruvate to only lactic acid.
What is Heterolactic Fermentation?
Converts glucose into lactic acid, acetic acid, and CO2.
What is Mixed Acid Fermentation?
Converts pyruvate into multiple types of acids.
What is Chemiosmosis?
Process where hydrogen ions create a concentration gradient for ATP production.
What is the Terminal Step of ETS?
Cytochrome oxidase picks up hydrogen and forms water with oxygen.
What are Lipases?
Break down fats into glycerol, which enters glycolysis.
What is Beta Oxidation?
Oxidation of fats to generate energy.
What are Proteases?
Break down proteins into amino acids.
What is Deamination?
Removal of amino groups from amino acids.
What is Amphibolism?
Pathways that integrate catabolism and anabolism.
What is the Light Dependent Reaction?
Catabolic reaction that requires light for photosynthesis.
What is the Light Independent Reaction?
Anabolic reaction that uses Calvin cycle for carbon fixation.
What is metabolism?
All chemical reactions and workings of a cell.
Define anabolism.
Synthesis of cell molecules and structures.
Define catabolism.
Break the bond of larger molecules to release energy.
What are enzymes?
Proteins that may require cofactors and act as organic catalysts.
What is the role of enzymes in chemical reactions?
Lower activation energy required for chemical reactions to proceed.
List some unique characteristics of enzymes.
- Shape
- Specificity
- Function
What is the size relationship between enzymes and their substrates?
Enzymes are much larger in size than their substrates.
How do enzymes affect metabolic reactions?
Enable metabolic reactions to proceed at a speed compatible with life.
What factors greatly affect enzymes?
Temperature and pH.
What is an apoenzyme?
Protein portion of the enzyme.
Define cofactor.
Non-protein portion of the enzyme.
What is a coenzyme?
Organic factors that work with apoenzymes to alter substrates.
What is a simple enzyme composed of?
Consists of protein alone.
What is a substrate?
Molecule upon which enzymes act.
What are enzymes?
Enzymes are biological catalysts that speed up chemical reactions in living organisms.
True or False: Enzymes are consumed in the reactions they catalyze.
False
What is the active site of an enzyme?
The active site is the region on the enzyme where substrate molecules bind and undergo a chemical reaction.
Fill in the blank: Enzymes are made up of ______.
proteins
Which factor does NOT affect enzyme activity?
The color of the enzyme
What is the role of a substrate in an enzymatic reaction?
The substrate is the reactant that an enzyme acts upon.
What term describes the maximum rate of reaction for an enzyme?
Vmax
True or False: All enzymes require cofactors to function.
False
What is a cofactor?
A cofactor is a non-protein chemical compound that is required for the enzyme’s activity.
Which of the following is an example of an enzyme? A) Amylase B) Glucose C) Starch
A) Amylase
What does the term ‘enzyme specificity’ refer to?
Enzyme specificity refers to the ability of an enzyme to choose exact substrates from a group of similar chemical molecules.
Fill in the blank: Enzymes lower the _______ energy of a reaction.
activation
What is an enzyme inhibitor?
An enzyme inhibitor is a molecule that decreases or stops the activity of an enzyme.
True or False: Competitive inhibitors bind to the active site of an enzyme.
True
What is the difference between competitive and non-competitive inhibitors?
Competitive inhibitors bind to the active site, while non-competitive inhibitors bind to another part of the enzyme.
What is the effect of temperature on enzyme activity?
Enzyme activity typically increases with temperature up to a certain point, after which it decreases due to denaturation.
Fill in the blank: The pH level can affect enzyme activity; most enzymes work best at a pH of around ______.
7
What is enzyme denaturation?
Enzyme denaturation is the process in which the enzyme loses its three-dimensional structure, leading to loss of activity.
What is the term for the model that describes how enzymes and substrates fit together?
Induced fit model
True or False: Enzymes can catalyze multiple types of reactions.
False
What is an allosteric site?
An allosteric site is a specific location on an enzyme where a molecule can bind, affecting the enzyme’s activity.
Fill in the blank: Enzymes can be regulated by molecules called ______.
effectors
Which enzyme is responsible for breaking down hydrogen peroxide?
Catalase
What is the significance of enzyme kinetics?
Enzyme kinetics studies the rates of enzyme-catalyzed reactions and how they change in response to changes in conditions.
What does Km represent in enzyme kinetics?
Km is the Michaelis constant, representing the substrate concentration at which the reaction rate is half of Vmax.
True or False: Enzymes can only function within a narrow range of conditions.
True
