Enzymes Overview Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What role do enzymes play in chemical reactions?

They decrease the overall energy of the system.

They are consumed in the reactions.

They increase the reaction rate by decreasing activation energy. (correct)

They change the equilibrium of the reactions.

Which of the following is NOT a classification of enzymes?

Hydrolases

Oxidoreductases

Transferases

Substratases (correct)

What property is characteristic of enzymes regarding their specificity?

They have substrate specificity and can only use specific molecules. (correct)

They can catalyze any reaction.

They have no preference for their substrates.

They can function across different types of reactions without limitations.

What is the maximum rate increase that enzyme-catalyzed reactions can achieve compared to uncatalyzed reactions?

10^3 to 10^8 times faster Signup and view all the answers

Which statement about ribozymes is correct?

Ribozymes are catalytic RNA molecules that act as biocatalysts. Signup and view all the answers

Which factor can influence enzyme activity?

Temperature Signup and view all the answers

How do enzymes affect the activation energy of a reaction?

They decrease activation energy to facilitate reactions. Signup and view all the answers

Which enzyme is known as one of the fastest and hydrates a significant number of CO2 molecules per second?

Carbonic anhydrase Signup and view all the answers

What is the definition of activity in relation to enzyme function?

The speed at which substrates are converted to products. Signup and view all the answers

What is the term for the protein part of an enzyme?

Apoenzyme Signup and view all the answers

Which factor does NOT affect enzyme activity?

Enzyme mass Signup and view all the answers

The optimum temperature for enzyme activity in humans generally falls within which range?

35-40 °C Signup and view all the answers

What does Km represent in enzyme kinetics?

The affinity of the enzyme for the substrate. Signup and view all the answers

Which type of inhibitor permanently prevents enzyme activity?

Irreversible inhibitor Signup and view all the answers

Which statement accurately describes the role of cofactors in enzymes?

They assist in enzyme function but are not proteins. Signup and view all the answers

What is the term for substances that decrease the velocity of an enzyme-catalyzed reaction?

Inhibitors Signup and view all the answers

Study Notes

Enzymes

Enzymes are biocatalysts, speeding up biochemical reactions.
They are proteins (most cases) or ribozymes (RNA).
Enzymes lower activation energy, making reactions proceed faster.
They are not consumed in reactions.
Enzymes have specificity for reactions and substrates.
Enzyme activity depends on factors like concentration, temperature, pH, inhibitors, and cofactors.
Enzymes are composed of an apoenzyme and a cofactor or coenzyme.
The combination of the apoenzyme and cofactor forms a holoenzyme.
The active site of an enzyme interacts with the substrate.
Reaction velocity is a measure of enzyme activity.
Optimal temperature and pH levels are optimal for enzyme function.
Enzyme inhibitors can decrease reaction velocity.
Enzyme kinetics describe how enzymes interact with substrates, and Km is a measure of enzyme affinity.
Enzyme regulation includes changes in enzyme amount or modification, and compartmentalization.
Isozymes are different forms of the same enzyme, with different structures and functions.
Isozymes can be seen in different areas of the body.

Learning Objectives

Students will be able to describe enzymes and their properties.
Students will be able to list the classifications of enzymes.
Students will be able to explain factors affecting enzyme activity.
Students will be able to expalin the relationship between Km and enzyme activity.
Students will be able to describe and explain enzyme inhibition.

Metabolic Reactions

Enzymes facilitate both anabolic and catabolic reactions.
Enzymes speed up reactions by lowering activation energy.
Classic biochemical reaction has an enzyme that speeds it up.
Enzymes can modify or transport substrate molecules.
With some specific molecules, enzymes aid in different processes.

Glycolysis

Glycolysis is a series of enzymatic reactions converting glucose into pyruvate.
Several enzymes are involved, each catalyzing a specific step.

Activation Energy

Activation energy is the energy required for a reaction to start.
Enzymes lower the activation energy, thus making it easier for the reaction to start.
Enzymes are not consumed during the reaction process.
Activation energy is the minimal amount of needed energy for the reaction to start.

Activation Energy and Catalysts

Catalysts, including enzymes, increase the reaction rate.
Catalysts do not change the reaction or reaction equilibrium.
Catalysts lower activation energy, making reactions happen faster.
Catalysts remain unchanged at the end of the reaction.

Enzymes (Page 8)

Enzymes are biocatalysts that speed up reactions.
Substrates bind to the active site.
Enzymes increase the reaction rate for substrate to product conversion.

Properties of Enzymes

Most enzymes are proteins.
Ribozymes are catalytic RNAs.
Enzymes change the reaction rate.
Enzymes have specificity for substrates and the reaction.
Enzymes cause the amount of reaction to increase, but don't change the equilibrium.

Efficiency

Enzyme-catalyzed reactions are significantly faster than uncatalyzed reactions.
Carbonic anhydrase is a highly efficient enzyme.

Specificity

Reaction specificity describes the type of reaction an enzyme catalyzes.
Substrate specificity describes the specific types of molecules enzymes use.

Enzyme Nomenclature: Classification

Enzymes are classified according to their function and the types of reactions they catalyze.
An enzyme is listed based on its function. This determines the classification of the enzyme.

ExploreNZ - The Enzyme Database (Page 13)

This database organizes enzymes by class, subclass, and sub-subclass.
Allows users to search and find information on enzymes.
Provides complete classification tree.

Enzyme Structure

Apoenzyme = protein part
Cofactor = non-protein part
Holoenzyme = catalytically active form
Active site = the location of the substrate binding and reaction.

Enzyme Structure: Active Site

Active site is composed of many amino acids.
Amino acids in active site bind to the substrates.

Enzyme Activity

Enzyme activity is measured in units like U/min or µmol/min.
Activity is a measure of speed.
Enzyme activity converts the substrate into product in a certain time.

Factors Affecting Enzyme Activity

Enzyme and substrate concentration affect reaction rate.
Temperature affects enzyme structure and function.
pH affects enzyme structure and function.
Inhibitors affect enzyme function.
Ionic bonds and denaturation change shape of enzyme.

Enzyme Concentration

Increasing enzyme concentration increases reaction rate to products.
Increase in enzyme and substrate concentrations increases reaction velocity and product amount.

Substrate Concentration

Increasing substrate concentration increases reaction rate until the active sites become saturated.

Temperature

Increasing temperature generally increases reaction rate but above a certain point, it may decrease activity due to denaturation.
Optimum temperature is best for enzyme function. Different enzymes have different optimum temps.

pH

Enzymes have an optimal pH range.
Different enzymes have different optimal pH values; they vary in their activity levels and change according to the change in pH.
Optimum pH changes activity of enzymes.

Inhibitors

Inhibitors decrease enzyme activity.
Inhibitors are substances that decrease reaction velocity.
Inhibitors can be reversible or irreversible.
Different types of inhibitors impact the enzyme in different ways.

Reversible Inhibition

Competitive inhibitors compete with the substrate for the active site.
Noncompetitive inhibitors bind to the enzyme at a site other than the active site.
Uncompetitive inhibitors bind to the enzyme-substrate complex, decreasing the reaction rate.
All types of reversible inhibitors decrease enzyme activity.

Enzyme Kinetics and Km

Km is a measure of enzyme affinity for its substrate.
Affinitive describes the substrate-enzyme bond.
High Km values indicate low affinity and vice-versa.
Vmax represents the maximum velocity or speed of an enzyme-catalyzed reaction.

Km, A Clinical Example

Km values can be clinically important and are used to measure the toxicity of the substrate.
Km can be used to measure the toxicity of certain substrates.

Regulation of Enzyme Activity

Enzyme activity can be regulated by changing enzyme amount (synthesis and degradation).
Enzyme activity can be regulated by covalent and non-covalent modifications.
Enzyme location, or compartmentalization, affects activity.
Different forms of the same enzyme can exist (isozymes).
Factors including regulation by covalent modifications, protein interactions, and feed-forward and feedback inhibition.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on enzymes, their functions, and kinetics with this concise quiz. Learn about enzyme specificity, factors affecting activity, and the structure of holoenzymes. Perfect for biology students looking to reinforce their understanding of this essential topic.