WorksheetsBIO150 Enzyme Exercise
Total questions: 40
Worksheet time: 45mins
The main function of an enzyme is to:
Act as a reactant
Speed up chemical reactions
Be consumed in a reaction
Act as a substrate
The enzyme-substrate interaction is explained by which theory where the substrate fits perfectly into the enzyme's active site?
Induced Fit Theory
Lock and Key Theory
Activation Energy Theory
Energy-Substrate Theory
The factor that does NOT affect enzyme activity is:
pH
Enzyme concentration
Activation energy
Light intensity
When the temperature exceeds the optimum for an enzyme, what happens?
The enzyme's activity increases
The enzyme becomes denatured
The substrate binds more effectively
The enzyme's active site becomes more flexible
An example of an organic cofactor is:
NAD+
Zn2+
FAD
Mg2+
Cofactors bind to enzymes in the form of:
Permanently
Only temporarily
Irreversibly
Only under extreme conditions
The active site of an enzyme is:
Nonspecific
Fixed in shape
Complementary to the substrate
Unaffected by pH
Competitive inhibition occurs when:
The inhibitor binds at a site other than the active site
The inhibitor binds tightly and irreversibly to the enzyme
The inhibitor competes with the substrate for the active site
The inhibitor increases the enzyme's activity
The effect of a non-competitive inhibitor on the enzyme is:
It competes with the substrate for the same active site
It alters the enzyme's shape without competing for the active site
It increases the enzyme's efficiency
It is always irreversible
Allosteric regulation affects enzyme activity by:
Increasing the rate of enzyme synthesis
Binding substrates at the active site
Modifying the enzyme's shape and activity
Preventing enzyme denaturation
Metabolism is defined as:
The breakdown of complex molecules
The total of all chemical reactions in a cell
The production of energy from sunlight
The process of cellular respiration
An enzyme classification that involves the transfer of functional groups is:
Oxidoreductases
Transferases
Hydrolases
Ligases
Increasing substrate concentration in an enzyme-catalyzed reaction will:
Decrease the rate of reaction
Increase the rate of reaction up to a saturation point
Denature the enzyme
Cause the reaction rate to remain constant immediately
An enzyme in its apoenzyme form is:
Inactive without its cofactor
More stable
Capable of catalyzing reactions without a cofactor
More active than the holoenzyme
Which type of inhibition cannot be overcome by increasing substrate concentration?
Competitive inhibition
Non-competitive inhibition
Irreversible inhibition
Feedback inhibition
During an exergonic reaction:
Energy is consumed to form bonds
Energy is released as the reaction proceeds
Energy is constant throughout the reaction
No energy change occurs
An example of an irreversible inhibitor is:
Ibuprofen
Cyanide
Penicillin
All of the above
Enzyme activity is influenced by temperature in the following way:
It increases the activation energy
It slows down the substrate's movement
It increases enzyme-substrate collisions
It has no effect on enzyme reactions
The binding of an inhibitor to the allosteric site results in:
Increased enzyme activity
Decreased enzyme activity
No effect on enzyme activity
A change in the substrate's shape
The specific region of an enzyme where the substrate binds is called the:
Active site
Allosteric site
Substrate pocket
Catalytic domain
When the enzyme-substrate complex forms, the result is:
The enzyme changes permanently
The substrate is broken down into product
The enzyme loses its specificity
The reaction is slowed down
The enzyme denatures when:
At high temperatures or extreme pH
Only under acidic conditions
At low temperatures
At moderate temperatures
The enzyme class involved in breaking down substances using water is:
Oxidoreductases
Hydrolases
Lyases
Ligases
The enzyme responsible for breaking down urea is:
Lactase
Urease
Amylase
Lipase
An irreversible inhibitor binds to an enzyme:
At a site other than the active site
Tightly, causing permanent damage to the enzyme's structure
Only temporarily
Reversibly
The class of enzymes involved in transferring electrons between molecules is:
Oxidoreductases
Transferases
Hydrolases
Isomerases
The specificity of an enzyme for a particular substrate is determined by:
The enzyme's temperature
The enzyme's active site shape
The coenzyme concentration
The enzyme's pH level
The enzyme activity decreases in the following condition:
High substrate concentration
Low enzyme concentration
Optimum pH
High temperature
The role of a coenzyme in enzyme catalysis is:
To bind tightly to the enzyme
To provide the enzyme with energy
To form part of the active site
To alter the shape of the substrate
The enzyme class involved in joining two molecules is
Ligases
Isomerases
Hydrolases
Lyases
Explain how enzymes catalyze chemical reactions and describe how substrates bind to the active site.
Describe what happens when enzymes are denatured due to changes in temperature or pH, and how this affects their activity.
How does enzyme concentration affect the rate of enzyme-catalyzed reactions, especially when the substrate is saturated?
What is enzyme specificity, and how do enzymes interact with only certain substrates?
Explain competitive inhibition and how it can be reversed by increasing substrate concentration.
What are the differences between coenzymes, prosthetic groups, and metal ions as cofactors in enzyme activity?
What is feedback inhibition, and how does it regulate enzyme activity in metabolic pathways?
What is the difference between catabolic and anabolic reactions, and how do enzymes facilitate each type?
How does substrate concentration affect enzyme activity, and what happens when saturation occurs?
Explain allosteric regulation and how activators and inhibitors influence enzyme activity.
