What are enzymes?
Proteins that act as catalysts in biochemical reactions.
Enzymes speed up reactions without being consumed in the process.
What are the basic building blocks of proteins?
Amino acids.
Amino acids are joined together by peptide links to form proteins.
What is a peptide link?
A bond formed between two amino acids with the removal of a water molecule (condensation).
Peptide links are essential for protein structure.
List the four groups attached to the central alpha carbon atom in alpha amino acids.
- A hydrogen atom
- An amino group
- A carboxyl group
- A variable R group
What is primary structure in proteins?
The specific sequence of amino acids in the protein strand.
Maintained by strong covalent bonds (peptide links).
What are the two types of secondary structure in proteins?
- Alpha helix
- Beta pleated sheet
Held in place by hydrogen bonds between backbone molecules.
What is tertiary structure in proteins?
The three-dimensional folding of protein chains due to various bonds between R groups.
Includes hydrogen bonds, ionic bonds, disulphide bridges, and Van der Waals interactions.
What is quaternary structure in proteins?
The structure formed when multiple protein strands bind together.
Example: Hemoglobin is made up of four polypeptide chains.
What is the active site of an enzyme?
The area of an enzyme that the substrate binds to.
The shape of the active site is critical for the enzyme’s function.
What happens when an enzyme is denatured?
The active site is altered, preventing binding with the substrate.
Denaturation disrupts the enzyme’s ability to function.
What is denaturation?
A change in the tertiary structure of a protein molecule.
Can be caused by extreme pH or temperature conditions.
What is a catalyst?
A substance that speeds up a chemical reaction while remaining unchanged.
Enzymes serve as biological catalysts.
What is collision theory?
The idea that reactants must collide with sufficient energy and the correct orientation for a reaction to occur.
What is activation energy?
The minimum kinetic energy required by the substrate for a chemical reaction to occur.
List four ways to increase the rate of a chemical reaction.
- Increasing the concentration of reactants
- Increasing the surface area of a solid reactant
- Increasing the temperature
- Adding a catalyst
What role does a catalyst play in a reaction?
Lowers the activation energy needed for a successful reaction.
This increases the proportion of substrate with sufficient energy to react.
What is an enzyme-substrate complex?
The formation when the active site of an enzyme binds with the substrate.
This is crucial for the chemical reaction to take place.
What factors can affect enzyme activity?
- Concentration of substrate
- Concentration of enzyme
- Temperature
- pH
What happens to enzyme activity at high temperatures?
The rate of reaction decreases as heat breaks hydrogen bonds, altering the enzyme’s shape.
At very high temperatures, enzymes become denatured.
What is the optimum temperature for enzymes in the human body?
About 40°C.
What is the effect of pH on enzyme activity?
Enzymes have an optimum pH; extreme pH levels can lead to denaturation, affecting function.
Most human enzymes work best around pH 7 or 8.
Why is measuring initial rates of reaction important?
Reactant concentrations change over time, affecting reaction rates.
In enzyme-catalyzed reactions, substrate concentration decreases as products are formed.
What is a limiting factor in enzyme activity?
When substrate concentration is much higher than enzyme concentration, limiting the reaction rate.
What is the importance of practical experiments in enzyme studies?
They help illustrate the effects of temperature, pH, and concentration on enzyme activity.
