Chapter 2: Enzymes Flashcards
What are enzymes?
Biological catalysts made up of globular proteins
Give two examples of where enzymes are found
Stomach, saliva
What do enzymes do?
They catalyse metabolic reactions
What is the structure of a globular protein?
ionic bonds, disulphide bridges, hydrophobic/hydrophilic reactions + hydrogen bonds make up the tertiary structure which is important for maintaining the active site’s shape
Give an example of an intracellular place that enzymes are found
Catalase - catalyses the breakdown of hydrogen peroxide into oxygen and water
What is trypsin and where is it found?
Enzyme found in the small intestine - catalyses the hydrolysis of peptide bonds
What is the purpose of an active site?
Where the substrate molecules bind to - it is COMPLEMENTARY to the substrate
Define activation energy
minimum level of energy required for a reaction to take place
Explain the lock and key model
Active site = lock and substrate = key, when the substrate binds to the active site it forms an enzyme substrate complex and breaks down into products
Explain the Induced fit theory
When the substrate binds to the enzyme it alters the shape of the enzyme slightly to make a better fit
What are the four factors that affect enzymes
Temperature, pH, enzyme concentration and substrate concentration
What will happen if the temperature is too hot (describe in detail)?
The enzyme will denature - active site will be permanently altered due to the vibration of the enzymes breaking some of the hydrogen bonds that hold the tertiary structure in place, meaning the substrate won’t be able to fit and bind to the enzyme
What will happen if the temperature is too cold?
Decreased reactions - not enough kinetic energy to collide
What’s the optimum temperature for enzymes?
37C in the body and 40 - 45C in a lab
What can happen if the pH is above or below the optimum pH?
The H+ and OH- ions in the solution can interfere with the ionic and hydrogen bonds in the enzyme
