Flashcards in Enzymes Deck (67)
What is the structure of all enzymes?
3D globular proteins in the tertiary structure
Why do enzymes hold their shape?
They hold their shape due to hydrogen, ionic and disulphide bonds
What effects the activity of enzymes?
Temperature and pH
What is the function of enzymes?
To work as a biological catalyst - speed up chemical reactions without being used up
Are enzymes specific or not specific?
What is an example of the use of enzymes in the body?
Used in digestion to hydrolyse polymers into monomers
What is the definition for activation energy?
The excess energy needed to enable a reaction to occur
What do enzymes do to the activation energy?
Lowers the activation energy
What is the pocket cleft on an enzyme?
A specific shape on the enzyme called an active site
What is complementary to the active site of an enzyme?
The complementary substrate
Can any enzyme break down any substrate?
No, only specific enzymes can break down specific substrates
What is an example of the lock and key model enzyme used in the body?
Lactase breaking down lactose into glucose and galactose
Can the lock and key model of enzymes catalyse both ways of a reaction?
What holds the substrate to the enzyme in the lock and key model?
Oppositely charged groups on the amino acids in the active site
What are the 6 steps to the induced fit model for enzymes?
1. The substrate collides with the active site.
2. The active site moulds around the substrate molecule and it is held in position by oppositely charged groups on the amino acids in the active site.
3. An enzyme-substrate complex is formed.
4. An enzyme-product complex now forms.
5. The product no longer fits into the active site.
6. The product is released.
What is the function of binding during the induced fit model in enzymes?
Binding the substrate to the active site results in a change of shape in the enzyme so that it fits around the substrate more closely.
Is the active site the same shape as the substrate?
The active site is NOT the same shape as the substrate but it is complementary.
Do substrates have active sites?
Define a Catabolic reaction
The break down of larger molecules into smaller ones
What is an example of a catabolic reaction?
Polypeptide into an amino acid
Define a Anabolic reaction?
Large molecules made from smaller units
What is an example of anabolic reaction?
Alpha glucose into startch
What is a intracellular enzyme?
A type of enzyme found inside the cell
What is a extracellular enzyme?
A type of enzyme released outside cell
What is glucose isomerase?
A type of enzyme
What is pepsin?
A type of enzyme
Define turnover number
The number of converted molecules of substrate per unit of time
ENZYME + SUBSTRATE =
Product - if a successful collision leading to a enzyme-substrate complex
What are the three main ways enzyme reactions can be measured?
1. Time taken for reaction to occur
2. Number or concentration of products produced
3. Rate of reaction