National 5 Biology - 1.4 - Proteins & Enzymes

Proteins

Molecules made of amino acid sequences.

The sequence of amino acids

Controls the shape and function of proteins

Structural Proteins

Hold tissues together e.g. collagen

Hormones

Are chemical messengers which carry a message from a gland to a receptor via the blood.

Antibodies

Antibodies are proteins, made by white blood cells, which destroy pathogens

Receptors

Bind to a hormone and tell the target cell what to do.

Enzymes

Are biological catalysts and are made by all living cells.

Biological catalysts

Speed up chemical reactions in cells and remain unchanged in the process

Active site

Where the substrate fits into the enzyme and is complementary shape to it.

Substrate

The reactant in a reaction, and is specific to an enzyme

Catalase

Enzyme that breaks down hydrogen peroxide.

Product

The molecule made by an enzyme-controlled reaction.

Optimum conditions

Are the temperature and pH which the enzymes are most active.

Denatured

When the active site changes shape and affects the rate of reaction.

An example of a degradation reaction is?

starch - amylase → maltose

An example of a synthesis reaction is?

G-1-P - phosphorylase → starch

Catalase formula

hydrogen peroxide - catalase → oxygen + water

Which type of substance are enzymes made of?

Protein

Which word describes the relationship between the shape of the active site of an enzyme and the shape of its specific substrate?

Complementary

What effect does denaturation have on the activity of an enzyme?

Decreased

What is the name of a substance that speeds up the rate of a chemical reaction, but is unchanged by the process?

Catalyst

What are the two variables that can affect an enzyme

Temperature and pH

What is degradation?

Breaking a large substrate into small molecules

What is synthesis?

Making a large product from small molecules

Explain a degradation reaction?

Enzyme and substrate joins together. It forms enzyme-substrate complex. A reaction occurs at active site of the enzyme. Two products have been made.

Explain a synthesis reaction

A substrate (the smaller molecules) binds to the active site of the enzyme. A reaction occurs at active site of the enzyme. One product has been made