Biological Molecules

Monomers - sub-units of larger molecules that can be bonded together in a chain to form polymers.

There are four main biological molecules:

1. Carbohydrates - monomers are known as monosaccharides.

   1. they are a fast source of energy

2. Lipids (fats) - formed by fatty acids and glycerol. Lipids are not polymers.

   1. they are good as insulators within cells
   2. they are a long-term source of energy
   3. the make up cell membranes

3. Proteins - monomers are known as amino acids.

   1. they are good for muscle building
   2. they strengthen the immune system

4. Nucleic acids - monomers are known as nucleotides.

   1. they code for proteins

Hydrolysis

Hydrolysis is the process of breaking polymers into their respective monomers using water.

“Hydro“ = water, “lysis“ = splitting

Above: a polymer being split into two sub-sections using water and an enzyme catalyst. This is a hydrolysis reaction.

Condensation

The opposite of a hydrolysis reaction is a condensation reaction. This is when two monomers are combined to form a polymer, which also gives water as a product.

Q: Which type of reaction would form a molecule of starch?

A: A condensation reaction.

Q: Which type of reaction would form molecules of glucose?

A: a hydrolysis reaction.

Biological Molecules as evidence for evolution

1. all living organisms contain carbon

2. DNA is present in all living organisms and code for the same amino acids

   This suggests a common ancestor.

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