1. Introduction to biological molecules

Give 6 uses of proteins

1. In cell membranes

2. For transport e.g haemoglobin

3. For defence e.g antibodies

4. For enzymes e.g amylase

5. For structural uses e.g collagen

6. For contraction e.g muscle fibres

Define ‘metabolism’

All the chemical reactions that occur in a living organism

Describe the primary structure of proteins

• Long chain molecule that consists of covalent bonds (peptide)

• NH2 (amine group) at one end & carboxylic group (COOH) at the other end

Define essential amino acids

Amino acids we need to consume in order for survival

Define non-essential amino acids

Amino acids that are not necessary in our diet

What is the monomer in proteins?

A single amino acid

Describe the structure of amino acids

• All other components (except from R group) are identical in amino acids

Define molar solution

Solution that contains one mole of solute in each litre of solution

Define covalent bonding

When atoms share a pair of electrons in their outer shells to achieve a full outer shell & become stable`

Define ionic bonding

Ions with opposite charges form an electrostatic attraction

What is a dipeptide?

Two polypeptides

Define a condensation reaction

Each time a sub-unit is attached, a molecule of water is formed

Define a hydrolysis reaction

Water molecules are used to break the bonds that link the sub-units of a polymer, thereby splitting the molecule into its constituent parts

Define polymerisation

When long chains of monomers are formed

What are monomers of polymers usually based on?

Carbon

What are the two types of polymers?

• Many such as polythene & polyesters are industrially produced

• Others such as polysaccharides, polypeptides & polynucleotides are made naturally by living organisms

What is the basic sub-unit of a polysaccharide?

• A monosaccharide or simple sugar e.g glucose

What are polynucleotides formed from?

• Mononucleotide sub-units

What are polypeptides formed from?

Formed by linking together peptides with amino-acids as sub-units

Describe hydrogen bonding

• Electrons within a molecule are not evenly distributes but tend to spend more time at one position → Polarised molecule

• This region is more negatively charged from the rest of the molecule

• The negatively charged region of a polarised molecule & the positively charged region attract each other, forming a weak electrostatic bond that can collectively form important forces that alter physical properties of molecules.

What is the purpose of an R group in an amino acid molecule?

To make each amino acid chemically unique and determine how proteins bind, fold and function.