Lipids and proteins

1A4 and 1A5 of the Biology AS book

Formula of glycerol

C₃H₈O₃

structure of fatty acids

Long hydrocarbon chains with a carboxyl group on one end

What are the factors that lipids can vary in

• Saturation/ unsaturation

• Carbon chain length

Hydrocarbon fatty acid chain with 1 unsaturated carbon atom

A monounsaturated fatty acid

Hydrocarbon fatty acid chain with multiple unsaturated carbon atoms

Polyunsaturated fatty acid

Lipids the body cannot synthesise

Essential lipids (Polyunsaturated fatty acids)

Name of a lipid made of 3 fatty acids and a glycerol

triglyceride

Reaction that joins a glycerol and fatty acid

esterification reaction

What groups react to join a glycerol and fatty acid

The glycerol hydroxyl (-OH) group and fatty acid Carboxyl (-COOH) group

Features of typical saturated lipids

solid, found in animals

Features of typical unsaturated lipids

Liquid even in cold temp

Features of typical long chained lipids

Solid at room temp

General formula for saturated fatty acids

C_nH_2nO₂

Structure of an amino acid

Amino group (NH2), Carboxyl group (COOH), and R group attached to a central carbon atom

Types of bonds in proteins

• Hydrogen bonds

• Disulfide bonds

• Ionic bonds

What is primary structure

The sequence of amino acids bonded by peptide bonds

What is secondary structure

The arrangement of the polypeptide chain into 3D structures

What is tertiary structure

The further folding of secondary structures

What is quaternary structure

How multiple polypeptide chains fit together

Features of fibrous proteins

• Little/ no tertiary structure

• tough

• Not water soluble

Structure of collagen

-Alpha helixes

-Arranged in a triple helix quaternary structure

-These molecules assemble into fibrils

-Which form fibres

Types of proteins

• Fibrous

• Globular

• Conjugated

A type of mixture where particles of one substance are suspended throughout another

Colloid

Structure of haemoglobin

Conjugated protein made of 4 polypeptide chains each surrounding a haem group containing iron

Features of glycoproteins

The carbohydrate allows them to

• hold water

• Be digested slower by proteases

The water makes them slippery

Features of lipoproteins

The lipid allows them to combine with cholesterol to transport it

Types of lipoproteins

Heigh density and low density