Carbohydrates

Proteins

Lipids

Elements Present

• Carbon
• Hydrogen
• Oxygen

Present in ratio:

C:H:O

1:2:1

• Carbon
• Hydrogen
• Oxygen
• Nitrogen

Some also contain Sulfur, Phosphrus or other elements.

Only biomolecule that contains nitrogen

• Carbon
• Hydrogen
• Oxygen

Structure

Monosaccharides

one sugar unit

Eg. glucose, fructose

Disaccharides

two sugar units

Eg. maltose (glucose+glucose), sucrose (fructose+glucose)

Polysaccharides  

many monosaccharides joined together

Eg. starch (stored by plants)

cellulose (in plant cell walls)

 glycogen (stored by animals in liver and muscles)

Made up of subunits called amino acids

There are about 20 common amino acids

The sequence and number in which the amino acids combine determines the protein formed

<20 amino acids join to form a peptide

20-200 amino acids join to form a polypeptide

>200 amino acids join to form a protein

The chains of amino acids also fold in specific way to give the protein its characteristic 3D shape

Eg. Keratin in hair  is fibrous

Albumin is globular shape

Fats – solid at room temperature

Oils – liquid at room temperature

Lipids are composed of subunits called triglycerides

Triglycerides are made up of a glycerol unit and 3 fatty acids.

Phospholipids are lipids in which a phosphate group replaces one of the fatty acid groups.

Sources

Sugars – fruit, jam

Starch – bread, pasta

Fibre – Wholegrain bread

Animal sources – meat,fish, eggs

Plant sources – peas, beans

Butter, Milk, Cream

Meat

Functions

Structural

cellulose in cell walls

Metabolic

glucose provides energy in respiration,

glycogen stores energy in animals, starch stores energy  in plants

Structural

Keratin is found in hair and skin

Metabolic

Enzymes control reactions

Antibodies destroy pathogens

Source of energy

Energy Store (contains almost twice as much energy as carbohydrates)

Phospholipids form part of cell membranes

Test

1. Heat with Benedicts solution
2. Colour change from blue to brick red occurs if reducing sugar (eg. glucose) present

1. Test with Biuret Reagent
2. Colour change from blue to violet if protein is present

1. Rub a sample on brown paper.
2. Fats cause a translucent spot that won’t evapourate  to form on the paper

Vitamin

Source

Function

Deficiency

Solubility

Vitamin C

Citrus fruits – oranges, limes, lemons

Blackcurrents

General health

Healthy teeth and gums

Needed for iron absorption

Scurvy

Poor gums, tooth loss, bruising

Water Soluble

Vitamin D

Liver

Milk

Fish oils

Can be made by skin when exposed to uv rays of sun.

Needed for calcium absorption from the intestine

Rickets in children

Osteomalacia in adults

Causes weak, brittle bones that break easily

Fat Soluble

Mineral

Function

Calcium

Calcium pectate acts as cement between cell walls

Magnesium

Makes green pigment, chlorophyll

Mineral

Function

Calcium

Forms healthy bones and teeth

Iron

Needed to make haemoglobin in red blood cells