Chemical elements, water and carbohydates
Introduction

Topic 1 Elements and carbohydrates

Topic 2 Lipids and Proteins

Topic 3 Enzymes

Photo page
Chemicals and water
There are about 100 different elements in live and only 16 are found in our body. The most common ones are: OXYGEN is found in all molecules of life and is needed in cell respiration. HYDROGEN is part of water and it is also found in all molecules of life. CARBON is found in organic molecules which is able to form strong bonds with oxygen and nitrogen. NITROGEN is part of all proteins. CALCIUM is found in bones. PHOSPHORUS part of DNA and ATP. IRON which si part of haemoglobin in blood.

Wate is a polar molecule. It means that the charges don't cancel out. This makes water a hydrophobic molecule.

The properties of water are:

>high heat capacity
>high surface tension
>density and freezing

Carbohydrates:
The formula for a carbohydrate is --> Cy(H2O)n. Carbohydrates contain oxygen, carbon and hydrogen. Carbohydrates are aldehydes or ketones and all contain several hydroy groups. Allmost all compounds containing carbon are found in living organisms.
Carbohydrates are divided into MONOSACCHARIDES, DISACCHARIDES and POLYSACCHARIDES:

>Monosaccharide:

This haves a formula of (CH2O)n. They are clasified by the number of carbon atoms eg. trioses 3C, tetroses 4C ... . A hexone hydrocarbon is GLUCOSE ( C6 H12 O6 ). Monosaccharides are allways in a ring form. In the photo page you can find a picture of a 3D glucose molecule.

>Disaccharides:

These are formed when two monosaccharides, usually hexoses, combineby means of a chemical reacton known a comdensation. This means the removal of water. An example of a monosaccharide ois maltose. You can see 3D picture of it in the photo page. The bond bettween the two monosaccharides usually takes places at the 1st carbon and at the C4 carbon. Examples:

Maltose: glucose + glucose
Lactose: glucose + galatose
Sucrose: glucose + fructose

Polysaccharides:

These are long chains of monosaccharides ( from 3 to 00 monosaccharides ). They are made for food and energy storage and structural material. Polysaccharides are usually storage because:

Their large size makes them more or less insoluble in water.
They fold into compact shapes
They are easelly converted to sugars by hydrolysis when requiered.

Glycogen is a common polysaccharide which means storing of glucose. Starch is a polymer of glucose. It is a major fuel storage in plants but it is absence in animals because it is replaced by glycogen, which can be more easely converted back into glucose for respiration.