•The large molecules that compose life are known as macromolecules.
- • Examples of macromolecules are: carbohydrates, lipids, proteins and nucleic
- Macromolecules may be composed of several
- smaller identical / similar molecular units known as monomers
- Cells link
- monomers together to form a polymer accompanied by the elimination of water, by
- a process known as dehydration synthesis.
- cells breakdown
- macromolecules (eg during digestion) with the help of water. This process is
- known as hydrolysis.
• Synthesis of carbohydrates begins with carbon fixation that occurs in photosynthesis. Most carbohydrates are forms by chemical steps that modify glucose.
- • Carbohydrates are
- made up of monomers known as monosaccharides / single unit sugars.
- Example: Glucose and Fructose.
- •A carbohydrate
- composed of two monosaccharides is known as a disaccharide, i.e.
- + Glucose = Maltose
Glucose + Fructose = Sucrose
- are long chains of sugar units.
- polysaccharide. Examples are: Starch, Glycogen, Cellulose and Chitin.Each
- of the four differs in some way.
- MADE FROM HYDROCARBONS: Hydrocarbons are mainly
- Hydrogen and carbon. This makes them
- insoluble in water. Lipids include fats, oils waxes, phosholipids and steroids
- Proteins are
- made up of 20 kinds of amino acids in various combinations
- Nucleic Acids are made up of monomeric units
- called ‘nucleotides’
- There are two nucleic acids,. deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).