Essential Idea:
Living organisms control their composition
by a complex web of chemical reactions
Understandings:
- Molecular biology explains living processes in terms of the chemical substances involved
- Carbon atoms can form four covalent bonds allowing a diversity of stable compounds to exist
- Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids
- Metabolism is the web of all the enzyme-catalysed reactions in a cell or organism
- Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions
- Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers
Applications:
- Urea as an example of a compound that is produced by living organisms but can also be artificially synthesized
Skills:
- Drawing molecular diagrams of glucose, ribose, a saturated fatty acid and a generalised amino acid
- Identification of biochemicals such as sugars, lipids or amino acids from molecular diagrams