1. Molecules

A1.1.1 Water as the medium for life

A1.1.2 Hydrogen bonds as a consequence of the polar covalent bonds within water molecules

A1.1.3 Cohesion of water molecules due to hydrogen bonding and consequences for organisms

A1.1.4 Adhesion of water to materials that are polar or charged and impacts for organisms

A1.1.5 Solvent properties of water linked to its role as a medium for metabolism and for transport in

A1.1.6 Physical properties of water and the consequences for animals in aquatic habitats

A.1.2.1 DNA as the genetic material of all living organisms

A.1.2.2 Components of a nucleotide

• DNA as the genetic material of all living organisms

• Components of a nucleotide

• Sugar–phosphate bonding and the sugar–phosphate “backbone” of DNA and RNA

• Bases in each nucleic acid that form the basis of a code

• RNA as a polymer formed by condensation of nucleotide monomers

• DNA as a double helix made of two antiparallel strands of nucleotides with two strands linked by hydrogen bonding between complementary base pairs

• Differences between DNA and RNA

• Role of complementary base pairing in allowing genetic information to be replicated and expressed

• Diversity of possible DNA base sequences and the limitless capacity of DNA for storing information

• Conservation of the genetic code across all life forms as evidence of universal common ancestry