Below is how the official curriculum organizes it. Each strand will get full lessons like the ones in Grade 1 Mathematics.
Genes are the foundation for the diversity of living things (DNA, inheritance, mutation)
Chemical processes require energy change as atoms are rearranged (reactions, acids and bases)
Energy is conserved, and its transformation can affect living things and the environment (including nuclear energy)
The formation of the universe can be explained by the big bang theory