Cells are the basic unit of living things. Each cell has some common basic structures. Within every cell, there are genetic materials, DNA, which carry the instructions for defining the different traits of a living thing. Reproduction is the essential life process that leads to the formation of a new life. There are specialised cells and organs responsible for reproduction in living things. Through reproduction, new individuals with some traits looking very alike to their parents will be formed. The passing of traits from generation to generation is called heredity.

In this Unit, students will learn about cells, human reproduction and heredity. Through preparing slides of live specimens for observation of different cells, students practice the science process skills of using a microscope, observing and making biological drawing. The study of the basic structure of cells and the level of organisation highlights the unifying concepts “systems and organisation”. The concept “constancy” can be illustrated by the fixed number of 46 chromosomes found in every body cell of humans. The unifying concepts “change and constancy” can be further exemplified in the process involved in heredity.