Key Stage 3 (KS3) Biology Practice Test

The food store in ova, or egg cells, is essential for providing energy to the developing organism. After fertilization, the embryo relies on the nutrients stored in the egg for its initial growth and development. These nutrients include proteins, lipids, and carbohydrates that serve as a critical energy source until the embryo can establish its own means of gaining nourishment from the surrounding environment, such as through a placenta in mammals or by means of yolk in other species.

The energy from the food store is vital for processes such as cell division and growth, allowing the developing organism to use these resources effectively during the early stages of its life cycle. This energy is particularly important in species where the embryo must rely solely on the egg's nutrient supply before it can access external food sources.