Illustration of a germ cell showing DNA within the nucleus during interphase.

Let’s go step by step to answer question #3 from the Gizmo Warm-up section:

Question 3: Why is it necessary for the cell to grow and duplicate its DNA before the start of meiosis?

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Step-by-step reasoning:

Meiosis is a special kind of cell division that makes sex cells (like sperm or egg). These sex cells need to have half the number of chromosomes as normal body cells — so when two sex cells join during fertilization, the baby gets the right total number.

But here’s the catch:
Before meiosis starts, the cell must first make a copy of all its DNA. Why?

Because in meiosis, the cell divides twice:
- First division → separates homologous chromosome pairs
- Second division → separates sister chromatids (the copied parts)

If the DNA didn’t duplicate first, then after two divisions, each daughter cell would end up with only one-quarter of the original genetic material — which is too little! The resulting gametes wouldn’t be able to form a healthy zygote.

Also, the cell needs to grow bigger and make more organelles (like mitochondria, ribosomes, etc.) because it’s going to split into four smaller cells. It needs enough “stuff” to give each new cell what it needs to survive and function.

So, growing and duplicating DNA ensures:
✔ Each of the four final gametes gets a complete set of instructions (DNA)
✔ Each gamete has enough cellular machinery to live and do its job
✔ When two gametes fuse later, the offspring gets the correct full set of chromosomes

This happens during interphase, which comes *before* meiosis officially begins.

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Final Answer:
The cell must grow and duplicate its DNA before meiosis so that when it divides twice to make four gametes, each gamete ends up with a complete set of chromosomes and enough cellular components to function properly. Without this preparation, the resulting sex cells would not have enough genetic material or resources to support life after fertilization.