Let’s go step by step through each part of the DNA replication practice.
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Step 1: What is happening to the DNA molecule in the figure? (Explain the first step in DNA replication)
In the first image, you can see the DNA ladder starting to unzip at the bottom. The two strands are pulling apart. This is called “unwinding” or “separating.” In real life, an enzyme called helicase does this job — it breaks the bonds between the base pairs so the two strands can separate. Each strand will then be used as a template to build a new matching strand.
So, the first step is:
The DNA double helix unwinds and the two strands separate.
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Step 2: What happens to the DNA molecule during the second step of DNA replication?
In the second image, you can see free-floating nucleotides (the little pieces with letters like A, T, C, G) coming in and attaching to each separated strand. They match up according to base-pairing rules: A always pairs with T, and C always pairs with G. Enzymes help put these new pieces together to form new strands.
So, the second step is:
New nucleotides come in and pair with the bases on each original strand to build two new complementary strands.
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Step 3: What happens during the third step of DNA replication?
In the third image, you now have two complete DNA ladders side by side. Each one has one old strand (from the original DNA) and one brand-new strand. That means replication is finished — we started with one DNA molecule and ended with two identical copies.
So, the third step is:
Two identical DNA molecules are formed, each made of one original strand and one new strand.
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Final Answer:
1. The DNA molecule unwinds and the two strands separate.
2. New nucleotides pair with the bases on each separated strand to build new complementary strands.
3. Two identical DNA molecules are formed, each containing one original strand and one new strand.
Parent Tip: Review the logic above to help your child master the concept of dna replication worksheet.
