The diagram above shows the process of replication that was introduced in this unit. In your Science Notebook, create a flow chart that demonstrates how genetic changes are created during this process. Be sure to label any concepts that were also introduced in this unit. Use your flowchart and information to answer the following questions: Where would a mutation be introduced during replication? What nucleotide bases pair together to create new strands of DNA? Where do environmental factors impact DNA? How does crossing-over and independent assortment contribute to genetic variation?

Answer 1

To create a flow chart demonstrating how genetic changes are created during DNA replication, you can follow these steps, which will also help in answering your questions.

Flow Chart for DNA Replication and Genetic Changes

1. Start of Replication

   • Enzyme: DNA Helicase unwinds the double helix.

2. Formation of Replication Fork

   • The two strands of DNA separate.

3. Synthesis of New Strands

   • Leading Strand: Synthesized continuously (using DNA Polymerase).
   • Lagging Strand: Synthesized in short segments (Okazaki Fragments).

4. Base Pairing

   • Nucleotide Bases Pairing:
     • Adenine (A) pairs with Thymine (T)
     • Cytosine (C) pairs with Guanine (G)

5. Error Introduction (Mutation)

   • During replication, if there is a mismatch in base pairing or an uncorrected error by DNA Polymerase, a mutation can be introduced.

6. Proofreading and Repair

   • DNA Polymerase and other enzymes check for errors and correct them, but if they miss an error, a permanent mutation may remain.

7. Impact of Environmental Factors

   • Environmental factors (like UV radiation, chemicals) can cause DNA damage, leading to mutations that may be introduced during replication.

8. Crossing-Over in Meiosis

   • During meiosis, homologous chromosomes exchange genetic material (crossing over).

9. Independent Assortment

   • Chromosomes segregate independently during gamete formation, leading to genetic variation.

10. Resulting Genetic Variability

    • Mutations, crossing-over, and independent assortment all contribute to genetic diversity.

Answers to Your Questions:

1. Where would a mutation be introduced during replication?

   • A mutation can be introduced during the synthesis of DNA strands when there is a mismatch in base pairing or if DNA Polymerase makes an error that isn't corrected during proofreading.

2. What nucleotide bases pair together to create new strands of DNA?

   • Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).

3. Where do environmental factors impact DNA?

   • Environmental factors can alter DNA by causing damage (e.g., via UV light or chemical exposure), leading to mutations during the replication process.

4. How does crossing-over and independent assortment contribute to genetic variation?

   • Crossing-over results in the exchange of genetic material between homologous chromosomes, creating new combinations of alleles. Independent assortment ensures that alleles segregate into gametes randomly, leading to varied genetic combinations in offspring.

This flowchart can be neatly drawn and include arrows to show the flow of processes, emphasizing each step in DNA replication that leads to genetic changes.