Questions: Question 6 (2 points) After replication, - one DNA double helix consists of two old strands and one DNA double helix consists of two new strands - each new DNA double helix consists of one old strand and one new strand - each new DNA double helix contains 25% of the old DNA double helix - each new DNA double helix consists of two old strands - each new DNA double helix consists of two new strands Question 7 (2 points) What occurs during DNA replication? - New bases attach to the original sugar-phosphate backbone. - DNA polymerase separates the two DNA strands. - Adenine forms a base pair with either cytosine or guanine.

The answer to Question 6 is the second one: each new DNA double helix consists of one old strand and one new strand.

Explanation for each option:

1. Incorrect: After replication, one DNA double helix does not consist of two old strands and one DNA double helix does not consist of two new strands. This would imply a conservative model of replication, which is not how DNA replication occurs.
2. Correct: This describes the semi-conservative model of DNA replication, where each new DNA double helix consists of one old (parental) strand and one new (daughter) strand.
3. Incorrect: Each new DNA double helix does not contain 25% of the old DNA double helix. This statement is not accurate in describing the semi-conservative replication process.
4. Incorrect: Each new DNA double helix does not consist of two old strands. This would imply no new DNA synthesis, which is incorrect.
5. Incorrect: Each new DNA double helix does not consist of two new strands. This would imply a dispersive model of replication, which is not how DNA replication occurs.

The answer to Question 7 is: New bases attach to the original sugar-phosphate backbone.

Explanation for each option:

1. Correct: During DNA replication, new nucleotides are added to the original sugar-phosphate backbone to form the new strand.
2. Incorrect: DNA polymerase does not separate the two DNA strands. This function is performed by the enzyme helicase.
3. Incorrect: Adenine forms a base pair with thymine (in DNA) or uracil (in RNA), not with cytosine or guanine.

Summary:

• Question 6: The answer is the second one: each new DNA double helix consists of one old strand and one new strand.
• Question 7: The correct statement is that new bases attach to the original sugar-phosphate backbone.