Question

question 1 - 3
which of the following statements correctly describes the difference between the semiconservative model of dna replication and the conservative model of dna replication?
the semiconservative model states both strands of dna remain together after replication and the conservative model states both strands separate.
the semiconservative model states single - stranded dna strands are used as a template strand to create newly synthesized dna strands and the conservative model states only one side is used as a template.
the semiconservative model states the dna strands are randomly paired with a newly synthesized dna strand and the conservative model states only new strands are paired.
the semiconservative model states the two original dna strands separate and are used as template strands to create newly synthesized dna strands and the conservative model states the two original strands remain together.

Explanation:

1. Recall the definitions of semiconservative and conservative DNA replication models:

• Semiconservative model: During DNA replication, the two strands of the original DNA molecule separate, and each strand serves as a template for the synthesis of a new complementary strand. So, each new DNA molecule consists of one original (parental) strand and one newly synthesized (daughter) strand.
• Conservative model: In this model, the two original (parental) strands of DNA remain together after replication, and a completely new double - stranded DNA molecule is synthesized from scratch. So, one DNA molecule is made up of the two original strands, and the other is made up of two newly synthesized strands.

1. Analyze each option:

• Option 1: The semiconservative model does not have both original strands remaining together, and the conservative model does not have both strands separating. So, this option is incorrect.
• Option 2: The semiconservative model uses both strands as templates (not a single - stranded template in the way described), and the conservative model does not use a single - stranded template. So, this option is incorrect.
• Option 3: The semiconservative model does not have random pairing, and the conservative model does not have only new strands paired. So, this option is incorrect.
• Option 4: This option correctly describes the semiconservative model (original strands separate and act as templates) and the conservative model (original strands stay together).

Answer:

The semiconservative model states the two original DNA strands separate and are used as template strands to create newly synthesized DNA strands and the conservative model states the two original strands remain together.