Question

Which of the following statements about DNA repair is TRUE? A. There is no DNA repair system to deal with damage caused by exposure to ultraviolet light. B. All mutations are detected and fixed by DNA repair systems. C. DNA repair systems recognize distortions in the DNA double helix. D. All of the mistakes made in DNA replication are fixed by the proofreading activity of DNA polymerase.

Answer 1

The true statement about DNA repair is that DNA repair systems recognize distortions in the DNA double helix. Multiple mechanisms, including nucleotide excision repair, have evolved to repair damaged DNA.

Step-by-step explanation:

The true statement about DNA repair is that DNA repair systems recognize distortions in the DNA double helix.

Multiple mechanisms have evolved to repair damaged DNA. One of these mechanisms is nucleotide excision repair, which plays a crucial role in correcting thymine dimers caused by ultraviolet light. Thymine dimers are two thymine nucleotides that are covalently bonded to each other instead of their complementary bases.

The balance between retained and repaired DNA is imperfect, but it is necessary for the continuance of life itself and the process of evolution.

Answer 2

B. All mutations are detected and fixed by DNA repair systems.

C. DNA repair systems recognize distortions in the DNA double helix.

D. All of the mistakes made in DNA replication are fixed by the proofreading activity of DNA polymerase.

Step-by-step explanation: