Question

Figure 1 represents a segment of DNA. radiation can damage the nucleotides in a DNA molecule. to repair some types of damage, a single nucleotide can be removed from the DNA molecule and replaced with an undamaged nucleotide. which of the four labeled bonds in figure 1 could be broken to remove and replace the cytosine nucleotide without affecting the biological information coded to the DNA molecule?

Answer 1

Answer:

This question is incomplete as it lacks options; the options are:

A) Bond X only

B) Bond W only

C) Bonds Y and Z at the same time

D) Bonds W and Z at the same time

The answer is C. Bond Y and Z at the same time

Explanation:

A DNA molecule is a double-stranded molecule made up of nucleotide units. According to this question, radiation can damage the nucleotides in the DNA molecule. However, the cell can repair this DNA molecule by removing the single damaged nucleotide and replacing it with an undamaged one.

In this case, the cytosine nucleotide is the damaged nucleotide. To repair this DNA in the image, the covalent bond holding the one nucleotide to another in one of the DNA strands must be broken.

The sugar-phosphate bonds as represented by letters Y and Z are the bonds that could be broken to replace the cytosine nucleotide by an undamaged one, without affecting the biological information coded to the DNA molecule. The bonds holding the neighboring nucleotides are also broken during the repair process. Note that, this form of repair is called BASE EXCISION REPAIR