Question

Single strands of nucleic acids are directional, meaning that there are two different ends. What functional groups define the two different ends of a strand? Select all that apply. Select all that apply.

A. a free carboxyl group on the 5' carbon
B. a free hydroxyl group on the 5' carbon a free hydroxyl group on the 3' carbon
C. a free amino group on the 5' carbon
D. a free amino group on the 3' carbon
E. a free carboxyl group on the 3' carbon
F. a free phosphate group on the 3' carbon
G. a free phosphate group on the 5' carbon

Answer 1

The functional groups that define the two different ends of a single strand of nucleic acids are:

B. a free hydroxyl group on the 5' carbon a free hydroxyl group on the 3' carbon

G. a free phosphate group on the 5' carbon

Step-by-step explanation:

A nucleic acid is a polymer formed of nucleotides that are linked with a phosphodiester bond. The structure of a nucleotide consists on a phosphate group linked to a pentose (ribose in RNA and deoxyribose in DNA) that is also attached to a nitrogenous base. The nitrogenous bases are adenine, guanine, cytosine, thymine (in DNA) and uracil (in RNA).

DNA and RNA are nucleic acids which can be found in a double or single strand presentation.

Nucleic acids are synthesize in the 5’ to 3’ direction, so that is why the convention is that the sequences are written and read in that direction.

The strand of a nucleic acid is directional with an end-to-end orientation, where the 5’ end has a free hydroxyl or phosphate group on the 5' carbon of the terminal pentose, and the 3’ end has a free hydroxyl group on the 3’ carbon on the terminal pentose (ribose/ deoxyribose).