How is the directionality of a DNA molecule described based on the orientation of sugar molecules within the strand?
A) left to right
B) top to bottom
C) 5′ to 3′
D) A to T or G to C
E) All DNA molecules are different in their directionality.

Question

How is the directionality of a DNA molecule described based on the orientation of sugar molecules within the strand?
A) left to right
B) top to bottom
C) 5′ to 3′
D) A to T or G to C
E) All DNA molecules are different in their directionality.

Quizplus · Accepted Answer

The direction of a DNA molecule is described based on the orientation of sugar molecules within the strand, with one end having a 5′ carbon and the other end having a 3′ carbon. Thus, DNA strands are always read from the 5′ end to the 3′ end. This directionality is denoted by convention as being in the direction of the arrow that points from left to right. Therefore, the correct answer is C) 5′ to 3′.

How Is the Directionality of a DNA Molecule Described Based on the Orientation