Question

A segment of a DNA molecule has the base sequence ATGAAC. Write a shorthand structure for this segment and for its comp

Answer 1

Answer: The sequence will be 5' ATGAAC 3' and 3' TACTTG 5'.

Explanation:

DNA is a molecule that contains genetic information that codes for protein synthesis in all organisms. This molecule consists of two strands that coil together to form a double helix structure. Each of these chains is formed by nucleotides, which are the monomers of nucleic acids and are formed by the union of a five-carbon sugar (pentose) called deoxyribose, phosphate groups and a nitrogenous base. The nitrogenous bases can be:

• Adenine (A)
• Cytosine (C)
• Guanine (G)
• Thymine (T)

The two chains are held together by bonds called hydrogen bonds between the bases. Consider that A is only linked to T by two hydrogen bridges, and that C is only linked to G by three hydrogen bridges.  This means, both chains are complementary to each other.

The 5' and 3' stand for "five prime" and "three prime", which indicate the carbon numbers on the sugar of DNA. For the classification of the pentoses (which are made of 5 carbones attached to each other), we consider that carbon with the phosphate group is the 5' carbon; and the carbon of with the hydroxyl group, is the 3' carbon. This asymmetry gives a DNA strand a "direction" and causes it to be considered antiparallel, meaning that the nucleotide at the 5' end is first and the nucleotide at the 3' end is last.

Then in this example, the sequence will be 5' ATGAAC 3' and 3' TACTTG 5'.