In molecular biology, the abbreviation DNA stands for which full chemical name?

Introduction / Context:
DNA is one of the most commonly used terms in biology, but it is important to know its full form. Many examinations test this basic fact. This question checks whether you can correctly expand the abbreviation DNA into its full chemical name, which describes both its sugar component and its nucleic acid nature.

Given Data / Assumptions:

• The abbreviation DNA is given.
• Four possible expansions are listed.
• We assume knowledge of basic nucleic acid terminology.

Concept / Approach:
DNA is a nucleic acid built from nucleotides. Each nucleotide contains a phosphate group, a nitrogenous base, and a sugar. The sugar in DNA is deoxyribose, which lacks one oxygen atom compared with ribose. The full name therefore includes the term deoxyribo and nucleic acid, combined as deoxyribonucleic acid. RNA, by contrast, stands for ribonucleic acid, reflecting the presence of ribose sugar.

Step-by-Step Solution:
Step 1: Recognise that the D in DNA refers to deoxy, indicating the deoxyribose sugar. Step 2: Recognise that the N and A refer to nucleic acid. Step 3: Combine these parts to get the full form: deoxyribonucleic acid. Step 4: Select the option that matches this exactly, which is Deoxyribonucleic acid.

Verification / Alternative check:
Standard biology textbooks and reliable references consistently state that DNA stands for deoxyribonucleic acid. They also contrast it with RNA, ribonucleic acid. This confirmation from multiple sources makes the correct choice certain.

Why Other Options Are Wrong:

• Option A (Di nucleic acid): The prefix di suggests two, and this term is not a valid chemical name for DNA.
• Option B (Deoxy nucleic acid): This leaves out the ribo part and is incomplete and inaccurate.
• Option C (Diribonucleic acid): This mixes up ribo and incorrect prefixes and does not match the known full form.

Common Pitfalls:
The most common error is choosing an option that partially sounds correct but is incomplete, such as Deoxy nucleic acid. Remember that the sugar component, deoxyribose, must appear in the full name. Also do not confuse DNA with RNA, which uses ribose instead of deoxyribose and is therefore called ribonucleic acid.

Final Answer:
DNA stands for Deoxyribonucleic acid.