Select the most correct statement regarding nucleic acids.
A) Three forms exist: DNA, RNA, and tDNA.
B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
C) RNA is a long, single-stranded molecule made up of the bases A, T, G, and C.
D) tDNA is considered a “molecular slave” of DNA during protein synthesis.
The Correct Answer and Explanation is:
The correct answer is:
B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
Explanation (300+ words):
Nucleic acids are vital biomolecules that store and transmit genetic information in all living organisms. There are two primary types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Each of these plays a specific role in the storage and expression of genetic information.
DNA (Deoxyribonucleic Acid) is a long, double-stranded molecule composed of two complementary chains that form a double helix. Each strand consists of a sequence of nucleotides, which include a phosphate group, a deoxyribose sugar, and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). In DNA, adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G) through hydrogen bonds. The double-helix structure provides stability and the means for accurate replication during cell division. Therefore, option B correctly describes DNA as a double-stranded molecule made of A, T, G, and C bases.
Now, examining the other options:
- Option A is incorrect because there is no such recognized form of nucleic acid called tDNA. The two known types of nucleic acids are DNA and RNA. Some subtypes of RNA (e.g., tRNA, mRNA, rRNA) exist, but tDNA is not a standard classification.
- Option C is incorrect because RNA does not contain thymine (T). Instead, uracil (U) replaces thymine in RNA. Thus, the bases in RNA are adenine (A), uracil (U), cytosine (C), and guanine (G). RNA is typically single-stranded.
- Option D is incorrect and misleading. While the term “molecular slave” might loosely refer to molecules like transfer RNA (tRNA) that help translate genetic code during protein synthesis, there is no nucleic acid known as tDNA, making the option scientifically invalid.
In conclusion, option B is the most accurate and scientifically correct description regarding nucleic acids.