Absence of which of the following nitrogen-containing bases would prevent RNA synthesis?
a. Adenine
b. Cytosine
c. Guanine
d. Thymine
e. Uracil

Verified step by step guidance

1. Step 1: Understand the structure of RNA. RNA is a nucleic acid composed of a sugar-phosphate backbone and nitrogen-containing bases. The bases in RNA are adenine (A), cytosine (C), guanine (G), and uracil (U). Unlike DNA, RNA does not contain thymine (T).
2. Step 2: Recall the role of nitrogen-containing bases in RNA synthesis. These bases pair with complementary bases on the DNA template during transcription. Adenine pairs with uracil, and cytosine pairs with guanine.
3. Step 3: Identify the bases necessary for RNA synthesis. Since RNA synthesis involves pairing with the DNA template, the absence of adenine, cytosine, guanine, or uracil would disrupt the process. Thymine is not required for RNA synthesis because it is replaced by uracil in RNA.
4. Step 4: Eliminate thymine as a correct answer. Thymine is a nitrogen-containing base found in DNA, not RNA, and its absence does not affect RNA synthesis.
5. Step 5: Conclude that adenine, cytosine, guanine, and uracil are essential for RNA synthesis. Their absence would prevent the formation of RNA strands during transcription.

Key Concepts

RNA Structure

RNA, or ribonucleic acid, is a nucleic acid composed of a long chain of nucleotides, each containing a nitrogenous base, a sugar, and a phosphate group. The nitrogenous bases in RNA include adenine, cytosine, guanine, and uracil. Unlike DNA, RNA does not contain thymine, which is replaced by uracil. Understanding the structure of RNA is essential for recognizing which bases are necessary for its synthesis.

Transcription Process

Transcription is the process by which RNA is synthesized from a DNA template. During transcription, RNA polymerase reads the DNA sequence and assembles a complementary RNA strand using the available nitrogenous bases. The absence of any of the required bases—adenine, cytosine, guanine, or uracil—would halt this process, preventing RNA synthesis. This highlights the importance of each base in forming a complete RNA molecule.

Nitrogenous Bases in RNA

Nitrogenous bases are critical components of nucleotides, which make up RNA and DNA. In RNA, the four bases are adenine (A), cytosine (C), guanine (G), and uracil (U). Each base pairs with its complementary base during the synthesis process, and the absence of any of these bases would disrupt the formation of RNA. Understanding which bases are present in RNA is crucial for answering questions about RNA synthesis.