Question

What are the four nitrogenous bases found in RNA? a. cytosine, guanine, thymine, uracil (C, G, T, U) b. adenine, cytosine, guanine, thymine (A,C, G, T) c. adenine, cytosine, guanine, uracil (A,C, G, U) d. alanine, cysteine, glycine, threonine (A, C, G, T)

Short answer

The four nitrogenous bases found in RNA are adenine, cytosine, guanine, and uracil (A,C, G, U). Option c is the correct answer.

Step-by-step solution

Understand the structure of RNA

Ribonucleic acid (RNA) is a nucleic acid that plays a crucial role in the genetic machinery of cells. RNA is composed of a sugar-phosphate backbone and nitrogenous bases. The nitrogenous bases are the specific molecules that encode genetic information.

Eliminate the incorrect options

a. cytosine, guanine, thymine, uracil (C, G, T, U) Thymine is not a nitrogenous base found in RNA but is present in DNA, so option a is incorrect. b. adenine, cytosine, guanine, thymine (A,C, G, T) This option lists the nitrogenous bases in DNA, not RNA. Thymine is specific to DNA, so option b is incorrect. d. alanine, cysteine, glycine, threonine (A, C, G, T) These are amino acids, not nitrogenous bases. Amino acids are the building blocks of proteins, not nucleic acids like RNA. Therefore, option d is incorrect.

Confirm the correct option

c. adenine, cytosine, guanine, uracil (A,C, G, U) This option lists the correct nitrogenous bases found in RNA. Unlike DNA, RNA contains uracil instead of thymine. Therefore, option c is correct.

Conclusion

The four nitrogenous bases found in RNA are adenine, cytosine, guanine, and uracil (A,C, G, U), making option c the correct answer.

Key concepts

RNA Structure

RNA, or ribonucleic acid, is a vital molecule that plays various roles in encoding, transmitting, and regulating genetic information. Its structure is similar to DNA, but with a few key differences. One defining feature of RNA is the sugar in its backbone, which is ribose, as opposed to the deoxyribose sugar found in DNA. This ribose sugar has one more hydroxyl (OH) group than deoxyribose, making RNA more reactive and less stable than DNA.

Furthermore, RNA is single-stranded, allowing it to fold into complex 3D shapes, unlike the double helix of DNA. This single-stranded nature and flexibility enable RNA to participate in diverse biological processes, from acting as a messenger carrying instructions from DNA for protein synthesis, to playing structural and catalytic roles in cells.

Nitrogenous Bases in RNA

The nitrogenous bases in RNA are adenine (A), cytosine (C), guanine (G), and uracil (U). These bases are critical for RNA's function, as they form the sequence that determines the genetic code.

Genetic Information Encoding

The genetic information in an organism is encoded by the sequence of nitrogenous bases along the nucleic acid strands, such as RNA and DNA. In RNA, these sequences are read by the cell's machinery to create proteins, which perform a multitude of functions necessary for life. Each group of three bases in an RNA sequence, called a codon, corresponds to a specific amino acid, the building block of proteins.

For example, the codon ACC in RNA would link to the amino acid threonine. This process of translating RNA sequences into proteins is known as translation, and it is a key part of the central dogma of molecular biology, which diagrams the flow of genetic information from DNA to RNA to protein.

Difference Between DNA and RNA

While both DNA and RNA are essential for life, these nucleic acids have distinct characteristics. DNA — deoxyribonucleic acid — is the genetic blueprint for a living organism and is found mainly in the cell nucleus. It's double-stranded, forming the iconic double helix and is more stable than RNA due to its deoxyribose sugar and lack of a hydroxyl group at the 2' position.

RNA, on the other hand, typically exists as a single strand, making it more versatile but also more prone to degradation. The most significant difference between RNA and DNA, though, is in their nitrogenous bases; RNA contains uracil in place of thymine (T), which is found in DNA. This difference is not just structural but functional, as thymine makes DNA more stable and less susceptible to mutations, while uracil allows for temporary and flexible encoding in RNA, fitting for its various roles in the cell.