QUESTION: Which of the following base is not present in DNA?
A Uracil
B Adenine
C Cytosine
D Thymine
ANSWER: Uracil
| Characteristic | DNA | RNA |
| Structure | · Double-stranded, typically a double helix.
· Discovered by Friedrich Miescher in 1869. |
Single-stranded, but can be double-stranded in some viruses. |
| Type of sugar | Deoxyribose sugar | Ribose sugar |
| Base pairs | · Adenine (A)
· Thymine (T) · Cytosine (C) · Guanine (G) |
· Adenine (A)
· Uracil (U) · Cytosine (C) · Guanine (G) |
| Composition | Composed of nucleotides with deoxyribose, phosphate group and one of the four nitrogenous bases. | Composed of nucleotides with ribose, phosphate group and one of the four nitrogenous bases. |
| Base Pairing | · A always pairs with T (in DNA)
· G always pairs with C |
· A pairs with U in RNA
· C pairs with G |
| Function | Stores genetic information in cells. | Transmits genetic information and is involved in protein synthesis. |
| Stability | More stable and less prone to degradation. | Less stable and can be more susceptible to degradation by RNases. |
| Location | Mainly found in the cell nucleus. | Found in the nucleus, cytoplasm and ribosomes. |
| Types | · Genomic DNA
· mitochondrial DNA |
· mRNA (1-5% of total RNA)
· tRNA (10-15% of total RNA) · rRNA (80-85% of total RNA) |
| Role in Protein Synthesis | DNA serves as the template for mRNA synthesis during the process of transcription. | RNA play important role in protein synthesis during the process of translation. |
| Genetic Variability | Less susceptible to mutations and less diverse. | More susceptible to mutations, which can lead to genetic diversity. |