Which base will pair with uracil in RNA?

The presence of organic matter, such as saliva, pus, blood, or feces, can interfere with the effectiveness of disinfectants. Organic materials can physically shield microorganisms from contact with the disinfectant, reducing its ability to reach and inactivate pathogens. Additionally, some organic compounds can chemically react with the disinfectant, neutralizing its antimicrobial activity. For example, sodium hypochlorite (bleach) can be inactivated by blood or protein-rich substances. Proper pre-cleaning of surfaces to remove organic matter is essential before disinfection to ensure that the disinfectant works effectively and reliably eliminates harmful microorganisms.

A. Point: A point mutation involves a change in a single nucleotide base in the DNA sequence. While it describes the location of the change, it does not specify the effect on the amino acid. A point mutation can result in silent, missense, or nonsense outcomes depending on the codon affected.

B. Nonsense: A nonsense mutation changes a codon to a stop codon, prematurely terminating protein synthesis. This produces a truncated and usually nonfunctional protein, which is distinct from a mutation that does not alter the amino acid sequence.

C. Back: A back mutation (or reverse mutation) occurs when a mutated gene reverts to its original sequence. While this restores the original function, it is not the type of mutation that leaves the amino acid unchanged on the first occurrence.

D. Silent: A silent mutation changes a nucleotide base in the DNA but does not alter the amino acid sequence due to the redundancy of the genetic code. For example, both GAA and GAG code for glutamic acid, so a change from A to G at the third base is silent. This mutation does not affect protein function but may still influence gene expression in rare cases.

E. Missense: A missense mutation changes a single nucleotide and results in a different amino acid being incorporated into the protein. This can alter protein function and structure, unlike a silent mutation which leaves the amino acid unchanged.