The ionized molecules may lose critical chemical and physical structures, or react with other molecules, making the biochemicals useless. Ultraviolet light does not have enough energy to cause ionization. UV causes damage to nucleic acids by inducing covalent bonds between adjacent thymine bases, resulting in thymine dimerization. The thymine dimers change the structure of DNA, preventing DNA replication and RNA transcription. Chemical agents of microbial control act by changing critical cell chemicals, or interfering with cellular processes.
Many antibiotics are structurally similar to chemicals processed by enzyme systems.
They work by competing with normal chemicals for enzyme active sites. Other antibiotics interfere with RNA or protein synthesis at some point in the process. 1 bent glass rod. 2 sterile 1 mL pipettes. Alcohol for sterilization.