If the alcohol concentration in PEA agar was increased, it would inhibit both Gram - and Gram + bacteria by breaking down membrane absorbency barrier, tolerating influx of substances that are generally blocked and leakage of cellular potassium. High alcohol concentrations would lead to disruption or halting of DNA synthesis in both Gram + and Gram - bacteria
This is because not all genes are expressed at the same time, so not all the proteins are present at a certain moment. The mechanisms that cell uses to control gene expression are called regulation of the gene expression. Thanks to regulation of the genes, cells have the ability to increase or decrease the production of specific gene products such as proteins. This property is important for the adaptability of an organism because it allows the cell to express protein when needed.
A. The mutation that occurs during meiosis is a sure way of gene splitting I presume:)