Pathogens are harmful because they are tiny organisms like a bacterium, a fungi, or a virus that causes people to be sick. It causes diseases like the rhinovirus which is the cause of common cold. It is commonly found in hospital wastes and even the water used in swimming.
The phenomenon where one gene can modify the effect on the second gene is known as epistasis.
In genetics, epistasis is a phenomenon in which the effect of a gene mutation is determined by the presence or absence of mutations in one or more other genes, which are referred to as modifier genes. To put it another way, the genetic background in which the mutation appears determines its effect. It has long been acknowledged that epistasis, or interactions between genes, is fundamental to comprehending both the structure and function of genetic pathways and the evolutionary dynamics of complex genetic systems.
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The presence of lactose enables the lac operon genes to function.
Answer
Eukaryotic cells contain membrane-bound organelles, such as the nucleus, while prokaryotic cells do not
Explanation:
Answer:
The culture medium must be selective
Explanation:
Selective media are the media that have those ingredients which favor the growth of a particular bacterium and inhibit the growth of unwanted bacteria. So a selective media is used to selectively grow a particular micro-organism.
For example, MacConkey agar is a selective media that is used to isolate gram-negative enteric bacteria based on lactose fermenting ability. It contains ingredients like bile salt and crystal violet which inhibits the growth of gram-positive bacteria therefore it only allows the growth of gram-negative bacteria.
<em>Staphylococcus</em> <em>epidermidis</em> is a gram-positive bacteria and <em>E.coli</em> is gram-negative enteric bacteria so MacConkey agar can be used to select E.coli over <em>Staphylococcus</em> <em>epidermidis</em>. So the correct answer is the culture media must be selective.
