Answer:
The colonies are carrying the resistance genes from plasmids
Explanation:
Bacteria can acquire beneficial characteristics that they didn’t have. One way for these is through plasmids, which ones are little fragments of DNA that usually contains resistance genes (for antibiotics, disinfectants, heavy metals, etc.) or other capacities, like the ability to use some substances (for example sugars).
In this specific situation, we already know that the plasmid carrying genes for tetracycline resistance and the <em>lacZ</em> gene.
A little explanation:
Tetracycline is an antibiotic that inhibits bacterial growth and kills the bacteria. The bacteria can “fight” to this antibiotic if it has a resistant gene, the result is that the antibiotic can’t affect the bacteria and survive. An analogy is like a Police Officer (bacteria) that have a bulletproof vest (tetracycline-resistant gene) so the bullets (tetracycline) didn’t affect the police.
In the case of X-gal, is a compound consisting primarily in one sugar called galactose. Not all bacteria can eat galactose, they need an enzyme called β- galactosidase (comes from <em>lacZ</em> gene) that helps the bacteria “eat” the sugar (cuts the sugar in little pieces so the bacteria can eat).
Then, as the bacterial colonies can grow in the medium with tetracycline and X-gal, we know that those bacteria are carrying the resistance genes for tetracycline (does not affect the bacteria) and the <em>lacZ</em> gene (bacteria produce β- galactosidase that cuts galactose). These genes are coming from the plasmids because we already know that the plasmid carries these genes and not from the exogenous DNA.
The monomers<span> of these organic groups are:</span>Carbohydrates...<span>monosaccharides. Lipids...glycogen and fatty acids...Nucleic acids...nucleotides.
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Skeletal muscle fiber is a muscular tissue that is attached to the skeletal system. the skeletal muscle fibers are striated muscles i.e have striations in their structure. The skeletal muscle fibers are voluntary muscles i.e they can be controlled.
Motor unit is a composed of a motor nerve cell attached to a muscle fiber with its axon terminals. Motor nerve cells or neurons are the types of neurons that send impulses from the central nervous system to the responding organ. The muscle fiber may be attached to many neurons not only one neuron. Collectively, all the neurons attached to the same muscle fiber are called motor pool.
A skeletal muscle twitch is the contraction of a muscle fiber in response to the minimum stimulation.
The electrical stimulus is the stimulation of a skeletal muscle fiber by using external electrical impulses. The electrical stimulus is important in many sporting and medical situations.
A latent period is a period between applying a stimulus to a muscle fiber and the response of this muscle fiber by contraction.
