The trp repressor blocks transcription of the trp operon (B) when the repressor binds to tryptophan.
trp operon or the tryptophan operon codes enzymes for the amino acid tryptophan. The operon is on when the tryptophan is low in amount whereas the operon is off when the tryptophan is low in amount. The operon is an assimilation of five genes.
Repressor is a small protein that is supposed to prevent the synthesis of proteins. It does so binding to the operator gene. Therefore, presence or absence of repressor is a determining factor for an operon to be on or off.
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Answer:
Lipids are hydrophobic because they do not mix with water. Lipids are made of long chains of carbon and hydrogen. ... The partial charges on the water molecule cannot interact with the neutral lipid molecule and thus water and lipids do not mix.
The reason for the loss of color after the industrial revolution is that the light-colored moths were "selected against" by predators. These birds could only see the light ones against the newly dark, sooted background. Over time, these predators could no longer distinguish the dark ones from their natural dark, sooted background. Thus more light-colored moths stood out against the dark soot, and were eaten. And more dark-colored moths eluded the birds, survived to reproduce, passing on more of their dominant genes for dark color to their offspring. After several decades of hundreds of thousands of generations, most of the later generations were dark, due to selective advantage of camouflage to survive predation.
The answer is B) <span>Nuclear power has far less environmental impact than using coal or natural gas to produce electricity.</span>
Answer:
C) Nucleic Acid
D) Capsid
Explanation:
A virus is structure that is dependent on a living host to replicate itself. Viruses are majorly pathogenic in nature and have a structure that is made up of two parts namely: nucleic acid and capsid.
The nucleic acid, which can either be RNA or DNA holds the genetic information of the virus while the capsid is a protein coat that enclosed and protects the virus' genetic material. The capsid is also used during the infection life cycle of a virus where it helps the virus to attach to receptor cells on the host's cell membrane.