The operon is effectively the center of transcriptional control. In addition to its main structural genes, the operon houses an operator and a promoter. In front of the promoter lies a regulatory gene that produces repressor proteins. When a repressor is in its active state, it binds to the operator.
Hope this helped.
Answer:
c. It is a systemic inflammatory disease.
Explanation:
One of the main characteristics of rheumatoid arthritis is that is a systemic inflammatory disease. This disease can affect the entire body and is not just localized to the individual's joints. In many cases the disease has been known to attack an individual's skin, eyes, lings, heart and even the blood vessels within the individual's system.
Answer:
A step that is not part of natural selection is people select which individuals breed and which ones do not.
Explanation:
Natural selection is a process in which favorable or unfavorable environmental conditions determine the evolution of species, producing differences in their genotype over a long period of time.
As its name indicates, it is a natural selection, in which no intervention by people is contemplated, so that <u>people cannot determine which individuals breed</u>.
Natural selection implies that the characteristics on which the environment influences are inheritable, that there is genetic variability in the population and that the variability of these characteristics implies the ease of reproduction and survival capacity.
<em>The other options do form part of natural selection, since they are based on the three premises of this process:
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- <em>Inheritable characteristics.
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- <em>Genetic variability.
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- <em>The variability of characteristics influences reproduction and survival.</em>
Answer:
Explanation:
Duchenne muscular dystrophy acts as a X-linked recessive disease. Which means the gene sits on the X chromosome, and you need two bad copies to show disease (for females) and one bad copy (to show in males).
Now from our knowledge, we know males are XY and females are XX. Males have only one copy of the X chromosome from their mother and one copy of the Y chromosome from their father, thus if they get the mutated version of the gene that causes this disease, they will get the disease. However, if a female has a mutated version of gene on one of the X chromosome, the other X chromosome could have a normal gene and that normal gene would take over and produce a normal phenotype/function.
Since, boys only have one X chromosome, if they get the mutated gene they will get the disease, whereas females have two X chromosome (so even if one copy is bad and the other is good, the good version can take over, however boys don't have this) thus mostly male children are affected by this.
