Many types of obstacles hinder biomedical scientists from solving health-related challenges. Money that is needed for researches is one of them and you must cooperate with funding agencies. For innovative work you must think outside the box. Also you need to spend too much time for "paperwork".
Answer: <u>Both parents are heterozygous carriers</u>.
Explanation: Since sickle cell disease is a recessive trait, it means the affected person will have "homozygous recessive" state of genotype only. Here parents are normal, which means they are carriers. So their genotype would be Ss, heterozygous.
Heterozygous parents only will have 25% chances of having their children affected.
Option 1 is incorrect, because if one parent has two recessive alleles, it means he/she is affected and this contradicts the situation mentioned in question.
Option 3 and 4 are incorrect because it is mentioned in question that both parents are normal.
Answer:
Since there is presence of excess tryptophan, the trp operon will be switched off, since the bacterial need not to synthesize.
Explanation:
Understand the following.
The trp operon is a group of gene that encode biosynthetic enzymes for the amino acid tryptophan.
The transcription gene in the operon is switched off when the tryptophan is in excess but is switched on by the bacterium when the tryptophan is low, so that more tryptophan can be produced.
The answer that makes most sense to me is D. We stopped needing to kill whales, yay! :P
The important point is that the surface area<span> to the </span>volume ratio<span> gets smaller as the </span>cell<span> gets larger. Thus, if the </span>cell<span>grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased </span>cellular volume<span>.</span>
