Answer:
The type of mutation responsible for changing a base in the mRNA strand, without changing the coding aminoacid or protein, is called a <u>silent</u> mutation.
Explanation:
In a silent mutation occurs the change of a nitrogenous base in one of the codons that encodes an aminoacid, without changing the aminoacid or altering the structure or function of the protein to be synthesized.
In this type of mutations the change of the base does not mean the change of the aminoacid, because some aminoacids can be coded with more than one codon. In the case of Leucine, the codons that encode it are CUU, CUC, CUG or CUA, so even if a base changes, the final protein will be the correct one.
For the other options:
- <u><em>Missense</em></u><em>: the change of the base in the DNA chain implies the change of the codon in the mRNA and of the encoded aminoacid, in that way a structural and functional alteration of the synthesized protein occurs. </em>
- <u><em>Nonsense</em></u><em>: the change in the nitrogenous base in the DNA leads to the coding of a termination codon, so that the protein is ultimately incomplete.</em>
- <u><em>Insertion</em></u><em>: in this case there is the addition of more nitrogenous bases to the DNA chain, with respect to the original one.</em>
germ cells
it occours in the germ cells
<span>Cocaine Preparations
-Coca leaves --> Coca Paste (60% pure): Not water soluble, so you can't inject it into the bloodstream -- you need an additional chemical step to turn the paste into crystal powder that can be injected or snorted
-Coca --> Cocaine Hydrochloride (99% pure): Doesn't hold up very well to heat, so you can't smoke cocaine hydrochloride
-Cocaine Hydrochloride (99% pure) --> Free-Base Cocaine or Crack Cocaine:
-Reconvert cocaine hydrochloride back to base state by removing hydrochloride from cocaine (that's why it's called free-base cocaine)
-Crack cocaine is a crystallized form, mixture of cocaine and baking soda
-75% pure
-Can be used at lower doses and is much cheaper than cocaine
-Can be smoked</span>
