Answer:
If a DNA molecule has 30% Adenine the percentage of the other bases is Thymine: 30% Cytosine: 20% Guanine: 20%.
Explanation:
When the percentage that a base has in a DNA molecule is given, the percentage of the other bases can be known using the Chargaff's base pair rule.
A DNA molecule has the information of the genome of a living being, according to a specific sequence of its nitrogenous bases adenine, guanine, cytosine and thymine.
Chargaff was able to establish that in a DNA molecule the ratio of purine : pyrimidine of 1:1, so there must be the same amount of thymine as adenine and a similar amount of guanine for the cytosine, taking into account the complementarity of bases.
Taking into account the law of the base pair, if in a DNA chain there is 30% of Adenine, in the molecule there is:
- <em>Adenine 30%.
</em>
- <em>Thymine 30%.
</em>
- <em>Cytosine 20%.
</em>
- <em>Guanine 20%.
</em>
- <em>Total ..... 100%
</em>
In this case, the <u>Chargaff rule is useful to determine the percentage of nitrogenous bases that exist in a DNA molecule, knowing the percentage of a single base</u>.
Answer:
D. Many amino acids are encoded by multiple codons. A gene mutation that encodes the same amino acid would have no observable effect on the cell or the organism
Explanation:
If gene mutation does not change code (gene still encodes for the same amino acid), the same protein with its function will be produced. This is called synonymous mutation.
Silent mutations might also occur when codon is altered to produce an amino acid with similar function as previous (e.g. leucine to isoleucine) so that the function of protein is not significantly changed.
Answer:
Mechanical incompatibility.
Explanation:
Mechanical incompatibility: occurs when species cannot mate because their reproductive structures are incompatible – In animals with internal fertilization, male and female sexual organs may not fit together – For example, snails of species whose shells have left-handed spirals may be unable to copulate successfully.
Mechanical incompatibility of male and female genitalia is common in animals with internal fertilization. However, our knowledge regarding the precise mechanisms is limited.
