Explanation:
The modern theory of chemical evolution is based on the assumption that on a primitive earth a mixture of simple chemicals assembled into more complex molecular systems, from which, eventually came the first functioning cell(s).
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>.
A. They impede fish migration and spawning
Answer:
breaking bonds of sugars to form new molecules
Explanation:
Answer:
Reproductive isolation refers to the inability of an organism or species to breed successfully with other organism or species.
It may arise from various factors such as:
- Geographical isolation such as river, mountain, etc
- Behavioral changes such as mating time or season, mating rituals, mating location etc.
- Physiological differences such as change in shape of sex organs which causes lack of fit between copulatory organs.
- Genetic differences.
Reproductive and geographical isolations between two populations (of same species) inhibit the flow of genes among them. Slowly, these isolations increase the variations in the gene pools of the two populations.
These genetic variations keep on increasing with time. In addition, as an adaptation to their surrounding or habitat the two populations would develop different behavioral and physiological changes
With time, these differences will increase up to such an extent that the two populations would not be able breed with each other. Hence, it would lead to the evolution of one or both the populations into new species.
