D. It must go from areas of low concentration to high, and this is only achievable with the use of energy, ATP!
Answer:
Directional Selection
Explanation:
The type of natural selection that favors one of the extreme phenotypes over the intermediate and another extreme phenotype is called directional selection. Here, the extreme phenotype exhibits better survival and reproductive fitness over the other phenotypic ranges.
In the given example, the frequency of the heat-tolerant allele in microbes is shown to increase under the conditions of higher temperatures of the water of the springs in which they live.
When the temperature of spring water is increased, the frequency of the heat-tolerant allele is reduced and is increased again upon an increase in water temperature.
Since the natural selection favors the extreme phenotype (microbes with heat tolerance) when the spring water exhibits higher temperatures, it is directional selection.
This is True because the Eco-System is aways changing since pollution is killing birds animals and other insects.
Answer: Yes. Splicing can be done in different ways to yield different mRNAs wich will create different proteins. Prokaryotes are not able to do this.
Explanation:
DNA (deoxyribonucleic acid) is a molecule that contains the genetic information for synthesizing amino acids that form proteins. To do this, DNA must first be transcribed into RNA (ribonucleic acid) and this is the molecule used for protein synthesis (translation). The newly transcribed RNA (called primary messenger RNA) from DNA results in a very long molecule and also has regions that do not code for anything, called introns, which are removed by a process called splicing. Exons are segments in the RNA that do code for amino acids and remain in the mature mRNA after splicing.
<u>Splicing is a process by which introns are cleaved from the primary messenger RNA and exons are joined to generate mature messenger RNA.</u> In addition, alternative splicing occurs which allows different mRNA isoforms and thus different proteins to be obtained from a primary mRNA transcript. This is because the exons will be joined or spliced in different ways, giving rise to different mature messenger RNA sequences. This process occurs mainly in eukaryotes, although it can also be observed in viruses. But it does not take place in Prokaryotes (Bacteria).
In summary, exons/introns can be spliced together in different ways to yield different mRNAs sequences. Each different mRNA sequence will code for a different protein.
