Apbio

Construct a diagram below to depict the four possible normal products of meiosis that would be produced by the F, progeny. Show the chromosomes and the allele(s) they carry. Assume the genes are located on different chromosomes and the gene for flower color is on chromosome 1.

The possible phenotypic ratio is 1 green dwarf: 1 green tall: 1 purple dwarf: 1 purple tall

Predict the possible phenotypes and their ratios in the offspring of a testcross between an F1 individual and a ggdd individual.

If the genes were linked, then greater than 25 percent would be green dwarf plants and greater than 25 percent would be purple tall plants and the ratio wouldnt be 1:1:1:1.

If the two genes were genetically linked, describe how the proportions of phenotypes of the resulting offspring would most likely differ from those of the testcross between an F, individual and a ggdd individual.

A single base pair mutation of the insertion or deletion type results in a frameshift mutation, meaning that none of the codons transcribed after that mutation will be correct. These new codons code for entirely different amino acids and match with different tRNA anticodons. After the mutation, the primary structure will be completely different, which can disrupt the folding of the protein at secondary, tertiary, and even quaternary levels. This can change how the protein functions—or stop it from working altogether.

Since DNA follows the central dogma (DNA → RNA → protein), a mutation at the DNA level carries over into transcription and translation. The mRNA produced will have the wrong sequence, and when it’s read at the ribosome, the resulting polypeptide will likely misfold or lose its original function. For example, if the mutation happens in an enzyme, the active site might not form correctly, so it won’t bind to its substrate properly. If the protein is structural, like collagen, it might not provide the necessary support. Either way, even a single base-pair change can have major effects on the protein’s final shape and role in the cell.

Explain how a single base-pair mutation in DNA can alter the structure and, in some cases, the function of a protein.

In sickle cell anemia, the genetic mutation alters, one of the proteins and red blood cells, causing them to become sickled shape and not transport O2 and CO2 as well as normal shaped cells do. This results in weakness, decreased fitness, and sickness in sickle cell patients, but also grant them resistance to the malaria virus as it usually latches onto the groove in the donut shaped red blood cells. Most mutations have neutral consequences. Some are harmful, and few of them are beneficial.

Explain, using a specific example, the potential consequences of the production of a mutant protein to the structure and function of the cells of an organism. (4 points maximum)

A mutant allele can increase in frequency over time if it provides a reproductive or survival advantage in a given environment. When individuals carrying this beneficial allele are more likely to survive and reproduce, they pass the allele on to their offspring at higher rates. Over multiple generations, natural selection amplifies the allele’s presence in the population. Additionally, factors like genetic drift (especially in small populations) or changes in the environment that favor the new trait can further boost the allele’s frequency. As a result, what starts as a rare mutation may eventually become common—or even fixed—within the population. Reword this please

Describe how the frequency of an allele coding for a mutant protein may increase in a population over time. (4 points maximum)