16. Which of the following rows identify the type of mutation and the process in protein synthesis that is most affected by an insertion of a nucleotide in a gene that codes for a ribosome?
Select one:
a.
Mutation Process
Substitution Translation
b.
Mutation Process
Substitution Transcription
c.
Mutation Process
Frameshift Transcription
d.
Mutation Process
Frameshift Translation
17. Identify the following sources of induced mutations, all of which increase the rate of mutation in human body cells. Which is Physical mutagens or Chemical mutagens?
Radiation exposures from airport security and during high altitude air travel. Answer
Ingredients such as toluene and dibutyl phthalate in nail polish. Answer
Exposure to BPA by heating up food wrapped in plastic wraps in microwaves. Answer
Obtaining a base tan at a tanning salon prior to a beach vacation. Answer
18. Tay Sachs is a rare autosomal recessive disorder that causes mental and physical disabilities leading to death in infants. Affected individuals are lacking the enzyme hexosaminidase, causing lipids to build up in the brain.
The HEXA gene on chromosome 15 codes for hexosaminidase, and a four base pair insertion in the gene results in an altered reading frame and non-functional enzyme being produced. Individuals who are carriers (heterozygotes) of the Tay-Sachs allele are not affected by the disease but appear to have increased protection against tuberculosis.
The incidence of Tay-Sachs disease is much higher among Ashkenazi Jews originating from Eastern Europe than the general population of the United States. About 1 in 3 500 babies of Ashkenazi Jewish heritage are born with Tay-Sachs disease and about 1 in 30 Ashkenazi Jews are carriers compared to about 1 in 320 000 babies born with the disease and about 1 in 300 carriers in the general United States population. Ashkenazi Jews living in Europe at the turn of the century often lived in urban areas with a high incidence of tuberculosis.
A possible explanation for the increased incidence of Tay-Sachs disease among Ashkenazi Jews is
Select one:
a. infection with tuberculosis provided a selective disadvantage to individuals who were heterozygous for the Tay-Sachs allele
b. Ashkenazi Jews are genetically predisposed to carry the Tay-Sachs allele
c. overcrowding predisposed Ashkenazi Jews to an increased chance of Tay-Sachs disease
d. the prevalence of tuberculosis in Eastern Europe provided a selective advantage to individuals who were heterozygous for the Tay-Sachs allele
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