Genetics Answers

2.4) A third triplet in a bacterial gene is TTT. A substitution mutation changes it to ATT. State specifically what effect this would have on the resulting protein.

2.3) During translation, an mRNA molecule has a codon with the triplet sequence 5’-AUC-3’. Which anticodon sequence in tRNA molecule would pair with the codon?

1. 3’-AUC-5’
2. 5’-TAG-3’
3. 3’-GAT-5’
4. 3’-UAG-5’

2.3) What kind of bonds joins amino acid in a polypeptide chain?

1. Ionic bonds
2. Peptide bonds
3. Hydrogen bonds
4. Double bonds

2.3) At what region of DNA does RNA polymerase first bind to a gene?

1. Initiation site
2. Transcribed region
3. Promoter
4. Intron

2.3) RNA polymarases add nucleotides to the growing RNA’s __________

1. 3’
2. 5’
3. Both
4. 3’ to 5’ of the complementary strand

According to Swedish geneticists, some forms of schizophrenia are inherited as autosomal dominant characters. In homozygous potency, the gene is 100%, and in heterozygotes it is 20%. Determine the probability of giving birth to sick children in a family where both parents are heterozygous. What does penetrance show?

Scientists nowadays looking for life in Mars planet. In a research funded by NASA, a team of scientist have synthesized a new genetic material molecule known as “Mars-X” that can be used for living organism in the planet. The chemical composition of this molecule is almost similar to that of life on Earth. As a young scientist, what properties should “Mars-X” molecule have?

a.      A certain form of sickle cell anemia is caused by an autosomal recessive allele. Assume that the mutation rate is 1 x 10-5 and that persons having this condition can only produce about 80% of the normal offspring.

i.        At equilibrium between mutation and selection, what will the frequency of the allele for sickle cell anemia be? Show your calculation.

a.      A recessive allele for green eye (g) has a frequency of 0.25 in population Y and a frequency of 0.025 in population Z. A food shortage in population Y causes a number of people in population Y to migrate to population Z, where they reproduce randomly with the members of population Z. Geneticists estimate that after migration, 25% of the people in population Z consist of people who migrated from population Y.

i.        Determine the frequency of green eye in population Z after the migration by showing its calculation.

You have just discovered a drug that is able to inhibit DNA ligase.

You add this DNA ligase inhibitor to a cell population and let these cells divide. You then isolate the DNA from the daughter cells and analyze it. Before the analysis, the DNA molecules were denatured (the DNA strands were separated into single strands). What do you expect to see?