26. Nucleic Acids and Protein Synthesis

The following is a segment of the DNA template that codes for human insulin: TTT GTG AAC CAA CAC CTG 

b. Write the three-letter and one-letter abbreviations for this corresponding peptide segment.

Consider the following segment of mRNA produced by the normal order of DNA nucleotides:

ACA UCA CGG GUA

e. What is the amino acid order if an insertion mutation adds a G to the beginning of the mRNA segment?

Consider the following segment of mRNA produced by the normal order of DNA nucleotides:

ACA UCA CGG GUA

f. What is the amino acid order if a deletion mutation removes the A at the beginning of the mRNA segment?

A point mutation in the mRNA for an enzyme results in the replacement of leucine with alanine in the resulting enzyme molecule. Why does this change in amino acids have little effect on the biological activity of the enzyme?

A specific virus contains RNA as its genetic material.

a. Why would reverse transcription be used in the life cycle of this type of virus?

A specific virus contains RNA as its genetic material.

b. What is the name of this type of virus?

How do protease inhibitors disrupt the life cycle of the HIV virus?

The following is a segment of the template strand of human BRCA1 gene:

TGG AAT TAT CTG CTC TTC GCG

b. Write the three-letter and one-letter abbreviations for the corresponding peptide segment.

What is the effect of a deletion mutation on the amino acid sequence of a polypeptide?

How is protein synthesis affected if the normal base sequence TTT in the DNA template strand is changed to TTC?

Consider the following segment of mRNA produced by the normal order of DNA nucleotides:

ACA UCA CGG GUA

a. What is the amino acid order produced from this mRNA?

Consider the following segment of mRNA produced by the normal order of DNA nucleotides:

ACA UCA CGG GUA

b. What is the amino acid order if a point mutation changes UCA to ACA?

 A polypeptide contains 36 amino acids. How many nucleotides would be found in the mRNA for this polypeptide?

A point mutation changes a codon in the mRNA for an enzyme from GCC to GCA. Why is there no change in the amino acid order in the protein?

In sickle-cell anemia, a point mutation in the mRNA for hemoglobin results in the replacement of glutamate with valine in the resulting hemoglobin molecule. Why does the replacement of one amino acid cause such a drastic change in biological function?