Instructions: Consult your textbook if necessary. These are practice questions; you do not have to turn in your answers.
- The following is a base sequence in one coding strand of a DNA molecule:5′ — T A C A T A G T A G T T A C G T C G C C C G G A ↓ A A T A T C — 3′Using the base-pairing rules, write out the base sequence in the complementary strand of DNA (5′ to 3′).
- Using the base-pairing rules, write out the base sequence of the mRNA strand that is made from the above coding strand of DNA (5′ to 3′).
- Using the genetic code chart, write out the amino acid sequence of the polypeptide that is made if a ribosome begins translating the above mRNA strand.
- Suppose that during replication, an extra “C” nucleotide is accidentally inserted into the DNA coding strand at the point in the sequence indicated by the arrow. Write out the amino acid sequence of the polypeptide that is made when the mutated DNA strand is transcribed and translated.
- Referring to the last question, at how many positions in the original sequence and the mutated polypeptide sequence are the amino acids the same? What type of mutation has occurred?