Given the sequence of the following DNA strand below, what would be the sequence of DNA that is the complementary strand?
GATTCCTAACTGG
CTAAGGATTGACC
Correct! A pairs with T and C pairs with G.
What percentage of bases in a stretch of double-stranded DNA that contains 40% Adenine (A) bases would be Guanine (G)?
10%
Correct! If you had a double stranded DNA that contains 40% adenine, you could deduce that 10% of the DNA would be guanine. You know that if you have 40% adenine, you must also have 40% thymine as its complementary pair, so this leaves a total of 20% that would be divided between an equal proportion of cytosine (10%) and guanine (10%) that are also complementary pairs.
Can't Determine
Incorrect
Antiparallelism means that
the two strands of a DNA molecule run in opposite directions.
Correct! The two chains of nucleotides align in a head to toe relationship- or an opposing direction
the DNA double helix twists first one way, then the other.
Incorrect
the DNA bases are sometimes on the outside of the molecule.
Incorrect
the DNA molecule cannot dissolve in water.
Incorrect
DNA replication is called semiconservative because ___________of the original double stranded DNA molecule appears in the newly synthesized DNA strand formed in replication.
Half
Correct! This is the correct answer because newly synthesized DNA double helices are “hybrid” molecules made up of one parental strand and one new daughter strand.
All of the following are possible genotypes for the parents of a person affected by Huntington’s disease EXCEPT?
hh + hh
Correct! c. is the correct answer because Huntington’s disease is an autosomal dominant disorder, so that at least one of the parents carries the mutated HD gene. It is theoretically possible to have HH + HD or HH or HH, but HH is usually not compatible with life. To muddy the water, it is possible though uncommon for an offspring to have a de novo mutation (a new mutation) for HD when one of the parents carries a high “normal” allele (high number of CAG trinucleotide repeats, but within the normal range) for the HD gene.