Question

question 39
a dna profile using 15 strs may show as many as ___ bands on a gel.
a 60
b 30
c 15
d 32
e none of the above
question 40
dna is called a double helix because.
a two bases are the rungs.
b the bases are complementary paired.
c two dna strands twist together.
d one dna strand binds to a sugar.
e a dna strand folds into an alpha helix.

Explanation:

For question 39, each STR (Short Tandem Repeat) locus has two alleles (one from each parent), so for 15 STRs, the maximum number of bands is 15*2 = 30. For question 40, DNA is called a double - helix because two DNA strands twist together to form its characteristic structure.

Answer:

Question 39: B. 30
Question 40: C. two DNA strands twist together.