In a double-stranded DNA molecule 35 percent of the bases are adenine. What percentage are guanine?
Answer and explanation
Correct answer: B. 15%
- Step 1: A pairs with T, so thymine is also 35%.
- Step 2: A + T = 70%; the remaining 30% is G + C, shared equally, so G = 15%.
Answer
15%.
Why not the others: 35%: guanine was assumed to be as common as adenine. 30%: this is the combined percentage of guanine and cytosine. 85%: the percentages were added.
Practise more Genetics and molecular biology.
Free questions with an explanation for every one, and full timed Wazari Exam (Iraq Baccalaureate) - Scientific Branch mock tests.
More Genetics and molecular biology questions
- Two heterozygous tall pea plants (Dd) are crossed. Tall is completely dominant. What fraction of the offspring are short?
- A heterozygous tall plant (Dd) is crossed with a short plant (dd). What fraction of the offspring are tall?
- Two healthy parents are both carriers (Aa) of an autosomal recessive disease. Their child is healthy. What is the probability that the child…
- In a cross AaBb x AaBb with independent assortment, what fraction of offspring are aabb?
- A woman who carries the allele for X-linked red-green colour blindness marries a man with normal colour vision. What is the probability that…
- A woman who carries the allele for X-linked red-green colour blindness marries a man with normal colour vision. What is the probability that…