A molecular biologist is engineering a synthetic plasmid for mammalian gene expression. Analysis of a specific double-stranded promoter region within this plasmid reveals that 31% of the nitrogenous bases are cytosine.
What is the percentage of each of the other three bases in this double-stranded promoter region?
31%31\%31% Adenine, 19%19\%19% Guanine, 19%19\%19% Thymine
19%19\%19% Adenine, 31%31\%31% Guanine, 19%19\%19% Thymine
19%19\%19% Adenine, 19%19\%19% Guanine, 31%31\%31% Thymine
38%38\%38% Adenine, 31%31\%31% Guanine, 38%38\%38% Thymine
72 exam-style questions on OCR GCSE Biology 1.2 What happens in cells (and what do cells need)?, covering 1.2.1 Structure of DNA, 1.2.2 Nucleotides and complementary bases, 1.2.3 Protein synthesis, 1.2.4 DNA structure and the proteins made, 1.2.5 Investigating enzymatic reactions, and 1.2.6 Mechanism of enzyme action. Each one has a worked solution and a mark scheme showing where the marks go.