A DNA sequence specifies an enzyme containing 120 amino acids. A substance prevents carrier molecules from delivering one particular amino acid to ribosomes. The first position requiring this amino acid is position 41.
Assume ribosomes cannot skip a position or use a different amino acid, and no new complete enzyme molecules can be made. Existing complete enzyme molecules are initially unaffected.
Which prediction correctly links the immediate effect on protein synthesis to the later effect after existing enzyme molecules have been broken down?
New chains stop at 41 amino acids; the enzyme-controlled reaction later slows.
New chains stop at 40 amino acids; the enzyme-controlled reaction later slows.
New chains stop at 40 amino acids; the enzyme-controlled reaction later continues unchanged.
New chains stop at 41 amino acids; the enzyme-controlled reaction later continues unchanged.
76 exam-style questions on AQA GCSE Biology 6.1 Reproduction, covering 6.1.1 Sexual and asexual reproduction, 6.1.2 Meiosis, 6.1.3 Advantages and disadvantages of sexual and asexual reproduction, 6.1.4 DNA and the genome, 6.1.5 DNA structure, 6.1.6 Genetic inheritance, 6.1.7 Inherited disorders, and 6.1.8 Sex determination. Each one has a worked solution and a mark scheme showing where the marks go.