UNIT 5 BIOLOGY PAST PAPERS AND ANSWERS Why is the genetic code described as trial universal? (In all organisms/DNA,) the same triplet codes for the same amino acid; The genetic code uses four different DNA bases. What is the maximum number of different DNA triplets that can be made using these four bases? 64 Transcription of a gene produces pre-mRNA. Name the process that removes base sequences from pre-mRNA to form mRNA Splicing Figure 1 shows part of a pre-mRNA molecule. Geneticists identified two mutations that can affect this pre-mRNA, as shown in Figure 1. Mutation 1 leads to the production of a non-functional protein. Explain why. (Mutation) changes triplets/codons after that point/causes frame shift; Changes amino acid sequence (after this)/codes for different amino acids (after this); Affects hydrogen/ionic/sulfur bond (not peptide bond); Changes tertiary structure of protein (so nonfunctional); What effect might mutation 2 have on the protein produced? Explain your answer. Intron non-coding (DNA)/only coding; (So) not translated / no change in mRNA produced / no effect (on protein) / no effect on amino acid sequence; OR Prevents/changes splicing; (So) faulty mRNA formed; Get different amino acid sequence; A biologist investigated the behaviour of a species of worm that in soil. He cultured three samples of worms in three separate trays of soil for many days. Each culture:
UNIT 5 BIOLOGY PAST PAPERS AND ANSWERS Why is the genetic code described as universal? (In all organisms/DNA,) the same triplet codes for the same amino acid; The genetic code uses four different DNA bases. What is the maximum number of different DNA triplets that can be made using these four bases? 64 Transcription of a gene produces pre-mRNA. Name the process that removes base sequences from pre-mRNA to form mRNA Splicing Figure 1 shows part of a pre-mRNA molecule. Geneticists identified two mutations that can affect this pre-mRNA, as shown in Figure 1. Mutation 1 leads to the production of a non-functional protein. Explain why. (Mutation) changes triplets/codons after that point/causes frame shift; Changes amino acid sequence (after this)/codes for different amino acids (after this); Affects hydrogen/ionic/sulfur bond (not peptide bond); Changes tertiary structure of protein (so nonfunctional); What effect might mutation 2 have on the protein produced? Explain your answer. Intron non-coding (DNA)/only coding; (So) not translated / no change in mRNA produced / no effect (on protein) / no effect on amino acid sequence; OR Prevents/changes splicing; (So) faulty mRNA formed; Get different amino acid sequence; A biologist investigated the behaviour of a species of worm that in soil. He cultured three samples of worms in three separate trays of soil for many days. Each culture: trial