Table 4.1 shows a sequence of 12 nucleotides in the template strand of a short length of a DNA molecule, the corresponding primary transcript and the four amino acids coded for by the sequence. The table is incomplete. (i) Complete Table 4.1 to show the sequence of nucleotides in the primary transcript that would result from transcription of this short length of DNA. (ii) Table 4.2 shows all the possible template strand DNA triplets that code for the amino acids labelled aa1, aa2, aa3 and aa4 in Table 4.1. (iii) One type of gene mutation is caused by the substitution of a DNA nucleotide. Using the information in Table 4.2, state and explain the effect on the final protein structure of a substitution of the nucleotide at position 3 in Table 4.1. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ................................................................................................................................. (iv) A second type of gene mutation is caused by the deletion of a DNA nucleotide. Using the information in Table 4.2, state and explain the effect on the final protein structure of a deletion of the nucleotide at position 3 in Table 4.1. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . .................................................................................................................................

Biology

IGCSE&ALevel

CAIE

Exam No：9700_m24_qp_22 Year：2024 Question No：4(a)

Answer:

Knowledge points:

6.2.1 state that a polypeptide is coded for by a gene and that a gene is a sequence of nucleotides that forms part of a DNA molecule

6.2.2 describe the principle of the universal genetic code in which different triplets of DNA bases either code for specific amino acids or correspond to start and stop codons

6.2.3.1 RNA polymerase

6.2.3.2 messenger RNA (mRNA)

6.2.3.3 codons

6.2.3.4 transfer RNA (tRNA)

6.2.3.5 anticodons

6.2.3.6 ribosomes

6.2.4 state that the strand of a DNA molecule that is used in transcription is called the transcribed or template strand and that the other strand is called the non-transcribed strand

6.2.5 explain that, in eukaryotes, the RNA molecule formed following transcription (primary transcript) is modified by the removal of non-coding sequences (introns) and the joining together of coding sequences (exons) to form mRNA

6.2.6 state that a gene mutation is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide

6.2.7 explain that a gene mutation is a result of substitution or deletion or insertion of nucleotides in DNA and outline how each of these types of mutation may affect the polypeptide produced

Answer:

Knowledge points:

Solution:

Related Question