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6 (a) Describe how a section of DNA determines the structure of a protein - Edexcel - GCSE Biology - Question 6 - 2013 - Paper 1
Question 6
6 (a) Describe how a section of DNA determines the structure of a protein. (b) Describe the structure of DNA, including the roles of the scientists involved in its ... show full transcript
Worked Solution & Example Answer:6 (a) Describe how a section of DNA determines the structure of a protein - Edexcel - GCSE Biology - Question 6 - 2013 - Paper 1
Step 1
Describe how a section of DNA determines the structure of a protein.
Answer
A section of DNA contains a sequence of nucleotides that is transcribed into messenger RNA (mRNA) during the process of transcription. Each group of three nucleotides in the mRNA, known as a codon, corresponds to a specific amino acid.
During the process of translation, the mRNA is read by ribosomes, which facilitate the assembly of amino acids in the order specified by the codons. As a result, the sequence of amino acids determines the primary structure of the protein. This sequence subsequently folds into various shapes, which are critical for the protein's function.
Step 2
Describe the structure of DNA, including the roles of the scientists involved in its discovery.
Answer
DNA, or deoxyribonucleic acid, is a double helix composed of two long strands of nucleotides. Each nucleotide consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The two strands are held together by hydrogen bonds between complementary bases (A with T and C with G), forming the rungs of the ladder-like structure.
The structure of DNA was elucidated by James Watson and Francis Crick in 1953, who built upon the foundational work of Rosalind Franklin, whose X-ray diffraction images provided critical insights into its helical structure. Chargaff's rules, established by Erwin Chargaff, also played a crucial role in understanding base pairing, which further aided Watson and Crick in confirming the double helix model.