Content Objective: Understand the triplet nature of the genetic code, including the concepts of "degeneracy" and "universality," and its role in encoding amino acids. Explore transcription as the synthesis of RNA using a DNA template, focusing on the roles of RNA polymerase, complementary base pairing, and DNA stability in conserving genetic sequences for gene expression. Examine translation as the process of synthesizing polypeptides from mRNA, emphasizing codon-anticodon interactions, directionality, ribosomal movement, and peptide bond formation during elongation.
Language Objective: Use precise scientific terminology, including "template strand," "RNA polymerase," "codon," "anticodon," and "peptide bond," to describe the processes of transcription and translation. Explain how complementary base pairing enables RNA synthesis, how mRNA codons determine amino acid sequences, and the functional roles of ribosomal binding sites, demonstrating the regulation of gene expression and protein synthesis.
Syllabus Details:
Transcription:
D1.2.8 - Features of the genetic code - "Students should understand the reasons for a triplet code. Students should use and understand the terms 'degeneracy' and 'universality'."
D1.2.1 - Transcription as the synthesis of RNA using a DNA template - "Students should understand the roles of RNA polymerase in this process."
D1.2.2 - Role of hydrogen bonding and complementary base pairing in transcription - "Include the pairing of adenine (A) on the DNA template strand with uracil (U) on the RNA strand."
D1.2.3 - Stability of DNA templates - "Single DNA strands can be used as a template for transcribing a base sequence, without the DNA base sequence changing. In somatic cells that do not divide, such sequences must be conserved throughout the life of a cell."
D1.2.4 - Transcription as a process required for the expression of genes - "Limit to understanding that not all genes in a cell are expressed at any given time and that transcription, being the first stage of gene expression, is a key stage at which expression of a gene can be switched on and off."
Translation
D1.2.5 - Translation as the synthesis of polypeptides from mRNA - "The base sequence of mRNA is translated into the amino acid sequence of a polypeptide."
D1.2.6 - Roles of mRNA, ribosomes, and tRNA in translation - "Students should know that mRNA binds to the small subunit of the ribosome and that two tRNAs can bind simultaneously to the large subunit."
D1.2.7 - Complementary base pairing between tRNA and mRNA - "Include the terms 'codon' and 'anticodon'."
D1.2.9 - Using the genetic code expressed as a table of mRNA codons - "Students should be able to deduce the sequence of amino acids coded by an mRNA strand."
D1.2.10 - Stepwise movement of the ribosome along mRNA and linkage of amino acids by peptide bonding to the growing polypeptide chain - "Focus on elongation of the polypeptide, rather than on the special events of initiation and termination."
D1.2.12 - Directionality of transcription and translation - "Students should understand what is meant by 5' to 3' transcription and 5' to 3' translation."
D1.2.17 - Initiation of translation - "Include attachment of the small ribosome subunit to the 5' terminal of mRNA, movement to the start codon, attachment of the large subunit, the initiator tRNA and another tRNA. Students should understand the roles of the three binding sites for tRNA on the ribosome (A, P, and E) during elongation."
Activity 1 - Translation and Transcription Notes
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