7.3: Translation
Teaching time: 3 hours Practical time: 0 hours
key vocabulary
Prior learning & retrieval practice
Review 7.2 transcription & translation
Review 7.1 DNA & RNA structure
Essential idea: Information transferred from DNA to mRNA is translated into an amino acid sequence.
Exercise 1: Watch this video from the end of the process of transcription (7min30secs) and connect-extend-challenge.
Exercise 2: Click on the link below to find out more about translation and answer the following questions:
What are the three stages of translation?
What is the role of the ribosome?
What structures does the ribosome have to aid translation?
What is the role of tRNA?
Guidance from the syllabus Names of the tRNA binding sites are expected as well as their roles.
Translation
S2: The use of molecular visualization software to analyse the structure of eukaryotic ribosomes and a tRNA molecule.
Exercise 3: Review the articles below to visualise the structures of ribosomes and tRNA.
Exercise 4: Watch some additional sources related to the discovery of the structure of ribosomes and the process of translation.
A1: tRNA-activating enzymes illustrate enzyme–substrate specificity and the role of phosphorylation.
Exercise 5: Outline the role of tRNA activating enzymes. How do they illustrate enzyme-substrate specificity? What is the role of phosphorylation?
U1: Initiation of translation involves assembly of the components that carry out the process.
Exercise 6: Outline the initiation stage of translation. Guidance from the syllabus: Examples of start and stop codons are not required.
U2: Synthesis of the polypeptide involves a repeated cycle of events.
Exercise 7: Outline the elongation stage of translation.
U3: Disassembly of the components follows termination of translation.
Exercise 8: Outline the termination stage of translation.
U4: Free ribosomes synthesize proteins for use primarily within the cell.
U5: Bound ribosomes synthesize proteins primarily for secretion or for use in lysosomes.
U6: Translation can occur immediately after transcription in prokaryotes due to the absence of a nuclear membrane.
Exercise 9: List some proteins and their functions that are synthesised on free ribosomes and some on bound ribosomes.
S1: Identification of polysomes in electron micrographs of prokaryotes and eukaryotes.
Exercise 10: What is a polysome? Can you identify them in the pictures below?
NoS: Developments in scientific research follow improvements in computing—the use of computers has enabled scientists to make advances in bioinformatics applications such as locating genes within genomes and identifying conserved sequences. (3.7)
Exercise 11: List some of databases that bioinformatic researchers use to study genetics.
Protein Structure
U7: The sequence and number of amino acids in the polypeptide is the primary structure.
U8: The secondary structure is the formation of alpha helices and beta pleated sheets stabilized by hydrogen bonding.
U9: The tertiary structure is the further folding of the polypeptide stabilized by interactions between R groups.
Guidance from the syllabus: Polar and non-polar amino acids are relevant to the bonds formed between R groups.
U10: The quaternary structure exists in proteins with more than one polypeptide chain.
Guidance from the syllabus: Quaternary structure may involve the binding of a prosthetic group to form a conjugated protein.
Exercise 12: Outline the primary, secondary, tertiary and quaternary structure of proteins.
Big Picture Proteins.pdf