Translation

LO 25.1: Explain the relationship of the genetic code to transcription and translation, including redundancy.

The genetic code consists of triplet codons, which translate to specific amino acids during protein synthesis. Each codon corresponds to an amino acid or serves as a start/stop signal. The redundancy, also known as codon degeneracy, allows for multiple codons to encode the same amino acid, which helps mitigate the effects of mutations.

LO 26.2: Label components of translation diagrams:

Small/Large ribosomal subunits: The ribosome is composed of a small and a large subunit that come together during translation.
mRNA, tRNA, rRNA: mRNA carries the genetic information, tRNA transports amino acids, and rRNA forms an integral part of the ribosomal structure.
Reading frame, start/stop codons: The reading frame is the way the mRNA is divided into codons. Start codons (AUG) signal the beginning of translation and stop codons (UAA, UAG, UGA) indicate termination.
Release factor, and tRNA binding sites (E, P, A): The release factor aids in recognizing stop codons, prompting the release of the newly synthesized polypeptide.
- E site: Exit site for tRNA after it has added its amino acid to the growing polypeptide chain.
- P site: Peptidyl site where the tRNA carrying the growing polypeptide chain is located.
- A site: Aminoacyl site where new tRNA molecules bind to the next codon on the mRNA.
Identify locations for codon-anticodon recognition and peptide bond formation, highlighting the intricate biochemical processes involved in translation.

LO 26.3: Predict amino acid sequences from mRNA/DNA fragments, identifying start and stop codons.

Utilizing the genetic code table, students should be able to convert mRNA sequences back into their corresponding DNA sequences and vice versa, and recognize the importance of the start and stop codons in determining the length and composition of the resulting protein.

Link tRNAs to corresponding codons using base-pairing.
Application: Predict consequences of incorrect amino acid introduced by aminoacyl tRNA synthetase, emphasizing the potential for functional impairments or diseases resulting from errors in protein synthesis.

Describe how the ribosome recognizes and binds to mRNA, including the importance of the ribosomal RNA's structural features that facilitate accurate binding.
Discuss E, P, and A sites of ribosome:
- E site: Exit for tRNA after amino acid transfer ensures that the ribosome remains efficient in synthesizing polypeptides.
- P site: Where the growing peptide is held, ensuring correct elongation of the polypeptide is maintained.
- A site: Where new tRNA binds to codon, playing a critical role in determining the sequence of the polypeptide.
Translation Process:
- Initiation: Start codon (AUG) signals the beginning of translation, and ribosomal subunits assemble around the mRNA.
- Elongation: Polypeptide chain grows as ribosome moves along the mRNA, with each tRNA bringing the appropriate amino acid.
- Termination: Stop codon is reached, releasing the complete polypeptide through interaction with release factors that facilitate the disassembly of the ribosome.

Identify 5’ UTR, coding region, and 3’ UTR from genomic DNA, outlining their roles in regulation, stability, and translation.
Translate an mRNA sequence to produce a protein, emphasizing how modulation of different components can affect protein expression levels and functions.

"One-gene, one-protein" is too narrow: Consider RNA/protein processing, including post-transitional modifications that further diversify protein functionality.
Point Mutation Impact: Analyze how a single base-pair mutation changes mRNA codons and affects protein synthesis, illustrating real-world examples of disease linked to genetic mutations.

Contrast DNA replication, transcription, and translation across cellular types, highlighting differences in ribosome structure, initiation factors, and the processing of mRNA.

Codon specifics:
- 4 base combinations lead to 64 possible codons, encoding for 20 different amino acids, which allows for versatility in protein synthesis.
- Start codon: AUG; Stop codons: UAA, UAG, UGA, each playing a critical role in ensuring the fidelity of protein synthesis.
- Aminoacyl-tRNA Synthetase Role: Charges tRNA with the correct amino acid, ensuring high fidelity in protein synthesis.
Peptide Bond Formation: Directed by ribosomal rRNA, facilitating the linkage of amino acids, which is cumulatively responsible for the formation of proteins that determine cell function and structure.

Chloramphenicol: Blocks elongation by binding to the 50S ribosomal subunit, inhibiting peptide bond formation.
Erythromycin: Interferes with the translocation step, preventing ribosome progression along the mRNA.
Puromycin: Causes premature polypeptide release by mimicking an aminoacyl-tRNA, effectively terminating translation early.
Tetracycline: Inhibits tRNA binding to the A site, stalling translation process.
Streptomycin: Causes misreading of codons, leading to faulty proteins being produced, showcasing the potential for antibiotic resistance adaptations.

Differentiates from prokaryotic initiation with a guanosine cap and cap-binding proteins, which facilitate ribosome binding and aid in the stability of mRNA molecules.

Translation Steps: Involves charging tRNAs, initiation, elongation, and termination; all orchestrated by intricate interactions between ribosomal components and tRNA molecules, leading to the synthesis of functional proteins that underlie cellular and organismal life.