| Concept | Description |
|---|---|
| Genetic Code | The set of rules by which information encoded in genetic material is translated into proteins. |
| Replication and Transcription | Processes that involve copying a nucleic acid to form another nucleic acid based on complementarity. |
| Translation | Process requiring transfer of genetic information from nucleotides to synthesize a polymer of amino acids. |
| Complementarity | Exists in replication and transcription but not in translation. |
| Evidence of Genetic Code | Changes in nucleic acids lead to changes in amino acids in proteins, suggesting a genetic code. |
| Proposition of Triplet Code | George Gamow proposed that a combination of three nucleotides (triplet) could code for 20 amino acids. |
| Codon | A sequence of three nucleotides that together form a unit of genetic code. |
| Number of Codons | 64 codons (4^3 combinations), with 61 coding for amino acids and 3 as stop codons. |
| Proof of Triplet Codon | Developed by Har Gobind Khorana and Marshall Nirenberg through chemical methods and cell-free systems. |
| Polynucleotide Phosphorylase | An enzyme used by Severo Ochoa to polymerize RNA sequences without a template. |
| Checker-Board for Genetic Code | A table showing the codons for various amino acids. |
| Codon is Triplet | 61 codons code for amino acids and 3 are stop codons. |
| Code is Degenerate | Some amino acids are coded by more than one codon. |
| Codon is Read Contiguously | Codons are read in mRNA without punctuations. |
| Nearly Universal Code | Codons generally code for the same amino acids across different organisms. Exceptions in mitochondria/protozoans. |
| AUG Codon | Codes for Methionine and acts as an initiator codon. |
| Stop Codons | UAA, UAG, and UGA do not code for any amino acid and signal termination of protein synthesis. |
| Wobble Hypothesis | The third nucleotide of a codon is less specific, allowing some tRNA to pair with multiple codons. |
| Redundancy | Multiple codons can code for the same amino acid, reducing the impact of mutations. |
| No Overlapping | Codons are read one after another without overlapping in the genetic sequence. |
| Non-ambiguity | Each codon specifies only one amino acid or a stop signal, ensuring precise protein synthesis. |
| Start Codon | The codon AUG not only codes for Methionine but also indicates the start of translation. |
| Stop Codons Role | UAA, UAG, and UGA signal the end of translation, ensuring the protein chain is correctly terminated. |
| Reading Frame | The way nucleotides are grouped into codons, starting from the start codon. Shifting the frame alters the protein. |
| Codon Usage Bias | Different organisms prefer certain codons over others, influencing gene expression efficiency. |
| Mitochondrial Genetic Code | Mitochondria have a slightly different genetic code, reflecting their evolutionary origin. |
Mcq
