Me Salva! GEN06 - Genética - Código genético

Summary

In this molecular genetics class, the focus is on the genetic code and the process of translation. The ribosome decodes messenger RNA (mRNA) codons, translating them into specific amino acids to form proteins. The genetic code is described as 'degenerate,' meaning multiple codons can represent the same amino acid. Additionally, the code is 'universal,' meaning it is consistent across nearly all living organisms. The lesson also highlights the role of stop codons and initiation codons, including methionine, in protein synthesis. The session concludes with an introduction to how the ribosome uses the genetic code table to produce proteins.

Takeaways

• 😀 The genetic code is part of the translation process in protein production.
• 😀 Translation occurs after transcription, where messenger RNA (mRNA) is formed from DNA.
• 😀 Codons in mRNA are sequences of three nitrogenous bases that the ribosome reads to form amino acids.
• 😀 The ribosome decodes mRNA codons to assemble polypeptides (proteins) by adding the corresponding amino acids.
• 😀 The genetic code is composed of four nitrogenous bases: adenine (A), cytosine (C), guanine (G), and uracil (U).
• 😀 There are 64 possible codons, but only 20 amino acids, leading to a 'degenerate' genetic code.
• 😀 Most amino acids have more than one possible codon, but some, like methionine, have only one.
• 😀 Some codons serve as 'stop codons' (UAA, UAG, UGA) that signal the end of translation.
• 😀 The genetic code is 'universal', meaning the same codon sequence codes for the same amino acid across all living organisms.
• 😀 The ribosome uses the mRNA codons to incorporate specific amino acids into the growing polypeptide chain.
• 😀 The process of translation is essential for protein production, with mRNA, ribosomes, and amino acids playing crucial roles.

Q & A

What is the main subject of the class?

The main subject of the class is the genetic code, which is part of the study of translation, a stage in protein production.

What is translation in the context of protein production?

Translation is the process through which the genetic information in messenger RNA is used to synthesize proteins or polypeptides in the ribosome.

How is the recipe for protein synthesis stored in the cell?

The recipe for protein synthesis is stored in the DNA, specifically in regions known as genes.

What is the role of messenger RNA in the process of translation?

Messenger RNA (mRNA) carries the genetic code from the DNA to the ribosome, where it is read in triplets known as codons, each corresponding to a specific amino acid.

What does the ribosome do when it encounters a codon in mRNA?

The ribosome reads the codons in the mRNA sequence and uses them to assemble the corresponding amino acids into a polypeptide chain.

What is meant by the term 'degeneracy' of the genetic code?

Degeneracy of the genetic code means that multiple codons can encode the same amino acid, providing redundancy in the code.

How many possible codons exist in the genetic code?

There are 64 possible codons, formed by combinations of four nitrogenous bases (adenine, cytosine, guanine, and uracil) in triplets.

Why are there more codons than amino acids in the genetic code?

There are 64 possible codons and only 20 amino acids because many amino acids are encoded by more than one codon, allowing for redundancy and protection against mutations.

What are stop codons and what role do they play in translation?

Stop codons (UAA, UAG, and UGA) signal the end of the translation process, instructing the ribosome to stop adding amino acids and release the polypeptide.

What is meant by the genetic code being universal?

The genetic code is universal because the same codons correspond to the same amino acids in all living organisms, from bacteria to humans, with very rare exceptions.