Translation and the Genetic Code

This set of flashcards covers key concepts, processes, and terminology related to translation and the genetic code.

What is the role of the cell nucleus in protein synthesis?

It houses the genetic material and is where transcription occurs.

What is transcription?

The process of converting DNA into messenger RNA (mRNA).

Define mRNA.

Messenger RNA is a single-stranded RNA molecule that serves as a template for protein synthesis.

What is the cytoplasm's role in translation?

It is where translation occurs and ribosomes are located.

What is translation?

The process of synthesizing proteins from the mRNA template.

What enzyme synthesizes mRNA during transcription?

RNA polymerase.

What is the function of tRNA?

Transfer RNA carries amino acids to the ribosome during protein synthesis.

What is a growing polypeptide chain?

A sequence of amino acids linked together during translation.

How does tRNA interact with mRNA?

tRNA has an anticodon that base pairs with a specific mRNA codon.

Define ribosome.

Ribosomes are the cellular machinery that synthesize proteins by reading mRNA.

What are codons?

Triplet sequences of bases on mRNA that code for specific amino acids.

What significant event does the wobble hypothesis explain?

It describes how the third base in a codon-anticodon interaction can allow for flexibility in base pairing.

What are the stages of translation?

Initiation, elongation, and termination.

What role do amino acids play in proteins?

They are the fundamental building blocks of proteins.

What is the importance of transfer RNA (tRNA) in protein synthesis?

tRNA helps decode the mRNA by delivering the correct amino acid.

Define polyribosome.

Clusters of ribosomes translating a single mRNA strand simultaneously.

How is the genetic code organized?

It is organized into triplet codons that are degenerate and may include wobble pairing.

What does the term degeneracy refer to in genetics?

Multiple codons can code for the same amino acid.

What happens during the initiation stage of translation?

The ribosome assembles on the mRNA at the start codon (AUG) with the help of an initiator tRNA.

Where does the termination of translation occur?

When a stop codon on mRNA is reached, signaling completion of polypeptide synthesis.

What role do aminoacyl-tRNA synthetases play?

They attach the correct amino acid to its corresponding tRNA.

What is the significance of the start codon?

It signals the start of translation and codes for methionine.

Name a key discovery regarding the genetic code made by Nirenberg and Matthaei in 1961.

They identified specific codons that correspond to specific amino acids.

What is the significance of the anticodon on tRNA?

It determines which amino acid the tRNA will carry by matching with mRNA codons.

What does the triplet code imply about how many amino acids can be encoded by the genetic code?

There are 20 amino acids encoded by 64 possible codons (due to redundancy).

What is the importance of the exit tunnel in the ribosome?

It allows the growing polypeptide chain to exit the ribosome.

What are the three binding sites on a ribosome?

A site (aminoacyl-tRNA site), P site (peptidyl-tRNA site), and E site (exit site).

How do ribosomes increase the efficiency of protein synthesis?

By forming polyribosomes that allow multiple ribosomes to translate the same mRNA.},

What is the primary function of enzymes in biological systems?

Enzymes catalyze chemical reactions.

What key role do antibodies play in the immune system?

They protect against disease.

What general function do structural proteins provide?

They support cells and tissues.

What is a key function of hormones?

They transmit information within the body.

What does translation ultimately produce?

A polypeptide chain that folds into a functional protein.

What happens during the elongation phase of translation?

The ribosome moves along mRNA, adding amino acids to a growing polypeptide.

What signifies the end of the elongation phase?

The ribosome encounters a stop codon.

What does the term 'wobble' in the wobble hypothesis imply?

Some non-standard base pairings can occur between the tRNA and mRNA codons.

In what direction does the ribosome read mRNA during translation?

From the 5' end to the 3' end.

What are stop codons?

Codons that signal the termination of protein synthesis (UAA, UAG, UGA).

What role does energy play in translation?

Energy is required for tRNA charging and ribosome movement.

What experiment helped establish that UUU codes for phenylalanine?

Nirenberg and Matthaei's experiment using an artificial mRNA.

What is protein synthesis?

The process of creating proteins from amino acids based on mRNA sequences.

What is the role of the large subunit of the ribosome?

It catalyzes peptide bond formation between amino acids.

What discovery involved amino acids in 1806–1901?

Various chemists discovered amino acids as fundamental building blocks of proteins.

What was elucidated about nucleic acids in 1869?

Friedrich Miescher discovered nucleic acids, which are vital to genetic information.

What did Hershey & Chase prove about DNA in 1952?

They proved that DNA is the genetic material.

What is the significance of the A site in the ribosome?

It is where the incoming aminoacyl-tRNA binds.

What happens at the E site of the ribosome?

tRNA is released from the ribosome after donating its amino acid.

What was the Wobble Rule concerning 'U' at the first position of the tRNA anticodon?

U can pair with A or G at the third position of the mRNA codon.

What was a major takeaway from the listed learning objectives?

Understanding the roles of tRNA and stages of translation is crucial to protein synthesis.

What is the process that occurs prior to translation, known as decoding genetic information?

Transcription.

Describe the importance of the exit site in the ribosome during translation.

It allows the completed polypeptide to exit the ribosome.

Why is the genetic code described as universal?

It is largely the same across different organisms.

What is the relationship between DNA, RNA, and proteins described as the central dogma?

DNA is transcribed to RNA, which is then translated into proteins.

What is the first step in deciphering the Genetic Code?

Determining which codons correspond to which amino acids.

What experiment demonstrated that specific codons result in specific amino acids?

The experiment conducted by Nirenberg and Matthaei using artificial mRNA.

What does ATP provide during the aminoacyl-tRNA charging process?

It provides energy for attaching amino acids to tRNA.

How does translation contribute to protein diversity?

By allowing permutations of codons, resulting in a variety of proteins.

What is the role of the small ribosomal subunit during initiation?

It binds to mRNA and identifies the start codon.

What does the growing polypeptide represent during translation?

The chain of amino acids being formed into a protein.