Translation and Protein Synthesis

These flashcards cover key concepts related to translation and protein synthesis, including processes, terminology, and implications of mutations.

Translation

The process that bringsby which mRNA is converted into a protein sequence

Codons

Three-letter sequences in mRNA that code for amino acids

How many possible combinations can three letters from the RNA base pairs produce?

64 possible combinations.

What is the start codon that signals the beginning of protein synthesis?

AUG (codes for Methionine).

What are the stop codons?

UGA, UAG, UAA- Do NOT code for an amino acid

The genetic code applies to (nearly) ALL organisms

rRNA

molecules make up ribosomes where translation occurs

Elongation factors

mRNA

Carries genetic information from the DNA

tRNA

Converts the codons in mRNA to a proper amino acid sequence

Silent mutation

A mutation that does not change the amino acid produced

What is the role of tRNA in protein synthesis?

To bring the appropriate amino acid to the ribosome based on codon-anticodon pairing.

What happens if a ribosome encounters a stop codon?

Translation ends, and the protein is released.

What kind of mutation causes a shift in the reading frame of a DNA sequence?

Frameshift mutation.

Which RNA makes up the ribosome?

Ribosomal RNA (rRNA).

Aminoacyl tRNA synthetase

Attaches amino acids to the correct tRNA

Why is the order of amino acids in a protein important?

It determines the protein's shape and function.

What type of mutation introduces a premature stop codon?

Nonsense mutation.

Translation initiation complex

The complex created when the large ribosomal subunit locks the mRNA and tRNA into the rRNA (ribosome)

What RNA molecule has enzymatic activity?

rRNA (ribozymes)

A site

Where the tRNA first enters the ribosome to add add the next amino acid

P site

Holds the tRNA as the polypeptide chain grows

E site

Where the used tRNA gets ejected from the ribosome

Elongation factors

Proteins that help the translation elongation process

Peptide bond

Forms between the two adjacent amino acids and the growing polypeptide is attached to the tRNA in the A site so it moves to the p site holding the new polypeptide chain

release factor

Promotes a hydrolysis of the amino acid and the tRNA in the P site, releasing the polypeptide

Polyribosome / polysome

Many proteins made from one mRNA simultaneously

Signal peptide

A sequence of about 20 amino acids at or near the N- terminus of a polypeptide- targets the protein to the endoplasmic reticulum in a eukaryotic cell

Signal recognition particle (SRP)

Binds to the signal peptide site and carries the whole ribosome to the ER so that the polypeptide is inserted into the ER lumen

Point mutation

Classified in three different types: A change in a single nucleotide base pair in a gene