Describe the process of translation (initiation, elongation, termination) Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Initiation translation

A
  1. Translation begins when the small and large subunits of the ribosome bind to the 5’ cap of the mRNA molecule.
  2. The ribosome scans the mRNA to locate the start codon (AUG), which sets the reading frame for translation.
  3. The start codon corresponds to methionine, the first amino acid in the polypeptide chain.
  4. A transfer RNA (tRNA) with the complementary anticodon (UAC) binds to the start codon, delivering methionine.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Elongating the polypeptide chain

A
  • The ribosome has three binding sites for tRNA: the A site (acceptor or aminoacyl), the P site (peptidyl), and the E site (exit).
    1. An aminoacyl-tRNA binds to the A site.
    2. Peptidyl transferase cleaves the amino acid from the P site tRNA and bonds it to the amino acid on the A site tRNA, forming a peptide bond and elongating the polypeptide chain.
    3. The ribosome moves along the mRNA to the next codon, bringing the tRNA with the polypeptide to the P site and moving the empty tRNA to the E site to exit.
    4. After the ribosome moves over one codon, the empty tRNA in the E site is released, and the cycle is ready to start again. If a stop codon is reached, a release factor binds to the ribosome, causing the release of the finished polypeptide.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Termination of protein synthesis

A
  1. Translation ends when the ribosome encounters a stop codon (UAG, UGA, or UAA) on the mRNA.
  2. No tRNA matches the stop codons; instead, a release factor binds to the ribosome, signaling it to release the newly synthesized polypeptide chain.
  3. The ribosome disassembles, and the polypeptide folds into its functional three-dimensional structure.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly