LECTURE 5 - STUDY GUIDE Flashcards
(18 cards)
- When mRNA meets in a ribosome (rRNA), what can occur? (know the information discussed on chapter fifteen slide twenty-one)
So as the mRNA molecules move through the ribosome, successive codons on the mRNA are exposed at the anticodon and tRNa is added to each codon one at a time. You’re adding those amino acids one at a time.
- The key translation steps are carried out by ___________________ since they are responsible for binding the certain three-nucleotide sequence with the appropriate amino acid. Fill in the blank.
activating enzymes
- One type of activating enzyme used during the translation process is called aminoacyl-tRNA synthase. What is its function?
Aminoacyl-tRNA synthases - they’re going to be specific tRNA molecules which become attached to specific amino acids to complete the action of these enzymes.
- Within your cells, there are similar quantities of aminoacyl-tRNA synthase and amino acids. What is that number?
20
- For three of the sixty-four codons known (shown on your codon chart), there exists no tRNA with a complementary anticodon, these are known as _____________. Fill in the blank.
nonsense codons
- In prokaryotes and eukaryotes, polypeptide synthesis (translation) begins with the formation of an initiation complex. What components make up this initiation complex?
Initiation complex is formed only in eukaryotes for transcription
We have an initiation complex in prokaryotes for translation
You need energy for this process and you can create an initiation complex which basically has the rRNA ribosome.
Inside it is storing the mRNA because that’s going to be again where youre reading off the codons and it’s going to have specific sites where it will attach your tRNA
- Be able to describe what is occurring during this picture of the initiation stage of translation and also be able to know the different parts (as discussed in class).
- What is the abbreviation of the first amino acid placed within prokaryotes within the ribosome to begin the translation process?
tRNAfMET
- Regarding the process of translation, is the function of the initiation factors used during the first process of initiation?
Initiation factors: types of proteins, responsible for positioning tRNA on the surface at the P site
- Which statement describes the difference between what occurs at the P, A, and E sites of a ribosome?
P site: where the peptide bond forms, first location in which the tRNA is attached
A site (aminoacyl): Where successive amino acid barring tRNA will bind
E site (exit): where empty tRNA will exit ribosome so they can go pick up more amino acids within the cytoplasm
- In prokaryotes (and most eukaryotes), the beginning of each mRNA is marked by a ____________ complementary to one of the rRNA molecules on the ribosome, making sure it will be read from the beginning. Fill in the blank.
- Leader sequence
- Which statement does not describe a difference between the initiation stage of translation in eukaryotes verses prokaryotes?
Process of translation in prokaryotes: this process is going to begin when the initial portion of an mRNA molecule binds to an rRNA molecule in a ribosome
- Which statement describes what occurs during the elongation stage of translation in prokaryotes and eukaryotes? (know the different steps we discussed in class with the drawings on the board with the A, P, and E sites)
You dropping off amino acid after amino acid and so on at the A site, there attaching the amino acids to the P site that was sitting there to start with and then they are exiting out the E site
- Regarding the process of translation, what is the function of elongation factors?
Amino acid attached to adjacent initial methionine
- Which statement describes translocation which takes place during the elongation phase of translation?
Your relocating the initial tRNA from the A site ot the P site
- Know how to understand and interpret this picture (the elongation and translocation stage of translation)
- Which statement describes what occurs during the termination stage of translation in prokaryotes and eukaryotes?
Terminations occurs when you are going to read the stop codons, nonsense codons are also recognized
- Regarding the process of translation, what is the function of released factors?
Nonsense codons there are three different codes, if you off one of them and it doesnt code for any amino acid was then that when the process is okay then we done
So overall, nonsense goes before released factor
