Chapter 10.6 The Stages of Translation

What is the selection of a start codon in eukaryotes during translation?

According to Kozak's sequences

During ______, an mRNA, the first tRNA, and the ribosomal subunits assemble into a complex.

During Initiation, an mRNA, the first tRNA, and the ribosomal subunits assemble into a complex.

During the _____ _____, a complex is formed between an mRNA molecule, the first tRNA, and the ribosomal subunits.

During the initiation stage, a complex is formed between an mRNA molecule, the first tRNA, and the ribosomal subunits.

What is the protein that recognizes a stop codon in the termination stage or translation and promotes the termination of translation?

Release Factor

What is required for the initial binding of mRNA in eukaryotes during translation?

Requires a 7-methylguanosine

What is required for the initial binding of mRNA in bacteria during translation?

Requires a ribosomal-binding site

In the __________ stage, the ribosome moves in the 5' to 3' direction from the start codon in the mRNA toward the stop codon, synthesizing a polypeptide according to the sequence of codons in the mRNA

In the Elongation stage, the ribosome moves in the 5' to 3' direction from the start codon in the mRNA toward the stop codon, synthesizing a polypeptide according to the sequence of codons in the mRNA

What is the protein that facilitates the interactions among mRNA, the first tRNA, and the ribosomal subunits during the initiation stage of translation?

Initiation Factor

What is the first step in the process of transcription?

Initiation Stage

What is the specific tRNA that recognizes the start codon AUG in mRNA and binds to it, initiating translation?

Initiator tRNA

What are the termination factors in eukaryotes during translation?

One factor: -eRF

During translation, what is the transfer of the polypeptide from the tRNA in the P site to the amino acid at the A site reaction called?

Peptidyl Transfer Reaction

What are the simple three-steps in termination?

1.) A release factor binds to the stop codon at the A site 2.) The polypeptide is released from the tRNA in the P site. The tRNA is then released 3.) The mRNA, ribosomal subunits, and release factor dissociate

What are the simple three-steps in initiation?

1.) mRNA binds to the small ribosomal subunit 2.) Initiator tRNA binds to the start codon in mRNA 3.) Large ribosomal subunit binds

What are the simple three-steps in elongation?

1.) tRNA entry 2.) Peptidyl transfer reaction 3.) Translocation of ribosome and release of tRNA

What is the ribosome composition in bacteria during translation?

70S ribosomes: - 30S subunit: 21 proteins + 1 rRNA - 50S subunit: 34 proteins + 2 rRNA

What is the ribosome composition in eukaryotes during translation?

80S Ribosomes: - 40S subunit: 33 proteins + 1 rRNA - 60S subunit: 49 proteins + 3 rRNA

A _____ _____ _____ is termed because the reaction is catalyzed by an rRNA molecule within a region of the 50S subunit known as the peptidyltransferase center.

A peptidyl transfer reaction is termed because the reaction is catalyzed by an rRNA molecule within a region of the 50S subunit known as the peptidyltransferase center.

What promotes the binding between the mRNA and the small ribosomal subunit?

A region near the 5' end of the mRNA is complementary to a region of rRNA in the small subunit These complementary regions hydrogen-bond with each other to promote the binding of the mRNA to the small ribosomal subunit

A specific tRNA, which functions as the ______ ____, recognizes the start codon in mRNA (AUG) and binds to it.

A specific tRNA, which functions as the Initiator tRNA, recognizes the start codon in mRNA (AUG) and binds to it.

A tRNA carrying a polypeptide would never be found in...

A tRNA carrying a polypeptide would never be found in the E site

The hydrolysis of GTP by proteins that function as ____ ____ provides the energy for the binding of the tRNA to the A site

The hydrolysis of GTP by proteins that function as elongation factors provides the energy for the binding of the tRNA to the A site

The process is ______ when the ribosome reaches a stop codon and the complex disassembles, releasing the completed polypeptide.

The process is Terminated when the ribosome reaches a stop codon and the complex disassembles, releasing the completed polypeptide.

What is the initiator tRNA in bacteria during translation?

tRNA Formyl-methionine

What is the initiator tRNA in eukaryotes during translation?

tRNA Methionine

to complete the initiation stage....

to complete the initiation stage the large ribosomal subunit associates with the small subunit

What are the termination factors in bacteria during translation?

Two factors: -RF1 -RF2

A key difference in the initiation phase of translation between bacteria and eukaryotes is that in eukaryotes....

- The 5' cap promotes binding of mRNA to the small ribosomal subunit - The selection of the start codon depends on the sequence around it - The initiator tRNA carries methionine rather than formyl-methionine

Where is the cellular location of translation in bacteria?

Cytoplasm

Where is the cellular location of translation in eukaryotes?

Cytosol

What is the protein that is needed for the growth of a polypeptide during translation?

Elongation Factor

What is the second step in transcription or translation, where RNA strands or polypeptides are made?

Elongation stage

What is the selection of a start codon in bacteria during translation?

Just a downstream from ribosomal-binding site

What is the final stage of transcription or translation, in which the process ends?

Termination Stage

The _____ _____ involves the covalent bonding of amino acids to each other, one at a time, to produce a polypeptide

The Elongation stage involves the covalent bonding of amino acids to each other, one at a time, to produce a polypeptide

The assembly in initiation also requires....

The assembly in initiation also requires an input of energy such as GTP being hydrolyzed by certain initiation factors

The assembly of the complex in the initiation stage requires the help of translation factors called _____ _____

The assembly of the complex in the initiation stage requires the help of translation factors called Initiation Factors

The three stop codons, UAA, UAG, and UGA, are recognized by a protein known as a _____ ______

The three stop codons, UAA, UAG, and UGA, are recognized by a protein known as a release factor

To elongate a polypeptide by one amino acid....

To elongate a polypeptide by one amino acid a tRNA brings a new amino acid to the ribosome, where it is attached to the end of a growing polypeptide