Translation

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Questions and Answers

What is the purpose of the Shine Dalgarno sequence in prokaryotes?

To export mature mRNA from the nucleus

To determine the correct reading frame (correct)

To decode the mRNA sequence in sets of 3 nucleotides

To initiate translation

How many possible combinations of 3 nucleotides are there?

64 (correct)

What does the correct reading frame depend on?

The Shine Dalgarno sequence in eukaryotes

The first AUG sequence in eukaryotes (correct)

The mature mRNA exported from the nucleus

The number of codons in the mRNA sequence

What demonstrates the redundancy of the genetic code?

The multiple codons that specify the same amino acid Signup and view all the answers

What happens if a nucleotide is accidentally inserted into the middle of a gene?

The reading frame will be shifted Signup and view all the answers

How many amino acids are there?

20 Signup and view all the answers

Which of the following is true about translation in prokaryotes?

Prokaryotic mRNA is polycistronic Signup and view all the answers

Which step of translation involves the formation of peptide bonds?

Elongation Signup and view all the answers

Which of the following is true about termination in translation?

The ribosome dissociates into the large and small subunits Signup and view all the answers

What is the first amino acid added to any polypeptide chain during translation?

Methionine Signup and view all the answers

Which of the following describes the correct order of translation initiation in eukaryotes?

Small ribosomal subunit binds to the met-tRNAi, it binds to the 5' cap of mRNA, small ribosome then moves along the mRNA in search of the start codon, large ribosomal unit binds. Signup and view all the answers

What is the function of polysomes in protein synthesis?

To speed up the rate of protein synthesis Signup and view all the answers

What happens after a ribosome has translated enough of the nucleotide sequence to move out of the way?

A new ribosome complex is formed Signup and view all the answers

Why is proper folding of proteins important?

The structure of a protein dictates its function Signup and view all the answers

What modification can occur to proteins in the endoplasmic reticulum?

Glycosylation - addition of mono- or oligosaccharide Signup and view all the answers

How do many antibiotics function in inhibiting bacterial protein synthesis?

By interfering with the correct functioning of prokaryotic ribosomes Signup and view all the answers

Which subunit of the ribosome binds to the Shine Dalgnaro sequence on the mRNA?

Small ribosomal subunit Signup and view all the answers

Where does protein folding occur?

In the endoplasmic reticulum Signup and view all the answers

What is the role of Met-tRNAi in protein synthesis?

To serve as the initiator tRNA Signup and view all the answers

Which step of translation requires an ATPase enzyme?

Initiation Signup and view all the answers

What is the function of Peptidyl transferase?

Catalysis of Peptide bonds Signup and view all the answers

Study Notes

Shine Dalgarno Sequence

Functions as a ribosomal binding site in prokaryotic mRNA, facilitating translation initiation.

Possible Combinations of Nucleotides

There are 64 possible combinations of three nucleotides (4 nucleotides raised to the power of 3).

Correct Reading Frame

The correct reading frame of an mRNA molecule depends on the initial start codon and the position of nucleotide sequences following it.

Redundancy of the Genetic Code

Demonstrated through multiple codons coding for the same amino acids, allowing for minimal impacts of mutations.

Nucleotide Insertion Effects

An accidental nucleotide insertion in the middle of a gene can lead to a frameshift mutation, altering downstream amino acid sequences.

Number of Amino Acids

There are 20 standard amino acids used in protein synthesis.

Translation in Prokaryotes

Prokaryotic translation can initiate before transcription has finished, allowing simultaneous processes in the cytoplasm.

Peptide Bond Formation

The step of translation that involves the formation of peptide bonds occurs during the elongation phase.

Termination in Translation

Translation termination occurs when a stop codon is reached, prompting the release factor to disassemble the translation complex.

First Amino Acid in Translation

Methionine (Met) is the first amino acid added to any polypeptide chain during translation.

Translation Initiation in Eukaryotes

The correct order includes the assembly of the small ribosomal subunit, initiation factors, tRNA carrying Methionine, and the large ribosomal subunit.

Function of Polysomes

Polysomes enhance the efficiency of protein synthesis, allowing multiple ribosomes to translate the same mRNA simultaneously.

Ribosome Movement post-Translation

After sufficient translation, the ribosome moves and allows the mRNA to be accessed by additional ribosomes for efficient protein synthesis.

Importance of Protein Folding

Proper folding is crucial for protein functionality, as incorrect folding can lead to loss of activity and potential diseases.

Protein Modifications in the Endoplasmic Reticulum

Post-translational modifications such as glycosylation and disulfide bond formation can occur in the endoplasmic reticulum.

Antibiotic Mechanisms

Many antibiotics inhibit bacterial protein synthesis by targeting ribosomal functions, thereby affecting the translation process.

Ribosomal Subunit Binding

The small ribosomal subunit binds to the Shine-Dalgarno sequence on the mRNA during initiation of translation.

Protein Folding Location

Protein folding typically occurs within the endoplasmic reticulum, where chaperones assist in the process.

Role of Met-tRNAi

Met-tRNAi serves as the initiator tRNA carrying Methionine, key for starting protein synthesis in both prokaryotes and eukaryotes.

ATPase Enzyme Requirement

The elongation step of translation requires an ATPase enzyme for the delivery of amino-acyl tRNA to the ribosome.

Function of Peptidyl Transferase

Peptidyl transferase catalyzes the formation of peptide bonds between amino acids during translation elongation.

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Description

Test your knowledge on mRNA translation and codons with this quiz! Learn about the process of mRNA export from the nucleus and its subsequent translation into proteins. Explore the relationship between nucleotide codons and amino acids.