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Questions and Answers
What role do ribosomes play in translation?
What role do ribosomes play in translation?
Which sequence represents a start codon in mRNA?
Which sequence represents a start codon in mRNA?
What is the primary function of tRNA during translation?
What is the primary function of tRNA during translation?
How does the ribosome move during translation?
How does the ribosome move during translation?
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Which component of the ribosome catalyzes peptide bond formation?
Which component of the ribosome catalyzes peptide bond formation?
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What is the relationship between codons and anticodons?
What is the relationship between codons and anticodons?
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Which of the following correctly describes the genetic code?
Which of the following correctly describes the genetic code?
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What is contained within the anticodon of tRNA?
What is contained within the anticodon of tRNA?
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What is the primary function of aminoacyl-tRNA synthetase in translation?
What is the primary function of aminoacyl-tRNA synthetase in translation?
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Which site on the ribosome is responsible for holding the tRNA with the growing polypeptide chain?
Which site on the ribosome is responsible for holding the tRNA with the growing polypeptide chain?
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What occurs when a stop codon is reached during translation?
What occurs when a stop codon is reached during translation?
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What is the direction in which codons are read on the mRNA during translation?
What is the direction in which codons are read on the mRNA during translation?
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Which component is NOT required during the initiation of translation?
Which component is NOT required during the initiation of translation?
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What term describes multiple ribosomes translating a single mRNA molecule simultaneously?
What term describes multiple ribosomes translating a single mRNA molecule simultaneously?
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What role do peptide bonds play during the elongation stage of translation?
What role do peptide bonds play during the elongation stage of translation?
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Which is true about the redundancy of the genetic code?
Which is true about the redundancy of the genetic code?
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What is the primary role of aminoacyl-tRNA synthetase in protein synthesis?
What is the primary role of aminoacyl-tRNA synthetase in protein synthesis?
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Which statement accurately describes the function of the anticodon in tRNA?
Which statement accurately describes the function of the anticodon in tRNA?
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During which stage of translation are amino acids added sequentially to a polypeptide chain?
During which stage of translation are amino acids added sequentially to a polypeptide chain?
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What is the role of exons in gene expression?
What is the role of exons in gene expression?
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What does the genetic code determine?
What does the genetic code determine?
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Which site on the ribosome holds the tRNA that carries the growing polypeptide chain during elongation?
Which site on the ribosome holds the tRNA that carries the growing polypeptide chain during elongation?
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How are introns characterized in the context of gene structure?
How are introns characterized in the context of gene structure?
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What does a codon in mRNA specify?
What does a codon in mRNA specify?
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What is the significance of a peptide bond?
What is the significance of a peptide bond?
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Which of the following best describes a polyribosome?
Which of the following best describes a polyribosome?
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What role does a release factor play in translation?
What role does a release factor play in translation?
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How does redundancy in the genetic code benefit organisms?
How does redundancy in the genetic code benefit organisms?
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What is the first amino acid incorporated into a polypeptide chain during translation?
What is the first amino acid incorporated into a polypeptide chain during translation?
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What is the function of transfer RNA (tRNA) during translation?
What is the function of transfer RNA (tRNA) during translation?
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What indicates the end of the translation process?
What indicates the end of the translation process?
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What happens during translocation in translation?
What happens during translocation in translation?
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Study Notes
Translation: RNA to Protein
- Definition: Ribosomes synthesize proteins using the mRNA nucleotide sequence as a guide to determine amino acid order.
- Location: Occurs in the cytoplasm of both prokaryotes and eukaryotes; in eukaryotes, mRNA is transcribed in the nucleus and then transported to the cytoplasm for translation.
The Genetic Code
- Genetic Code: A set of rules translating mRNA nucleotide sequence into amino acid sequence.
- Universality: Nearly universal across organisms (bacteria to humans).
- Codons: Three nucleotides in mRNA specifying a particular amino acid or stop signal.
- Start Codon: AUG (methionine), signals the start of protein synthesis.
- Stop Codons: UAA, UAG, UGA, signal the termination of translation.
Ribosome Structure and Function
- Ribosomes: Cellular structures composed of rRNA and proteins that facilitate translation.
- Subunits: Two subunits (small and large) that bind to mRNA and initiate translation.
- Large subunit function: Catalyzes peptide bond formation between amino acids.
- Movement: Ribosomes move along mRNA in the 5' to 3' direction, reading codons.
- Assembly: Assembles amino acids into a polypeptide chain.
Key Components of Translation
Types of RNA Involved
- mRNA (Messenger RNA): Carries genetic information from DNA to ribosomes for protein synthesis.
- tRNA (Transfer RNA): Delivers specific amino acids to the ribosome during translation. Anticodon pairs with mRNA codon to ensure correct amino acid addition.
Stages of Translation
A. Initiation
- Small ribosomal subunit binds to the 5' end of mRNA, along with initiator tRNA carrying methionine (AUG).
- Large ribosomal subunit joins, positioning the initiator tRNA at the P-site.
B. Elongation
- The ribosome has three binding sites (A, P, E sites).
- tRNAs deliver amino acids to the ribosome based on mRNA codons.
- Peptide bonds form between amino acids, extending the polypeptide chain.
C. Termination
- Stop codon (UAA, UAG, or UGA) is reached.
- Release factors bind to the stop codon, prompting ribosome to release the completed polypeptide chain.
The Genetic Code and Protein Synthesis
- Reading the Genetic Code: Codons are read in the 5' to 3' direction on the mRNA strand.
- Redundancy: Multiple codons can code for the same amino acid.
- Polyribosomes: Multiple ribosomes can simultaneously translate a single mRNA molecule, increasing protein synthesis efficiency.
Vocabulary
- A-site, Aminoacyl Site
- Amino Acid
- Aminoacyl-tRNA Synthetase
- Anticodon
- Codon
- E-site
- Elongation
- Exon
- Genetic Code
- Initiation
- Intron
- mRNA
- P-site
- Peptide Bond
- Polypeptide
- Polysome
- Ribosomal RNA (rRNA)
- Ribosome
- Stop Codon
- tRNA
- Translocation
- Translation
- Universal Genetic Code
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Description
Test your knowledge on how ribosomes synthesize proteins from mRNA sequences. Explore the structure and function of ribosomes, the genetic code, and the importance of codons in translation. This quiz covers fundamental concepts applicable to both prokaryotes and eukaryotes.
