Questions and Answers
What does mRNA stand for?
What is the role of tRNA?
Helps assemble the protein by reading the mRNA
What is transcription?
The process of copying a segment of DNA into RNA by RNA polymerase.
RNA has ___ instead of thymine.
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___ are the removed segments from RNA.
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MRNA leaves the nucleus to find a ____.
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Transcription from DNA to mRNA occurs in the ___ of eukaryotes.
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What is translation?
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Each tRNA binds to a specific sequence of 3 bases called a ___.
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Translation from mRNA to proteins occurs on ribosomes in the ___ of the cell.
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What is a codon?
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What is an anticodon?
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A single amino acid is coded for by multiple codons, but any given codon codes for only ___.
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What is the function of RNA polymerase?
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What is the initiation promoter region?
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What is elongation in protein synthesis?
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What is the purpose of the 5' cap and Poly-A tail?
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What are introns?
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What are exons?
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What does charged tRNA refer to?
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What does uncharged tRNA refer to?
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What is a silent mutation?
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What is a missense mutation?
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What is a nonsense mutation?
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What is a reading frame shift?
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What are mutagens?
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Is mRNA synthesized during translation or transcription?
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Study Notes
Protein Synthesis Terms
- mRNA (messenger RNA): Acts as a copy of a gene from DNA; crucial for protein synthesis during translation.
- tRNA (transfer RNA): Assembles proteins by decoding the sequence of mRNA codons.
Processes of Protein Synthesis
- Transcription: RNA polymerase copies a specific segment of DNA into RNA, producing mRNA.
- Translation: Converts the mRNA sequence into a polypeptide or protein, occurring on ribosomes in the cytoplasm.
Key Components of RNA
- Uracil: Replaces thymine in RNA nucleotides.
- Introns: Non-coding segments of RNA that are removed during processing.
- Exons: Coding sequences in RNA that remain after splicing and are translated into proteins.
Translation Mechanics
- Codon: A three-nucleotide sequence on mRNA that specifies a particular amino acid.
- Anticodon: A three-nucleotide sequence on tRNA that pairs with a codon on mRNA during translation.
- Charged tRNA: tRNA with an attached amino acid, ready to contribute to the growing protein chain.
- Uncharged tRNA: tRNA without an amino acid; if mischarged, it can lead to protein misfolding.
Genetic Code and Mutations
- The genetic code is redundant but not ambiguous; multiple codons can code for one amino acid, but each codon codes for only one amino acid.
- Silent mutations: Do not significantly alter the phenotype; can occur in coding or non-coding regions.
- Missense mutations: Substitutes one amino acid in a protein, resulting from a single nucleotide change.
- Nonsense mutations: Prematurely stop protein synthesis due to an erroneous stop codon.
- Reading frame shifts: Cause shifts in the codon sequence when nucleotides are added or deleted, potentially altering the resulting protein sequence.
- Mutagens: Agents like radiation or chemicals that can induce genetic mutations.
Additional Notes on RNA Processing
- 5' Cap and Poly-A Tail: Modifications essential for mRNA stability and export from the nucleus; protect against degradation and assist in translation initiation.
- Nucleus: Location of transcription in eukaryotic cells; mRNA processing occurs here before mRNA's exit to the cytoplasm.
Transcription Initiation
- Promoter regions: DNA sequences that signal RNA polymerase to start transcription; located near the start site of the gene.
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Description
Test your knowledge on protein synthesis and gene expression with these flashcards. Explore key terms like mRNA, tRNA, and transcription to understand the molecular processes behind genetic expression. Perfect for students studying biology or molecular genetics.