Questions and Answers
A codon consists of _____ bases and specifies which _____ will be inserted into the polypeptide chain.
three, amino acid
The flow of information in a cell proceeds in what sequence?
from DNA to RNA to protein
Where does RNA polymerase begin transcribing a gene into mRNA?
At the promoter
What is the function of RNA polymerase?
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After an RNA molecule is transcribed from a eukaryotic gene, what are removed and what are spliced together?
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What is a ribozyme?
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Which of these is currently considered the best definition of a gene?
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How is translation initiated?
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Each tRNA binds a particular amino acid.
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What does a mutagen cause?
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Study Notes
Codons and Information Flow
- A codon consists of three nucleotide bases that specify an amino acid to be inserted in the polypeptide chain.
- The flow of information in a cell follows the sequence: DNA → RNA → Protein.
RNA Transcription
- RNA polymerase initiates transcription by binding to the gene's promoter region.
- The transcription starts at a nucleotide called the start point, which requires transcription factors in eukaryotes.
Role of RNA Polymerase
- RNA polymerase unwinds the DNA double helix during transcription.
- It also adds RNA nucleotides to form a growing RNA strand.
RNA Processing in Eukaryotes
- Introns (non-coding sequences) are removed from the transcribed RNA.
- Exons (coding sequences) are spliced together to produce a continuous coding sequence in mRNA.
Ribozyme Definition
- Ribozymes are biological catalysts made of RNA that catalyze chemical reactions.
- They include snRNAs and ribosomes, showcasing diverse functions of RNA.
Defining a Gene
- The definition of a gene has evolved; it may code for multiple polypeptides.
- There are also many RNA molecules with crucial roles in cellular processes.
Translation Initiation
- Translation starts when the small ribosomal subunit attaches to mRNA.
- tRNA carrying methionine binds to the start codon, followed by the large ribosomal subunit assembling with the small one.
tRNA Characteristics
- Each tRNA molecule is specific to one amino acid, facilitating accurate protein synthesis.
Effects of Mutagens
- Mutagens cause alterations in the DNA sequence, potentially leading to mutations in genetic material.
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Description
Explore the fundamental concepts of codons, RNA transcription, and the role of RNA polymerase in gene expression. This quiz also delves into RNA processing in eukaryotes and introduces the concept of ribozymes, highlighting their importance in biological reactions. Test your understanding of these key topics in molecular biology.
