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Questions and Answers
What distinguishes RNA from DNA in terms of sugar structure?
What distinguishes RNA from DNA in terms of sugar structure?
Which base is not found in RNA?
Which base is not found in RNA?
What is the main function of ribosomal RNA (rRNA)?
What is the main function of ribosomal RNA (rRNA)?
What is the role of microRNA in cellular function?
What is the role of microRNA in cellular function?
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How does RNA typically exist in terms of structure?
How does RNA typically exist in terms of structure?
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Which type of RNA serves as an adaptor between mRNA and amino acids?
Which type of RNA serves as an adaptor between mRNA and amino acids?
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In the production of RNA, what is the initial step from DNA?
In the production of RNA, what is the initial step from DNA?
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What is the primary function of non-coding RNAs such as long non-coding RNA?
What is the primary function of non-coding RNAs such as long non-coding RNA?
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Which step occurs first in the transcription process?
Which step occurs first in the transcription process?
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What is the function of RNA polymerase during transcription initiation?
What is the function of RNA polymerase during transcription initiation?
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What triggers the start of transcription elongation?
What triggers the start of transcription elongation?
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What is a major regulatory step in transcription for protein synthesis?
What is a major regulatory step in transcription for protein synthesis?
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Which of the following describes a consequence of protein over-expression in Escherichia coli?
Which of the following describes a consequence of protein over-expression in Escherichia coli?
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Which component is essential for starting transcription termination?
Which component is essential for starting transcription termination?
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What is a likely impact of under-production of mRNA?
What is a likely impact of under-production of mRNA?
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Which statement is true regarding transcription in prokaryotes and eukaryotes?
Which statement is true regarding transcription in prokaryotes and eukaryotes?
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What is the primary function of mRNA in eukaryotic cells?
What is the primary function of mRNA in eukaryotic cells?
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Which of the following processes occurs in the cytoplasm of prokaryotic cells?
Which of the following processes occurs in the cytoplasm of prokaryotic cells?
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What role do promoters play in transcription?
What role do promoters play in transcription?
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In eukaryotic cells, what happens during the 5' cap addition?
In eukaryotic cells, what happens during the 5' cap addition?
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What is one reason why an intermediate mRNA is necessary in the process of protein synthesis?
What is one reason why an intermediate mRNA is necessary in the process of protein synthesis?
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Which of the following statements about RNA is NOT true?
Which of the following statements about RNA is NOT true?
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What distinguishes transcription in prokaryotes from transcription in eukaryotes?
What distinguishes transcription in prokaryotes from transcription in eukaryotes?
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Which component is responsible for synthesizing RNA during transcription?
Which component is responsible for synthesizing RNA during transcription?
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What is the primary function of RNA polymerase during transcription?
What is the primary function of RNA polymerase during transcription?
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In which direction does RNA polymerase move during RNA synthesis?
In which direction does RNA polymerase move during RNA synthesis?
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How many RNA polymerases can transcribe a single gene simultaneously?
How many RNA polymerases can transcribe a single gene simultaneously?
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Which of the following is NOT a characteristic of RNA polymerase?
Which of the following is NOT a characteristic of RNA polymerase?
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What is the structure of RNA polymerase often likened to?
What is the structure of RNA polymerase often likened to?
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During transcription, what happens to the DNA strands as RNA polymerase moves?
During transcription, what happens to the DNA strands as RNA polymerase moves?
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What is the average reaction rate of RNA polymerase during transcription?
What is the average reaction rate of RNA polymerase during transcription?
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What is the length of the RNA-DNA hybrid helix during transcription?
What is the length of the RNA-DNA hybrid helix during transcription?
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Which region of the gene is responsible for directing RNA polymerase where to start transcription?
Which region of the gene is responsible for directing RNA polymerase where to start transcription?
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Which process is NOT directly involved in transcription?
Which process is NOT directly involved in transcription?
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What is used as the template for RNA synthesis during transcription?
What is used as the template for RNA synthesis during transcription?
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What is the significance of RNA's complementary base pairing during transcription?
What is the significance of RNA's complementary base pairing during transcription?
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Which of the following describes the nature of the control region in a gene?
Which of the following describes the nature of the control region in a gene?
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What occurs as soon as the first RNA polymerase starts moving down the gene?
What occurs as soon as the first RNA polymerase starts moving down the gene?
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Study Notes
Transcription Overview
- Transcription is the process of creating RNA from a DNA template
- RNA polymerase is the enzyme that carries out transcription
- RNA is a linear polymer like DNA, with residues linked by phosphodiester bonds
- RNA contains ribose, not deoxyribose, and is single-stranded
- RNA contains A, G, C, and U, instead of T
- U pairs with A in RNA
- RNA polymerase separates the two DNA strands and uses one as a template to synthesize a complementary RNA copy
- RNA polymerase moves along the DNA in a 5' to 3' direction
Transcription in Prokaryotes
- Prokaryotes and Eukaryotes use similar transcription steps (initiation, elongation, termination).
- Prokaryotic RNA polymerase is different from eukaryotic RNA polymerase
- Transcription occurs in the cytoplasm
- The DNA template strand is read 3' to 5' during synthesis and the mRNA is synthesized 5' to 3'
Transcription in Eukaryotes
- RNA transcription occurs in the nucleus
- Eukaryotic RNA polymerase is different from prokaryotic RNA polymerase
- Eukaryotic genes contain non-coding segments (introns) that need to be removed before translation
- mRNA needs to be processed before export with a 5' cap and poly(A) tail
- Transcription occurs in the nucleus
Transcription Mechanisms
- RNA polymerase unwinds the DNA double helix for transcription
- The bubble is 12-14 base pairs long
- Reaction rate is around 40 bases per second
- RNA polymerase moves along the DNA template, adding complementary RNA bases (A to U, G to C)
Types of RNA
- rRNA (ribosomal RNA): Part of the ribosome, essential for protein synthesis
- tRNA (transfer RNA): Transfers amino acids to the ribosome
- mRNA (messenger RNA): Carries the genetic code for protein synthesis
- microRNA/non-coding RNAs: Can regulate gene expression
Regulation of Transcription
- Controlling transcription is a key mechanism of protein expression regulation
- More protein needed = more mRNA synthesis
- Less protein needed = less mRNA synthesis
The Importance of Control (via examples)
- E. coli pET system for protein over-expression: Cloning a gene into a vector and introducing it to E-coli. Use of an inducer (such as IPTG) allows fine control and more protein production
- Protein over-expression in E.coli often triggers resistance mechanisms similar to antimicrobial resistance. Overexpression can lead to cell death.
Summary- Transcription Processes
- Initiation: Template recognition
- Elongation: Polymerase places RNA in exit hole
- Termination: Termination sequence and RNA polymerase release
- Both prokaryotes and eukaryotes use these steps and the number of mRNA transcripts produced is often the key point of regulation.
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Description
This quiz covers the essential concepts of transcription, focusing on the process of creating RNA from a DNA template. It explores the differences in transcription between prokaryotes and eukaryotes, highlighting the role of RNA polymerase and the structural properties of RNA. Test your knowledge of this fundamental biological process.
![Transcription in Prokaryotes: RNA Polymerase [Part 1]](https://assets.quizgecko.com/cdn-cgi/image/width=800,quality=90,format=webp/quiz/baed4520f1a7fc99e7641e1e05a42c62.jpg)
