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Questions and Answers
What does "gene expression at the molecular level" affect?
What does "gene expression at the molecular level" affect?
The structure and function of cells, ultimately determining the traits an organism expresses.
What are the three steps involved in gene expression?
What are the three steps involved in gene expression?
- Using a gene as a template to create an RNA molecule. 2. Modifying the RNA into a functional molecule in eukaryotes. 3. Using RNA to direct the formation of a protein.
What are genes that encode polypeptides called?
What are genes that encode polypeptides called?
Protein-encoding genes
What are changes in genetic material that can be inherited called?
What are changes in genetic material that can be inherited called?
What did research on the effects of mutations help to determine?
What did research on the effects of mutations help to determine?
At what two levels can we look at gene function?
At what two levels can we look at gene function?
At what level does gene function relate to the protein product?
At what level does gene function relate to the protein product?
At what level does gene function relate to the characteristic conferred by the gene?
At what level does gene function relate to the characteristic conferred by the gene?
The "one gene, one enzyme" hypothesis was the original understanding of gene expression.
The "one gene, one enzyme" hypothesis was the original understanding of gene expression.
What is the modern understanding of gene expression, replacing the "one gene, one enzyme" hypothesis??
What is the modern understanding of gene expression, replacing the "one gene, one enzyme" hypothesis??
What is the name of the hypothesis that stated that a single gene controlled the synthesis of a single enzyme?
What is the name of the hypothesis that stated that a single gene controlled the synthesis of a single enzyme?
The "one gene, one polypeptide" hypothesis applies to all proteins.
The "one gene, one polypeptide" hypothesis applies to all proteins.
What does the term "polypeptide" refer to?
What does the term "polypeptide" refer to?
When comparing the term "polypeptide" to "protein", what does the term "protein" denote?
When comparing the term "polypeptide" to "protein", what does the term "protein" denote?
A single gene can contain the information to make a single protein, even if it's composed of multiple polypeptides.
A single gene can contain the information to make a single protein, even if it's composed of multiple polypeptides.
What protein carries oxygen in red blood cells and is composed of two alpha globin and two beta globin polypeptides?
What protein carries oxygen in red blood cells and is composed of two alpha globin and two beta globin polypeptides?
A single gene can encode more than one polypeptide through alternative splicing of mRNA.
A single gene can encode more than one polypeptide through alternative splicing of mRNA.
All genes encode for polypeptides.
All genes encode for polypeptides.
What are the two main steps of gene expression?
What are the two main steps of gene expression?
What does the term "transcription" literally mean?
What does the term "transcription" literally mean?
What is messenger RNA (mRNA) and why is it called that?
What is messenger RNA (mRNA) and why is it called that?
What is the second step of gene expression?
What is the second step of gene expression?
Why is the second step of gene expression called "translation"?
Why is the second step of gene expression called "translation"?
What is the name given to the process of transcription from DNA to mRNA and the translation of mRNA into a polypeptide?
What is the name given to the process of transcription from DNA to mRNA and the translation of mRNA into a polypeptide?
What does transcription produce?
What does transcription produce?
What does translation involve?
What does translation involve?
Provide a 3-word summary of the central dogma of gene expression.
Provide a 3-word summary of the central dogma of gene expression.
What are the two types of RNA that are not translated into proteins?
What are the two types of RNA that are not translated into proteins?
RNA processing occurs before transcription in eukaryotes.
RNA processing occurs before transcription in eukaryotes.
Where do transcription and translation occur in bacteria?
Where do transcription and translation occur in bacteria?
Where do transcription and translation occur in eukaryotes?
Where do transcription and translation occur in eukaryotes?
The flow of genetic information from DNA to RNA to protein is the only pathway for gene expression.
The flow of genetic information from DNA to RNA to protein is the only pathway for gene expression.
What is the role of the genetic material?
What is the role of the genetic material?
What do structural genes code for?
What do structural genes code for?
What do one or several polypeptides act as?
What do one or several polypeptides act as?
What do the activities of proteins determine?
What do the activities of proteins determine?
What does the genetic material provide?
What does the genetic material provide?
What does each protein-encoding gene store the information for?
What does each protein-encoding gene store the information for?
What is the key purpose of the genetic material?
What is the key purpose of the genetic material?
What is a gene?
What is a gene?
What does transfer RNA (tRNA) do?
What does transfer RNA (tRNA) do?
What does ribosomal RNA (rRNA) do?
What does ribosomal RNA (rRNA) do?
How is a working copy of a DNA sequence made for gene expression?
How is a working copy of a DNA sequence made for gene expression?
Transcription permanently alters the DNA structure.
Transcription permanently alters the DNA structure.
What is made when a protein-encoding gene is transcribed?
What is made when a protein-encoding gene is transcribed?
What happens to the polypeptide after it is made?
What happens to the polypeptide after it is made?
Most genes are protein-encoding genes.
Most genes are protein-encoding genes.
What is non-coding RNA and when is it produced?
What is non-coding RNA and when is it produced?
What are two common types of non-coding RNA?
What are two common types of non-coding RNA?
What is a gene composed of?
What is a gene composed of?
What is a promoter in transcription?
What is a promoter in transcription?
What does the terminator in transcription specify ?
What does the terminator in transcription specify ?
What are the two boundaries between which transcription occurs?
What are the two boundaries between which transcription occurs?
What does the promoter signal?
What does the promoter signal?
What does the terminator signal?
What does the terminator signal?
What does the transcribed region in transcription contain?
What does the transcribed region in transcription contain?
What do regulatory sequences in transcription function as?
What do regulatory sequences in transcription function as?
What is the direction of transcription from DNA to mRNA?
What is the direction of transcription from DNA to mRNA?
What is the function of regulatory sequences in transcription?
What is the function of regulatory sequences in transcription?
What is the role of sigma factor in transcription initiation?
What is the role of sigma factor in transcription initiation?
What is the function of RNA polymerase in transcription initiation?
What is the function of RNA polymerase in transcription initiation?
What does the term "template strand" refer to in transcription elongation?
What does the term "template strand" refer to in transcription elongation?
What is the name given to the opposite DNA strand in transcription elongation?
What is the name given to the opposite DNA strand in transcription elongation?
The coding strand has the same base sequence as the resulting mRNA.
The coding strand has the same base sequence as the resulting mRNA.
How is RNA synthesized during transcription elongation?
How is RNA synthesized during transcription elongation?
What happens during transcription termination?
What happens during transcription termination?
DNA is always transcribed from left to right.
DNA is always transcribed from left to right.
Transcription is a complex process that involves different components and stages.
Transcription is a complex process that involves different components and stages.
The same transcription process and components are used in bacteria and eukaryotes.
The same transcription process and components are used in bacteria and eukaryotes.
How many forms of RNA polymerase are present in eukaryotes?
How many forms of RNA polymerase are present in eukaryotes?
Which RNA polymerase is responsible for transcribing the mRNA from eukaryotic protein-encoding genes?
Which RNA polymerase is responsible for transcribing the mRNA from eukaryotic protein-encoding genes?
What do RNA polymerases I and III transcribe?
What do RNA polymerases I and III transcribe?
Bacteria have multiple RNA polymerases and sigma factors.
Bacteria have multiple RNA polymerases and sigma factors.
The initiation stage of transcription in eukaryotes is simpler than in prokaryotes.
The initiation stage of transcription in eukaryotes is simpler than in prokaryotes.
What are transcription factors and what is their role in eukaryotic transcription initiation?
What are transcription factors and what is their role in eukaryotic transcription initiation?
What is a preinitiation complex and how is it formed?
What is a preinitiation complex and how is it formed?
What modifications do eukaryotic mRNA transcripts undergo to become functional?
What modifications do eukaryotic mRNA transcripts undergo to become functional?
What does the term "pre-mRNA" refer to?
What does the term "pre-mRNA" refer to?
What is the name given to the final, modified RNA product?
What is the name given to the final, modified RNA product?
What are the two modifications that are made to the ends of pre-mRNA?
What are the two modifications that are made to the ends of pre-mRNA?
What is splicing and what does it involve?
What is splicing and what does it involve?
Where does the mature mRNA leave the nucleus?
Where does the mature mRNA leave the nucleus?
What is capping and what is its purpose?
What is capping and what is its purpose?
When does capping occur?
When does capping occur?
What are two functions of the 5' cap?
What are two functions of the 5' cap?
The 5' cap is crucial for the stability of mRNA.
The 5' cap is crucial for the stability of mRNA.
Flashcards
Gene Expression
Gene Expression
The process by which genetic information in a gene is used to create a functional product, typically a protein.
Steps of Gene Expression
Steps of Gene Expression
The process of gene expression occurs in two main steps: transcription and translation.
Transcription
Transcription
The process of copying a gene's DNA sequence into a messenger RNA (mRNA) molecule.
Translation
Translation
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Central Dogma
Central Dogma
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Protein-Encoding Genes
Protein-Encoding Genes
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Non-Coding RNA (ncRNA)
Non-Coding RNA (ncRNA)
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Transfer RNA (tRNA)
Transfer RNA (tRNA)
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Ribosomal RNA (rRNA)
Ribosomal RNA (rRNA)
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Promoter
Promoter
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Terminator
Terminator
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Transcription Factors
Transcription Factors
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RNA Polymerase
RNA Polymerase
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Template Strand
Template Strand
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Coding Strand
Coding Strand
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Pre-mRNA
Pre-mRNA
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Mature mRNA
Mature mRNA
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Capping
Capping
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Poly-A Tail
Poly-A Tail
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Introns
Introns
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Exons
Exons
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Splicing
Splicing
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Initiation (Transcription)
Initiation (Transcription)
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Elongation (Transcription)
Elongation (Transcription)
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Termination (Transcription)
Termination (Transcription)
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Ribosomes
Ribosomes
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Amino Acids
Amino Acids
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Central Dogma of Molecular Biology
Central Dogma of Molecular Biology
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tRNA (Transfer RNA)
tRNA (Transfer RNA)
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rRNA (Ribosomal RNA)
rRNA (Ribosomal RNA)
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Gene Regulation
Gene Regulation
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Study Notes
Gene Expression at the Molecular Level: mRNA and Protein Production
- Gene expression influences cell structure and function, determining organism traits.
- Gene expression involves three steps: creating an RNA molecule from a gene, modifying the RNA (in eukaryotes), and using RNA to make a protein.
- Protein-encoding genes are those whose expression results in polypeptides.
- Mutations, changes in genetic material, can affect gene function, revealing molecular gene function.
- Gene function can be examined at two levels: molecular function of the protein product, and the organism's trait conferred by the gene.
- The original "one-gene, one-enzyme" hypothesis is now understood as "one-gene, one-polypeptide."
- Some proteins are composed of multiple polypeptides, requiring information from multiple genes.
- Polypeptide refers to amino acid structure; protein refers to function.
- A single gene can produce multiple polypeptides through alternative mRNA splicing.
- Non-coding RNA genes produce RNA molecules that aren't translated into proteins.
Central Dogma of Molecular Biology
- The general dogma is DNA → RNA → Protein, representing transcription and translation.
- Transcription produces an RNA copy (transcript) of a gene's DNA sequence; mRNA carries this information to ribosomes for translation.
- Translation synthesizes polypeptides (specific sequences of amino acids) on ribosomes using mRNA as a template.
- Some genes encode structural RNA (like tRNA and rRNA) not directly translated into polypeptides. Other genes may encode regulatory RNA to control gene expression.
- While fundamental to both prokaryotes and eukaryotes, eukaryotic gene expression has a crucial additional step of RNA processing.
Eukaryotic Transcription
- Eukaryotic transcription (DNA to RNA) is more complicated, involving multiple RNA polymerases (I, II, III).
- RNA polymerase II is a key enzyme for transcribing most protein-encoding genes.
- RNA polymerases I and III transcribe genes for non-coding RNAs (tRNA, rRNA).
- In eukaryotes, transcription occurs in the nucleus, and mRNA then moves to the cytoplasm for translation.
- Eukaryotic mRNA undergoes modifications (capping, tailing, and splicing) within the nucleus before entering the cytoplasm.
RNA Processing
- Pre-mRNA is the initial transcript before modifications; mature mRNA is the final form.
- Capping and tailing involve modifications at the ends of the pre-mRNA (5' cap and polyA tail).
- Splicing removes introns (non-coding segments) to create mature mRNA containing exons (coding segments).
- Capping protects mRNA and facilitates its export from the nucleus; modification on the end of pre- mRNA.
- The 5’ cap is a 7-methylguanosine structure crucial for RNA processing.
- Tailing with the polyA tail is also essential for RNA processing.
Transcription Details
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Transcription initiation requires recognition of the promoter (start signal) followed by unwinding of the DNA.
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Transcription elongation involves RNA polymerase sliding along the template DNA strand.
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Transcription termination occurs at a terminator sequence and triggers the release of RNA polymerase and the newly synthesized mRNA.
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Promoters, terminators, and regulatory sequences govern the transcription process.
General Features of Genes and Protein-Encoding Genes
- Genes are functional units of DNA, transcribed into RNA and producing specific protein products.
- Genes control the characteristics of an organism based on their protein products.
- All organisms use the basic transcription process, although the exact details can differ between species.
- In contrast to the basic process (DNA>RNA>Protein), some viruses use RNA as a template to synthesize DNA.
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Description
This quiz explores gene expression at the molecular level, focusing on the processes of mRNA creation, protein synthesis, and the impact of mutations. It covers concepts such as the 'one-gene, one-polypeptide' hypothesis and the relationship between gene function and organism traits. Test your knowledge of how genes influence cell structure and function.
