Questions and Answers
What is the functional gene product of gene expression?
What type of genes are continually expressed and not regulated?
What is the term for a group of genes organized together in prokaryotes?
What is the term for a DNA segment that turns a gene 'on' or 'off'?
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What type of regulation occurs before transcription in eukaryotes?
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What are the regulatory proteins called that bind to cis-acting elements?
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What is the term for parts of hnRNA that carry genetic information that will be translated into protein?
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What is the main difference between protooncogenes and oncogenes?
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What is the term for a gene whose protein product normally plays a role in regulating normal cell cycle?
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What is the term for a part of DNA that turns a gene 'on' or 'off'?
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What is the term for a group of genes that are expressed together in response to a specific signal?
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What is the result of a mutation in a protooncogene?
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What is the term for the process of removing introns and joining exons together to form a mature mRNA?
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What is the term for genes that are only expressed under certain conditions?
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What is the role of DNA enhancers in gene expression?
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Which of the following is NOT a post-transcriptional modification in eukaryotes?
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What is the purpose of adding a methyl-guanosine cap to the 5' end of mRNA?
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What is the function of poly(A) polymerase (PAP) in mRNA processing?
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What is the difference between introns and exons?
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Which of the following is the correct order of post-transcriptional modifications in eukaryotes?
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Study Notes
Gene Expression
- Gene expression is a multistep process that involves the production of functional gene products such as proteins and RNA.
Levels of Gene Expression
- There are two levels of gene expression: Level 1 and Level 2.
Constitutive Vs Regulated Genes
- Constitutive genes (housekeeping genes) are continually expressed and not regulated.
- Regulated genes are expressed only under certain conditions.
Regulation of Gene Expression in Prokaryotes
- In prokaryotes, genes are organized in a group called operons.
- An operon consists of a promoter, operator, and structural genes that code for proteins needed for a particular function.
- The operator is a DNA segment that allows a gene to be transcribed.
Regulation of Gene Expression in Eukaryotes
- There are three levels of regulation: pre-transcriptional, transcriptional, and post-transcriptional.
- Pre-transcriptional regulation involves epigenetic mechanisms.
- Transcriptional regulation involves regulatory proteins and sequences on DNA called cis-acting elements.
- Post-transcriptional regulation involves modifications to RNA molecules.
Transcriptional Regulation of Gene Expression
- Regulatory proteins are called trans-acting factors.
- Cis-acting elements on DNA include enhancers, silencers, and promoters.
- Enhancers are special DNA sequences that increase the rate of initiation of transcription of a specific gene.
Post-transcriptional Regulation of Gene Expression
- In eukaryotes, all three types of RNAs (mRNA, tRNA, and rRNA) are synthesized in precursor forms.
- Post-transcriptional modifications include capping at the 5' end, splicing, and addition of a poly(A) tail at the 3' end.
Post-transcriptional Modifications
- Capping at the 5' end involves adding a methyl-guanosine cap to the RNA molecule.
- Splicing involves removing introns (non-coding regions) and joining exons (coding regions).
- Addition of a poly(A) tail involves adding a string of adenine nucleotides to the 3' end of the RNA molecule.
Protooncogenes and Oncogenes
- Protooncogenes are genes that normally play a role in regulating normal cell growth and division.
- Oncogenes are altered protooncogenes that can cause cancer.
- The difference between protooncogenes and oncogenes is related to the activity or amount of protein product of the gene.
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Description
This quiz covers the process of gene expression, including its levels, constitutive vs regulated genes, and regulation. Understand how genes produce functional products like proteins and RNA.
