Gene Expression Regulation

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Questions and Answers

What is the functional gene product of gene expression?

Protein (correct)

DNA

tRNA

RNA

What type of genes are continually expressed and not regulated?

Housekeeping genes

Operon genes

Constitutive genes (correct)

Regulated genes

What is the term for a group of genes organized together in prokaryotes?

Gene complex

Gene family

Gene cluster

Operon (correct)

What is the term for a DNA segment that turns a gene 'on' or 'off'?

Operator Signup and view all the answers

What type of regulation occurs before transcription in eukaryotes?

Pre-transcriptional regulation Signup and view all the answers

What are the regulatory proteins called that bind to cis-acting elements?

Trans-acting proteins Signup and view all the answers

What is the term for parts of hnRNA that carry genetic information that will be translated into protein?

Exons Signup and view all the answers

What is the main difference between protooncogenes and oncogenes?

The activity or amount of protein product Signup and view all the answers

What is the term for a gene whose protein product normally plays a role in regulating normal cell cycle?

Protooncogene Signup and view all the answers

What is the term for a part of DNA that turns a gene 'on' or 'off'?

Enhancer Signup and view all the answers

What is the term for a group of genes that are expressed together in response to a specific signal?

Operon Signup and view all the answers

What is the result of a mutation in a protooncogene?

The formation of an oncogene Signup and view all the answers

What is the term for the process of removing introns and joining exons together to form a mature mRNA?

Splicing Signup and view all the answers

What is the term for genes that are only expressed under certain conditions?

Regulated genes Signup and view all the answers

What is the role of DNA enhancers in gene expression?

They increase the rate of transcription initiation. Signup and view all the answers

Which of the following is NOT a post-transcriptional modification in eukaryotes?

Replication Signup and view all the answers

What is the purpose of adding a methyl-guanosine cap to the 5' end of mRNA?

All of the above Signup and view all the answers

What is the function of poly(A) polymerase (PAP) in mRNA processing?

It adds a poly(A) tail to the 3' end of pre-mRNA. Signup and view all the answers

What is the difference between introns and exons?

Introns are non-coding sequences, while exons are coding sequences. Signup and view all the answers

Which of the following is the correct order of post-transcriptional modifications in eukaryotes?

Capping, Splicing, Polyadenylation Signup and view all the answers

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.