T.15 Definición de exón

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Questions and Answers

What is the primary function of exons in a gene transcript?

To provide regulatory functions

To code for proteins (correct)

To introduce premature stop codons

To inhibit protein synthesis

What is the result of a frameshift mutation occurring within an exon?

The amino acid sequence of the protein is altered

A premature stop codon is introduced

The codon usage is optimized

The reading frame of the genetic code is altered (correct)

What is the effect of exon skipping on protein function?

It has no effect on protein function

It always leads to protein degradation

It can alter protein interactions (correct)

It increases protein complexity

What is the role of regulatory elements in exons?

They provide binding sites for transcription factors Signup and view all the answers

What is the outcome of alternative splicing in a single gene?

Generation of multiple mRNA isoforms Signup and view all the answers

What is the effect of a nonsense mutation occurring within an exon?

It introduces a premature stop codon Signup and view all the answers

What is the primary function of the EJC in the cytoplasm?

To facilitate the transportation of mRNA Signup and view all the answers

What is the effect of intron insertion or deletion on gene expression?

Genes with introns are more expressed than those without Signup and view all the answers

What is the significance of the 5' end of the RNA exiting the nucleus first?

To facilitate the export of RNA Signup and view all the answers

What is the role of TAP/Mex in the EJC-mediated transport process?

To facilitate the interaction between EJC and the nuclear pore Signup and view all the answers

What is the purpose of the splicing process in eukaryotic gene expression?

To process the RNA molecule for export Signup and view all the answers

What is the significance of eucromatin association with nuclear pores?

To export RNA molecules Signup and view all the answers

What is the effect of the EJC on messenger RNA degradation?

The EJC prevents messenger RNA degradation Signup and view all the answers

What is the relationship between the spliceosome and the EJC?

The EJC is a marker that binds to the spliceosome Signup and view all the answers

What is the significance of the polyadenylation process in eukaryotic gene expression?

It adds a poly-A tail to the RNA molecule Signup and view all the answers

What is the advantage of the 5' end of the RNA exiting the nucleus before transcription is complete?

It allows for simultaneous transcription and translation Signup and view all the answers

Study Notes

Exon Structure

An exon is a sequence of DNA or RNA that is included in the final, mature form of a gene transcript
Typically, exons are interspersed with introns (non-coding regions) in a gene
Exons can be further divided into:
- Coding exons: contain the instructions for protein synthesis
- Non-coding exons: do not code for proteins, but may have regulatory functions

Alternative Splicing

The process by which a single gene can generate multiple mRNA isoforms
Exons are selectively included or excluded from the final mRNA transcript
Alternative splicing allows for:
- Generation of protein isoforms with different functions
- Regulation of gene expression
- Increased complexity of the proteome

Exon Mutation

A mutation that occurs within an exon can affect the resulting protein product
Types of exon mutations:
- Missense mutation: alters the amino acid sequence of the protein
- Nonsense mutation: introduces a premature stop codon
- Frameshift mutation: alters the reading frame of the genetic code
Exon mutations can lead to:
- Loss of protein function
- Gain of toxic function
- Altered protein interactions

Exon Skipping

A type of alternative splicing where an exon is intentionally excluded from the final mRNA transcript
Exon skipping can be:
- Constitutive: always skipped
- Tissue-specific: skipped in certain tissues or cell types
- Developmental-stage specific: skipped during specific stages of development
Exon skipping can have significant effects on protein function and gene regulation

Exon Function

Exons contain the genetic information necessary for protein synthesis
Exons can also contain:
- Regulatory elements: binding sites for transcription factors and other regulatory proteins
- Untranslated regions (UTRs): regions that do not code for proteins, but may have regulatory functions
Exon function can be influenced by:
- Epigenetic modifications: chemical modifications to DNA or histone proteins
- RNA-binding proteins: proteins that interact with RNA and influence its processing and translation

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Description

Learn about the structure and function of exons, including alternative splicing, exon mutations, and exon skipping. Understand how exons affect protein synthesis and gene regulation.