Mutation and gene editing Flashcards
What is a gene mutation?
A gene mutation is a structural change in the DNA sequence of a gene that can affect the function of the resulting protein.
What are the three main types of gene mutations?
The three main types of gene mutations are substitutions, insertions, and deletions.
What is a substitution mutation?
A substitution mutation occurs when one nucleotide in the DNA sequence is replaced by another nucleotide, potentially altering the corresponding amino acid.
How can a substitution mutation affect protein function?
A substitution can lead to a silent mutation (no change), a missense mutation (different amino acid), or a nonsense mutation (premature stop codon), impacting protein function.
What is an insertion mutation?
An insertion mutation involves adding one or more nucleotides into the DNA sequence, which can shift the reading frame and alter the entire downstream amino acid sequence.
What are the potential effects of an insertion mutation on protein synthesis?
An insertion can cause frameshift mutations, leading to significant changes in protein structure and function, or it may introduce new amino acids if it occurs in multiples of three.
What is a deletion mutation?
A deletion mutation occurs when one or more nucleotides are removed from the DNA sequence, which can also result in a frameshift and alter protein synthesis.
How do deletions impact gene expression?
Deletions can disrupt the reading frame, leading to altered amino acid sequences and potentially nonfunctional proteins.
Why is it important to understand gene mutations?
Understanding gene mutations is crucial for studying genetic diseases, evolution, and mechanisms of genetic variation within populations.
How do different types of mutations contribute to genetic diversity?
Mutations introduce new alleles into a population, contributing to genetic diversity and providing raw material for natural selection and evolution.
What is a base substitution mutation?
A base substitution mutation occurs when one nucleotide in the DNA sequence is replaced by another nucleotide.
What are single-nucleotide polymorphisms (SNPs)?
SNPs are variations in a single nucleotide that occur at specific positions in the genome and are often the result of base substitution mutations.
How can base substitutions affect protein synthesis?
Base substitutions can change the amino acid sequence of a protein, potentially altering its structure and function.
What is a silent mutation?
A silent mutation is a type of base substitution that does not change the amino acid sequence due to the redundancy of the genetic code.
What is a missense mutation?
A missense mutation is a base substitution that results in the incorporation of a different amino acid into the polypeptide chain, which may affect protein function.
What is a nonsense mutation?
A nonsense mutation is a base substitution that creates a premature stop codon, leading to truncated proteins that are usually nonfunctional.
Why does degeneracy in the genetic code matter for base substitutions?
The degeneracy of the genetic code means that multiple codons can code for the same amino acid, so some base substitutions may not affect protein function.
How do SNPs contribute to genetic diversity?
SNPs introduce variations in the DNA sequence, contributing to genetic diversity within populations and influencing traits and susceptibility to diseases.
What role do SNPs play in personalized medicine?
SNPs can influence individual responses to drugs and susceptibility to diseases, allowing for tailored medical treatments based on genetic profiles.
What are insertions and deletions in the context of gene mutations?
Insertions and deletions are types of mutations where one or more nucleotides are added (insertion) or removed (deletion) from the DNA sequence.
Why is understanding base substitutions important in molecular biology?
Understanding base substitutions helps elucidate mechanisms of genetic variation, evolution, and the basis of many genetic disorders.
How can insertions affect protein synthesis?
Insertions can lead to frameshift mutations, altering the reading frame of the genetic code and potentially changing the entire amino acid sequence downstream.
How do deletions impact gene expression?
Deletions can also cause frameshift mutations, which may result in altered amino acid sequences and nonfunctional proteins.
What is the likelihood that insertions or deletions will cause polypeptides to cease functioning?
The likelihood is high, as frameshift mutations often produce proteins that are truncated or have incorrect amino acid sequences, rendering them nonfunctional.
Can insertions and deletions affect multiple genes?
Yes, large insertions or deletions can disrupt multiple genes or regulatory elements, leading to broader effects on gene expression and function.
Why is it important to understand the consequences of insertions and deletions?
Understanding these mutations helps elucidate mechanisms of genetic disorders, evolution, and the functional impact of genetic variation.
What role do insertion and deletion mutations play in evolution?
Insertions and deletions can introduce new genetic variations that may confer advantages or disadvantages, influencing evolutionary processes.
How can cells repair insertion and deletion mutations?
Cells have DNA repair mechanisms that can correct these mutations; however, if unrepaired, they may lead to permanent changes in the genome.
What is an example of a disease caused by insertion or deletion mutations?
Cystic fibrosis can result from a deletion mutation in the CFTR gene, leading to dysfunctional protein production and associated symptoms.
What are the primary causes of gene mutations?
Gene mutations can be caused by mutagens and errors in DNA replication or repair.
What are mutagens?
Mutagens are agents that increase the frequency of mutations in DNA, leading to changes in the genetic sequence.
Can you provide examples of chemical mutagens?
Examples of chemical mutagens include alkylating agents (like mustard gas), base analogs (like 5-bromouracil), and intercalating agents (like ethidium bromide).
How do chemical mutagens induce mutations?
Chemical mutagens can alter DNA bases, disrupt base pairing, or cause misincorporation of nucleotides during DNA replication.
What are mutagenic forms of radiation?
Mutagenic forms of radiation include ultraviolet (UV) light, X-rays, and gamma rays, which can cause DNA damage.
How does ultraviolet (UV) radiation lead to mutations?
UV radiation can cause the formation of pyrimidine dimers, which distort the DNA structure and interfere with normal base pairing during replication.
What role do errors in DNA replication play in mutations?
Errors during DNA replication can result in incorrect base pairing, leading to substitutions, insertions, or deletions in the DNA sequence.
How does DNA repair contribute to mutation prevention?
DNA repair mechanisms correct errors that occur during replication or damage caused by mutagens, reducing the likelihood of permanent mutations.
Why is it important to understand the causes of gene mutations?
Understanding the causes of gene mutations is essential for studying genetic diseases, cancer development, and mechanisms of evolution.
How can exposure to mutagens impact human health?
Exposure to mutagens can increase the risk of developing genetic disorders and cancers due to the accumulation of harmful mutations in critical genes.
