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Questions and Answers
What is the effect of a point mutation in the non-coding region of a gene?
What is the effect of a point mutation in the non-coding region of a gene?
- It has no effect on the gene's function.
- It always results in a silent mutation.
- It can change protein binding sites, promoter sequences, or splice sites. (correct)
- It always results in a change in the amino acid sequence.
What is an example of a missense mutation?
What is an example of a missense mutation?
- CGA (Arg) >>> UGA (Stop)
- CGA (Arg) >>> CCA (Pro) (correct)
- CGA (Arg) >>> CGG (Arg)
- CGA (Arg) >>> CGA (Arg)
What is the effect of a frameshift mutation?
What is the effect of a frameshift mutation?
- It changes the amino acid sequence.
- It has no effect on the gene's function.
- It always results in a silent mutation.
- It shifts the reading frame. (correct)
What type of mutation results from the insertion or deletion of 3 nucleotides (or multiples of 3)?
What type of mutation results from the insertion or deletion of 3 nucleotides (or multiples of 3)?
What is the term for a mutation that changes the amino acid specified to a stop codon?
What is the term for a mutation that changes the amino acid specified to a stop codon?
What is the term for a base substitution that is a purine to purine or pyrimidine to pyrimidine change?
What is the term for a base substitution that is a purine to purine or pyrimidine to pyrimidine change?
What type of mutation results from the insertion or deletion of one or more bases to the DNA sequence?
What type of mutation results from the insertion or deletion of one or more bases to the DNA sequence?
What is the effect of a silent mutation?
What is the effect of a silent mutation?
What is the primary function of the protein encoded by the CFTR gene?
What is the primary function of the protein encoded by the CFTR gene?
What is the effect of a nonsense mutation on the resulting protein?
What is the effect of a nonsense mutation on the resulting protein?
What type of mutation is the CTT deletion in the CFTR gene?
What type of mutation is the CTT deletion in the CFTR gene?
Why is the loss of the CTT codon (phenylalanine) in the protein sequence of clinical significance?
Why is the loss of the CTT codon (phenylalanine) in the protein sequence of clinical significance?
What type of mutation is responsible for Cystic fibrosis?
What type of mutation is responsible for Cystic fibrosis?
Why was PCR technique used for the detection of the CTT deletion?
Why was PCR technique used for the detection of the CTT deletion?
Which of the following mutations is likely to have a variable effect on the protein function?
Which of the following mutations is likely to have a variable effect on the protein function?
What is the effect of a point mutation in a regulatory region on protein production?
What is the effect of a point mutation in a regulatory region on protein production?
What type of mutation is the homozygous mutation in the non-coding region of the β-globin gene?
What type of mutation is the homozygous mutation in the non-coding region of the β-globin gene?
What type of mutation is responsible for Gaucher disease?
What type of mutation is responsible for Gaucher disease?
Which of the following is a spontaneous cause of mutations?
Which of the following is a spontaneous cause of mutations?
What is the effect of a frameshift insertion/deletion on protein function?
What is the effect of a frameshift insertion/deletion on protein function?
What is the purpose of PCR genetic analysis in the diagnosis of Cystic fibrosis?
What is the purpose of PCR genetic analysis in the diagnosis of Cystic fibrosis?
What is the result of trinucleotide repeat expansion mutation in Huntington's disease?
What is the result of trinucleotide repeat expansion mutation in Huntington's disease?
What is the mechanism of DNA damage caused by X-Ray?
What is the mechanism of DNA damage caused by X-Ray?
What is the effect of a mutation in a non-coding region on protein production?
What is the effect of a mutation in a non-coding region on protein production?
What is the result of UV light exposure on DNA?
What is the result of UV light exposure on DNA?
What type of mutations are caused by exposure to mutagens?
What type of mutations are caused by exposure to mutagens?
What is the effect of smoking on DNA?
What is the effect of smoking on DNA?
Where do somatic mutations occur?
Where do somatic mutations occur?
What type of transmission is responsible for inherited diseases?
What type of transmission is responsible for inherited diseases?
What is the primary function of proofreading by DNA Polymerase during DNA replication?
What is the primary function of proofreading by DNA Polymerase during DNA replication?
What is the consequence of failing to repair DNA damage?
What is the consequence of failing to repair DNA damage?
What is the frequency of mutations during DNA replication?
What is the frequency of mutations during DNA replication?
What type of mutations are due to the combined effects of vertical and horizontal transmission?
What type of mutations are due to the combined effects of vertical and horizontal transmission?
What is the purpose of DNA repair mechanisms?
What is the purpose of DNA repair mechanisms?
What is the primary cause of DNA damage?
What is the primary cause of DNA damage?
What is the role of enzymes that catalyze repair of mismatched bases during DNA replication?
What is the role of enzymes that catalyze repair of mismatched bases during DNA replication?
Study Notes
Small Mutations: Single Gene Mutations
- Small mutations can occur in a single gene, resulting in a change in the nucleotide sequence
- Types of small mutations include:
- Substitutions (Point mutations): a single base (nucleotide) change
- Silent: a mutation that does not alter the amino acid specified
- Missense: a mutation that replaces one amino acid with another
- Nonsense: a mutation that changes the amino acid specified to a stop codon
- Insertions, Deletions, and Frameshift mutations: an insertion or deletion of one or more bases to the DNA sequence
- Non-frameshift: insertion or deletion of 3 nucleotides (or multiples of 3)
- Frameshift: insertion or deletion of nucleotides other than 3 or multiples of 3
- Substitutions (Point mutations): a single base (nucleotide) change
Effects of Mutations
- Mutations can occur in:
- Coding regions of a gene
- Affect the amino acid sequence of the protein
- Non-coding regions of a gene
- Affect protein binding sites, promoter sequences, splice sites, etc.
- Coding regions of a gene
- Effects of mutations on protein function:
- Frameshift insertion/deletion: usually nonfunctional; often shorter than normal
- Non-frameshift insertion/deletion: possible decrease in function; variable effects
- Point mutations: do not affect quality of protein, but may affect quantity; affect rate of transcription
- Examples of genetic disorders caused by mutations:
- Cystic fibrosis: deletion of CTT in the CFTR gene
- Sickle cell anemia: non-conservative substitution in the HBB gene
- Gaucher disease: insertion of a single DNA base prevents production of an enzyme
Mutation Identification and Repair
- Causes of mutations:
- Spontaneous mutations: DNA replication errors, tautomeric shift, DNA polymerase slippage, trinucleotide repeat expansion
- Induced mutations: exposure to mutagens such as chemicals, UV light, X-rays, and tobacco smoke
- DNA repair mechanisms:
- During DNA replication: proofreading by DNA polymerase
- After completion of replication: repair of mismatched bases and DNA damage
- Importance of DNA repair: failure of DNA repair can have serious consequences, leading to disease
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Description
This quiz covers the different types of small mutations that occur in a single gene, including substitutions, insertions, and deletions. Learn about point mutations and their effects on gene expression.
