33 Questions
What can cause mutations?
Spontaneous changes and environmental factors
What is a mutation?
A change in DNA sequences
How common are mutations in terms of base pairs?
1 in every 1 billion base pairs
Why don't all mutations result in visible changes?
Mutations may have no effect on the organism
Which type of mutation results in the replacement of a single base by another?
Missense mutation
What type of mutation changes a codon into a stop codon, resulting in premature protein synthesis termination?
Nonsense mutation
Which type of mutation does not affect the protein product as most amino acids are encoded by multiple codons?
Silent mutation
What type of mutation prevents the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences?
Splice-site mutation
Which type of mutation involves alterations in the number of base pairs, potentially altering the reading frame and leading to non-functional proteins?
Large-scale changes, insertions, and deletions
What causes Fragile X Syndrome?
Trinucleotide repeat mutations
When do mutations occur and affect offspring?
Only in gametes (egg and sperm)
What is the result of translocations?
Changes in gene function or creating a hybrid gene
What is the consequence of large-scale changes, insertions, and deletions?
Alteration of reading frame (frameshift)
Which type of mutation results in the expansion of a stretch of repeated nucleotides?
Trinucleotide repeat mutations
What is the effect of missense mutations on the protein product?
Production of different amino acid in the protein product
What is the primary cause of spontaneous mutations?
Errors during DNA replication
Which environmental factor can induce mutations through natural exposure?
Chemical carcinogens
What is the frequency of mutations in terms of base pairs?
1 in every 1 billion base pairs
Why don't all mutations result in visible changes in an organism?
Mutations may have no effect on the organism
Which type of mutation involves the alteration of a single base, leading to different types of mutations like missense, nonsense, transition, or transversion?
Single-base substitution
What is the result of a missense mutation?
Altered codon producing a different amino acid
Which type of mutation changes a codon into one of the stop codons (UGA, UAA, or UAG), resulting in premature protein synthesis termination?
Nonsense mutation
What is the consequence of large-scale changes, insertions, and deletions?
Altering the reading frame and leading to non-functional proteins
What type of mutation prevents the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences?
Splice-site mutation
What causes Fragile X Syndrome?
Trinucleotide repeat
What is the primary cause of spontaneous mutations?
Chemical instability of purine and pyrimidine bases
Which environmental factor can induce mutations through natural exposure?
Aflatoxin B1
What is the frequency of mutations in terms of base pairs?
1 in every 1 billion base pairs
Why don't all mutations result in visible changes in an organism?
Affected genes may still function
Which type of mutation involves the alteration of a single base, leading to different types of mutations like missense, nonsense, transition, or transversion?
Silent mutation
What type of mutation changes a codon into one of the stop codons (UGA, UAA, or UAG), resulting in premature protein synthesis termination?
Nonsense mutation
What is the result of a missense mutation?
Altered codon producing a different amino acid
What type of mutation prevents the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences?
Splice-site mutation
Study Notes
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Mutations only occur in gametes (egg and sperm) and are passed onto offspring, mutations in body cells do not affect offspring.
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Single-base substitutions, also called point mutations, occur when a single base is replaced by another, leading to different types of mutations like missense, nonsense, transition, or transversion.
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Missense mutations alter the codon, producing a different amino acid in the protein product. For example, sickle-cell disease is caused by the replacement of glutamic acid (GAG) with valine (GTG) in the beta chain of hemoglobin.
-
Nonsense mutations change a codon into one of the stop codons (UGA, UAA, or UAG), resulting in premature protein synthesis termination, producing truncated and defective proteins.
-
Silent mutations do not affect the protein product, as most amino acids are encoded by multiple codons.
-
Splice-site mutations alter the nucleotide signals, preventing the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences.
-
Large-scale changes, insertions, and deletions, involve alterations in the number of base pairs, potentially altering the reading frame (frameshift), and leading to non-functional proteins.
-
Trinucleotide repeat diseases, such as Fragile X Syndrome, result from the expansion of a stretch of repeated nucleotides (CGG) in the human X chromosome, eventually causing a fragile chromosome and resulting in mental retardation in males and mild symptoms in females.
-
Translocations occur when a piece of one chromosome is transferred to a non-homologous chromosome, altering the phenotype through changes in gene function or creating a hybrid gene.
-
The significance of mutations varies depending on whether they occur in the germline (passed onto offspring) or soma (affecting the individual only).
-
Mutations only occur in gametes (egg and sperm) and are passed onto offspring, mutations in body cells do not affect offspring.
-
Single-base substitutions, also called point mutations, occur when a single base is replaced by another, leading to different types of mutations like missense, nonsense, transition, or transversion.
-
Missense mutations alter the codon, producing a different amino acid in the protein product. For example, sickle-cell disease is caused by the replacement of glutamic acid (GAG) with valine (GTG) in the beta chain of hemoglobin.
-
Nonsense mutations change a codon into one of the stop codons (UGA, UAA, or UAG), resulting in premature protein synthesis termination, producing truncated and defective proteins.
-
Silent mutations do not affect the protein product, as most amino acids are encoded by multiple codons.
-
Splice-site mutations alter the nucleotide signals, preventing the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences.
-
Large-scale changes, insertions, and deletions, involve alterations in the number of base pairs, potentially altering the reading frame (frameshift), and leading to non-functional proteins.
-
Trinucleotide repeat diseases, such as Fragile X Syndrome, result from the expansion of a stretch of repeated nucleotides (CGG) in the human X chromosome, eventually causing a fragile chromosome and resulting in mental retardation in males and mild symptoms in females.
-
Translocations occur when a piece of one chromosome is transferred to a non-homologous chromosome, altering the phenotype through changes in gene function or creating a hybrid gene.
-
The significance of mutations varies depending on whether they occur in the germline (passed onto offspring) or soma (affecting the individual only).
-
Mutations only occur in gametes (egg and sperm) and are passed onto offspring, mutations in body cells do not affect offspring.
-
Single-base substitutions, also called point mutations, occur when a single base is replaced by another, leading to different types of mutations like missense, nonsense, transition, or transversion.
-
Missense mutations alter the codon, producing a different amino acid in the protein product. For example, sickle-cell disease is caused by the replacement of glutamic acid (GAG) with valine (GTG) in the beta chain of hemoglobin.
-
Nonsense mutations change a codon into one of the stop codons (UGA, UAA, or UAG), resulting in premature protein synthesis termination, producing truncated and defective proteins.
-
Silent mutations do not affect the protein product, as most amino acids are encoded by multiple codons.
-
Splice-site mutations alter the nucleotide signals, preventing the enzymatic machinery from removing intron sequences properly, leading to incorrect mRNA sequences.
-
Large-scale changes, insertions, and deletions, involve alterations in the number of base pairs, potentially altering the reading frame (frameshift), and leading to non-functional proteins.
-
Trinucleotide repeat diseases, such as Fragile X Syndrome, result from the expansion of a stretch of repeated nucleotides (CGG) in the human X chromosome, eventually causing a fragile chromosome and resulting in mental retardation in males and mild symptoms in females.
-
Translocations occur when a piece of one chromosome is transferred to a non-homologous chromosome, altering the phenotype through changes in gene function or creating a hybrid gene.
-
The significance of mutations varies depending on whether they occur in the germline (passed onto offspring) or soma (affecting the individual only).
Test your knowledge about mutations, the changes in DNA sequences that can affect protein structure and function. Learn about the effects of mutations on organisms and how they can occur spontaneously or be induced.
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