Podcast
Questions and Answers
What is a mutation that involves the addition of an extra nucleotide into a DNA sequence called?
What is a mutation that involves the addition of an extra nucleotide into a DNA sequence called?
- Point mutation
- Insertion (correct)
- Deletion
- Substitution
What major effect can a frame shift caused by an insertion or deletion mutation have on protein synthesis?
What major effect can a frame shift caused by an insertion or deletion mutation have on protein synthesis?
- Creates additional amino acids without altering their sequence
- Causes premature termination of the polypeptide chain (correct)
- Results in the same primary protein structure
- Increases the production of enzymes
What type of mutation occurs when there is a loss of a nucleotide from the normal DNA sequence?
What type of mutation occurs when there is a loss of a nucleotide from the normal DNA sequence?
- Duplication
- Translocation
- Deletion (correct)
- Insertion
From which cells can mutations be inherited to the next generation?
From which cells can mutations be inherited to the next generation?
What term describes changes in the structure or number of whole chromosomes?
What term describes changes in the structure or number of whole chromosomes?
What effect can an insertion of three nucleotides have on the resulting protein?
What effect can an insertion of three nucleotides have on the resulting protein?
What role do DELLA proteins play in seed germination?
What role do DELLA proteins play in seed germination?
How does oestrogen affect gene expression?
How does oestrogen affect gene expression?
Which characteristic of organisms is an example of continuous variation?
Which characteristic of organisms is an example of continuous variation?
What initiates the breakdown of DELLA proteins in the context of gibberellins?
What initiates the breakdown of DELLA proteins in the context of gibberellins?
Which of the following best explains gene mutations?
Which of the following best explains gene mutations?
How are characteristics showing discontinuous variation typically controlled?
How are characteristics showing discontinuous variation typically controlled?
What is the primary effect of cystic fibrosis on mucus production?
What is the primary effect of cystic fibrosis on mucus production?
What type of mutation results in the premature termination of a polypeptide chain?
What type of mutation results in the premature termination of a polypeptide chain?
What is the result of a mis-sense mutation?
What is the result of a mis-sense mutation?
How does sickle cell anemia affect red blood cells?
How does sickle cell anemia affect red blood cells?
Why do dominant alleles normally not spread in populations?
Why do dominant alleles normally not spread in populations?
What happens when the repeat sequence CAG in the huntingtin gene is mutated?
What happens when the repeat sequence CAG in the huntingtin gene is mutated?
What is a characteristic of repressible enzymes?
What is a characteristic of repressible enzymes?
What role do allosteric sites play in enzyme regulation?
What role do allosteric sites play in enzyme regulation?
What is the role of the repressor protein in the lac operon system when lactose is absent?
What is the role of the repressor protein in the lac operon system when lactose is absent?
What happens to the repressor protein when lactose is present in the medium?
What happens to the repressor protein when lactose is present in the medium?
Which enzyme hydrolyzes lactose into glucose and galactose?
Which enzyme hydrolyzes lactose into glucose and galactose?
Which genes are involved in the production of lactose permease and beta-galactosidase?
Which genes are involved in the production of lactose permease and beta-galactosidase?
What is the purpose of the transcription factors in eukaryotic cells?
What is the purpose of the transcription factors in eukaryotic cells?
Which component of the lac operon is responsible for switching the structural genes on and off?
Which component of the lac operon is responsible for switching the structural genes on and off?
Why does E. coli only express the genes for lactose metabolism when lactose is available?
Why does E. coli only express the genes for lactose metabolism when lactose is available?
Which of the following statements regarding the lac operon is true?
Which of the following statements regarding the lac operon is true?
What is the primary function of lactose permease in E. coli?
What is the primary function of lactose permease in E. coli?
What happens when the primary repressor protein binds to the operator?
What happens when the primary repressor protein binds to the operator?
Flashcards
Gene Mutation (Insertion)
Gene Mutation (Insertion)
A mutation where an extra nucleotide is added to the DNA sequence.
Frame Shift
Frame Shift
A change in the reading frame of codons caused by insertion or deletion of nucleotides.
Premature Chain Termination
Premature Chain Termination
A stop codon is created earlier than expected, resulting in a shorter polypeptide chain.
Gene Mutation (Deletion)
Gene Mutation (Deletion)
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Chromosome Mutation
Chromosome Mutation
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Point Mutation
Point Mutation
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Cystic Fibrosis Mutation
Cystic Fibrosis Mutation
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Substitution Mutation
Substitution Mutation
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Nonsense Mutation
Nonsense Mutation
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Missense Mutation
Missense Mutation
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Silent Mutation
Silent Mutation
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Huntington's Disease Cause
Huntington's Disease Cause
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Dominant Allele
Dominant Allele
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Repressible Enzyme
Repressible Enzyme
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Transcription Factor
Transcription Factor
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Oestrogen Receptor (ER)
Oestrogen Receptor (ER)
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DELLA Protein
DELLA Protein
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Gibberellin
Gibberellin
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Continuous Variation
Continuous Variation
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Discontinuous Variation
Discontinuous Variation
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Inducible Enzyme
Inducible Enzyme
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Lac Operon
Lac Operon
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Repressor Protein
Repressor Protein
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Operator
Operator
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Allolactose
Allolactose
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Promoter
Promoter
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Enhancer Region
Enhancer Region
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Transcription Initiation Complex
Transcription Initiation Complex
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Translation
Translation
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Study Notes
Mutations
- Mutations are changes in the DNA sequence of an organism.
- Mutations in body cells are not heritable.
- Mutations during gamete formation can be inherited, leading to differences between individuals.
- Chromosome mutations involve changes in chromosome structure or number.
- Gene mutations (point mutations) affect a single gene locus, creating different alleles.
Gene Mutations: Insertions
- Insertion mutations add extra nucleotides to the DNA sequence.
- This shifts the reading frame (triplet code) during translation, altering amino acid sequences in the protein.
- Frame shifts can create premature STOP codons, resulting in shorter, non-functional polypeptide chains.
- This can disrupt biochemical pathways and have detrimental effects on the organism.
- Insertions of multiples of three nucleotides do not cause a frame shift but can still affect tertiary protein structure.
Gene Mutations: Deletions
- Deletion mutations remove nucleotides from the DNA sequence.
- This also shifts the reading frame, altering the amino acid sequence of the protein.
- Deletions often result in non-functional proteins and disrupt biochemical pathways.
- Cystic fibrosis is an example of a genetic disorder caused by a deletion mutation.
Gene Mutations: Substitutions
- Substitution mutations replace one nucleotide with another.
- Three types of substitution mutations exist:
- Nonsense mutations: result in a STOP codon, creating a shorter, non-functional protein.
- Missense mutations: result in a different amino acid being coded for. This can change a protein's function. (e.g., sickle cell anemia)
- Silent mutations: result in the same amino acid being coded for, with no apparent effect on the polypeptide.
Huntington's Disease
- Huntington's disease is a dominant genetic disorder.
- It results in a progressive deterioration of brain cells.
- Symptoms appear after age 30.
- The huntingtin gene (HTT) on chromosome 4 codes for a protein with many repeats of the amino acid glutamine.
- An increased number of CAG repeats in the HTT gene leads to more glutamine repeats in the protein, causing the disease.
- The more repeats, the earlier and more severe the symptoms.
Control of Protein Synthesis
- Repressible enzymes are produced continuously but their production can decrease when the product of the reaction increases.
- Inducible enzymes are produced only when needed, triggered by the presence of a specific molecule (e.g. substrate).
- Lac operon in E.coli controls inducible enzymes involved in lactose metabolism:
- Structural genes: code for enzymes necessary for lactose metabolism
- Operator: regulates the expression of structural genes
- Promoter: where RNA polymerase binds
- Regulatory gene: codes for a repressor protein
- Repressor protein binds to operator when no lactose is present, blocking RNA polymerase from transcribing structural genes
- Lactose converts to allolactose, which binds to the repressor protein, changing its shape and allowing RNA polymerase to bind, triggering transcription of structural genes.
- Eukaryotic transcription involves transcription factors that bind to promoter or enhancer regions, initiating transcription.
- Oestrogen is an extracellular factor, binding to oestrogen receptor (ER), creating an initiation complex
- Gibberellins are plant growth regulators that break down DELLA proteins, activating transcription factors involved in germination.
Variation
- Phenotypic variation can be classified into continuous and discontinuous.
- Continuous variation involves a range of phenotypes without distinct classes (e.g., height, mass).
- Continuous variation is controlled by many genes (polygenes) and influenced by the environment.
- Discontinuous variation involves distinct phenotype classes with little overlap (e.g., blood types, some genetic diseases).
- Discontinuous variation is typically controlled by a few genes.
- Genetic variation results from mutations in reproductive tissues, crossing over during meiosis, random assortment of chromosomes, random mating, and random fusion of gametes.
- Environmental factors influence genetic expression in many species. (e.g., arctic foxes, Siamese cats)
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Description
Explore the world of mutations and their impact on genetics. This quiz covers types of mutations, including gene insertions and deletions, and their effects on protein synthesis and organism traits. Test your understanding of how these genetic changes can lead to variations among individuals.
