What are Genetic mutations?
They are changes in the DNA sequence that are caused by various mechanisms.
What are Small Scale Mutations? (point mutations)
These are changes in a single nucleotide or small groups of pairs paired, within a gene
What are Large Scale Mutations?
These are mutations that involve multiple nucleotides, entire genes or whole regions of chromosomes.
What are a few small scale mutations? (4)
- Substitution
- Insertion
- Deletion
- Inversion
What is Substitution?
This is the replacement of one base (pair) (ex, A-T becomes C-G)
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(In Small Scale Mutations)
What is Insertion?
This is the addition of one or more base (pairs)
- nucleotides shift over to make space
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(In Small Scale Mutations)
What is Deletion?
This is the removal of 1 or more base (pairs)
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(In Small Scale Mutations)
What is Inversion? (Small scale)
This is the reversal of 2 adjacent base pairs. (Ex. TCG becomes TGC)
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(In Small Scale Mutations)
What are the differences in DNA caused by Point mutations called?
Single Nucleotide Polymorphism
What are the 4 Functional groups of affect on protein caused by point mutations?
- Missense mutation
- Nonsense mutation
- Silent mutation
- Frameshift mutation
What is a missense mutation?
This is a mutation that causes a different amino acide code. It can change protein function or lead to a non-functional protein.
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(1 of the 4 Functional groups of point mutations)
What is a nonsense mutation?
This is a mutation that causes a premature stop codon. This makes the peptide be cut short, making the protein typically non-functional
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(1 of the 4 Functional groups of point mutations)
What is a Silent Mutation?
These are mutations that do not alter any amino acids: They have NO effect on resulting protein.
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(1 of the 4 Functional groups of point mutations)
What is a Frameshift Mutations?
This is insersion/deletion that leads to multiple nonsense or missense mutations.
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(Deletion/insersion of multiples of 3 bases do not cause frameshift)
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(1 of the 4 Functional groups of point mutations)
What are a few Large Scale Mutations? (4)
- Amplification (Gene duplication)
- Deletion
- Translocation (chromosomal)
- Inversion
What is Amplification (Gene Duplication)?
- This is when a gene/group of genes is copied in the chromosome. It provides opportunities to evolve new function.
(This is a Large scale mutation)
What is Deletion (Large Scale)?
This is a mutation where an entire coding region is removed. This typically has a negative impact.
(This is a Large scale mutation)
What is Translocation?
This is when an entire sequence/gene is moved from one chromosome to another.
(This is a Large scale mutation)
What is Inversion (Large Scale)
This is a mutation where a portion of DNA molecules reverses its direction in a genome.
What is Trinucleotide Repeat Expansion?
This is when a normal sequence of a trinucleotide repeats.
- It becomes unstable & expands uncontrollably.
(Ex. CAGCAGCAGCAG)
What are the (2) causes of Genetic Mutation?
-Spontaneous Mutations: They’re caused by an error in DNA replication
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- Induced Mutations: They’re caused by an environmental agent called a mutagen
What are Mutagens?
They are environmental agents that cause mutations (ex. chemicals & radiation)
What do are Chemical Mutagens? Ex?
This is any chemical agent that can enter the cell nucleus and chemically alter the structure of DNA.
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Ex. Nitrous Acid: modifies nucleotides and can resemble different nucleotides.
What are Radiation Mutagens? Ex?
This electromagnetic radiation that can cause mutations.
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Ex: Lower energy: causes bonds to form between nucleotides, causing kinks.
Higher energy: strips DNA of electrons & breaks bonds, leading to change/deletion of DNA
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3.1 Molecular Basis Of Inheritance18
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3.2 History Of Genetics13
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3.3 DNA Replication & Repair19
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3.6 Transcription20
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3.7 Translation23
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3.8 Controlling Gene Expression21
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3.9 Mutations29
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3.10 Genomes And Gene Organization16
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3.111
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3.120
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3.1313
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3.4 DNA Organization And Aging12
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3.5 Protein Synthesis11
