During DNA replication, what type of mutation occurs when a single base in the DNA sequence is replaced by another?
substitution
Only one base pair is swapped. May or may not change the amino acid due to the degeneracy of the genetic code.
What mutation occurs when one or more bases are inserted into a DNA sequence during replication?
Addition
Also called insertion; may cause a frameshift if not in multiples of three bases.
What type of mutation results when one or more bases are removed from a DNA sequence?
Deletion
Often causes a frameshift, altering all downstream triplets.
What mutation occurs when a section of DNA is copied and repeated within the gene?
Duplication
Produces extra copies of a DNA segment within the same gene.
What mutation occurs when a segment of DNA is reversed within the sequence?
Inversion
A section of bases flips orientation within the DNA molecule.
What mutation involves a segment of DNA breaking off and attaching to a different chromosome or different location?
Translocation
More commonly discussed as a chromosomal mutation but can disrupt gene sequences.
True or False:
A mutation that changes a single DNA triplet always changes the amino acid coded for in the polypeptide.
False
Because the genetic code is degenerate, multiple codons can code for the same amino acid.
When a mutation changes the reading frame of a gene so that all downstream triplets are altered, what type of mutation has occurred?
Frameshift
Usually caused by addition or deletion of bases not in multiples of three.
Fill in the blank:
The genetic code is described as ______ because more than one codon can specify the same amino acid.
degenerate
This property means some base substitutions do not change the amino acid sequence.
What process during the cell cycle most commonly gives rise to spontaneous gene mutations?
DNA replication
Errors in copying DNA can introduce changes to the base sequence.
True or False:
Mutagenic agents increase the probability that mutations will occur in DNA.
True
Examples include radiation, certain chemicals and some viruses.
Why can a frameshift mutation have a larger effect on a protein than a single base substitution?
It alters the reading frame, changing every downstream codon and often resulting in a different polypeptide.
What general outcome may occur if a mutation alters the sequence of bases in a gene?
different amino acid sequence
This can alter the structure and function of the encoded protein or even shorten the protein prematurely.
Fill in the blank:
Mutations that arise without exposure to mutagenic agents are described as ______ mutations.
spontaneous
These often result from errors during DNA replication.
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3.1.1 Monomers & Polymers9
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3.1.2 Carbohydrates22
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3.1.3 Lipids17
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3.1.4 Proteins39
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3.1.5 Nucleic Acids32
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3.1.6 ATP11
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3.1.7 Water11
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3.1.8 Inorganic ions8
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3.2.1 Cell structure52
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3.2.2 Cell division20
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3.2.3 Transport across cell membranes20
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3.2.4 Cell recognition & the immune system36
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3.3.1 Surface area to volume ratio13
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3.3.2 Gas exchange24
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3.3.3 Digestion & absorption16
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3.3.4 Mass transport39
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3.4.1 DNA, genes & chromosomes13
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3.4.2 DNA & protein synthesis14
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3.4.3 Genetic diversity & meiosis14
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3.4.4 Genetic diversity & adaptation20
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3.4.5 Species & taxonomy20
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3.4.6 Biodiversity within a community12
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3.4.7 Investigating diversity12
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3.5.1 Photosynthesis23
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3.5.2 Respiration17
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3.5.3 Energy & ecosystems20
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3.5.4 Nutrient cycles15
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3.6.1 Stimuli & Response62
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3.6.2 Nervous coordination53
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3.6.3 Skeletal muscles14
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3.6.4 Homeostasis57
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3.7.1 Inheritance12
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3.7.2 Populations15
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3.7.3 Evolution may lead to speciation22
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3.7.4 Populations in ecosystems24
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3.8.1 Gene Mutations and Protein Structure14
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3.8.2 Control of Gene Expression44
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3.8.3 Applications of Genome Projects10
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3.8.4 Gene Technologies and Their Applications46
