13.3 Mutations ( bio worksheet answers) – Flashcards
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The change of one base to another in a DNA sequence
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substitution
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a change in one or a few nucleotides that occur at a single point in the DNA sequence
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point mutation
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part of one chromosome breaks off and attaches to another
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translocation
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a heritable change in genetic information
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mutation
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a mutation that produces an extra copy of all or part of a chromosome
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duplication
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a chromosomal mutation that reverses the direction of parts of a chromosome
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inversion
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a kind of mutation that can change every amino acid that follows the point of mutation
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frameshift mutation
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the addition of a base to the DNA sequence
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insertion
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complete the table to describe the processes and outcomes of the different types of gene(point) mutations
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LOOK AT HANDOUT!!!
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Deletion can happen as a gene mutation or as a chromosomal mutation. what is the difference?
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In a gene mutation, a deletion happens when a base is removed from the DNA
sequence. In a chromosomal mutation, deletion involves the loss of all or part of a
chromosome.
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the cellular machinery that replicates DNA inserts an incorrect base
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roughly once in every 10 million bases
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small changes in genes
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gradually accumulate over time
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a possible mutagen is
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ultraviolet light
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what happens when cells cannot repair the damage caused by a mutagen
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the DNA base sequence changes permanently
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which of the following most accurtaely summarizes the effects of mutations on living things
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many mutations have little or no effect, but some can be harmful or beneficial
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Mutations are important to the evolution of a species because they
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are a source of genetic variability
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cancer is the product of a mutation that
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causes the uncontrolled growth of cells
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polyploidy is the condition in which
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an organism has an extra set of chromosomes
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draw a normal blood cell and a sickle cell
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A gene that codes for one of the polypeptide chains of the blood protein hemoglobin lies on chromosome 11 in humans. A substitution mutation in that gene causes the amino acid valine to be incorporated into hemoglobin in a place where glutamic acid would normally lie. The result is sickle cell disease. Explain how a change in a single base in DNA can bring about such a serious disorder.
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A single DNA base-pair change in a gene can create an incorrect codon in the mRNA
molecule made from this DNA. When the incorrect codon is "read" on the ribosome,
the wrong amino acid (in this case valine rather than glutamic acid) is placed into the
polypeptide. With the wrong amino acid sequence, the protein does not form or func-
tion properly.
