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WorksheetsGene Mutations
Total questions: 20
Worksheet time: 11mins
Which statement best defines a mutation?
A random change in an organism's DNA
A planned improvement to an organism's traits
A temporary change in protein shape only
A predictable shift in chromosome number every generation
Which of the following is identified as a mutagen?
Ionizing radiation such as gamma rays
Seasonal temperature changes
Normal cell division
Dietary water intake
A substitution mutation is described as which of the following?
One base is exchanged for another base in the DNA strand
One or more bases are inserted, making the DNA strand longer
One or more bases are deleted, making the DNA strand shorter
A whole chromosome is duplicated during mitosis
Which of the following best illustrates an insertion mutation?
A guanine is added before the fourth base, lengthening the strand
The fifth base is exchanged for cytosine, keeping strand length the same
The second base is removed from the DNA strand, shortening it
A thymine is swapped with uracil to form RNA
Which description matches what happens with a deletion mutation?
One or more bases are removed from the DNA strand, making it shorter
A base is replaced with its complementary partner, keeping length constant
Extra copies of all chromosomes are added to the nucleus
A base is chemically modified but not added or removed
A student suggests that exposure to sunlight cannot cause genetic mutations because it is a natural part of the environment. Is this student's suggestion true or false?
The statement is false; sunlight contains UV rays, which are known mutagens
The statement is true; only artificial sources of radiation are mutagenic
The statement is true; natural factors cannot act as mutagens
The statement cannot be evaluated; there is not enough research on the relationship between sunlight and mutations
Which statement best explains why a DNA mutation can impact the protein synthesized in a cell?
Mutations only change sugars in DNA, so translation is unaffected.
Mutations alter the mRNA codon sequence, which can change the amino acid and thus protein structure and function.
Mutations occur only in tRNA, so they change ribosome size but not proteins.
Mutations make transcription skip over bases, leaving the amino acid sequence identical.
What is the effect of a silent mutation on the amino acid coded for by a codon?
No change in the amino acid because many amino acids are coded by multiple codons.
A change to a completely different amino acid, altering protein function.
A shift in the reading frame that changes many amino acids.
Creation of a stop codon that ends translation early.
A single base substitution changes one codon so that it now specifies a different amino acid from the original base sequence. Which mutation type does this describe?
Silent mutation
Missense mutation
Frameshift mutation
Nonsense mutation
Insertion of one nucleotide into a coding sequence causes the reading frame of mRNA codons to move forwards or backwards, changing many downstream amino acids. Which mutation does this describe?
Silent mutation
Missense mutation
Frameshift mutation
Nonsense mutation
A point mutation converts a codon into a stop codon, terminating translation early and often producing a non-functional protein. What type of mutation is this?
Silent mutation
Missense mutation
Frameshift mutation
Nonsense mutation
Original DNA: G T G A T A C G C
Mutated DNA: G A G A T A C G C
Which mutation type is this?
Insertion
Deletion
Substitution
Frameshift
Original DNA: GTG ATA CGC
Mutated DNA: GTG AAC GC
Which of the following mutations is illustrated in this example?
Missense: one amino acid changes but reading frame stays the same
Frameshift: the reading frame shifts and many codons change
Silent: base change but same amino acid
Nonsense: early stop codon created immediately
A mutation occurs where one base is changed but codes for the same amino acid as the unmutated sequence. Which type of mutation is described in this example?
Missense
Frameshift
Silent
Nonsense
A mutation changes GTG ATA CGC to GTG ATT ACG C.
What category of mutation is this and what is the most likely effect on the polypeptide?
Insertion; causes a frameshift altering downstream amino acids
Substitution; usually changes only one amino acid
Deletion; always creates an early stop codon
Insertion; always has no effect on the protein
Which of these mutations most likely results in the mutated hemoglobin gene?
A (a) and a (b)
Correctly label the mutations
have no effect on the amino acids produced during protein synthesis.
silent mutation
causes a stop codon instead of a normal amino acid codon. This causes translation to be terminated prematurely, causing a shorter protein.
nonsense mutation
causes a codon to code for a different amino acid than the original one.
missence mutation
causes the “reading frame” of the codons to shift forwards or backwards. This can change the entire sequence of amino acids.
frameshift mutation
causes a change to one base and potentially one amino acid of the polypeptide chain
point mutation
Choose the 3 cell types that if they contained a mutation, that mutation could be passed on to offspring.
sex cell
somatic (body) cell
egg cell
sperm cell
Choose the 3 mutagens listed below.
Tobacco
Ultraviolet(UV) light
Vitamin C
Water
Chemicals
