1 markDuring the replication of DNA spontaneous errors may occur, causing mutations. Which of the following mutations is most likely to be classified as a frameshift mutation?
Substitution of one base.
Insertion of a nucleotide.
Change in chromosome number.
Inversion of a gene section.
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1 markA polypeptide has the amino acid sequence:
histidine – glutamine – lysine – alanine – valine – histidine – valine
The table below gives the tRNA anticodons for each amino acid.
amino acid | tRNA anticodons |
histidine valine lysine alanine glutamine | CAU GUA AAA GCU CAG |
A mutation causes the 18th base in the DNA sequence to be deleted.
Which of the following shows the amino acid sequence after this mutation has occurred?
histidine – glutamine – lysine – alanine – valine – histidine
histidine – glutamine – lysine – alanine – valine – glutamine-valine
histidine – glutamine – lysine – alanine – valine – glutamine
histidine – glutamine – lysine – alanine – valine – histidine – valine
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1 markA bacterial population exposed to ionizing radiation may experience a higher rate of mutations.
Which of the following mechanisms is most likely to cause this increase in mutation rates?
Decreased gene expression.
Alteration in cell membrane structure.
Increased protein synthesis.
Damage to DNA strands.
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1 markA duplication mutation is a type of genetic mutation where a section of DNA containing a gene is copied. The evolution of the hemoglobin gene family is an example of gene duplication leading to the introduction of new alleles and new biological function.
Which of the following is the most likely prediction of the effects of a duplication mutation in a gene encoding a critical protein, such as hemoglobin?
It is always harmful and leads to the loss of protein function.
It will result in the production of larger proteins than the original protein.
It can create an opportunity for evolutionary change by allowing one gene copy to evolve a new function.
It introduces a premature stop codon, resulting in incomplete protein synthesis.
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1 markA population of bacteria is exposed to an antibiotic over several generations. Scientists observe that the bacteria evolve resistance to the antibiotic through a mutation in the gene encoding a membrane transport protein.
Which of the following best explains why this mutation increased in frequency in the bacterial population?
The antibiotic increased the mutation rate in the bacterial population, directly causing the resistance mutation to appear.
Bacteria with the mutation survived and reproduced more successfully than those without it.
The mutation was inherited from the parent bacteria and occurred in all individuals simultaneously.
Mutations occur in response to environmental stress, ensuring that all bacteria become resistant over time.
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