Summative Test on Mutations

What best describes a mutation?

• An alteration in the nucleic acid sequence of the genome of an organism or extrachromosomal DNA

• A permanent change in the protein structure that alters an organism's traits

• The rearrangement of amino acids in a polypeptide chain during translation

• The process of creating an entirely new chromosome during cell division

Which type of mutation specifically affects multiple genes rather than just one?

• Frameshift mutation, caused by insertions or deletions

• Gene mutation, which impacts only a single gene at a time

• Silent mutation, which doesn't produce noticeable effects

• Chromosomal mutation, which involves changes across large sections of a chromosome

Which of the following disorders is specifically caused by a chromosomal mutation involving an extra copy of chromosome 21?

• Huntington's disease, caused by repeated CAG nucleotide sequences

• Cystic fibrosis, caused by a gene mutation leading to defective proteins

• Anemia, caused by the substitution of one nucleotide in the hemoglobin gene

• Down syndrome, resulting from a chromosomal mutation involving nondisjunction

Why might a substitution mutation sometimes result in no visible effect on the organism?

• Substitution mutations always cause frameshifts, which are minor and insignificant.

• The genetic code is redundant, meaning some mutations result in silent mutations where the same amino acid is produced despite a nucleotide change.

• Substitution mutations reverse the orientation of a chromosome segment, which has no effect on the polypeptide chain.

• Substitution mutations often delete a codon entirely, which does not affect the organism.

What is the characteristic outcome of a nonsense mutation?

• It introduces a stop codon prematurely, resulting in a shorter polypeptide chain.

• It causes the creation of a longer protein than normal by adding extra amino acids.

• It has no impact on the reading frame or protein function due to genetic redundancy.

• It alters the amino acid sequence while keeping the protein's overall length unchanged.

What is the primary effect of insertions and deletions on the polypeptide chain?

• They alter the codon reading frame, causing a frameshift that can change all subsequent codons.

• They result in the duplication of large chromosomal segments, leading to protein overexpression.

• They cause the substitution of amino acids with chemically similar ones, minimizing effects.

• They prevent the expression of genes entirely by silencing them during transcription.

Based on the change from TAGCCA to TAGCGCA, which type of gene mutation occurred?

• Substitution, where one nucleotide is replaced by another

• Deletion, where a nucleotide is removed from the sequence

• Insertion, where an extra nucleotide is added to the sequence

• Translocation, where segments from different chromosomes are exchanged

What is the primary consequence of a duplication mutation?

• It creates additional copies of one or more genes, potentially leading to overexpression of proteins.

• It reverses the orientation of the genetic material, making it unreadable during transcription.

• It reduces genetic material by removing large segments of a chromosome.

• It halts protein synthesis entirely by silencing all gene activity.

Why are frameshift mutations often more impactful on an organism?

• Frameshift mutations introduce stop codons prematurely, terminating translation.

• Frameshift mutations change the codon reading frame, altering all amino acids following the mutation site.

• Frameshift mutations typically involve only one nucleotide, resulting in minor changes to proteins.

• Frameshift mutations occur only in chromosomal mutations, which affect more genes.