Cell Mutation: Somatic, Germ, and Chromosomal

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Questions and Answers

A researcher is studying a newly discovered organism. They observe that a specific mutation in a somatic cell line leads to increased cell proliferation but does not appear in subsequent generations. Which of the following conclusions is MOST likely?

The mutation involves a chromosomal translocation in reproductive cells, leading to heritable changes.
The mutation is a spontaneous mutation in a somatic cell, confined to the individual organism. (correct)
The mutation occurred during meiosis and will be propagated through sexual reproduction.
The mutation is an induced mutation caused by environmental mutagens affecting germ cells.

Frameshift mutations invariably result in a complete loss of function of the affected protein, rendering it entirely non-functional.

False (B)

Describe a scenario where a point mutation could have a more severe phenotypic effect than a chromosomal deletion.

A point mutation in a critical regulatory region, such as a promoter or enhancer, could disrupt the expression of multiple genes, leading to a more severe phenotype than a small chromosomal deletion that only affects a few genes.

Exposure to high levels of ionizing radiation, such as from a nuclear accident, often leads to an increased frequency of ______ in exposed individuals.

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Match the following types of chromosomal mutations with their MOST likely consequence:

Deletion = Loss of genetic material, potentially leading to developmental abnormalities. Insertion = Addition of genetic material, potentially disrupting gene regulation or protein structure Inversion = Reversal of a segment of DNA, potentially disrupting gene expression if breakpoints occur within genes or regulatory regions. Translocation = Movement of a DNA segment to a non-homologous chromosome, potentially disrupting gene regulation or creating fusion genes. Signup and view all the answers

A scientist is studying a newly discovered mutagen. Through a series of experiments, they determine that the mutagen primarily causes the formation of thymine dimers in DNA. Which of the following DNA repair mechanisms would be MOST crucial for cells to survive exposure to this mutagen?

Nucleotide excision repair (NER) (A) Signup and view all the answers

All induced mutations are inherently more harmful to an organism than spontaneous mutations.

False (B) Signup and view all the answers

Explain how a mutation in a non-coding region of DNA could still significantly impact gene expression and cellular function.

Mutations in non-coding regions, such as promoters, enhancers, silencers, or splice sites, can alter the binding of transcription factors, affect mRNA splicing, or disrupt the stability of mRNA, leading to changes in gene expression levels and subsequent effects on cellular function. Signup and view all the answers

A researcher is comparing the genomes of two closely related bacterial strains. They identify a region in one strain's genome that contains a gene present in the other strain, but the gene is flanked by insertion sequence (IS) elements. Which of the following mechanisms is MOST likely responsible for the observed difference?

Transposition of the gene via a transposon containing the IS elements. (A) Signup and view all the answers

Certain DNA polymerases have proofreading capabilities, which significantly reduce the rate of ______ by correcting errors during DNA replication.

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Flashcards

Mutation

Any change in the DNA sequence.

Somatic Cells

Cells that form the majority of the body and divide by mitosis; they do not play a role in reproduction.

Reproductive (Germ) Cells

Cells found in the testes of males or ovaries of females that divide by meiosis and play a role in reproduction.