Several members of the same family were diagnosed with the same kind of cancer when they were unusually young
Which one of the following is the most likely explanation for this phenomenon? It is possible that the individuals with the cancer have _______________________.
(a) inherited a cancer-causing gene that suffered a mutation in an ancestor's somatic cells.
(b) inherited a mutation in a gene required for DNA synthesis.
(c) inherited a mutation in a gene required for mismatch repair.
(d) inherited a mutation in a gene required for the synthesis of purine nucleotides.
Choice (c) is the correct answer. In fact, affected individuals in some families with a history of early-onset colon cancer have been found to carry mutations in mismatch repair genes. Mutations arising in somatic cells are not inherited, so choice (a) is incorrect. A defect in DNA synthesis or nucleotide biosynthesis would probably be lethal, so choices (b) and (d) are incorrect.
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You experimentally change the DNA sequence directly upstream of a start codon of an operon in E. coli to investigate the function of this region of DNA
Analysis reveals that after the change the same amount of mRNA is made from the operon, but there are very few proteins made from the operon. What is the most likely function of the DNA sequence that you changed? A) The DNA sequence likely functions as a ribosome-binding site. B) The DNA sequence likely functions as a promoter. C) The DNA sequence likely functions as a termination sequence. D) The DNA sequence likely functions as in transcriptional regulation.
Genetics is the study of
A) variation of inherited traits. B) how organisms reproduce. C) how life originated. D) how the environment causes disease.
A cancer that develops in muscle is
a. malignant melanoma. b. oat cell carcinoma. c. giant cell carcinoma. d. rhabdomyosarcoma. e. Wilm's tumor.
Explain what is meant by deamination. How does this mutation affect a cytosine (C) versus a methylcytosine (5meC)? What effect does deamination have on CpG islands, and how does that affect the mutation frequencies in these regions?
What will be an ideal response?