What makes a "frameshift" mutational event more serious than a "point" mutational event?
A. Frameshift mutations occur primarily in germline cells and point mutations occur only in somatic cells.
B. Frameshift mutations result in the deletion or addition of whole chromosomes (aneuploidy) and point mutations are undetectable at the chromosome level.
C. When the mutations occur in expressed genes, frameshift mutations always result in disruption of the gene function, whereas a point mutation can be silent.
D. The rate of frameshift mutations increases with aging as the function of DNA repair mechanisms declines, whereas the rate of point mutations is unchanged with age.
C
A point mutation is a single-base substitution. Often, this substitution does not disrupt protein synthesis, although the expressed protein may have one amino acid different than a protein made from a nonmutated gene. Frameshift mutations either delete one or more bases from the gene (most common) or add one or more bases to a gene. This deletion or addition of bases disrupts the correct "reading" of the gene and the wrong amino acids are placed into the protein. The protein made in this way does not resemble the correct protein and will not function.
You might also like to view...
The nurse is palpating the sinus areas. If the findings are normal, then the patient should report which sensation?
a. No sensation b. Firm pressure c. Pain during palpation d. Pain sensation behind eyes
Following the completion of a comprehensive assessment, a nurse has identified the following nursing diagnosis for a newly admitted client: Risk for aspiration related to dysphagia as evidenced by coughing during feeding
The phrase "related to dysphagia" constitutes what component of a nursing diagnostic statement? A) Etiology B) Pathophysiology C) Root cause D) Epidemiology
At 9:15 the nurse repeatedly instructs the client to remain in bed. At 9:30, the nurse enters the client's room, finds the client on the floor, and hears the client say, "I need pain medicine."
Which does the nurse use to document this event? 1. Labels the late entry using the time of 9:15 2. Encloses client statement within quotations 3. Documents completion of an incident report 4. Records medication before its administration
The nurse is caring for clients on a postoperative unit in the medical centre
The nurse is alert to the possibility that for 24 to 48 hours of the postoperative period, clients may experience which of the following symptoms as a result of the anaesthetic used during the surgery? a. Colitis b. Stomatitis c. Paralytic ileus d. Gastrocolic reflex