Questions and
Complete Solutions
Graded A+
Denning [Date] [Course title]
,mutation - Correct Ans: an alteration in dna sequence
mutations may be - Correct Ans: - single base pair substitutions
- deletion or insertion of one or more base pairs
- major alteration in chromosomal structure
mutations may occur in - Correct Ans: somatic or germ cells
somatic mutations - Correct Ans: occur in any cell except germ cells and are NOT heritable
germ-line mutations - Correct Ans: occur in gametes and are inherited
autosomal mutations - Correct Ans: occur within genes located on the autosomes
x and y linked mutations - Correct Ans: occurs within genes located on x and y chromosome,
respectively
spontaneous mutations - Correct Ans: happen naturally and randomly and are usually linked to normal
biological or chemical processes in the organism
rates of spontaneous mutations - Correct Ans: is low but vary among loci in different organisms
induced mutations - Correct Ans: result from the influence or an extraneous factor, either natural or
artificial
examples of induced mutations - Correct Ans: radiation, uv light, natural and synthetic chemicals
how do mutations arise? two theories are - Correct Ans: resistance is a physiological response to a
bactericide AND resistance arises from random mutations
,Luria-Delbruck fluctuation test - Correct Ans: Demonstrated mutations are not adaptive but occur
spontaneously and randomly
they shown that in bacteria, - Correct Ans: genetic mutations arise in the absence of selection, rather
than being a response to selection
If bacteriophage T1 caused T1 resistance, then the variance in the two procedures - Correct Ans: should
be the same
if the event leading to T1 resistance was random, it might occur at different times, leading to - Correct
Ans: different final proportions of T1-resistant cells= higher variance in mean number of resistant cells
per culture
conclusion of the luria-delbruck fluctuation test - Correct Ans: mutation to T1 resistance arises in a
random manner within bacterial populations.
- this is general result that seems true of most organisms
most mutations are not directed at specific genes by selective forces, but rather are - Correct Ans:
random with respect to genotype
mutations can be classified according to their phenotypic effects as - Correct Ans: LOF and GOF, visible,
nutritional, behavioral, and regulatory mutations
normal mutation - Correct Ans: Due to chromosome replication; 1 cell in a population of 100,000,000
cells.
missense mutation - Correct Ans: A base-pair substitution that results in a codon that codes for a
different amino acid.
nonsense mutation - Correct Ans: A mutation that changes an amino acid codon to one of the three
stop codons, resulting in a shorter and usually nonfunctional protein.
, frameshift mutation - Correct Ans: mutation that shifts the "reading" frame of the genetic message by
inserting or deleting a nucleotide
deletion mutation - Correct Ans: a mutation in which one or more pairs of nucleotides are removed
from a gene
insertion mutation - Correct Ans: a mutation in which one or more nucleotides are added to a gene
duplication mutation - Correct Ans: a mutation that involves duplication of a region of DNA on the same
strand
expanding mutation - Correct Ans: duplication runs over and over again; repetitive sequence gets longer
and longer again (F1, F2, ...)
neutral mutations - Correct Ans: can occur either in a protein-coding region or in any part of the
genome
- vast majority are likely to occur in large portions of the genome that do not contain genes
- they do not affect gene products or gene expression
- its effect on genetic fitness is NEUTRAL
can a cells dna repair mechanisms fail, be overwhelmed, or become less efficient with age? - Correct
Ans: YES
over time, - Correct Ans: mistakes can accumulate
mutations are - Correct Ans: inherited changes in genetic material
mutations provide - Correct Ans: new genetic variation that allows organisms to evolve
B-Thallasemia - Correct Ans: is an example of a genetic disease that can arise from a large number of
mutations