Define and give an example of position effect variegation
What will be an ideal response?
Ans: Position effect variegation (PEV) occurs when genetically identical cells are phenotypically different as a result of gene inactivation. This inactivation may be a result of local heterochromatin formation found in some cells but not in others. One example occurs in Drosophila fruit flies, when the wild-type white allele (expressed in the eye) in inactive in some cells and active in others, resulting in patches of red cells (wild-type allele is expressed) and white cells (wild-type allele is inactive).
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A wind system that influences large climatic regions and reverses direction seasonally, producing dry and wet seasons, is referred to as a(n):
a. geothermal ecosystem b. upwelling c. taiga d. monsoon e. hurricane
When using a reporter gene to investigate expression of a target protein, the promoter of the ________ is ligated to the coding sequence of the ________
a. green fluorescent protein / lacZ b. lacZ / green fluorescent protein c. reporter gene / target gene d. target gene / reporter gene
What is the function of the MutS protein in methyl-directed mismatch repair?
A. To excise the mismatched basepair. B. To find mismatches. C. To directly bind the DNA polymerase. D. To make a cut in the nonmethylated DNA strand. E. To digest the nonmethylated DNA strand.
Of the following fermentation pathways, which can be carried out by human muscle cells?
A) alcoholic B) butanediol C) lactic acid: homolactic D) lactic acid: heterolactic E) mixed acid