Which structural gene of the lac operon can be mutated without affecting the cell's ability to break down lactose?
A) lacZ
B) lacY
C) lacA
D) lacP
E) lacO
C
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There are organisms that go through meiosis but do not undergo recombination when forming haploid gametes. Which of the following statements correctly describes the gametes produced by such an organism
(Assume that these organisms are diploid, that each of the two homologous chromosomes are genetically distinct as typically found in the wild, and that these organisms have more than one chromosome.) (a) All gametes formed during a single meiosis will be identical. (b) Due to the random assortment of homologs, each of the gametes formed during a single meiosis will be different. (c) This organism could potentially produce 2n genetically distinct gametes, where n is its haploid number of chromosomes. (d) The fusion of any two gametes produced by such an organism that does not undergo recombination during meiosis will create a cell that is genetically identical to that individual.
Which of these is a correct statement about pH?
A) The pH of a solution increases as its acidity increases. B) The pH of a basic or alkaline solution is less than that of an acidic solution. C) As the concentration of H+ increases in a solution, the pH decreases. D) A solution to which HCl has been added will have a greater pH than a solution to which NaOH has been added. E) Each number on the pH scale represents an increase of 108.
Which specimen is quantitatively plated by using a calibrated loop?
a. Stool b. Sputum c. Joint fluid d. Urine
The part of a chromosome that shortens with each cell division, functioning as a "clock," is the
A) centromere. B) centrosome. C) centriole. D) telomere.