Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–, 

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from  these statements?

#Question id: 11755

#SCPH28 | Zoology

Which of the following solutions when infused intravenously would result in an increase in extracellular fluid volume, a decrease in intracellular fluid volume, and an increase in total body water after osmotic equilibrium?

#Question id: 11756

#SCPH28 | Zoology

A 65-year-old man has a heart attack and experiences cardiopulmonary arrest while being transported to the emergency room. The following laboratory values are obtained from arterial blood:

plasma pH = 7.12,

plasma PCO2 = 60mm Hg, and

plasma HCO3− concentration = 19 mEq/L.

Which of the following best describes his acid-base disorder?

#Question id: 11757

#SCPH28 | Zoology

Which of the following tends to decrease potassium secretion by the cortical collecting tubule?

#Question id: 11758

#SCPH28 | Zoology

In normal kidneys, which of the following is true of the osmolarity of renal tubular fluid that flows through the early distal tubule in the region of the macula densa?

#Question id: 11797

#SCPH05 I Biotechnology

A living cytoplasmic connection penetrate the walls between sieve tube elements and their companion cells; which are often complex and branched on the companion cell side, known as

#Question id: 11798

#SCPH05 I Biotechnology

Companion cells transport of photosynthetic products from producing cells in mature leaves to the sieve elements in the minor veins of the leaf. There are at least three different types of companion cells in the minor veins of mature, exporting leaves, All three cell types have dense cytoplasm and abundant mitochondria;