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 you have a wild type (Lac+) strain carrying a Tn5 insertion known to be near several Lac genes on the E. coli chromosome. You grow P1 phage on this strain and use the resulting phage lysate to infect the lac1– strain, selecting for kanamycin resistance (Kanr). Among 100 Kanr transductants, you find that 82 are Lac– and 18 are Lac+. Express the distance between Tn5 and the lac1– mutation as a cotransduction frequency;

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#Question id: 12516

#Unit 6. System Physiology – Plant

ABA Is Synthesized from a Carotenoid Intermediate is takes place in___

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#Question id: 12517

#Unit 6. System Physiology – Plant

Synthesis of violaxanthin is catalyzed by an enzyme known as__

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#Question id: 12518

#Unit 6. System Physiology – Plant

ABA inactivation by oxidation and by the conjugation process such as

a) ABA inactivation by oxidation with monosaccharides ABA-β-D-glucose ester

b) ABA inactivation by conjugation with monosaccharides ABA-β-D-glucose ester

c) ABA inactivation by oxidation into Phaseic acid

d) ABA inactivation by conjugation  by oxidation into Phaseic acid

Which of the following combination from the given above statements about conjugation and oxidation process

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#Question id: 12519

#Unit 6. System Physiology – Plant

Some given  statements about biosynthesis of Abscisic acid ;

a) ABA is synthesized in almost all cells that contain chloroplasts or amyloplasts

b) ABA is a 15-carbon terpenoid, or sesquiterpenoid, which is synthesized in plants by an indirect pathway via 40-carbon carotenoid intermediates

c) Cleavage of the carotenoid by the enzyme NCED (9-cis-epoxycarotenoid dioxygenase) is a rate-limiting

d) Oxidation by ABA-8′-hydroxylases lead to ABA inactivation, ABA can also be inactivated by conjugation, but this is irreversible. Both types of inactivation are also tightly regulated.

Which of the following  combination from the above statements  is correct?

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#Question id: 12520

#Unit 6. System Physiology – Plant

During the biosynthesis of precursor All-trans-β-carotene is isomerized to 9-cis-β-carotene by ____A_____While 9-cis-β-Carotene is cleaved by carotenoid cleavage_____B_______ to produce_____C______.

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#Question id: 12521

#Unit 6. System Physiology – Plant

Which of the following enzyme of ABA biosynthesis function as a rate limiting enzyme?