Epinephrine binding to its receptor stimulates:

#Question id: 1102

#Unit 4. Cell Communication and Cell Signaling

Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of which of the following molecules?

#Question id: 11814

#Unit 6. System Physiology – Plant

Simplified biosynthetic pathway for cytokinin biosynthesis followed given such steps;

a) isopentenyl transferase (IPT), is the addition of the isopentenyl side chain from DMAPP (dimethylallyl diphosphate) to an adenosine moiety (AMP)

b) iPRTP or iPRDP is converted to ZTP or ZDP respectively by cytochrome P450 monooxygenase  and eventually is converted to zeatin

c) The ribotide and riboside forms of trans-zeatin can be interconverted, and free transzeatin can be formed from the ribotide by the LONELY GUY (LOG) family of cytokinin

Which of the following steps is true of the cytokinin biosynthesis?

#Question id: 563

#Unit 1. Molecules and their Interaction Relevant to Biology

Both water and glucose share an —OH that can serve as a substrate for a reaction with the terminal phosphate of ATP catalyzed by hexokinase.  Glucose, however, is about a million times more reactive as a substrate than water.  The best explanation is that:

#Question id: 693

#Unit 1. Molecules and their Interaction Relevant to Biology

In an alpha helix, the R groups on the amino acid residues:

#Question id: 28743

#Unit 2. Cellular Organization

Which of the following enzymes that uses the H2O2 (in peroxisomes) to oxidize a variety of other substrates by the “peroxidation” reaction?