The trp operon is controlled by repression and attenuation, providing a two-stage response to progressively more stringent tryptophan starvation. But attenuation alone can provide robust regulation: other amino acid operons such as leu and his rely entirely on attenuation for their control. Correct number of codons in leader peptide of leu & his operon  in a row;

#Question id: 595

#Unit 1. Molecules and their Interaction Relevant to Biology

It is difficult to determine either Km or Vmax from a graph of velocity vs. substrate concentration because

#Question id: 596

#Unit 1. Molecules and their Interaction Relevant to Biology

The reason to rewrite the Michaelis-Menten equation (such as the Lineweaver-Burk plot) is to

#Question id: 597

#Unit 1. Molecules and their Interaction Relevant to Biology

The Km values for enzyme reactions such as A + B → C + D

#Question id: 598

#Unit 1. Molecules and their Interaction Relevant to Biology

Which might be a method used for distinguishing among several mechanistic possibilities in a multi-substrate reaction?

#Question id: 599

#Unit 1. Molecules and their Interaction Relevant to Biology

In a certain enzyme-catalyzed reaction the following steps occur:

1. A phosphate group on substrate A is transferred to a side chain of an active site residue of the enzyme.

2. The dephosphorylated form of substrate A dissociates from the enzyme.

3. Substrate B enters the active site and is phosphorylated with simultaneous regeneration of the enzyme in its original form.

What kind of kinetic mechanism is described?

#Question id: 600

#Unit 1. Molecules and their Interaction Relevant to Biology

Two substances are used to produce a certain biological product in an enzyme-catalyzed reaction. It is found that both substrates must bind to the enzyme, first one, then the other before the product is produced. This is an example of a/an ________.