When the cell is NOT in the presence of tryptophan,

A. RNA polymerase can transcribe mRNA.
B. the repressor proteins bind to the operator.
C. structural genes are not transcribed.
D. the repressor proteins are active.

4. rat liver is able to metabolize glucose by both the glycolytic and the pentose phosphate pathway. which of the following are properties of both the glycolytic and pentose phosphate pathway? a. nad+ is involved b. co2 is liberated c. phosphate esters are intermediates d. glyceraldehyde 3-phosphate is an intermediate e. fructose 6-phosphate is an intermediate4. rat liver is able to metabolize glucose by both the glycolytic and the pentose phosphate pathway. which of the following are properties of both the glycolytic and pentose phosphate pathway? a. nad+ is involved b. co2 is liberated c. phosphate esters are intermediates d. glyceraldehyde 3-phosphate is an intermediate e. fructose 6-phosphate is an intermediate

Paint and solvents pose no potential hazard to human health. select the best answer from the choices provided t f

1. an enzyme is considered a(n) because it speeds up a chemical reaction without being used up.2. in a catalyzed reaction, a reactant is often called a(n) . an enzyme is specific because the shape of its matches only particular reactants.4. an enzyme speeds up reactions by lowering the . the between an active site and its substrate often strains bonds and the reaction proceed.6. a( , which is often a vitamin, binds to an enzyme and plays a role in catalysis.7. high temperatures or changes in ph can an enzyme, causing it to lose its shape and biological activity.