Exam 3: Bioenergetics,enzymes and Metabolism

The presently accepted model of enzyme action was proposed by Daniel Koshland in the 1960s and suggested that the enzyme was a flexible structure with an active site roughly complementary to the substrate that binds it.After its initial interaction with the substrate,the enzyme alters its shape and thus improves the fit of the substrate in the active site)What is the name of this model?

You are observing an enzyme driven reaction.To the reaction mixture you add a chemical X which inhibits the reaction.If you add more substrate,the reaction rate approaches the V_max of the uninhibited reaction.Furthermore,the structure of X is similar to the natural substrate.What kind of inhibitor is X?

What are some ways that antibiotic resistance genes can be passed from bacterium to bacterium?

You are observing a reaction and discover that the reaction vessel is warm to the touch.The reaction also results in an increase in entropy.Is the reaction spontaneous? How do you know?

What kind of interaction is not involved in the binding of a substrate to a normally functioning enzyme?

Enthalpy is ________.

Entropy is associated with the _______ movement of particles of matter,which because they are _____ cannot accomplish a directed work process.

4 ATPs per glucose molecule are made during glycolysis.Why then is there a net production of only 2 ATPs for each glucose molecule in the pathway?

How does the AIDS virus manage to avoid the effects of drugs that attack its enzymes so effectively?

Which antibiotic inhibits the enzyme DNA gyrase,which is required for bacterial DNA replication?

A number of antibiotics attack prokaryotic protein synthesis,but not eukaryotic protein synthesis.Name two common antibiotics that work this way.What is their site of action and why don't they affect eukaryotic protein synthesis?

If an antibiotic were found to bind to a site on an essential bacterial enzyme other than the active site,what would its most likely mode of action be?

If people are kept on diets containing about 25% fewer calories than would be required to maintain their initial body weight,what happens?

Certain bacteria have an adaptation that allows them to render penicillin harmless; they have adapted due to their possession of an enzyme called penicillinase.How does it render them immune to the effects of penicillin?

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( $\Delta$ G = +5.4 kcal/mole) D + F <-> G + H ( $\Delta$ G = -4.4 kcal/mole)

In the reaction A + B <-> C + D,how might the reaction take place in the cell if the $\Delta$ G is very positive? How might the reaction occur if the $\Delta$ G is slightly positive?

What evidence suggests that lower blood levels of insulin may be important in promoting longevity?

Many bacteria have acquired resistance to penicillin by picking up the gene for -lactamase.However,some have developed resistance without acquiring this gene.How do these bacteria escape the fatal effects of penicillin?

Do the equations below represent coupled reactions? If not,why not? A + B <-> C + D ( $\Delta$ G = -5.4 kcal/mole) E + F <-> G + H ( $\Delta$ G = +4.4 kcal/mole)

Penicillin fits into the active site of transpeptidases and thus acts as what kind of inhibitor? How is the effect of such an inhibitor usually able to be reversed? Why would this approach not work with penicillin?