Which of the following statements is/are CORRECT from the following?

I. The chromosome of the small monkey DNA virus SV40 is a circular, double-helical DNA molecule of 5000 bp.

II. The phage Lambda genome is a linear single-stranded molecule in the virion particle.

III. Circular DNA molecules purified from both bacteria and eukaryotes are usually negatively supercoiled, having values of sigma of approximately –0.06.

IV. Prokaryotes have a special type I topoisomerase known as “DNA gyrase” that introduces, rather than removes, negative supercoils.

V. DNA disentanglement, generally catalyzed by a type II topoisomerase, is also required for a successful round of DNA replication and cell division in eukaryotes.

#Question id: 621

#Unit 1. Molecules and their Interaction Relevant to Biology

Michaelis and Menten assumed that the overall reaction for an enzyme-catalyzed reaction could be written as Using this reaction, the rate of breakdown of the enzyme-substrate complex can be described by the expression:

#Question id: 622

#Unit 1. Molecules and their Interaction Relevant to Biology

An enzyme-catalyzed reaction was carried out with the substrate concentration initially a thousand times greater than the Km for that substrate.  After 9 minutes, 1% of the substrate had been converted to product, and the amount of product formed in the reaction mixture was 12 micromol.  If, in a separate experiment, one-third as much enzyme and twice as much substrate had been combined, how long would it take for the same amount (12 micromol) of product to be formed?

#Question id: 623

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of these statements about enzyme-catalyzed reactions is false?

#Question id: 624

#Unit 1. Molecules and their Interaction Relevant to Biology

The following data were obtained in a study of an enzyme known to follow Michaelis-Menten kinetics: The Km for this enzyme is approximately:

#Question id: 625

#Unit 1. Molecules and their Interaction Relevant to Biology

For enzymes in which the slowest (rate-limiting) step is the reaction Km becomes equivalent to:

#Question id: 626

#Unit 1. Molecules and their Interaction Relevant to Biology

A metabolic pathway proceeds according to the scheme, R -> S -> T -> U -> V -> W.  A regulatory enzyme, X, catalyzes the first reaction in the pathway.  Which of the following is most likely correct for this pathway?