Genome size (the length of DNA associated with one haploid complement of chromosomes) varies substantially between different organisms. Because more genes are required to direct the formation of more complex organisms, it is not surprising that genome size is roughly correlated with an organism’s apparent complexity. Which of the following statements is/are correct in reference to this rough correlation?

I. Many organisms of apparently similar complexities have very different genome sizes.

II. The number of genes, rather than genome size, is more closely related to organism complexity.

III. There is a roughly inverse correlation between organism complexity and gene density—the less complex the organism, the higher the gene density.

IV. Gene density in eukaryotic organisms is consistently higher and more variable than in their prokaryotic counterparts.

#Question id: 617

#Unit 1. Molecules and their Interaction Relevant to Biology

Compare the two reaction coordinate diagrams below and select the answer that correctly describes their relationship.  In each case, the single intermediate is the ES complex.

#Question id: 618

#Unit 1. Molecules and their Interaction Relevant to Biology

 In the following diagram of the first step in the reaction catalyzed by the protease chymotrypsin, the process of general base catalysis is illustrated by the number ________, and the process of covalent catalysis is illustrated by the number _________.

#Question id: 619

#Unit 1. Molecules and their Interaction Relevant to Biology

The benefit of measuring the initial rate of a reaction V0 is that at the beginning of a reaction:

#Question id: 620

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following statements about a plot of V0 vs. [S] for an enzyme that follows Michaelis-Menten kinetics is false?

#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?