Photorespiration and the quantum yield differ between C3 and C4 photosynthesis, with changes particularly noticeable as temperatures vary quantum yield for photosynthesis as a function of leaf temperature in C3 plants and C4 plants. Following are some statements  based on this study.

 a.) In the C4 plants the quantum yield remains constant with temperature, reflecting low rates of photorespiration

 b.) At lower temperatures the quantum yield of C3 plants is higher than that of C4 plants

c.) C3 photosynthesis is more efficient at lower temperatures

 d.) At higher temperatures the quantum yield of C3 plants is higher  than that of C4 plants

 Which one of the following combination of above statements is correct?

#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?