A family of proteins known as cupredoxins contain a single redoxactive Cu ion coordinated by a Cys, a Met, and two His residues. The reduction potentials of cupredoxins range from about 0.15 V to 0.68 V. What does this information reveal about the role of the protein component of the cupredoxins?

A family of proteins known as cupredoxins contain a single redoxactive Cu ion coordinated by a Cys, a Met, and two His residues.

The reduction potentials of cupredoxins range from about 0.15 V to 0.68 V. This information reveals that the role of the protein component of the cupredoxins surpasses the maximum and minimun reduction potentials limits reported for any mononuclear cupredoxin, preserving the metal binding site furter than the typical values for the cupredoxin protein family.

Explanation:

These redox-active copper proteins´ structure and properties of native cupredoxins, and those modified by site-directed mutagenesis, although their wide range of E°, may have evolved to specifically bind copper, developed recognition sites for specific redox partners, tuned redox potential for a particular function, and allowed for efficient electron shuttle. The overall and active site structures are very similar in all T1 cupredoxins, 9 which contain a Cu ion coordinated by a Cys and two His residues in a trigonal planar geometry, and a weak axial ligand, such as Met121 in Az. This is basic to understand the roles of metals from energy metabolism, respiration, cell signaling, and photosynthesis, to catalysis in industrial and fuel cell research, as redox potentials are fine-tuned over a range with little change to the redox-active site or ET properties through a single redox active center, whose reduction potential (E°) must be tunable to match that of a given redox partner without compromising the structural and ET properties of the protein. A number of studies have shown that there is still a deep lack of knowledge about other long-range, non-covalent interactions responsible for tuning E°.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

: )