Sulfhydryl groups have the ability to react with the alkylating reagent n-ethylmaleimide (nem) in chemical modification experiments. when nem is added to a purified solution of creatine kinase, cys 278 is alkylated, but no other cys residues in the protein are modified. what can you infer about the cys 278 residue based on this observation?

pure substance: iron,copper

impure substance: water,charcoal

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

i think it's c. i'm not sure but i think so.