The epa sets national air-quality standards for common air pollutants. the
graph shows the change in the concentrations of these pollutants over time.
which pollutant have the air-quality standards had the greatest impact on?
monitored concentrations
of pollutants
1.00
pm 25
0.70
normalized concentration
ozone
pm 10
0.50
0.40
noz
so2
0.30
0.20
0.10
co
lead
0.0
1980 1985 1990 1995 2000 2005 2010
year
o a no
b. lead
o
c. ozone
o
d. pm10

Penicillin is hydrolyzed and thereby rendered inactive by penicillinase (also known as β-lactamase), an enzyme present in some resistant bacteria. the mass of this enzyme in staphylococcus aureus is 29.6 kd. the amount of penicillin hydrolyzed in 1 minute in a 10-ml solution containing 10-9 g of purified penicillinase was measured as a function of the concentration of penicillin. assume that the concentration of penicillin does not change appreciably during the assay. penicillin(μm) amount hydrolyzed(nmol) 1 0.11 3 0.25 5 0.34 10 0.45 30 0.58 50 0.61 (a) plot v0 versus [s] and 1/v0 versus 1/[s] for these data. does penicillinase appear to obey michaelis-menten kinetics? if so, what is the value of km? (b) what is the value of vmax? (c) what is the turnover number of penicillinase under these experimental conditions? assume one active site per enzyme molecule.