Question

Table 2: Amounts of buffer, substrate, and enzyme added for lactase assay Tube 0.1 M 200 uM Lactase Total Abs ONP PO4 ONPG added (420 nm) Formed (mL) (mL) (mL) (mL) (umol) 4.00 0.00 6.0 5.50 0.00 0.50 6.0 .120 5.25 0.50 6.0 -127 5.00 0.50 6.0 4.50 0.50 6.0 0176 -186 3.50 0.50 6.0 221 1.50 0.50 6.0 396

Answer 1

Calculations:

For Tube 3:W.K.T 1L=1000mL i.e 1mL=0.001L,therefore 0.4mL=0.4*0.001L=0.0004L

ONP stock=1mM,w.k.t 1M=1000mM,therefore 1mM=0.001M in 1 litre or 0.001moles/Litre

i.e 0.0004Litre*0.001moles/Litre=4*10^-7moles

Now we need to convert moles to micromoles i.e 1mol=10^6 micromoles

therefore 4*10^-7*10^6 micromoles=0.4micromoles

Therefore for tube 3 it is 0.4micromoles

For Tube 4:W.K.T 1L=1000mL i.e 1mL=0.001L,therefore 0.6mL=0.6*0.001L=0.0006L

ONP stock=1mM,w.k.t 1M=1000mM,therefore 1mM=0.001M in 1 litre or 0.001moles/Litre

i.e 0.0006Litre*0.001moles/Litre=6*10^-7moles

Now we need to convert moles to micromoles i.e 1mol=10^6 micromoles

therefore 6*10^-7*10^6 micromoles=0.6micromoles

Therefore for tube 4 it is 0.6micromoles

For Tube 5:W.K.T 1L=1000mL i.e 1mL=0.001L,therefore 0.8mL=0.8*0.001L=0.0008L

ONP stock=1mM,w.k.t 1M=1000mM,therefore 1mM=0.001M in 1 litre or 0.001moles/Litre

i.e 0.0008Litre*0.001moles/Litre=8*10^-7moles

Now we need to convert moles to micromoles i.e 1mol=10^6 micromoles

therefore 8*10^-7*10^6 micromoles=0.8micromoles

Therefore for tube 5 it is 0.8micromoles

For Tube 6:W.K.T 1L=1000mL i.e 1mL=0.001L,therefore 1mL=1*0.001L=0.001L

ONP stock=1mM,w.k.t 1M=1000mM,therefore 1mM=0.001M in 1 litre or 0.001moles/Litre

i.e 0.001Litre*0.001moles/Litre=1*10^-6moles

Now we need to convert moles to micromoles i.e 1mol=10^6 micromoles

therefore 1*10^-6*10^6 micromoles=1micromoles

Therefore for tube 6 it is 1 micromoles

For Tube 7:W.K.T 1L=1000mL i.e 1mL=0.001L,therefore 1.2mL=1.2*0.001L=0.0012L

ONP stock=1mM,w.k.t 1M=1000mM,therefore 1mM=0.001M in 1 litre or 0.001moles/Litre

i.e 0.0012Litre*0.001moles/Litre=1.2*10^-6moles

Now we need to convert moles to micromoles i.e 1mol=10^6 micromoles

therefore 1.2*10^-6*10^6 micromoles=1.2micromoles

Therefore for tube 7 it is 1.2 micromoles