D, by decreasing temperature. Cold has the effect for slowing things down.
Answer:
Wt Avg At Mass = 39.0229 amu
Explanation:
The Weight Average Atomic Mass in atomic mass units (amu) is the sum of the Weight Average Mass contributions of each isotopic mass. That is,
Wt. Avg. At. Mass (amu) = ∑ Wt. Avg. Contributions of each isotopic mass
Wt. Avg. Contribution = fractional abundance x isotopic mass(amu)
For this problem data:
Isotope %Abundance fractional Isotopic Wt Avg Isotopic
abundance mass(amu) Contribution (amu)
1 9.67% 0.0967 38 3.6746 amu
2 78.68% 0.7868 39 30.6852 amu
3 11.34% 0.1134 40 4.5360 amu
4 0.31% 0.0031 41 0.1271 amu
________________________________________________________
Wt. Avg. Atomic Mass (amu) = ∑ Wt. Avg. Contributions = 39.0229 amu
Answer:
The protein has 4 subunits: 2 subunits of 90 kDa, 1 subunit of 160 kDa and 1 subunit of 60 kDa
Explanation:
In gel electrophoresis, the SDS agent produces denaturation of the protein and confers negative charge, so the protein subunits can migrate according to their masses. It produces dissociation of the protein in its subunits but it cannot disrupt disulphyde bridges (S-S) that can bond subunits together.
From the data, with SDS we observe 3 bands ⇒ 180 kDa + 160 kDa + 60 kDa
The addition of dithiotreitol (DTT), a reducing agent, produces the disruption of disulphyde bridges. From the data:
With DTT ⇒ 160 kDa + 90 kDa + 60 kDa
We observe that 160 kDa and 60 kDa subunits are conserved (they are the same as with SDS only), but 180 kDa subunit is missing and in its place appears a band of 90 kDa - a half 180 kDa.
So, the band at 180 kDa is composed by two subunits bonded by a disulphyde bridge.
Therefore, the composition of the protein is: <em>1 subunit of 160 kDa, 2 subunits of 90 kDa and 1 subunit of 60 kDa</em>.
- log (1.5 x 10^-3) = pOH = 2.824
<span>14 - 2.824 = pH = 11.176 </span>
<span>10 ^ (-11.176) = [H3O+] = 6.668 x 10^-12</span>