3) For each of the following characteristics, will the migration of the protein speed up, slow down, or remain unchanged if you do not add SDS?

a)increase molecular weight of protein
b) increase concentration of acrylamide
c)decrease charge on protein
d) increase surface area of protein

To determine how the migration of a protein will be affected by the absence of SDS, we need to understand the role of SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) in protein separation. SDS is a detergent that is commonly used in PAGE gels to denature proteins and give them a negative charge proportional to their size. Without SDS, the migration of the protein will be influenced by other factors.

a) Increase molecular weight of protein:
Without SDS, the migration of a protein will slow down if the molecular weight increases. This is because larger proteins will have increased friction with the gel matrix, resulting in a slower migration.

b) Increase concentration of acrylamide:
Without SDS, a higher concentration of acrylamide in the gel will speed up the migration of the protein. This is because a higher concentration of acrylamide increases the pore size of the gel, allowing larger proteins to migrate faster.

c) Decrease charge on protein:
Without SDS, if the charge on the protein decreases, the migration will speed up. This is because the protein's movement in the gel depends on the balance between its charge and the charge of the gel matrix. A decrease in the protein's charge will result in less resistance to migration.

d) Increase surface area of protein:
Without SDS, an increase in the surface area of a protein will slow down its migration. This is because a larger surface area will result in increased friction with the gel matrix, hindering the movement of the protein.

In summary, without the presence of SDS, the migration of a protein will be affected differently depending on the characteristics discussed.