Dilutions & Separation Techniques

Question 1

What formula is used to make a fixed amount of a dilute solution from a stock solution?

Answer 1

C1V1 = C2V2

Question 2

What is V1?

Answer 2

The volume of stock solution needed to make the new solution.

Question 3

What is V2?

Answer 3

The final volume of the new solution.

Question 4

What is C1?

Answer 4

The concentration of stock solution.

Question 5

What will a buffer do?

Answer 5

Control pH especially in proteins.

Question 6

What does a colorimeter measure?

Answer 6

How much a solution will absorb in a particular wavelength.

Question 7

What separation techniques are used by biologists?

Answer 7

• Filtration
• Fractional distillation
• Paper/thin layer chromatography
• Centrifugation
• Iso-electric point

Question 8

What does filtration separate?

Answer 8

A solid from a liquid.

Question 9

What does distillation use to separate substances?

Answer 9

Boiling point.

Question 10

What does centrifugation use to separate substances?

Answer 10

Molecular weight.

Question 11

What is the iso-electric point?

Answer 11

The pH at which a protein has no net charge.

Question 12

What can be used as the defining value for proteins?

Answer 12

the iso-electric point.

Question 13

How can IEP be calculated?

Answer 13

By using info on all of the amino acid/basic characteristics and their number in the protein.
It can also be measured using a gel set up with a pH gradient and measuring the pH the protein migrates to.

Question 14

What is a linear dilution?

Answer 14

One where the dilutions differ by an equal interval.

Question 15

What is a log dilution?

Answer 15

One in which the dilutions differ by a constant proportion.

Question 16

How does a pH buffer allow the pH of a reaction mixture to be kept constant?

Answer 16

As the addition of acid or alkali have a very small effect on the buffer.

Question 17

What is affinity chromatography used for?

Answer 17

To separate proteins.

Question 18

How is affinity chromatography carried out?

Answer 18

A solid matrix of gel column is created with specific molecules bound to the matrix or gel. Soluble, target proteins in a mixture with a high affinity for these molecules become attached to them as the ,mixture passes down the column. Other non-target molecules with a weaker affinity are washed out.