Unit 1.1c

Question 1

What are the 4 separation techniques?

Answer 1

Centrifugation
Chromatography
Gel Electrophoresis
Iso-electric point

Question 2

What are the 4 features that molecules posses that allows us to separate them?

Answer 2

Size
Charge
Density
Solubility

Question 3

What does centrifugation do?

Answer 3

It separates the solution into a pellet and supernatant of different densities

Question 4

How does the centrifuge work?

Answer 4

It spins a high speeds to seperate the components

Question 5

What are the two phases of solubility?

Answer 5

Mobile and stationary

Question 6

Which of the two phases is the one in which mixture is dissolved in?

Answer 6

The mobile phase

Question 7

Which of the two phases is the one in which the mixture passes and is separated?

paper chromatography

Answer 7

The stationary phase

Question 8

What are the 3 types of chromatography?

Answer 8

Paper
Thin-layer
Affinity

Question 9

How does paper chromatography work?

Answer 9

Stationary phase I’d a polar strip of cellulose fibre paper
So, non-polar solvent is used
Dot of concentrated mixture used on bottom of paper
Place bottom of paper but not mixture dot into solvent
Solvent will move through the paper at different rates depending on solubility

Question 10

How does thin layer chromatography work?

Answer 10

Uses and absorbent layer of silica gel or cellulose
This medium is thinly placed on glass, plastic or metal
The rest is the same as paper

Question 11

Why is thin layer chromatography a more advantageous technique?

Answer 11

• only small volume of solvent required = less fumes
• development phase quicker
• separated pigments more defined and visible

Question 12

How does affinity chromatography work?

Answer 12

Relies on binding of proteins and ligand bound to a matrix or gel
Specific molecule passed through and inert (unreactive) support in a column
Protein mixture passed through the column
Complementary target protein binds to specific molecule binds in the column
Other components wash away
Target protein stripped from support
Separation and purification from original sample

Question 13

How does gel electrophoresis work?

Answer 13

A current is passed through a buffer to separate proteins

Question 14

In gel electrophoresis what two features separate the molecules?

Answer 14

Charge and size

Question 15

In gel electrophoresis which travels further, large or small proteins?

Answer 15

Small proteins

Question 16

What is electrophoresis gel made of?

Answer 16

Argarose

Question 17

Which direction does the solution/DNA move in during gel electrophoresis?

Answer 17

Towards the positive terminal

Question 18

Why do smaller molecules move further in gel electrophoresis?

Answer 18

Move through the gels pores easily

Question 19

What gives a protein it’s overall charge?

Answer 19

The amino acids that make up the protein with + - and neutral charges

Question 20

What does the term iso-electric mean?

Answer 20

The point were proteins have a neutral charge . If positive the pH is below this point, if negative the pH is above

Question 21

What happens to a protein at its iso-electric point?

Answer 21

Protein becomes a precipitate and can become solid in liquid suspension