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Separating Organic Compounds
Multiple Choice Quiz
Essay Quiz
Gel Electrophoresis Simulator
The Future of Molecular Bio.
Raven/Johnson: Chapter 19
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Biology Laboratory Manual, 6/e
Darrell S. Vodopich, Baylor University
Randy Moore, University of Minnesota--Minneapolis


Exercise 6-Separating Organic Compounds

Choose the one answer that best answers the question.



1

Column chromatography separates molecules according to their ___.
A)molecular size
B)polarity
C)solubility
D)matrix
2

In column chromatography, molecules that are ___ move around the beads in the matrix and therefore move through the column ____.
A)small, quickly
B)polar, quickly
C)large, slowly
D)large, quickly
3

In column chromatography, why is the buffer important?
A)It is the membrane that supports the matrix is the column.
B)It is the material that fractionates the chemicals in the sample.
C)It controls the pH of the sample so the shapes of the molecules won't change.
D)It conducts the electric charge.
4

Paper chromatography separates molecules according to their ___.
A)molecular size
B)polarity
C)solubility
D)matrix
5

What is the maximum Rf value for any molecule in paper chromatography?
A)0.1
B)1.0
C)10.0
D)infinity
6

Using paper chromatography, the Rf value for xanthophyll was 0.3 and the value for chlorophyll a was 0.7. What is true for these two pigments?
A)Xanthophyll is more soluble than chlorophyll a.
B)Chlorophyll a is a larger molecule than xanthophyll.
C)Chlorophyll a traveled farther up the paper than xanthophyll.
D)Chlorophyll a is more polar than xanthophyll.
7

Gel electrophoresis separates molecules according to their ___.
A)wavelengths of light absorbed
B)polarity
C)solubility
D)matrix
8

In gel electrophoresis, why is the buffer important?
A)It is the membrane that supports the matrix is the column.
B)It is the material that fractionates the chemicals in the sample.
C)It is the solvent in which the samples are dissolved.
D)It conducts the electric charge and controls the pH.
9

In gel electrophoresis, molecules with a negative charge will ____.
A)move towards the anode
B)move towards the cathode
C)move towards the negative electrode
D)stay in the well
10

If the voltage of the power supply in gel electrophoresis is reduced, how will this affect the results?
A)The pH will drop and destroy the samples.
B)The molecules will move slower.
C)The molecules will move faster.
D)The voltage of the power supply has no real effect on gel electrophoresis.