Domains, kingdoms or both?
Biochemical Relationships
What are biochemical relationships used for?
• To support or clarify the relationships between organisms that are based on
morphology by analysing the structure of chemicals and DNA to identify the
inter-relationships between groups or organisms
What is gel electrophoresis and why is it useful?
• Gel electrophoresis is a variation of chromatography which can be used to
separate DNA, and RNA fragments, proteins or amino acids according to their
size and electrical charge
• Patterns in DNA or RNA fragments are used in species identification and
comparisons between amino acids in similar proteins are used to classify them
or trace evolutionary pathways
Outline the main steps involved in the process of gel electrophoresis
1. Wells are made in a gel medium in a buffering solution
2. DNA molecules are cut into fragments by restriction endonucleases
3. DNA fragments added to the gel containing a dye which binds to the fragments
and fluoresces
4. DNA is dyed with a dye that moves faster through the gel than the DNA
5. Electric current is passed through the apparatus
6. DNA moves towards anode as it is negatively charged (due to phosphate
groups)
7. Current is turned off
8. Plate is placed under a UV light
9. Pattern of different bands represent different amino acids and can be compared
to known fragments
Explain how gel electrophoresis can be used to distinguish between species and
determine evolutionary relationships.
• Each species has its unique pattern of bands so comparing the patterns allows
scientists to distinguish between species
• By comparing the bands of different species scientists can determine how
closely related they are or to find common ancestors
Give some examples of how understanding the biochemical relationships between
organisms is playing an important roile in extending or understanding of classification
and evolution
Biochemical Relationships
What are biochemical relationships used for?
• To support or clarify the relationships between organisms that are based on
morphology by analysing the structure of chemicals and DNA to identify the
inter-relationships between groups or organisms
What is gel electrophoresis and why is it useful?
• Gel electrophoresis is a variation of chromatography which can be used to
separate DNA, and RNA fragments, proteins or amino acids according to their
size and electrical charge
• Patterns in DNA or RNA fragments are used in species identification and
comparisons between amino acids in similar proteins are used to classify them
or trace evolutionary pathways
Outline the main steps involved in the process of gel electrophoresis
1. Wells are made in a gel medium in a buffering solution
2. DNA molecules are cut into fragments by restriction endonucleases
3. DNA fragments added to the gel containing a dye which binds to the fragments
and fluoresces
4. DNA is dyed with a dye that moves faster through the gel than the DNA
5. Electric current is passed through the apparatus
6. DNA moves towards anode as it is negatively charged (due to phosphate
groups)
7. Current is turned off
8. Plate is placed under a UV light
9. Pattern of different bands represent different amino acids and can be compared
to known fragments
Explain how gel electrophoresis can be used to distinguish between species and
determine evolutionary relationships.
• Each species has its unique pattern of bands so comparing the patterns allows
scientists to distinguish between species
• By comparing the bands of different species scientists can determine how
closely related they are or to find common ancestors
Give some examples of how understanding the biochemical relationships between
organisms is playing an important roile in extending or understanding of classification
and evolution
