Comparisons between species

Question 1

What is molecular taxonomy?

Answer 1

Where organisms are classified based on similarities between their biological molecules

Question 2

Why is DNA used to classify organisms?

Answer 2

It is universal - DNA is found in all organisms

Question 3

What is the advantage in comparing DNA?

Answer 3

1. Make comparisons between organisms / determine relationships
2. Show how one species has evolved from another species
3. Classify organisms / shows evolutionary relationships

Question 4

What is a benefit on using proteins to show genetic comparison?

Answer 4

Comparing the Amino Acid sequences in these proteins allow us to :
1. Show similarities and differences between organisms
2. Classify organisms
3. Determine evolutionary relationships between organisms

Question 5

What are the 2 specifics proteins usually used for protein comparisons?

Answer 5

1. Haemoglobin
2. Cytochrome C

Question 6

What is DNA hybridisation?

Answer 6

Technique used to determine the similarity between two different species DNA

Question 7

What does DNA hybridisation depend upon?

Answer 7

DNA’s ability to denature at high temperatures

Question 8

How does DNA hybridisation take place?

Answer 8

1. DNA from 2 species is extracted
2. These are both heated until completely denatured
3. One of the species single strands are radioactively labelled
4. The single strands are then mixed and allowed to cool and then hybridise as they reform
5. Hybrid DNA is then extracted from the solution
6. This DNA is then heated in 2 degree increments
7. The Point at which 50% of the DNA is denatured is recorded
8. The higher the T50 point the more closely related the organisms are

Question 9

What is immunological protein comaprison?

Answer 9

1. A method used to compare the variations
2. In specific proteins in the blood
3. In different species

Question 10

Why would you carry out immunological protein comparison?

Answer 10

1. Proteins are too large to determine their amino acid sequences easily
2. Immunological comparison is faster
3. It involves the Antibody-antigen reaction

Question 11

How is the immunological protein comparison of proteins carried out?

Answer 11

1. A protein called serum albumin is taken from species a
2. This is then injected into a species
3. This triggers an immune response in species b which produces antibodies
   4.These antibodies are then extracted and in test tubes mixed with the protein albumin from different species
4. This results in agglutination
5. The degree of precipitate formed is measured as an indication of similarities in proteins