Biochemical evidence for evolution Flashcards
What is biochemistry?
The study of chemicals found in cells.
What is amino acid sequencing?
The arrangement of different amino acids within proteins is compared between organisms to measure evolutionary relatedness.
How does ammonia acid sequencing work?
Similarities and differences in the amino acid sequences of different organisms are identified. Similarities imply they organisms share a common ancestor. The number of differences is proportional to the amount of time since the species diverged.
What are phylogenetic trees?
Branching diagrams showing inferred evolutionary relationships.
Give an example of amino acid sequencing providing evidence for evolutionary relatedness.
The amino acid sequences of haemoglobin in humans and chimps is identical, so they are more closely related than humans and gibbons, which have three differences.
What are the four nucleotide bases?
Adenine
Guanine
Cytosine
Thymine
How are our genes determined?
Through the order, type and number of these nucleotides in our DNA.
What is complementary base pairing?
A - T
G - C
What is DNA - DNA hybridisation?
Involves splitting the double-stranded DNA molecule into single strands to expose the nucleotides. This is done through heat to cause the separation (disassociation). Separate strands from different species are mixed. The two strands combine and form a hybrid molecule. Then heat is applied again to determine the strength of the bond.
How does DNA - DNA hybridisation provide evidence of evolution?
The more closely all the bases in the two strands match and combine, and the stronger the bond between the strands, the closer the species are in evolutionary relatedness.
What is DNA sequencing?
The exact order of nucleotide bases in the DNA of two species is compared.
How does DNA sequencing work?
A piece of DNA from each organism is isolated, multiple copies of each gene are made, using fluorescent dyes to distinguish between nucleotide bases, mother linked device called DNA sequencer analyses and graphs the sequence.
How does DNA sequencing provide evidence of evolution?
Organisms that share a common ancestor have fewer differences in their DNA sequence.
What are some limitations of using biochemical evidence as evidence for evolution?
Some changes in DNA or amino acid sequences may not be identified if a particular change that occurred in the past reverted it to its original form in a more recent organism. Technology used to gather biochemical evidence is expensive and relies on specialised technology.
