4-5-1 Protein Synthesis, Part 1, One Gene, one Polypeptide Flashcards
Define Metabolic pathway
A series (chain) of reactions in the cell in which the result of one reaction is the substrate of the next. There is a different enzyme for each reaction.
The reaction steps in a metabolic pathway are controlled by _____
enzymes
What can be the consequence for a metabolic pathway if an enzyme is absent or not active.
The pathway can stop working.
What is the importance of British doctor Archibald Garrod
Proposed that an inherited disease involved the blockage of a metabolic pathway (causing an intermediate chemical in the pathway to build up and cause damage).
Year for Garrod’s work (1802, 1852, 1902, 1952)
1902
Who set the stage for Beadle and Tatum?
Archibald Garrod
Disease studied by Archibald Garrod
Alkaptonurea
organism studied by Beadle and Tatum
a mold called Neurospora crassa
Year of Beadle and Tatum’s work
1941
Significance of Beadle and Tatum
proposed “one gene, one enzyme” hypothesis (now revised to one gene, one polypeptide)
Experiment by Beadle and Tatum to support “one gene, one enzyme” hypothesis.
Beadle and Tatum used X-rays to cause mutations in Neurospora. The mutated spores were placed on growth media enriched with all essential amino acids. The mutated fungi were crossed with non-mutated forms. The spores produced were grown on media supplying only one of the 20 essential amino acids. If a spore lacked the ability to make a particular amino acid, such as Pro (proline), it would only grow if the proline were present in the growth medium. This made it easy to detect particular mutations that would shut down particular Neurospora pathways and result in no-growth. The mutations each affected a single gene and single enzyme in a specific metabolic pathway.
