Question

1. Beadle and Tatum used which of the following organisms to support their one gene one enzyme concept
a) E coli
b) Drosophilia
c) Neurospora
d) Salmonella
e) Homo sapien

2. Garrods concept regarding the relationship between the gene and metabolism can best be described as:
a) one gene - one polypeptide
b) one mutant gene - one metabolic block
c) one gene - one metabolism
d) one gene - one enzyme
e) one gene- one transcript

Answer 1

Ans 1: C) Neurospora. A bread mold Neurospora crassa was used in the experiment that helped Beadle and Tatum to hypothesize "one gene one enzyme" concept. The organism was much simpler as compared to Drosophila that Beadle and Tatum used in their early experiment. While carrying out the research the Drosophila proved to be complex to demonstrate the link between genes and their chemicals.

Ans 2: B) One mutant gene-one metabolic block. Archibald Garrod in the year 1902 put a great interest in research on alkaptonuria (a condition in which the body fails to process the amino acids called phenylalanine and tyrosine occuring in protein causing the urine to turn black in colour when exposed to air) described it as "inborn error of metabolism". He then proposed that a mutation on a gene causes a specific malfunction in the normal biochemical pathway for eliminating the urine or liquid wastes, the dark colour of the urine - a result of this malfunction. Which was proved by Beadle and Tatum in their experiment later in 1941.