Question

Beadle and Tatum based their "one gene one protein" hvpothesis on analvzing biosvnthetic pathwavs. Shown below is a hypothetical biosynthetic pathway, leading to products 1 and 2 (P1 and P2). Intermediates are A,B,C,D and E. The enzymes mediating the conversions as shown are I, II, III, IV, V and VI. The assumption is that single mutations inactivate these enzymes, leading to a block in the corresponding biosynthesis step. Fill in the table below. Which intermediate, ie A,B,C,D, E or acombination thereof, or none can override the block for P2? Inactivating mutation in Gives rise to product 1? Yes or no Gives rise to product 2? Yes or no Which intermediate, ie A,B,C,D, E or a combination thereof, or none can override the block for P1? IV VI

Answer 1

I - product 1 - no, product 2 - no, none, none

II - product 1 - no, product 2 - yes, none, FOR 2- B,D,E.

III- product 1- no, product 2- yes, none, For 2- B,D,E.

IV - Product 1- yes, product 2 - no, For 1 - C, for 2- none.

V - product 1- yes, Product 2- no, for 1- C, for 2- none,

VI - Product 1- yes, product 2- no, for 1- C, for 2- none.