one gene one polypeptide (1 Viewer)

[kafkan]

hey can someone please explain to me the idea behind this one gene one polypeptide and one gene one chromosome notions

cheerio

 

[Guernica]

Beadle and Tatum exposed bread mould to x-rays and found that it no longer survived after being exposed to the x-rays. So, they concluded that the radiation from the x-rays mutated the nutritional requirements of the mould (and so it could no longer grow on the bread). They assumed that the gene responsible for manufacturing protein was damaged.
This was the "one gene-one protein" theory but it was changed to the "one gene-one polypeptide" theory because proteins can consist of more than one polypeptide.

Hope i helped.

 

[phil2010]

hey can someone please explain to me the idea behind this one gene one polypeptide and one gene one chromosome notions

cheerio

It was never 'one gene one chromosome'. On one chromosome there are many genes which code for 'proteins' or polypeptides - (review protein synthesis).

 

[dagwoman]

Exactly what those two said.

 

[Tim035]

Beadle and Tatum produced mutated strains of pink bread mould that lacked the ability to produce one essential nutrient or amino acid caused by the absense of a particular enzyme. They were able to establish which enzyme was lacking in each mutant strain by growing different strains with different combinations of nutrients. They noted that changes in various genes of the bread mould resulted in failure of specific products to appear and thus the loss of specific enzymes. Finally they found that each genetic mutation was at a specific site on the moulds chromosome, thus concluding that different sites on each chromosome were associated with each enzymes. This showed the link between biochemical processes and genes, leading to the 'one gene, one enzyme protein'.
This has now been changed to 'one gene on polypeptide' as although all enzymes are made of proteins, not all proteins are globular (enzymes). Also one gene is the proportion of DNA specificying a polypeptide chain. Several genes are usually required to specify the production of the enzymes involved in biochemical processes.

 

[mzduxx2006]

one gene one enzyme ---> In other words, each gene controls the reproduction, function, and specificity of a particular enzyme.

one gene one polypeptide --> not all proteins are enzymes [ie. haemoglobin] so not one specific gene controls a particular enzyme.

 

[moreturyen]

ok, ive read all the replies to the original posts and i dont think that any of them have hit the nail right on the head, so to speak, so im going to give it a shot. the original scientific thinking deduced that, as mentioned in a previous post, because damaged chromosomes inhibited the protein production in cells, the genes or chormosomes must therefore be responsible for protein production. this theory however was rendered inadequate when scientists discovered that some proteins are actually made up of more than one component, or polypeptide chain. hence, scientists concluded that the chromosomes or genes must only be responsible for creating one polypeptide, generating the "one gene, one polypeptide" theory.

as for the "one chromosome, one gene", that doesent make sense. as also previously mentioned, a chromosome is made up of many, many genes.

hope there are no mistakes in this lol and im sorry if it just confused you if i screwed it up. at least i tried. lol

catch ya,
moreturyen:wave: