Amino acid synthesis in bacteria

[neon]

Could somebody confirm whether my assumptions are correct please?

Micro-organisms such as e.coli can synthesise all of the amino acids required for the proteins they produce. I assume the constituents of these amino acids come from molecules they ingest from the environment.

Is this correct? If so, what mechanism is responsible for converting resources in to the amino acids? I presume it cant be a gene, as these encode for amino acids themselves. Perhaps these amino acids arise as intermediary parts of metabolic pathways?
Does this make sense or I am way off target?

thanks

n

[seaseasea]

E.coli could synthesize 20 amino acids required for synthesis of proteins.If the environment is rich in one or two or all of 20 amino acids,E.coli doesn't sythesize those amino acids.
E.coli could use carbon resources and nitrogen resources to make amino acids through metabolic pathways.Those reactions are catalyzed by all kinds of enzymes encoded by genes.
U could look biochemistry.
Good luck!

[mkwaje]

Yep seaseasea is right. All the amino acids needed by E. coli can be synthesized via transcription then translation from the bacterial chromosome. The instance a particular bacterium can no longer synthesize a specific a.a. then it is called an auxotroph and the a.a. should be supplied in the medium so that that bacteria can grow.

[xientian]

i want to clear something...

do all bacteria contain amino acids???

sorry for that dumb question...i'm only in grade8.

tnx!

[mith]

what do you mean contain?

[xientian]

sorry...

i mean, do all bacteria 'produce' amino acids?

[MrMistery]

i don't knwo of any bacteria that can't produce any aminoacid(but then again, i don't know all the bacteria on Earth) but there are some bacteria that can't produce all them, and can just produce some. For these organisms to grow, you have to give them the special aminoacids they require(put them in the growth medium)

[chemistry_freako]

Not sure if all of them do, but for those which do, it's most likely not produced all the time, only when they need - e.g. those control mechanisms of operons (e.g. tryptophan operon?)? Not too sure if i'm going the right way, pardon me if i'm wrong

[mkwaje]

I think all organisms can produce all the necessary amino acids for them to grow, some amino acids does not exist in nature though but can be synthesized chemically. All bacteria therefore can produce their own amino acid EXCEPT the auxotrophs, or the mutants that contain damaged/deleted DNA and thus you have to supply the lacking amino acid onto the culture medium for it to grow and multiply.

To screen for auxotrophy is to just place the bacteria in minimal medium (culture media without amino acid but with N and C sources) and watch for growth/ absence of growth.

[lara]

theoretically....
why don't we insert the genes for essential amino acids into our own genome and put the deficiency question to rest????