A gene- what is it exactly?:S

What is it exactly, i mean i know the definition well, but i dont know in practical terms what it is

ive drawn this diagram, i know that 3 bases code for an amino acid, and a polypeptide is made up of a number of amino acids, but if a gene codes for a polypeptide, is the gene just all of the bases that make up a polypeptide?

Reply 1

Revd. Mike

17

Essentially yes. It is the sequence of bases that codes for a polypeptide.

Reply 2

Phugoid

dogdogdogcatcat

What is it exactly, i mean i know the definition well, but i dont know in practical terms what it is

ive drawn this diagram, i know that 3 bases code for an amino acid, and a polypeptide is made up of a number of amino acids, but if a gene codes for a polypeptide, is the gene just all of the bases that make up a polypeptide?

This is an issue of biology which has been open to debate for many years, still is, and I can't imagine a way you can 'close' the debate.

You can look at a chain of genes, and say 'yep, that's definitely a chain of genes'. However, much difficulty comes with asking 'but where does one gene begin, and another gene end in this chain of genes'?

So no, we can't tell you how long ONE gene is, or how many amino acids or polypeptides or nucleotide bases make up ONE unit gene. But for all intents and purposes, such a concept isn't really useful, because a single gene on its own never really does anything, it usually works in conjunction with the chain of genes of which it is a part, so it's practically more advantageous to consider chains of genes than to consider individual genes.

Reply 3

dogdogdogcatcat

OP

Revd. Mike

Essentially yes. It is the sequence of bases that codes for a polypeptide.

thanks man

and to the guy above, thanks but im just learnning as level bio so i dont want to go into mega depth

Reply 4

MrBlackwood

8

A Gene is a section of DNA. Three base pairs to be precise, which holds the coding for the sequence of amino acids to make certain proteins in your body.

MrBlackwood

Reply 5

dogdogdogcatcat

OP

is a gene always a sequence of 3 bases then(make up an amino acid)?Or is it the sequence of ALL of the bases that make up the polypeptide?

Reply 6

Revd. Mike

17

MrBlackwood

A Gene is a section of DNA. Three base pairs to be precise, which holds the coding for the sequence of amino acids to make certain proteins in your body.

MrBlackwood

Three base pairs is not a gene! Are you thinking of a codon?

Reply 7

Carrie*0

1

dogdogdogcatcat

is a gene always a sequence of 3 bases then(make up an amino acid)?Or is it the sequence of ALL of the bases that make up the polypeptide?

The gene is the sequence of all the bases that make up the polypeptide(threes bases make one amino acid in the chain), the last three bases are a "stop code" that marks the end of the polypeptide chain
.. or atleast this is what my textbook suggests :wink:

Reply 8

Xerophelistica

9

Yeah, the definition of a gene is strongly debated even today. It ranges from anything like "A length of DNA which codes for a specific protein", to "An inheritable piece of genetic information"

But yeah, in the exams I would just use the defintion your textbook gives you. They would be being pretty harsh to ask that anyway seeing as there is no real consensus.