some questions about genes

[erskine]

I have a few extremely simple questions regarding genetics that I’m hoping someone could enlighten me upon. I’m slightly ashamed since these deal with fundamental topics...

1). .What is a gene? Is it just the sequence coding a polypeptide (and RNA) or can it also include the regions where regulatory proteins like insulators bind? And what about introns? Are they considered a part of a gene even though they don’t code for a polypeptide?
2). .How many copies of a particular gene do we have?...this is a serious question. I was always under the impression that we have two copies of each gene- hence the diploidy. But I was listening to EK audio osmosis and one of the speakers stated that eukaryotes, for the most part, only possess one copy of their genes.
3). .What information does the non-coding strand complementary to the sequence of the coding strand contain? Is it just there to protect the coding strand?

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[Hah]

A gene is generally considered the basic unit of heredity and with that in mind it is possible to to say that yes introns are part of genes. The main purpose of introns are not completely clear to scientists yet so this is a toss up. Also, since regions of regulatory interactions with proteins is inherited it can also be infered that they are part of the gene. The exact definition of "gene" is hard to say (as my genetic professor told me) but I think for the mcats you really have to just think of it as the basic unit of heredity.

A diploid eukaryote contains two copies of the gene while a haploid eukaryote would contain one copy of the gene. (Some fungi are primarily haploid) I would think its wrong to assume eukaryotes in general have two copies or one copy of a gene. The more proper way to think of it is that a diploid organism would have two copies while a haploid organism would only have one.

I don't think the non coding strand is "protecting" the coding strand per say. It's just there to complement the coding strand for it to exist as DNA. If it didn't have a non complementary strand it wouldn't be double stranded. DNA is double stranded because its structure imparts stability that RNA doesn' have allowing it to become the main genetic heriditary genetic material.

I hope this helps, this is just my understanding of your questions.