00:01
Okay, this question here says, early geneticists thought that the number of genes would be almost equal to the number of proteins.
00:08
However, the human genome consists of about 21 ,000 genes that call for millions of different proteins.
00:14
We now know that the one gene calls for one protein hypothesis is not entirely accurate because you have many options.
00:21
So let's look at option one.
00:24
It says, transcription produces diverse messenger rna from a single dna template strand.
00:30
And this one is actually true, okay, because of a process called alternative splicing.
00:42
So alternative splicing can generate multiple messenger rna transcripts from a single gene resulting in different proteins.
00:47
For example, if you have these codons in your messenger rna, one, two, three, and four, from a single gene, then because of alternative splicing, you can rearrange these like one, three, four, and two.
01:03
And this is going to call for protein one, and this one is going to call for protein two.
01:10
Okay, so this is one reason.
01:12
The second option says some genes call for immature messenger rnas that are processed into different mature messenger rnas that call for different proteins.
01:23
And this one is also true.
01:24
Okay, practically post -transcriptional modifications and processing can lead to variations in the mature messenger rna molecules, which can then call for different proteins.
01:34
Then you have option three that says a single gene may call for a single polypeptide chain and many proteins are made up of more than one polypeptide chain quaternary structure.
01:49
And this one is also true...