Is it very difficult to get funding for doing PhD in Molecular Biology in Uk universities? Without scholarship, I find it quite difficult to meet the expenses

Have a look at the BBSRC and MRC research council websites - they would be a good source. I had BBSRC funding, but mine was allocated like this: the department was awarded 2 studentships, i had been accepted by my supervisor (given that i could get the money) and so I went for the interview for the studentship held by the department, and fortunately, got the studentship. Some PhD proposals will already have money from the BBSRC or MRC attached, I think those will probably be listed on the website. Alternatively, contact some potential supervisors because they might already have money allocated to a project.

I wouldn't personally do one without funding. I've only ever met one self-funded student.
You tend to get offered one if there is money available and you do the best in interview, or you're already known in the lab from an undergrad/Msc project. It tends not to happen if the money isn't there.

Thank You all for replying guys!
The thing is it is a year now since I have completed my post graduation in Biotechnology from Indiaand I really must get abck to studying. As one of you said, going for funded projects is a good idea. But the problem in my case is I want to work on Cell Biology and the superiors I have chosen in many of the universities are allotting the project on self support basis.Thats my problem. The remaining projects that are funded are mostly in the field of microbiology and plant biology which i peersonally have no interest in. The British Educatio fair is coming to India in my place on NOv 30. I hope Luck shines on me at least then. I really need to do this.

Thank You all for replying guys!
The thing is it is a year now since I have completed my post graduation in Biotechnology from Indiaand I really must get abck to studying. As one of you said, going for funded projects is a good idea. But the problem in my case is I want to work on Cell Biology and the superiors I have chosen in many of the universities are allotting the project on self support basis.Thats my problem. The remaining projects that are funded are mostly in the field of microbiology and plant biology which i peersonally have no interest in. The British Educatio fair is coming to India in my place on NOv 30. I hope Luck shines on me at least then. I really need to do this.

There are usually a few university funded PhDs, you could ask about that. I'd bear in mind you may end up changing projects, I've done a different PhD to the one I applied to.
Taking a year out should not be a problem, it is the experience in the lab from your degree, or work that they would ask you about.