Shall I include a list of workshops and conferences attended during my UG in my 4 page CV? I'm currently applying for US graduate programs (doctoral study in Molecular biology). I'm asked to submit a maximum of 3-4 page CV. I have  participated in nearly 20 workshops and conferences in my 3 year undergraduate  period. As the list is big I didn't include in the CV. 

I would like to know how to prove or tell to grad committee members that I'm ardent on learning techniques and that is the reason I went beyond college curriculum to learn it individually and in depth?

Thanks.
You should definitely mention that you attended conferences. How much detail to include depends on how much space you have left after you included all of the more important information on your CV. I cannot tell what is more or less important. You have to figure it out yourself. Here is what I usually do in such situations:


Make a CV listing everything you have that is even slightly relevant to what you are applying for. If you went over the page limit proceed to step 2.
Divide your CV into absolutely necessary/required info and 'other stuff'.
Rank the 'other stuff' from very important to barely relevant on some continuous scale, say 1 to 10. 
Delete the least relevant info until you reach the page limit of your CV.


You can apply the same procedure to your conference list. I would say it is important, but not 100% of it if you don't have enough room. Rank the conferences you attended from the most prestigious/impressive to the least impressive. Start listing them from the most prestigious until you hit the page limit. Leave one sentence to mention the conferences you omitted, generalizing them in some way to underline their relevance: "... and other (number) conferences on topics related to molecular biology.