So I have very little research experience, but I am hoping to volunteer in a lab to gain more experience/potentially do a thesis in upper years. After emailing a professor, they responded with wanting to see a CV. They are aware that I have very little research experience (though I have volunteered through many other venue's and work part time). A resume would definitely be better suited to my experience. What I am unsure of is when writing a CV, there are many headings in which I have nothing to put under (I am not published, nor do I have teaching experience). Has anyone encountered this? Or have any suggestions on how I should go about giving them a CV?

A CV = a resume. Resume's don't have to have specific headings, you don't need to be published or have teaching experience.

Have a section for experience where you list any jobs you did in the past, you could also have a section for featured academic work.. and list some of your university projects/labs/work that you are most impressed with that you'd like them to know about.

As you said, the prof isn't expecting you to have crazy amounts of experience so don't let that stop you. They just want to get to know you better by seeing some history about your work ethic.

I think most first years interested in some volunteer research experience have the same dilemma - I know I did a few years ago! Email broadly and tailor your communication towards the professor's research, so don't send out a mass-email - instead, take the time to read through what each lab focuses on. Attend lab meetings diligently if invited, be a committed volunteer, and if you have the right breaks, you can even get a full-time position in a lab for a summer, which provides for an even richer pre-thesis experience. The key is to be persistent from the beginning and open as many doors as you can.

There are lots of good CV tips online. I suggest that you take the course Science 2C00 next year, which will teach you tips about professionalism, networking, and CV writing. The SCCE office on the first floor of BSB - turn left from the main entrance and the office will be on your right - is a useful resource with advisors waiting to answer your questions.

A CV isn't exactly the same as a resume, but with your level of experience it will end up being pretty similar. A resume should be fine for what the prof was asking, but as was suggested, google CV tips and see what comes up, or see if you can find other people's CVs.

I'm following this to create my CV.