Question

what holds the chlorophyll in a plant cell

Answer 1

this pigment is enclosed in organelles called chloroplasts which in turn have structures like sacks called tilakoids
but there is more to it

Answer 2

To be much more picky, if I'm not mistaken it's actually locked in place by being a part of the membrane of the chloroplast, and chloroplasts are bunched into structures called "thylakoids"**

Answer 3

sure, you are probably right. its long since i studied this :-)