i need help finding what these words are from these clues:

possible opening found in the cell membrane

substance which makes up cell walls

granular material in the nucleus that thickens to become chromosomes

the endoplasmic reticulum is a network of....

structures responsible for the breakdown of the cell or cell parts

site in the mitochondria where food is converted to energy

compounds made by the ribosomes

If this is a crossword puzzle, please post the number of letters and the letters you've already found.