Chloroplast Physiology

The chloroplast is composed of several different parts. First, it has an outer membrane called the outer chloroplast membrane. This is then followed closely by an inner chloroplast membrane. Inside the membranes there are stacks of folded thylakoid membrane, called grana. between these folds is an interior called the lumen. Not all of the grana line up, leaving exposed sections called stromal lamellae. All of this is suspended in a fluid enterior in the chloroplast, called the stroma.