Chloroplasts are elliptical-shaped and have two membranes: an outer membrane and an inner membrane. Between the outer and inner membrane is the inter-membrane distance, 10-20 nm wide. The space within the inner membrane is the stroma, the dense fluid within the chloroplast. Chloroplasts are organelles of plant cells that, through the photosynthetic interaction, change light energy into balanced compound energy. Chloroplasts are organelles of plant cells that, through the photosynthetic process, transform light energy into steady chemical energy. Chloroplast is an organelle containing chlorophyll, a photosynthetic pigment that absorbs sunlight and turns it into usable energy, releasing oxygen from water. Chloroplasts are structures which are double-membrane-bound. They are divided into external and internal membranes, divided further into two different regions: grana and stroma.’
• Inter membrane space is found between the external and internal layers.
• The chloroplast within is outlined in a stroma called a colorless ground matrix.
• The stroma is a homogeneous matrix in which the grana is integrated. Several photosynthetic enzymes, DNA, and ribosomes are found in Stroma. It is the place where all chemical reactions occur and it synthesizes starch (sugar).
• Grana is a stack of flattened, membrane attached sacs containing chlorophyll molecules. One pile of thylakoid is known as granum. On its surface, each thylakoid has chlorophyll molecules that absorb sunlight and take part in the photosynthesis process.
• There are stromal lamellae linking the stacks of grana. Like the chloroplast skeleton, the lamellae work, keeping all sacs protected from the other sacs.
Grana is the main functioning chloroplast unit.
