Chloroplasts are the organelles responsible for photosynthesis.
There are abundant chloroplasts shown here in the palisade layer of the leaf.
They are specially designed to absorb light and convert it to chemical energy.
Electron micrograph of a chloroplast
Chloroplasts are organelles bounded by an outer membrane, but they also have an important inner membrane system.
The inner membrane system is where photosynthesis takes place.
Electron micrograph of a chloroplast
The inner membrane system of the chloroplast is called the thylakoid membranes and the matrix surrounding the thylakoids is called the stroma.
Stacks of thylakoids are termed the grana, while the membranes connecting the grana are called the stroma thylakoids.
Chloroplasts are interesting organelles because they are semiautonomous.
They resemble prokaryotic cells like bacteria.
They have their own DNA and prokaryotic-like ribosomes.
This suggests that chloroplasts are an example of a symbiotic relationship between a bacterium and an algae that led to the evolution of higher plants with the ability to convert light energy to chemical energy by the process of photosynthesis.
Interestingly, RuBP carboxylase is an enzyme made of subunits.
The large subunit is a protein coded for by DNA in the chloroplast, while the small subunit is coded for by the nuclear chromosomes.
This shows a high degree of coordination between the parent cell and the organelle.
