(i) Cyanobacteria or blue-green algae are gram(+) photosynthetic prokaryotes which perform oxygenic photosynthesis
(ii) Cell structure is typically prokaryotic-one envelope organisation with peptidoglycan wall naked DNA, 70S ribosomes, devoid of membrane bound cell organelles.
(iii) The outer part of the protoplast contains a number of photosynthetic thylakoids. It is called as chromoplasm.
(iv) Their membranes contain chlorophyll a, carotenes and xanthophylls. Chlorophyll b is absent.
(v) DNA lies coiled generally in central part of the cytoplasm known as centroplasm.
(vi) Small circular DNA segments may also occur in nucleoid, known as plasmid or transposons.
