Question

The characteristic of blue-green algae is
A. DNA without histone
B. Nuclear membrane absent
c. 70s ribosomes
D. All of the above

Answer 1

Hint: Blue-green alga is a part of the Monera Kingdom. In this kingdom, organisms are generally very primitive. It is somewhat similar to eukaryotic (eu= well developed, karyon= nucleus) algae and was treated as algae in the past, hence the name blue-green algae.

Complete answer:
Blue-green algae is a unicellular, prokaryotic (pro= primitive, karyon= nucleus) organism. It does not have a well-defined nucleus.
The DNA is not present inside the nucleus (means the DNA is naked) rather it is present in the cytoplasm (not enclosed by the nuclear membrane).
DNA has no histone protein. It consists of a 70S ribosome.

So, the correct answer is “Option D”.

Additional Information:
Some more characteristics of blue-green algae (cyanobacteria)-
1. They lack various cell organelles that include mitochondria, endoplasmic reticulum, chloroplasts, and Golgi bodies. The functions performed by these organelles in eukaryotes are performed by the cell membrane of the bacteria.
2. They can perform photosynthesis, unlike other prokaryotes.
3. They contain only one form of chlorophyll that is, chlorophyll a, which is a green-colored pigment.
4. They are found in moist environments or aquatic regions.
5. Some cyanobacteria can even fix atmospheric nitrogen in the soil.

Note: Blue-green algae (or cyanobacteria) is a prokaryotic organism not having DNA with histone, having no nuclear membrane, and having 70S ribosomes are some general characters of prokaryotic organisms. All prokaryotic organisms belong to the kingdom of Monera.