Question

True nucleus and mitochondria are absent in
A. Cyanophyceae
B. Chlorophyceae
C. Myxomycetes
D. Azolla

Answer 1

Hint: The cell organelles have their defined functions to make it work and function properly. They can be membrane or not. The well defined membranous organelles are features of eukaryotes usually while the prokaryotes have the simple non-membranous organelles.

Complete answer:
Nucleus is the brain of the cell which has the genetic material condensed in the nucleus of the cell. It is membraned in the eukaryotes and non-membrane in prokaryotes.
Mitochondria is the powerhouse of the cell which generates the ATP required by the cell. The most biochemical reactions occur in this organelle. It is the primary source of energy.

> Option A Cyanophyceae: these are the prokaryotic organisms. They have membrane fewer organelles like Golgi apparatus, plastids, mitochondria etc. They have one envelope organization with peptidoglycan wall, 70S ribosomes and naked DNA. So they lack true nucleus and mitochondria. They have nucleoid.

> Option B Chlorophyceae: They are the green algae class they have pigments chlorophyll a and b. their cell wall is made of cellulose. They have all the organelles which are membrane and true.

> Option C Myxomycetes: They are the class of slime moulds. They have fruity bodies having all the membrane organelles in their cell. They have a true nucleus and mitochondria.

> Option D Azolla: They are commonly called as water fern. They have intracellular mitochondria and nucleus.

Hence, the correct answer is option (A).

Note: Cyanophyceae are the algal bacterial photosynthetic group. They can produce cyanotoxins that can be poisonous to animals and humans. They produce skin rashes and fever. Some are non-toxic also. We can also use antibiotic erythromycin to get rid of these green algae growth.