Question

Which of the following is not correctly matched?
A. Heterocyst- Nitrogen-fixing structure of the blue-green algae
B. Hormogonia- a reproductive structure formed during the sexual reproduction
C. Floridian starch- stored food in fungi
D. Cyanophycean starch- stored food of blue-green algae

Answer 1

There are different kinds of organisms present on the earth that have specialized features to perform some specific function. Some organs are used in fixing atmospheric nitrogen, while some are used in reproduction and much more. To get to the answer, we need to infer the options with the matches being provided.

Complete answer:
Let us study each of the following matches being provided above:
A) Heterocyst- They are specialized structures that are generally formed during nitrogen starvation in some filamentous cyanobacteria such as Nostoc, Anabaena etc. They help in fixing nitrogen from the dinitrogen that is present in the air using the nitrogenase enzymes, in order to provide the cells in the filament with nitrogen for biosynthesis to take place. Cyanobacteria and many other blue-green algae fix nitrogen present in the air to get nutrients for the plant to survive and grow.

B) Hormogonia- They are the motile filamentous structure that is formed in some cyanobacteria. They are vegetative parts that are generally unicellular, filamentous and some of them may contain heterocysts and akinetes. They are formed in climate change or in any environmental stresses that play a major role in the fixation of nitrogen. They are formed only by the process of sexual reproduction mainly in the genus of Nostoc and their host.

C. Floridian starch- It is a type of glucan that is found in glaucophytes and in red algae. They consist of a polymer of glucose molecules that consists of a polymer of glucose molecules connected by alpha linkage. They are described to lack amylose, however, amylose is a major component of Floridian starch granules particularly in red algae.

D. Cyanophycean starch- When we talk about cyancapsule we refer to algal-like bacteria with photosynthetic capabilities. Blue-green algae, after performing photosynthesis, store the food in the form of cyanophycean starch, lipid globules and protein granules. Cyanophycean starch granules are referred to as their major part of the stored food.

Floridian starch is the stored food of red algae and not of the fungi. So, the correct answer is option ‘C’.

Note: Blue-green alga is a free-floating and colonial which are generally found in freshwater and terrestrial areas. They contain photosynthetic pigments such as carotenoid and phycobilin. Their stored food is cyanophycean starch whereas when we talk about Floridian starch it is the stored food of red algae. Blue-green algae contain a specialized structure called heterocysts that helps in the fixation of atmospheric nitrogen.