Question

Which of the following does not apply to ascomycetes?
A. Mycelium is coenocytic and septate.
B. Commonly known as sac fungi.
C. Asexual spores called conidia are produced exogenously.
D. Sexual spores called ascospores are produced endogenously.
E. They are saprophytic, decomposers, parasitic or coprophilous.

Answer 1

Ascomycetes are spore shooters. Fungi that produces microscopic spores inside cells or sacs. Ascomycetes are found on the dry land, tropical and temperate forests. They reproduce asexually by forming spores known as conidia at the filaments end.

Complete Answer:
Sac fungi or ascomycetes can be unicellular or multicellular body structure. Fungi are of two types Ascomycetes and Basidiomycetes.

Sl.No	Ascomycetes	Basidiomycetes
1.	Saprophytic, decomposers, parasitic, coprophilous. They are also known as sac fungi.	They are parasites.
2.	Produce ascospores and conidia.	They give basidiospores.
3.	Asexual reproduction by conidia.	Asexual reproduction is not present.

Some of the characteristics of Ascomycetes are:
- Contains reproductive structure called ascus or asci. Mostly they are terrestrial.
- Cell wall of ascomycetes is made up of beta glucans.
- Mycelium is made up of septate and branched hyphae.
- Each ascus consists of 4-8 ascospores.
- Fruiting body is called ascocarp which is produced endogenously.

Four types of ascocarps are:
(i) Cleistothecium- fruiting body is spherical and closed tightly like in Aspergillus.
(ii) Ascostroma- Asci present in stroma like Mycosphaerella.
(iii) Apothecium- cup- shaped fruiting body like in Peziza.
(iv) Perithecium- flask shaped fruiting body with one opening like Neurospora.

So the answer is option A because mycelium of ascomycetes is branched and separated.

Note: Zygote undergoes meiosis and forms 4 haploid nuclei which further undergo mitotic division and result in 8 haploid nuclei. These 8 nuclei accumulate cytoplasm and are surrounded by thick cell walls. These are called ascospores.