Question

Respiration may occur in the absence of oxygen in
(a) Potato
(b) Spirogyra
(c) Yeast
(d) Human

Answer 1

Hint In the lower group of organisms respiration takes place may be aerobically and anaerobically. The facultative aerobic organism lives in the absence and presence of oxygen both, whereas higher group organisms respire only aerobically in absence of oxygen they die.

Complete Answer:
Yeast is facultative aerobes, they live in both presence or absence of oxygen. Aerobic respiration takes place in the cytoplasm whereas anaerobic respiration takes place during fermentation.
Yeast belongs to ascomycetes of phylum fungi, which is also known as Saccharomyces. They are unicellular which multiply by budding or fission. They may be spherical, oval, and cylindrical with a cell wall made up of chitin, glucan, and mannan. They are mostly saprophytes and few are parasites. Sexual reproduction takes place by conjugation where dikaryotic cells are absent. Diploid cell multiplies by fission and produces ascospore through meiosis. Asci occur singly without the formation of ascocarp.

Additional information:
Yeast is helpful for the production of alcoholic beverages by fermentation which is also useful in baking in the baking industry. It is also helpful for imparting characteristic flavor to Roquefort cheese.
Yeast also causes harmful diseases in human-like inflammation in genitalia, brain tumor, meningitis, and lesion of viscera. Saprophytic yeast spoils foodstuff like fruits, vegetables, jams, jellies, pickles, cheese, butter, etc. Some yeast cause ergot of rye, powdery mildew of cereals, bakanae disease of rice, brown rot in pear, plum and peaches, etc. Neurospora causes red bread mould but some Neurospora uses it to study genetics.

So, the correct answer is ‘yeast’.

Note: Yeast is useful to study the biological process of humans, Neurospora crassa are used to conduct genetic studies. The cell of yeast consists of DNA containing a nucleus which is useful for metabolic process and study of the cellular pathway. It is also used to decompose plant cell walls and animal tissues.