Microbes in Human Welfare

Explanation

Beer and wine are produced by fermenting the substrate with yeast and are consumed without distillation, so their alcohol content stays low. Whisky, brandy and rum are all distilled after fermentation, which concentrates the ethanol. The distinction is the processing step after fermentation, not the organism, since Saccharomyces cerevisiae is used throughout.

Explanation

Streptokinase is a clot buster. Modified by genetic engineering, it is used as a clot dissolving agent for patients who have had a myocardial infarction, because it activates plasminogen to plasmin which digests fibrin. Curd is set by Lactobacillus, ethanol is produced by yeast, and statins rather than streptokinase relate to blood cholesterol.

Explanation

Azotobacter is a free living aerobic nitrogen fixing bacterium, and Oscillatoria, Anabaena and Nostoc are cyanobacteria that fix atmospheric nitrogen, the latter two doing so in specialised heterocysts. Volvox is a colonial green alga, a eukaryote, and nitrogen fixation is confined to prokaryotes because only they possess nitrogenase. So Volvox alone cannot fix nitrogen.