Tag: biology

Useful antibiotics are often discovered using a screening process. To conduct such a screen, isolates of many different microorganisms are cultered and then tested for production of products that inhibit the growth of test organisms.They are tested for their selective toxicities and therapeutic activities, and the best candidates are examined and modified. Once the process is complete, the antibiotic must be extracted and purified to a crystalline product. The copies of genes coding for enzymes involved in the antibiotic production can be inserted into a cell, via vectors such as plasmids.

Scientic theories about the origin-of-life theories have historically been characterized by the chicken-and-egg problem of which essential aspect of life was the rst to appear, replication or self-sustenance. RNA, the other nucleic acid, contained building blocks very similar to DNA, so biologists recognized early that RNA could store information in its linear sequences. With the discovery in the 1980s that RNA molecules were capable of biological catalysis, a function till now ascribed to proteins alone, RNA took on the role of the single entity that could act as both chicken and egg. Within a few years of the discovery of these catalytic RNAs (ribozymes) scientists had formulated an RNA hypothesis that posited an early phase in the evolution of life where all key functions were performed by RNA molecules. 

Beverages of low alcoholic content (less than about 9% alcohol) are fermented from grains and are usually considered to be beers. Wines, on the other hand, are fermented to a higher percentage of alcohol (10 - 18% alcohol) and are usually fermented from fruit juice. Higher levels of alcohol kill or inhibit bacteria stopping spoilage as well as fermentation. Vodka, whiskey, and other alcoholic beverages with alcohol contents well above 20% are produced by distilling alcohol from a yeast-fermented beverage. Many liquors are produced by using distilled alcohol (as high as 95% alcohol) to extract various flavoring materials after which the resulting extract is diluted with water and often sugar to make a flavored alcoholic beverages. Unless the alcoholic content of the resulting beverage is well above 15%, the material will not be stable and may start to ferment or even decay in storage. Hence, most liquors are atleast 20% alcohol.

Biotechnology has a long history of use in food production and processing. For ten thousand years fermentation, a form of biotechnology, has been used to produce wine, beer and bread. Selective breeding of essential foods such as rice, corn and wheat have created thousands of local varieties with improved yield compared to their wild ancestors.

G.M. Findley and McCallum (1937) reported a phenomenon, called viral interference in which the cell infected with one type of virus becomes reisstant to superinfection by other viruses. Alliac Issacs and Lindeman (1957) gave the term interferons to the chemical substances responsible for the viral inference. 

Genetic engineering is the branch of science which deals with the modification of genes. The desired genes is isolated from the host and are inserted into the vectors. The vectors carries the foreign gene into the desired organism and multiples. The foreign gene multiplies along with the vector and produce a new character.

Barley contains the largest amount of enzymes necessary for converting starches to ferment sugars. Barley is commonly used in breads, soups, stews though it is primarily grown as animal fodder and as a source of malt for alcoholic beverages, especially beer.
Thus, the correct answer is option (D), 'Barley'.