Английский язык: english for masters of chemistry
жүктеу/скачать 4.51 Mb. Pdf көрінісі
|
- Бұл бет үшін навигация:
- 7. Fermentation .
- 8. Sunscreens .
- 9. Nail Paint Removers .
| 6. Ripening of Fruits. A simple hydrocarbon gas ethylene switches on the necessary genes
that stimulate the secretion of the ripening enzymes which catalyze reactions to change the properties of the fruit. Ethylene channelizes the action of several other chemicals called hydrolase, amylase, kinase and pectinase. These enzymes convert starch to sugar, alter the cell walls to make them softer, neutralize acids and cause the fruit to emit an aroma. 7. Fermentation. Fermentation is the conversion of complex substances to simpler ones under anaerobic conditions. The specific product from fermentation is driven by the type of micro- organisms acting on the substance in which the fermentation occurs. The products of fermentation are alcohols or acids and the release of carbon dioxide. For example, wine produced from fruit juice is an alcohol as a result of fermentation by yeast, whereas beer is the result of yeast fermentation of grain. Antibiotics are obtained through fermentation by molds and some bacteria. Yogurt, cheese and vinegar are products of bacterial fermentation. Leavened bread is obtained by yeast fermentation. 8. Sunscreens. Sunscreens are a combination of organic and inorganic compounds. Inorganic chemicals like titanium dioxide or zinc oxide form a physical barrier that reflects or scatters UV waves. Organic components like octyl methoxycinnamate (OMC) or oxybenzone absorb UV rays and release their energy as heat. This protects our skin from sunburns and detrimental effects like cancer. 9. Nail Paint Removers. Nail paint consists of three types of ingredients which are organic solvents and drying agents, thickeners and hardening agents along with coloring agents. The remover is actually an organic solvent that is used as an ingredient in nail paint which may be acetone or ethyl acetate. So when you apply the remover you are just bringing it back to its original state. The solvent molecules get in between the chains of polymers and separate them, making it easy to wipe it off with a ball of cotton. жүктеу/скачать 4.51 Mb. Достарыңызбен бөлісу:
|