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The idea that the effect of a drug in the human body is mediated by specific interactions of the drug molecule with biological macromolecules, (proteins or nucleic acids in most cases) led scientists to the conclusion that individual chemicals are required for the biological activity of the drug. This made for the beginning of the modern era in pharmacology, as pure chemicals, instead of crude extracts of medicinal plants, became the standard drugs. Examples of drug compounds isolated from crude preparations are morphine, the active agent in opium, and digoxin, a heart stimulant originating from Digitalis lanata. Organic chemistry also led to the synthesis of many of the natural products isolated from biological sources.
Historically, substances, whether crude extracts or purified chemicals, were screened for biological activity without knowledge of the biological target. Only after an active substance was identified was an effort made to identify the target. This approach is known as classical pharmacology, forward pharmacology,[10] or phenotypic drug discovery.[11]
سلام علیکم
امروز پنج اسفنده. تا آخر اردیبهشت آزمون بدم؟
هفته ای چهار تا TPO. ریدینگ و لیسنینگ. تمام
شنبه
- 7-8.5 رایتینگ
- 9-10.5اسپیکینگ
- 10.45-12.15لیسنینگ
- 12.5-2 ریدینگ
- 2-4 استراحت
- 4-6 تز
- 6-8 حمام و شام
- 8-10 تز
45 نوشتن + 45 تصحیح-کالوکیشن. رونویسی
یک ساعت آزمون. نیم ساعت کلمه
یک ساعت آزمون لیسنینگ. نیم ساعت گرامر
یک ربع شدوئینگ. یک ساعت و ربع اسپیکینگ