Biology Revision for "O" level examinations

The most effective action anyone can take to prevent the spread of contagious illnesses is to wash his or her hands. Why? Because microbes (organisms so tiny that they can only be seen with microscopes) are ubiquitous. They live on doorknobs, money, your hands, and many other surfaces. If someone sneezes into his hand and touches a doorknob, and afterwards you touch that same doorknob, the microbes from the sneezer’s mucus are now on your hands. If you touch your hands to your mouth, nose, or eyes, those microbes can enter your body and could make you sick. However, not all microbes (also called microorganisms) cause disease; most are actually beneficial. You have microbes in your gut that make vitamin K. Other microorganisms are used to ferment beer and wine. Microbiologists are scientists who study microbes. Microbiologists can pursue a number of careers. Not only do they work in the food industry, they are also employed in the veterinary and medical fields. They can work in the...

-  Enhance quality of food: e.g. incorporation of beta carotene (vitamin A) producing gene in rice for areas that are affected by night blindness. -Production of human insulin, antibiotics and hormones in a very cost effective manne  - Treat diseases and conditions such as AIDS, cystic fibrosis, cancer and genetic disorders -Creating a crop that is resistant to a specific herbicide -Create plants that can tolerate high salinity and drought (helps in managing climate change) -Increase milk production in cattle or increase protein content in the milk produced -In the future, it can be used to regrow damaged body parts, teeth, and nerve cells (treat paralysis -Clone organisms or even Humans (but there are ethical concerns -Modify plants to produce larger, and “better” tasting fruits -Modified plants that can absorb pollutants from the environment and break them down into harmless substances  -Engineered bananas, potatoes, lettuce, ...