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| Frage | Antworten |
| What is an infectious disease? | One that can be passed to another person, such as the flu. |
| What are microorganisms? | A living organism that can only be seen through a microscope. |
| In good conditions how often can bacteria reproduce? | Once every twenty minutes. |
| What three things are needed for bacteria to live? | Warmth, nutrients, moisture |
| Describe how antibodies work. | Produced by white blood cells they latch onto foreign antigen markers and clump them together so other white blood cells can digest them. |
| Why are we sometimes ill for days then? | Antibodies have to match antigens. The body produces different antibodies until there's a match - then it makes millions of the one that works. |
| Why do we only catch chickenpox once? | Memory cells live on in the blood stream, carrying the antibody that matches the chickenpox antigen. |
| Why do we catch so many colds then? | The cold virus is actually hundreds of different viruses that mutate regularly. The old antibodies don't work on the new cold. |
| How does a vaccine work? | It contains dead or inactive microorganisms that the body produces antibodies against. Memory cells stick around, so if you meet the real disease, you destroy it quickly. |
| Why do vaccine rates have to be almost 100% to be effective? | The more people without the vaccine the more chance they'll meet someone who's infected, and the more chance it'll spread. |
| Why do people not have vaccines? | They worry about the side effects, such as allergic reactions. They believe since everyone else has the vaccine, they don't need it. |
| Why are vaccines not compulsory? | The government doesn't believe people should be forced to if they don't want to or if they think it dangerous. |
| Penicillin can be found in mouldy bread. Why is this? | Bacteria and fungi produce antibodies to kill other microorganisms. Penicillin is one of these. |
| What is an antibiotic? | A drug that kills bacteria or fungi. |
| Why do we have superbugs? | Bacteria mutates into a superbug. Antibiotics kill most of the bacteria so the patient stops taking the drugs. The new superdrug reproduces quickly. |
| Why are superbugs so dangerous? | They're resistant to antibiotics, and so there's nothing doctors can do. People die and become disabled because of superbugs. |
| Describe stage one of testing new drugs. | Early tests are done on human cells to get a rough idea of the effect. This is called in vitro tests. |
| Describe stage 2 of testing for new drugs. | The drugs are tested on animals, known as in vivo testing. This is very controversial. |
| Describe stage 3 of trials for new drugs. | Human or clinical trials, first on healthy volunteers and then on patients. |
| What is a placebo and a control group? | A control group is a group of people who take part in a clinical trial but are given a placebo, a drug that has no effect. |
| There are three types of clinical trial. Describe them. | Double-blind trial - neither Doctor nor patient knows who's in the control group. Blind trial - the doctor knows. Open label trial - everyone knows. |
| When are open-label trials used? | If the patient is near death with no hope of recovery, side effects hardly matter. No placebo's are used. |
| Describe the arteries. | Takes blood away from the heart. Has thick outer wall and can withstand the high pressure caused by the pumping heart. |
| Describe veins. | They bring blood back to the heart, and have thin walls that can squish blood back to the heart. Small valves stop the blood flowing backwards. |
| Describe capillaries. | Walls one cell thick, they allow oxygen and food to diffuse to cells, and waste products back in. |
| What is most common cause of a heart attack? | Fat building up in coronary arteries, blocking the passage of blood to the heart. Without energy the heart can't pump. |
| What factors cause heart disease? Name three. | Fatty foods, high salt intake, genes, smoking, lack of exercise - all of these are risk factors. |
| What are lifestyle diseases? | Diseases such as lung cancer and heart disease, caused not by infections or inheritance but the unhealthy way we live. |
| What is blood pressure and what is it used for? | Blood pressure measurements record the pressure of the blood on the walls of the artery. A warning sign of heart disease. |
| What does homeostasis do? | Keep the correct level of water, salt and nutrients, and rid the body of waste products. |
| All control systems have what three things? | A receptor to detect change or stimuli, a processing centre to receive the info and decide a response and an effector that does the responding. |
| What is negative feedback? | When there's a change in the system, an action occurs that reverses this change. |
| What does water homeostasis do to control water levels? | Controls water input (makes you thirsty) and output (urea, sweating). |
| What are the two jobs of the kidneys? | Water homeostasis and excretion. The kidneys control the water balance of the body. |
| If you have only a little water in your body, what do the kidneys do? | Make a smaller volume of urine (the water bit) with the same amount of waste (urea). The urine is more concentrated. |
| If the body has only a little water, what do the kidneys do? | Reabsorb a lot of the water, sending it back to the bloodstream. |
| What's the effect of alcohol on urine? | Urine becomes more dilute, and people become very dehydrated. |
| What effect does the drug Ecstasy have on homeostasis? | Makes it very, very concentrated. It also makes you overheat, so you drink more. This can make you 'drown'. |
| How do the kidneys know when to produce concentrated urine? | The brain releases ADH, a hormone which tells the kidneys to reabsorb more water. |
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