Diet and Excercise

A healthy contains the right balance of carbohydrates (for energy), fats (for energy and insulation), proteins (for growth and repair), mineral and vitamins (for keeping healthy).   
If a person’s diet is not balanced they might become malnourished.

This includes becoming underweight, develop deficiency diseases such as rickets or scurvy, conditions such as diabetes type 2 or becoming obese. Being obese could lead to arthritis, high blood pressure, blood clots, stroke or heart attacks. 

A healthy contains the right balance of carbohydrates (for energy), fats (for energy and insulation), proteins (for growth and repair), mineral and vitamins (for keeping healthy).   
If a person’s diet is not balanced they might become malnourished.

This includes becoming underweight, develop deficiency diseases such as rickets or scurvy, conditions such as diabetes type 2 or becoming obese. Being obese could lead to arthritis, high blood pressure, blood clots, stroke or heart attacks. 

Metabolic Rate is the speed at which chemical reactions in the cells of the body  are carried out. It is affected by how much exercise you do, your age, gender, the proportion of muscle to fat in your body (the more muscle the higher the metabolic rate) and your genetic make-up. 

Cholesterol  is a plaque like substances that builds up in the walls of the arteries. This build up slows down the flow of  blood and a blood clot could form. If the clot forms in an  artery that delivers oxygenated blood to the heart, a heart  attack might ensue. Eating a diet high in saturated fats  raises blood cholesterol levels. Inherited factors also  determine how much cholesterol builds up. 

Good and Bad Cholesterol...

There are two types of cholesterol: low-density lipoprotein (LDL) which builds up in the artery  Walls and high-density lipoprotein (HDL) which removes LDL from the walls of the arteries. 

Statins are drugs that have been developed to reduce blood cholesterol levels by stopping the liver from producing too much cholesterol and consequently lower the risk of heart diseases.

The danger is that people on the drug will not change their diet and exercise regime and  continue with their unhealthy life  style. 



Microorganisms that cause diseases are called pathogens. Examples are bacteria, viruses and some fungi.  Pathogens reproduce quickly and make us feel ill. Bacteria produce toxins and sometimes destroy cells. Viruses enter cells, reproduce inside them and then destroy the cells.  

White blood cells produce antitoxins to counteract the toxins produced by bacteria. Some white blood cells ingest pathogens and some produce antibodies. The pathogen’s surface has structures called antigens. Different antibodies have different shapes that fits a pathogen’s antigens. As antibodies attach themselves to the  antigens, the pathogens are slowed down and can be surrounded and ingested by white blood cells.  Once the body has produced a specific type of antibody you are immune to that pathogen.

Around 1850 a doctor called Semmelweis recognised that if doctors washed their hands before examining patients, fewer patients died. He thought that a disease could be passed from one person to another.  Hand gel dispensers are placed at ward entrances in hospitals today as the hand gel destroys pathogens and reduces the spread of diseases. This, together with better drugs and a better understanding about immunity, better sterilisation and isolation of patients means that the spread of diseases has been greatly reduced. 

To treat a bacterial infection the doctor can prescribe a course of specific antibiotics. An example is penicillin. Antibiotics cannot be used to kill viruses . As the viruses are found inside cells, and mutate frequently, they are  inaccessible to the antibiotics. If you have flu (which is caused by a virus) you can only take medication to reduce the symptoms. 
 

Diseases that spread quickly can cause either an epidemic or a pandemic. 
During an epidemic the disease spreads rapidly from one person to another within the same country.  
During a pandemic the disease spreads quickly worldwide (in several countries). Frequent air travel can be responsible for a pandemic. 

Diseases that spread quickly can cause either an epidemic or a pandemic. 
During an epidemic the disease spreads rapidly from one person to another within the same country.  
During a pandemic the disease spreads quickly worldwide (in several countries). Frequent air travel can be responsible for a pandemic. 

Due to gene mutation there might be a few bacteria who are resistant to antibiotics.  
A doctor prescribes a course of antibiotics to kill the bacteria. The problem is that the bacteria who are resistant to antibiotics are not killed. All other bacteria are killed, leaving the antibioticresistant ones without competition.The antibiotic-resistant bacteria  can now multiply rapidly.  (This is an example of natural selection) 
To reduce the chance of antibiotic-resistant  bacteria from forming, antibiotics should be used sparingly. MRSA is resistant to most antibiotics and  called a superbug. It can spread quickly in hospitals and can kill as patients are too weak to  fight the disease.  

PRE-INOCULATION: The Petri dish and agar are  sterilised to kill any unwanted bacteria. This  is achieved by passing the inoculation loop  through a flame so that it becomes sterile.  INOCULATION: The now sterile loop is dipped in a  suspension of bacteria which are transferred to the agar  (made of carbohydrates). The lid of the Petri dish is replaced quickly to prevent microbes from the air entering.  POST-INOCULATION: The Petri dish is sealed with tape to  prevent microbes from the air entering and contaminating  the culture. It is important to not seal the dish all the way  to ensure oxygen can enter. Otherwise harmful anaerobic  bacteria would grow. The Petri dish is then incubated at  25oC max to allow the bacteria to grow. Above 25oC  pathogens might grow instead. 

A small amount of dead or inactive pathogen is injected into the blood. 
The white blood cells produce antibodies to destroy the pathogens.If a vaccinated person is exposed to the live pathogen in the future the body can produce the antibodies quickly and destroy the pathogens before any harm is done. The MMR vaccine is used to protect children against mumps, measles and rubella. It is worth vaccinating a large number of a population to prevent an epidemic/pandemic and protect people during their holidays to other countries. 

Due to gene mutations, new infectious diseases appear all the time. Existing vaccinations don’t work against the new strain of pathogen and as scientists try to develop the new vaccination, the new disease can spread rapidly as people are not immune yet.  
Examples are HIV,  swine flu, bird flu, flu. 
