WHAT YOU NEED TO KNOW Diet & Exercise What constitutes a healthy diet Positive & negative effects of diet on the body Our immune system What are pathogens How white blood cells defend using antibodies & antigens The role of vaccines The uses of antibiotics

DIET & EXERCISE A healthy diet is one that has the right balance of nutrients to help fuel our bodies. Carbohydrates Fats Proteins Vitamins & minerals – small amounts needed for healthy functioning of the body. Malnourishment – when a person has an unbalanced diet. Leads to obesity or underweight Needed to make new cells & for energy

FOOD = FUEL = ENERGY Too much food = too much energy = overweight Too little food = too little energy = weight loss Exercise = increases the amount of energy used by the body If energy used is more than energy put into the body then a person will lose weight. Overweight: Diabetes Arthritis Heart disease

METABOLISM – WHAT IS IT?? Metabolism – the speed at which your cells carry out their chemical reactions High metabolism = fast breakdown of fat Low metabolism = slow breakdown of fat – tendency to put weight on Metabolism varies from person to person Affected by your genetics & fitness

CHOLESTEROL An important molecule for making our cells Too much – clogs our arteries Can cause heart attacks Cholesterol levels can be inherited High levels can run in the family Can be reduced with exercise and healthy diet

EXAM STYLE QUESTIONS Questions will usually give you the information. Your job is to assess the data given and use it to help you answer the question. June 2012 Q2 January 2012 Q4

PATHOGENS & INFECTIONS All diseases caused by bacteria, viruses or fungi A pathogen – any microorganism that causes disease Dr Semmelweis – 1 st to realise that disease was spread by pathogens. WASH YOUR HANDS! – Slow down/stop spread of infection Insisted all doctors washed their hands between patients – greatly reduced deaths from infectious disease

THE IMMUNE SYSTEM Pathogen – any microorganism that causes disease White blood cells try to kill pathogens Surround & ingest pathogens Make antitoxins to neutralise toxins made by pathogens Make antibodies

ANTIBODIES Antibodies are produced by white blood cells when they’re needed.

The antibodies need to be the right shape to match the pathogen. Pathogen with specific ANTIGENS on it’s surface Antibody that is the right shape For this specific pathogen

The antibodies need to be the right shape to match the pathogen. When the antibody binds to the pathogen it Can now be destroyed.

Your body only knows what shape to make the antibodies after you have caught the disease and become ill.

a b c d

IMMUNITY Don’t display symptoms of a disease because you have antibodies in your blood to fight it. Once your WBCs make the antibodies with the right shape they will stay in your blood. Should that pathogen enter your body again your antibodies will be ready to fight it off immediately.

VACCINATION Dead or inactive form of the virus injected into the body Stimulates your WBCs to make the antibodies with the right shape Kills off the virus and antibodies remain in your blood Person now immune

TREATING INFECTIONS - ANTIBIOTICS Viruses – hide INSIDE cells so very difficult to treat. Any treatment usually means damage to healthy cells Bacteria – stay on OUTSIDE of cells & so can be targeted with medicine ANTIBIOTICS CAN ONLY KILL BACTERIA Penicillin – 1 st antibiotic Overuse of antibiotics Given for viral infections etc Causes bacterial resistance

BACTERIAL RESISTANCE Happens due to too many antibiotics Some bacteria develop resistance and aren’t killed This is random process by natural selection MRSA How to prevent antibiotic resistance Only take antibiotics if you have a bacterial infection Always finish a course of antibiotics

HOW TO GROW MICROORGANISMS IN LAB Petri dishes & agar are sterilised before use Innoculating loop used is sterilised by passing it through a flame Innoculating loop used to transfer microbes to the agar Put lid on the dish and secure with tape to prevent contamination from the air Dish must be incubated at 25 o C – prevents growth of bacteria that could be harmful to humans Incubated at 37 o C in industry

EXAM QUESTIONS January 2012 Q 8 Specimen paper Q4 & Q 9