GCSE Biology Unit 1 AQA


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Archie Clay
Note by Archie Clay, updated more than 1 year ago
Archie Clay
Created by Archie Clay over 9 years ago

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Bio 1.1 Healthy Diet A balanced diet is having the correct amount of these different types of food Proteins – Build and repair tissue. Amino acids are the building blocks of proteins Carbs – Found in rice, bread, pasta. They are needed to provide energy for the body Fat – Found in butter, oils, lard. Provide stored energy that will be used when there is a lack of carbs. It is also there to insulate the body. Water – Hydrates the body and is important because all chemical reactions in the body happen in a watery environment. SO you need it. Fibre – Found in fruits, veg and cereals. Helps with the release of faeces. Vitamins and Minerals – Certain vitamins and minerals have different jobs. They give you good general health. Malnutrition – Can lead to being overweight or underweight. More energy taken in then lost = gain weight Less energy taken in then lost = lose weight Metabolic rate – The rate at which chemical reactions take place in your body. Things that affect this are: ·         Gender – Males on average have higher metabolic rate ·         Muscle/Fat Ratio – More muscle to fat means higher metabolic rate ·         Inherited Genetics Cholesterol – Cells use this to produce cell membranes. Too much of this can cause blocked arteries which can lead to heart attacks. Type 2 Diabetes – This is a result of insulin not being recognised in the body and it means you can’t control blood sugar levels. Tends to be in overweight people. There are two types of cholesterol. Good cholesterol and bad cholesterol. If this balance in the two cholesterols is bad then you can be at risk of health problems. The liver makes produces cholesterol that you inherited from your parents. Eating lots of high fat foods can cause the cholesterol levels to become unbalanced therefore putting you at risk of heart diseases.

Defence against Diseases   Microorganisms – Bacteria, Fungi, Viruses. The Microorganisms that cause disease are called pathogens. People can pass these pathogens on from person to person. This makes them Infectious diseases. Bacteria – Produces anti-toxins (poisons). Single cell living organisms. Much smaller then plant/animal cells. Many bacteria cells are harmless and some are actually beneficial in life. Bacteria multiply by splitting in two. Viruses – Gets into the cells and reproduces rapidly. This causes the cell to be permanently damaged. These microorganisms are much smaller then bacteria cells. Viruses cause disease in every single living organism. Symptoms – high temperatures, headaches, and rashes. This is caused by the damage the pathogens do to your body and also how your body reacts to the toxins they produce. There are a number of ways in which pathogens can be spread. The most likely ones are: ·         Droplet Infection – When you cough, sneeze or talk you expel tiny droplets. Other people breathe these droplets in along with the pathogens they contain, so they pick up the infection. ·         Direct Contact – When pathogens get in small breaks/cuts in skin. Injecting with dirty needles, eating raw undercooked food. Spread by direct contact of skin. Bodies’ defences Skin – your skin is your bodies’ main defence when it comes to pathogens. It acts as a barrier and covers your whole body. Clots – When you cut your skin, you blood instantly forms a clot which dries to make a scab. The scab seals of the cut so pathogens can’t get into the wound. Mucus – When you breathe, you breathe in pathogens. Luckily your body produces mucus. Mucus is a sticky liquid that pathogens get stuck in. It covers the lining of your lungs and tubes. You then swallow the mucus and acid in your stomach destroys the microorganism. When your outer body defences fail your white blood cells take action. White blood cells – ingest pathogens, produce antibodies or they can produce antitoxins. Ingest microorganisms – They ingest the pathogen. This destroys the pathogen so they can’t make you ill Antibodies – Some white blood cells produce special chemicals called antibodies. There is a different antibody for each pathogen. If the pathogen gets into your body a second time the antibody can be made very quickly Antitoxins – counter act the toxins that are released by the pathogens.

Drugs to treat disease When you get a disease you often take medicines. These medicines rarely effect the pathogen, they just ease the symptoms. Paracetamol and aspirin are very useful painkiller. But they have to effect on the actual virus that entered the body. Antibiotics – Antiseptics and disinfectants are used to kill bacteria outside the body but they are far too poisonous to use inside your body. They would kill the pathogen and you at the same time. Antibiotics are drugs we use inside the body to kill the bacteria that causes diseases. They work by damaging the bacterial cells without harming your own cells. They have saved many lives. Sadly they are not the full answer. Antibiotics do not kill pathogens caused by viruses. They can't kill viruses because viruses reproduce inside the cells of our body. It is extremely difficult to develop drugs that kill viruses without damaging the cells and tissues of your body at the same time.

Keeping Healthy


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