AQA CORE SCIENCE BIOLOGY

A healthy diet contains the right balance of the different foods The food groups are used by the body to release energy and to build cells.

Carbohydrates:starch are joined together with smaller glucose molecules so it takes longer to break down.where as glucose is a single molecule which is faster to break down realesing energy faster. Carbohydrates are used for respiration .Examples of carbohydrates are: cereal , bread , pasta, potatoes.

Fats: Made out of fatty acids and glycerol. Fats are used for a store of excess energy , cell membranes and for insulation. Too much fat can cause high cholestral. Examples of Fats: crisp , chocolate , Oils.

Protein : Body cells are made up of protein. Protein is made up of amino acids. Protein is needed for growth and repair. Examples of protein are: Fish , beans and chicken.

Fibre: Roughage in our diet. absorbs water in to the gut to help food run smoothly through intestines. Prevnts constipation. Fibre is not Digested and found in wheats.

Amount of energy needed depends on: Age, Gender, Amount of activity. If a person takes in more energy than needed the excess is stored as fat.

Obesity: more intake of enrgy than your body can burn off.

Diabetes: Type 1 = pancreas dosent make enough insulin.(inhertied)                                   Type 2 = cells dont respond to the insulin.

Cholestral: Fatty deposit that narrows artries,found in the blood and carried by liproproteins. LDL- BAD. HDL- GOOD. These carry cholestral from liver to cells. saturated fats increase cholestral. Monosaturated and polyunsaturated fats decrease cholestral found in plants and oils. If cholestral levels are to high it can cause plaques forming in walls of the artries slow down blood flow and cause blood clots. This can increase blood pressure and lead to heart attacks.

Arthiritus- inflamation of the joints                                                                        

High blood pressure- caused by to much salt in diet. Puts starin on your heart and can lead to heart attacks and strokes.                                               

A person is malnourished if their diet is not balanced. This may lead to a person being overweight or underweight. An unbalanced diet may also lead to deficiency diseases

Anorexia= less energy than you need cause health problems such as:

Mineral ions and vitamins are needed in small amounts for healthy functioning of the body.

Lack of vitiman C - canuse scurvy (swollen gums) , Lack of vitiman D - cause rickets (softning of the bones) , Lack of Iron - cause anemia lack of red blood cells. ,Lack of protein - cause kwashiokor (growth failure) ,Lack of calcium - cause oesteoporosis (brittle bones).

Metabolic rate MR- Rate at which chemichal reactions take place in the body. Metabolic rate is affected by

genetics , amount of activity , Temperature , Pregnancy , proportion of muscle to fat ratio.

• Microorganisms that cause infectious disease are called pathogens.

Bacteria- reproduce rapidly inside the body and produce poisonous toxins which make us feel ill. They destroy living tissues. Examples of bacteria: whooping cough and food poisoning.

Viruses - dont feed move or respire just reproduce inside a living cell. They damage the cells in which they reproduce. This is what makes us feel ill.

The body has different ways of protecting itself against pathogens. White blood cells help to defend against pathogens by:

• white blood cells- phacocytes engulf and injest the pathogen before it can do any harm.
• white blood cells- lymphocytes create antibodies that stick to the antigen and clump them together so the phagocytes can engulf them.
• white blood cells- create antitoxins to counteract with the toxins released by the pathogen.

The immune system of the body produces specific antibodies to kill a particular pathogen. This leads to immunity from that pathogen.

A weakend inactive form of a pathogen is injected in to the body .This stimulates the white blood cells lymphocytes to create antibodies to stick to the antigens and clump them together so they can be engulfed by the phagocytes. This is done so your body becomes immune to that disease or that particular pathogen as the antigens are no longer foreign to the body. This makes the person immune to future infections.The body can respond by rapidly making the correct antibody, in the same way as if the person had previously had the disease.

how our body prevents pathogens entering                                                            Tears - contain enzymes , nose - mucus , saliva - alkaline Ph ,lungs- mucus and cicilia hairs, stomach, alkaline pH , skin- antiseptic oils.  blood- open wounds sealed with blood platlets.

how microbes enter our body.                                                                             respiortory system - breathed in , digestive system - food and drink , reproductive system - sexual intercourse.                                                         

Some medicines, including painkillers, help to relieve the symptoms of infectious disease, but do not kill the pathogens. Antibiotics, including penicillin, are medicines that help to cure bacterial disease by killing infectious bacteria inside the body. Antibiotics cannot be used to kill viral pathogens (viruses) as they cannot be kiled with out damagin the cell. The use of antibiotics has greatly reduced deaths from infectious bacterial diseases. Overuse and inappropriate use of antibiotics has increased the rate of antibiotic resistant strains of bacteria.

Many strains of bacteria, including MRSA, have developed resistance to antibiotics as a result of natural selection. individual resistant pathogens survive and reproduce, so the population of the resistant strain increases now, antibiotics are no longer used to treat non-serious infections, such as mild throat infections, so that the rate of development of resistant strains is slowed down.To prevent further resistance arising it is important to avoid overuse of antibiotics. Antibiotics and vaccinations may no longer be effective against a new resistant strain of the pathogen. The new strain will then spread rapidly because people are not immune to it and there is no effective treatment.