Balanced diet is one which requires all of the necessary nutrients in the correct proportion there are 7 components:
carbohydrates- the main source of energy
proteins- essential for growth and repair of muscles and body tissue
fat- source of energy, water proofs membranes and dissolves fat soluble vitamins
vitamins- helps with the chemical processes in cells, can be water or fat soluble
minerals-inorganic elements in the body that help it function
water- helps transports substances around the body
fibre-indigestible part of food
Malnutrition is caused by an unbalanced diet. the biggest form of malnutrition is obesity. It is caused by an over consumption, this excess of energy is deposited as fat in the adipose tissue. obesity is defined as having a BMI of over 30 and a 20% higher than the average amount of fat.
Obesity can cause several diseases: cancer, cardio vascular, 2 diabetes, gallstone, osteoarthritis and high blood pressure (hypertension)
coronary heart disease) This is caused by a deposit of fatty substance in the coronary, this is known atherosclerosis. this reduces the size of the lumen and restricts blood flow to the heart. and leads to oxygen starvation. there are several component that increase CHD:
Salt decreases the water potential in the blood causing it to take up more water and increasing the blood pressure in blood vessels and diastole. which destroys the lining on the arteries
Fat which are saturated are more harmful than those in unsaturated and polyunsaturated and mono unsaturated fats can be beneficial for your health
Cholesterol can be found in the saturated fats in meat eggs and dairy products. they can also be made from saturated fats in the liver
Cholesterol is needed in the body as it is in cell membranes and is also needed to make sex hormones and bile. this means that cholesterol needs to be transported in the blood and has to be in the form which can dissolve in water e.g. lipoproteins. There are two types of lipoproteins: high density and low density, they travel till they reach the cell membrane with the correct receptors
High density Lipids (HDL)- Is a combination of unsaturated fat cholesterol and proteins they can help reduce or remove deposits on the arteries made from atherosclerosis. eating unsaturated fats will increase HDL.
Low density Lipids (LDL)- Are made of saturated fats cholesterol and proteins. if to much saturated fat and cholesterol is consumes LDL will rise in the blood and deposit on the arteries walls. saturated fats reduce the activity of LDL receptors sol more is deposited while mono and polyunsaturated fats increase activity so more is removed. LDL is increased by eating more saturated animal fat while having a low fat diet or consuming mono/polyunsaturated fats will reduce them.
Improving Food Production
There are 3 stages of selective breeding 1) isolation 2) artificial selection 3) line breeding
Animals and plants with desired characteristics are selected to reproduce. Their offspring with the best set of characteristics are then selected to reproduce. this is continued for many generations which exaggerates the characteristics.instead of natural selection, humans apply selection pressure.
Marker assisted selection) A section of DNA is used as a marker for a desired characteristic, so when a offspring is produced their DNA can be checked to allow selection at an early stage.
Fertilisers are used to replace minerals from the soil that other plants before may have taken up. they contain nitrate, phosphate and potassium. they increase the rate of growth and overall size of crops.
Pesticides are used to kill organisms which would otherwise cause diseases and kill the crops. fungicide is also used to stop fungus from growing on leaves and roots.
Antibiotics help treat infected animals. this reduces the spread of disease which would otherwise reduce the growth performance and impair reproduction.
Microorganisms To Make Food
Advantages of using microorganisms
- Production of the protein is quicker than with an animal or plant
- Production can be controlled to meet demand and no animal welfare issues
- There are no animal welfare issues
- Source of proteins for vegetarians and here are no animal fats of cholesterol
- Can be combined with removing waste
Disadvantages of using microorganisms
- People don't want to eat fungi grown from waste
- It has to be isolated from the waste it grows on
- The protein has to be purified so that it is not contaminated
- The condition the microorganisms grow is perfect for bacteria causing infections
- The taste may not be agreeable
Preventing food spoilage
- Fungi colonies can grow on food such as black mucor or blue penicillin
- Micro organisms can have external digestion processes reading food down into mush
- Clostridium botulinum can produce the toxin botulinum which is very toxic
- Can cause infection such as salmonella which attacks stomach lining
Ways of preventing spoilage
- Cooking- kills off microorganisms by denaturing enzymes and proteins
- Pasteurising- involves heating then cooling really rapidly killing off microorganisms
- Drying- removes water from microorganisms via osmosis, killing them
- Smoking- contains anti bacterial chemicals and harden the outer surface
- Pickling- raises ph which denatures enzymes and proteins
- Irradiation- kills organisms by disrupting their DNA
- Freezing- slows metabolic reaction in the organism also slowing growth and reproduction