Biology b1 Bits

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  • Created by: nom
  • Created on: 14-06-08 09:16

Diet 1

A healthy diet contains:

  • fats
  • carbohydrates
  • proteins
  • vitamins / minerals
  • water
  • fibre

Depending on the amount of exercise you do the amounts of eache change. For example, a sportsman would need more carbohydrates, for energy, than a office worker.

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Tests

To test for:

  • protein - biuret A - sodium hydroxide+ Biuret B - copper sulphate -> purple
  • carbohydrates(starch) - iodine - brown -> black/blue
  • carbohydrates(sugar) - benedicts solution -blue-> orange
  • fat - wipe on paper -> grease spot/paper becomes translucent - some light passes through
  • vitamin C - DCPIP solution -> blue -> clear
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Carbohydrates + Fats

Carbohydrates :

Sources of Energy - Made up of hydrogen, carbon and oxygen - bread pasta etc.

3 types:

  • monosaccarides - 1 saccaride unit - glucose
  • disaccarides - 2 saccaride units - sucrose
  • polysaccarides - many saccaride units - starch / cellulose

Fats:

energy stores - insulate body - prevents heat loss

examples - lard, animal fat made of fatty acids and glycerol

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Proteins + Fibre

Proteins:

Growth + repair

examples - fish + meat + dairy products

Made up of about 20 amino acids strung together

Made up of hydrogen, carbon, oxygen and some sulphur and nitrogen

Fibre:

stimulates contraction of gut muscles - peristalsis - moves food along the gut

insufficient fibre causes constipation

fruit + veg = good sources of fibre

indigestible plant cell walls

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Vitamins + minerals + Water

Vitamins/Minerals:

needed in very samll quantities by the body

Excess causes health problems

Insuficient causes deficiency diseases

Water:

taken in through drinking / in food

needed by body for chemical reactions to occur - in cells

keeps us cool

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Metabolic Rate / BMI

Metabolic Rate - rate at which chemical reactions take place in your body

BMI - weight (kg) ÷ height² (m)

normal BMI is between 20 - 30

less 20 thin - over 30 fat

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Obesity Starvation + Cholesterol

OBESITY:

  • Developed world - too much fatty food/less exercise
  • causes - arthiritus - diabetes - high blood pressure - heart disease

STARVATION:

  • developing world - lack of food
  • causes- reduced resistance to diseases - irregular periods in women
  • Developed world - anorexia - insufficient food is eaten - starves themselves

CHOLESTEROL:

  • created in liver - found in blood
  • amount made by liver depends on diet + inheritance
  • high levels of cholestrol increase risk of disease to heart and blood vessels
  • cholestrol carried by the body by lipoproteins
  • HDL - good cholestrol
  • LDL - bad cholestrol
  • balance important for good health
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Saturated Fats

Found in Animal Fats, Butter + Cheese

Increase blood cholesterol levels

Monounsaturated fats + Polyunsaturated fats - help reduce blood cholesterol levels and improve the balance between LDLs and HDLs

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