Physics for You : Plenaries

1
Ch 4
Whats for lunch?
Balanced diet

• carbohydrate
• protein
• fat
• minerals
• vitamins
• fibre
• water

A balanced diet contains
in the correct proportions.
OCR B1b
2
Ch 4
Whats for lunch?
Protein, carbohydrate and fat
the large biological molecules
Proteins are made out of a chain of 1..
Proteins are made out of a chain of amino acids
Starch is made out of a chain of 2.
Starch is made out of a chain of sugars
Fats are made from a 3 and 4..
Fats are made from a glycerol and fatty acids
OCR B1b
3
Ch4
Whats for lunch?
Energy Balance
energy in food
BMR
body energy balance
1
2
stored as fat
exercise
3

• Too much fat storage leads to 4
• These health problems are more likely in
  overweight people

obesity
high blood pressure
heart disease
diabetes
arthritis
OCR B1b
4
Ch 4
Whats for lunch?
Calculate body mass index or BMI
.. (...)2
mass (height)2
body mass index (BMI) Caroline has a mass
of 48 kilograms, her height is 1.5 metres
48 1.52
48 2.25
BMI
21.3
OCR B1b
5
Ch 4
Whats for lunch?
Digestion

• Digestion is the break down of large 1 food
  molecules into 2 soluble food molecules by
  3.. so that they can be absorbed into the 4
  in the 5 intestine.
• The mouth and bile break up food into smaller
  pieces to give a larger 6 for the enzymes to
  act 7.
• Carbohydrases break down larger carbohydrates,
  like starch, into 8 .
• Proteases break down proteins into 9. .
• Lipases break down fats (lipids) into 10.. .
  and 11 .

insoluble
small
enzymes
blood
small
surface
faster.
sugars.
amino acids.
fatty acids
glycerol.
OCR B1b
6
Ch 4
Whats for lunch?
Human digestive system
salivary gland oesophagus liver stomach pancreas s
mall intestine large intestine rectum anus appendi
x
1 2 3 4 5 6 7 8 9 10
OCR B1b
7
Ch 4
Whats for lunch?
Mouth and stomach

• Mouth
• Food is broken up by 1 .
• Saliva contains the carbohydrase 2
• Food moves down the gullet by 3
• Stomach
• hydrochloric acid keeps the pH low (4.) to
  kill 5
• and to provide the 6 pH for
• the 7.. enzyme to break down proteins.

chewing.
amylase.
peristalsis.
(acidic)
bacteria.
optimum
protease
OCR B1b
8
Ch 4
Whats for lunch?
Small intestine

• Bile from the liver contains an 1 to break up
  fat into smaller 2.
• Bile 3. acid from the 4.. to provide
  optimum 5 for
• digestive juice from the pancreas containing
  6.., amylase and 7... to break down large
  food molecules.
• Proteases, amylase and lipase in the small
  intestine complete the digestion so that sugars,
  8 , 9 .. and glycerol can be absorbed.

emulsifier
droplets
neutralises
stomach
pH
proteases
Lipase
amino acids
fatty acids
OCR B1b
9
Ch 4
Whats for lunch?
Absorption
The small intestine has millions of tiny ...
villi
capillaries absorb sugar and amino acid molecules
villus large surface, faster
lining one cell thick, faster
absorption
diffusion
lacteal absorbs fatty acids and glycerol
blood flow
OCR B1b
10
Ch 4
Whats for lunch?
Absorption at the villi
lining one cell thick, faster diffusion
large surface, faster absorption
OCR B1b