Food and Digestion 2

Kwarshiorkor

caused by proteins deficiency

calcium

makes teeth and bones strong, found in dairy products and fish

iron

part of haemoglobin, found in the red meat and eggs

What does haemoglobin deficiency lead to

anaemia

sodium/ chlorine

bodily fluids

magnesium

making bone

Vitamin A

makes chemical in the retina, deficient causes night blindness

B1 vitamin

helps with cell respiration, deficiency causes beri-beri

B2 vitamin

helps with cell respiration, deficiency causes dry skin and poor growth

B3 vitamin

helps with cell respiration, deficiency causes pellagra

Vitamin C

sticks together cell lining surfaces in the mouth, deficiency causes scurvy

Vitamin D

helps bones absorb calcium and phosphate, deficiency causes rickets

Test for starch

add a drop of iodine, blue/black if positive

Test for glucose

Benedicts is add to glucose , solution is placed in a water bath, orange/brick red if positive

What is the colour for traces of glucose in benedict’s solution

Green/yellow

What glucose can Benedict detect

monosaccharides and disaccharides except sucrose

Test of protein

Biurets is added to protein, lilac if positive

Test for lipids

add ethanol to lipids, shake, add equal amount of water, cloudy if positive

Energy content in carbohydrates

17

Energy content in fats

39

Energy content in proteins

18

How does the calorimeter measure energy content

by how much heat the food produces when burnt

How to improve validity of the calorimeter

insulate the sides, stir the water, minimise distance between bunsen burner and beaker

What affects daily energy needs

age, sex, physical activity, pregnancy/breastfeeding

Digestion

is the chemical and mechanical breakdown of food by breaking down large insoluble food molecules to small soluble molecules

Mechanical digestion

physical breakdown for food to increase surface area for enzymes

where does mechanical digestion happen

mouth, oesophagus, stomach, small intestine

Chemical digestion

the breakdown of food by enzymes

Polymers

starch, proteins, fats

monomers

maltose, amino acids, fatty acids

Peristalsis

muscles movement of the intestines to move food along the gut

Layers of muscles in the intestines

fibres arranged in rings, fibres along the length of the gut

How do the muscles work in the gut

they work antagonistically