January Exam Flashcards
What chemical is needed to test for starch
Iodine
What chemical is needed to test for sugar
Benedict’s solution
What chemical is needed to test for protein
Sodium hydroxide + copper sulfate (biuret solution )
What chemical is needed to test for fat
Ethanol
What is the initial colour of starch and what does it change to
Yellow - brown to blue - black
What is the initial colour of sugar and what does it change to
Blue to green»_space; brick - red
What is the initial colour of protein and what does it change to
Blue to purple / lilac
What is the initial colour of fat and what does it change to
Clear to white emulsion
What are the 7 main food groups
Water
Carbohydrates
Protein
Fat
Minerals
Dietary fibre
Vitamins
What is the function of carbohydrates
Energy source
What is the function of protein
Growth + repair of cells
What is the function of fat
Energy, insulation + protection of body organs
What is the function of vitamin C
Healthy cells and helps prevent diseases
What is the function of vitamin D
Strong bones + teeth
What is the function of calcium
Strong bones + teeth
What is the function of iron
Helps make red blood cells to carry oxygen around the body
What is the function of fibre
Prevents constipation
What is the function of water
Stops us becoming dehydrated (chemical reactions etc.)
How do you work out energy
Energy in 1g of food = rise in temperature x volume of water x 4.2
Why might energy on the label be higher on the food label then in the experiment
Heat lost to the atmosphere
Heat lost in apparatus
Water may have not been stirred
What is the ‘equation’ for tooth decay
Bacteria + sugar»_space; acid + time»_space; tooth decay
What is the value of critical pH
5.5
Food is taken into the body
Ingestion
Food is broken down into soluble substances
Digestion
The soluble products are absorbed into the bloodstream and transported round the body
Absorption
The soluble products of digestion are taken into the cells where they are used
Assimulation
Removal of waste (faeces)
Egestion
What is mechanical digestion
Happens in the mouth As our teeth cut and grind food into smaller pieces. This increases the surface area. This also happens in the stomach as it’s muscular walls churn the food
What is chemical digestion
Involves breaking the large molecules into smaller ones. Enzymes speed up chemical reactions and therefore are responsible for chemical digestion
What are the 3 main enzymes
Amylase
Protease
Lipase
Where are the 3 main enzymes found
Amylase - mouth, pancreas + small intestine
Protease - stomach, pancreas + small intestine
Lipase - pancreas + small intestine
What food group do the 3 main enzymes work on and what do they turn into after digestion
Amylase- starch - sugar molecules
Protease - protein - amino acids molecules
Lipase - fat - fatty acid + glycerol
What is the word equation for respiration
Glucose + oxygen»_space; carbon dioxide + water + energy
