Testing for biological molecules, Balanced Diet and Calorimeter Flashcards
(23 cards)
Identify the chemical elements present in carbohydrates, proteins and lipids
Carbohydrates and lipids both contain C, H and O; proteins contain C, H, O and N.
Give five examples of carbohydrate molecules
Glucose, starch, sucrose, cellulose, glycogen etc.
State the basic subunits of proteins
Amino acids
State the basic subunits of lipids
Glycerol and fatty acids.
Describe the functions of carbohydrates.
Respired to release energy.
Describe the functions of proteins.
Used in growth and repair.
Describe the functions of lipids
Insulation and as a high energy source
Name the bond which links amino acids to make a protein
peptide bond
State the chemical used to test for starch and give the positive result
Iodine; turns brown –> blue-black.
Describe the chemical test for lipids and give the positive result
Dissolve sample in ethanol and add cold water; lipids present if a cloudy, white emulsion appears.
State the chemical used to test for protein and give the positive result
Biuret; turns blue –> purple.
Describe the chemical test for glucose and give the positive result
Add Benedict’s solution to sample and HEAT in a hot water bath; if glucose present, turns blue –> brick red (green, orange intermediate colours).
Suggest a consequence of low iron in the diet
Anaemia (less haemoglobin so fewer red blood cells)
Suggest a consequence of low calcium in the diet
Poor bone and teeth development
Suggest a consequence of low vitamin D in the diet
Rickets
State two sources of iron in the diet
Red meat, spinach
State three factors that affect energy requirements of individuals
Age, pregnancy, activity levels
Describe four main things our bodies need a constant release of energy for.
Movement, growth, repair, maintain body temperature
What is the equation to find out the j of energy in 1 g of food?
Energy in 1g of food (J) = (volume of water x temperature rise x 4.2) ÷ mass of food
Arrange the food groups into the correct order based on energy content (largest first).
Lipids, proteins, carbohydrates
Suggest why oxygen gas is passed into a calorimeter
Helps combustion of the food
Suggest why a calorimeter’s waste gas pipe is coiled
To increase the surface area for heat to transfer into the water
Suggest why stirring the water in a calorimeter will improve the data collected
It distributes heat, makes all the water the same temperature
