revision - nutrition + enzymes feb 2023 Flashcards
chemical elements in carbohydrates
carbon, hydrogen + oxygen
chemical elements in protein
all have hydrogen, nitrogen, carbon + oxygen
most have sulfur
chemical elements in lipids
all contain carbon, hydrogen + oxygen
some have nitrogen, sulfur and phosphorus
describe the structure of carbs, proteins and lipids
larger molecules made from smaller, basic units
building blocks of carbs
made from starch and glycogen (polysaccharides), which are made from simple sugars (monosaccharides like glucose and fructose)
building blocks of protein
amino acids
building blocks of lipids
fatty acids and glycerol
test used for detecting glucose
benedict’s solution - orange/brick red if there is, blue, greeny-yellow if there isn’t much (requires heating to 80c)
test used for detecting protein
biurets solution - blue = none, lilac = has protein
test used for detecting lipids
emulsion test - add ethanol and water to solution and shake. milky white in presence of lipids
test used for detecting starch
iodine test - add iodine (blue/black if there’s starch, stays brown/orange if there isn’t)
functions of enzymes
biological catalysts in metabolic reactions, speeding up the reactions without really being affected itself
how temperature effects enzymes
Enzymes have an optimum temperature which is the temperature where the enzyme works the most effectively. enzymes aren’t living so they can’t die. but when enzymes exceed their optimum temperature, the shape of their active site changes, meaning the lock and key mechanism no longer works. we say that the enzyme is denatured
experiment with enzymes and temperature
iodine test for starch, heating enzymes and solution to different temperatures (use amalyse and starch)
what food groups would a balanced diet contain
carbs, proteins, lipids, vitamins, minerals, water, dietary fibre
sources and purposes of carbs
Carbohydrates (e.g.potatoes and bread)
Carbohydrates provide energy to our bodies and are one of the most important parts of our diets. They give us a steady source which keeps us going for a while. Too little carbs and we feel tired and lack energy, but too much may lead to obesity (over time), but in short term we have too much energy.
sources and purposes of proteins
Protein
(e.g meats like sausage or fish, but also things like nuts) Proteins are required to build up new cells, growth or muscle. They also form antibodies as part of our immune system. This is an incredibly important part of our diet.Too little can result in stunted growth, disease or bad immunity. However, too much can mean obesity, and sometimes, organ damage
sources and purposes of lipids
Lipids
(e.g. avocado is a fruit which is very high in lipids, but other examples of lipids are things like butter) Lipids, put simply as fat and oils, is a long term energy storage. They also form protective layers around important organs and keep us warm. They make up a smaller proportion of our diet but are still important. Too little causes fatigue or starvation (extreme case), but too much can mean obesity, heart disease or increased risk of cancer.
purposes of vitamins in general
Vitamins
Vitamins help to keep specific tissues in the body strong, keeping us healthy. A lack of vitamins can cause certain disease It is hard to have an excess of natural vitamins, but overdoses of vitamin supplements can cause long term damage.
effect of pH on enzymes
also denatures if pH is not right. Most enzymes optimum pH is around 7 but some exceptions, e.g. Pepsin with optimum pH of 2 cause it works in stomach (acidic place)
uses and sources of vitamin A
Vitamin A - used for vision, growth, reproduction, immunity + cell division (found in vegetables, fish oils, etc)
uses and sources of vitamin C
Vitamin C - reduces risk of heart disease and dementia, lowers blood pressure, protects body against free radicals (citrus fruits, broccoli etc)
uses and sources of vitamin D
Vitamin D - help body absorb and retain calcium and phosphorus (the sun, fish, egg)
