Food Flashcards
biomolecule
organic chemical produced and found only within living organisms
metabolism
the sum of all chemical reactions in an organism
anabolic
energy is required to convert smaller molecules into larger molecules eg photosynthesis, protein synthesis
catabolic
energy is released to convert larger molecules into smaller molecules eg respiration, digestion
why do we need food
energy source for respiration
for growth and repair of cells
chemical elements in food
carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur
salts of
sodium, magnesium, chlorine, potassium, calcium
trace elements
iron, copper, zinc
biomolecules
- carbohydrates
- lipids
- proteins
- vitamins
carbohydrates
composed of carbon, hydrogen, oxygen
C6H12O6
structural role of carbs
cell structure:
cellulose- found in plant cell walls
chitin- found in fungal cell walls
metabolic role of carbs
glucose- broken down to release energy in respiration
glucose- stored as glycogen in animal muscles after respiration
starch- stores glucose after respiration
types of carbs
monosaccaride- glucose,fructose (fruit)
disaccharide- sucrose, lactose (table sugar, milk)
polysaccharide- starch, cellulose (bread, cereal)
lipids
composed of carbon, hydrogen,oxygen
general structural components: fatty acids and glycerol
lipids examples
fats
oils
steroids that include cholesterol
some sex hormones`
sources of lipids
butter
sunflower oil
structural role of lipids
in cells: phospholipids are major components in cell membranes
in an organism: energy store/protection of organs/ heat insulation
types of lipids
triglycerides- 3 fatty acids 1 glycerol
phospholipids- 1 fatty acid is replaced by a phosphate group
sources of protein
lean meat, fish, eggs
composition of protein
carbon, hydrogen, oxygen, nitrogen
long chains of amino acids (20) joined together by peptide bonds/polypeptide chains
protein shapes
globular: lots of folding eg enzymes, albumin in egg white
fibrous: no folding eg keratin in hair and nails
structural role of proteins
keratin found in hair and skin
myosin in muscles
metabolic role of proteins
all enzymes are proteins: biological catalysts that control photosynthesis and respiration
hormones regulate body functions eg insulin regulates blood sugar levels
vitamins
needed in small amounts, cannot be produced by the body
vitamin c
ascorbic acid water soluble function: build connective tissue maintain bones and teeth good immune system function source: citrus fruits, green veg deficiency: scurvy symptoms: soft bleeding gums
vitamin D
calciferol fat soluble function: needed to absorb calcium from food forms bone source: dairy fish liver oil, egg yolk deficiency: rickets in children osteomalacia in adults symptoms: bones lose calcium and become weak bones break easily
minerals
inorganic and required in small amounts
plants absorb minerals through roots
animals get their minerals from food they eat
calcium (plant)
to form middle lamella between cells (cell wall)
magnesium (plant)
to form part of chlorophyll
calcium (animal)
forms bone and teeth
iron (animal)
forms part of haemoglobin
water
cells and body fluids are made of 70% water in animals, 90% in plants
importance/uses of water
universal solvent that transports substances in plants or blood, allows substances to move between membranes
Where all metabolic reactions take place: component of cytoplasm, controls shape of cell by osmosis
It is a reactant/product in chemical reactions: source of oxygen produced in photosynthesis
to test for starch
iodine solution and starch solution
blue/black if present, red/brown if not
to test for a reducing sugar
benedicts solution and glucose
brick red if present, stays blue if not
to test for fat
brown paper and oil
translucent if present, not if not
to test for protein
biuret reagent and milk
purple if present, blue if not
