ch 3 Food Flashcards
what are the elements present in food ?
c, h, o, n, (p, s)
why is food necessary?
as a source of energy
growth and repair etc.
what are the elements present in dissolved salts?
sodium, magnesium, chlorine, potassium, calcium.
what are the three trace elements?
iron, copper, zinc
only required in tiny amounts
what are biomolecules?
chemicals that are made inside a living thing.
carbohydrates - elements
what is the ratio?
formula?
example?
c, h, o
2:1
Cx(H2O)y
glucose C6H12O6
what are the three types of carbs?
monosaccharides
disaccharides
polysaccharides
what are monosaccharides?
single sugar unit, simplest carb, water soluble
what is a disaccharide?
composed of two sugar units joined together, water soluble e.g. maltose
what is a polysaccharide?
composed of many sugar units, insoluble in water, very large molecules, e.g. starch
structural role of carbs
cellulose is used to form plant cell walls.
metabolic role of carbs
glucose is broken down in respiration to produce energy.
lipids - elements
ratio?
temp?
structure?
c, h, o
no simple ratio, very little oxygen
fats = SOLID at room temp
oils = LIQUID at room temp
triglyceride - glycerol linked to three fatty acids
what is a phospholipid?
fat like substance in which one of the fatty acids is replaced by a phosphate group.
what is the structural role of lipids?
lipids are important food stores in plants and animals.