carbs and lipids Flashcards
monomers =
smaller units from which larger molecules are made
polymers =
molecules made from a large no. of monomers joined together
condensation reaction =
joining two molecules, creating a chemical bond & removing a molecule of water
hydrolysis reaction =
breaks a chemical bond between 2 molecules & involves the use of water
hydrophobic =
repels water
elements in carbs
C, H, O
monosaccharides
monomers which form larger carbs
common monosaccharides
•glucose
•galactose
•fructose
isomer =
same molecular formula, diff. structure
what are glucose’s 2 isomers?
•alpha glucose (H, OH)
•beta glucose (OH, H)
disaccharides =
2 monosaccharides joined together by a glycosidic bond, formed by a condensation reaction
disaccharide formulas
•glucose + glucose —> maltose + water
•glucose + galactose —> lactose + water
•glucose + fructose —> sucrose + water
polysaccharides
created by condensation reactions between many glucose monomers
starch (polysaccharide)
•monomer = alpha glucose
•bonds between monomers = 1-4 glycosidic bonds (amylose),1-4 & 1-6 glycosidic bonds (amylopectin)
•function = stores glucose
•location = plant cells
•struc. = amylose —> unbranched helix, amylopectin —> branched molecules
•how the struc. helps the function =
-insoluble —> water potential not affected
-amylose —> helix can compact to fit lots of glucose in a small space
-amylopectin —> branched so increases S.A for rapid hydrolysis back to glucose
cellulose (polysaccharide)
•monomer = beta glucose
•bonds between monomers = 1-4 glycos. bonds
•function = structural strength in cell walls
•location = plant cell walls
•struc = polymer forms long straight chains —> chains held in parallel by many H bonds, forming fibrils
•how the struc helps thr functions =
-insoluble —> water potential not affected
- the many H bonds provide collective strength
glycogen (polysaccharide)
•monomer = alpha glucose
•bonds between monomers = 1-4 & 1-6 glycos. bonds
•function = stores glucose (energy)
•location = animals (mainly in muscle & liver cells)
•struc = highly branched & coiled molecule
•how the struc helps the function =
-insoluble —> water potential not affected
-branched struc —> increases S.A for rapid hydrolysis back to glucose
saturated =
contains only single bonds
unsaturated =
contains at least one C=C double bond
elements found in lipids
C, H, O, P
name the two types of lipids
•triglycerides
•phospholipids
the formation of triglycerides
-formed via a condensation reaction between 3 fatty acids + 1 glycerol (1 glycerol = three hydroxyl groups attached to one carbon)
-an ester bond is formed between the glycerol & each fatty acid
(R groups of fatty acids may be saturated or unsaturated)
functions of triglycerides (& how they relate to the structure)
- energy storage —> large no of energy-storing carbon-hydrogen bonds
- metabolic water source —> can release water if oxidised > high ratio of hydrogen to oxygen atoms
- water potential stays same —> large & hydrophobic
formation of phospholipids
-formed via condensation reactions between 1 glycerol + 2 fatty acids
-has phosphate group too
function of phospholipids
- form bilayer —> head = hydrophilic (attracts water bc it’s charged) so head is exposed to water, fatty acid tail = hydrophobic (repels water bc of no charge)
- h20 soluble substances can’t pass through centre of bilayer —> hydrophobic
test for starch
- add iodine
- colour change to blue/black
test for reducing sugar
- (mash sample if solid)
- heat w benedicts reagent
- colour change to red
test for non-reducing sugars
- heat w benedicts —> no colour change
- add dilute hcl (hydrolyses glycosidic bond)
- then add sodium hydrogen carbonate (neutralises sol.)
- heat w benedicts —> colour change to red
test for lipids
> add ethanol, then water + shake
milky emulsion
use of a colourimeter to improve the repeatability of results
- quantitative
- standardises the method
