3.1 Biological Molecules Flashcards
define monomers
smaller units from which larger units are made
define polymer
made from larger no. of molecules joined together
define condensation reaction
joins two molecules together
formation of a chemical bond
releasing a molecule of water
define hydrolysis
breaks a chemical bond
between two molecules
involves using a water molecule
what are monosaccharides
monomers from which larger carbohydrates are made
glucose
fructose
galactose
how are dissacharides formed + list the equations
condensation of two monosaccharides
glucose + glucose = maltose
glucose + fructose = sucrose
glucose + galactose = lactose
draw the isomers of glucose
search
how are polysaccharides formed
condensation of many glucose units
structure + function of glycogen
function: energy strore in animal cells
structure: polysaccharide of a glucose
1-4, 1-6 glycosidic bonds
branched
structure related to function of glycogen
branched ; lots of active sites to be rapidly hydrolysed by enzymes for quick release of glucose for respiration for energy
large ; can’t leave cell
insoluble ; doesn’t affect water potential of cell
strucutre + function of starch
function: energy store in plant cells
structure: a glucose
made of amylose + amylopectin
amylose; 1-4 unbranched
amylopectin; 1-4, 1-6 branched
structure related to function starch
helical ; compact for storage
large; can’t leave cell
insouble; no osmostic affect on wp of cell
structure + function of cellulose
function: provides strength + structural support to plant cell walls
structure: b glucose
long, straight, unbranched cellulose chains
H bonds link parallel strands to form microfibrils
H bonds strong in numbers
provides strength + structural support to plant cells
benedicts test for reducing sugars
- add benedict’s reagent to food sample
- heat in boiling water bath
- positive = brick red ppt
benedicts for non reducing sugars
- add dilute HCL
- heat in boiling water bath
- neutralise with sodium bicarbonate
- normal benedicts
- positive = brick red ppt
determing glucose conc
- produce dilution series of glucose conc of known conc
- benedicts test on each sample + remove ppt
- use calorimeter, measure absorbance, establish calibration curve
- repeat with unknown sample + compare absorbance
iodine test for starch
add iodine dissolved in potassium iodide
shake/stir
positive = blue/black colour
how are triglycerides formed
condensation of
1 molecule of glycerol
3 molecules of fatty acids
forming an 3 ester bonds
the R group of a fatty acid can be
saturated - no c=c bond in hydrocarbon chain
unsaturated - one or more c=c bond
how are phospholipids formed
one of the fatty acids is substituted
by a phosphate group
emulsion test for lipids
add ethanol to sample
then shake
then add water
positive = milky/white emulsion
properties of triglycerides related to their structure
energy store - high ratio of c-h bonds to c atoms
release more energy than same mass of carbohydrated
insoluble in water - no effect on wp