module 2: biological molecules Flashcards
why is water needed
reactant in chemical reactions
a solvent
transports substances
temperature control- high SHC and high LHOE
habitat- less dense when freezes
structure of water
1 oxygen 2 hydrogen
polar molecule- negative O positive H
hydrogen bonding
properties of water
high specific heat capacity
high latent heat of evaporation
polarity causing cohesion
good solvent
less dense when solid
structure of alpha glucose
hexose monosaccharide
ADDUD
structure of beta glucose
hexose monosaccharide
BUDUD
structure of ribose
pentose monosaccaride
RUDD
what are the disaccharides
maltose- a glucose + a glucose
sucrose- a glucose + fructose
lactose- b glucose + galactose
what is starch made from
amylose
amylopectin
describe amylose
long unbranched chain of alpha glucose
coiled structure
compact so good for storage
describe amylopectin
long branched chain of alpha glucose
side branches allow enzymes to break down glycosidic bonds easily for quick energy
describe glycogen
main energy storage in animals
long branched chain of alpha glucose
compact
describe cellulose
long unbranched chain of beta glucose
straight cellulose chains
chains held by hydrogen bonds
structural support
what are triglycerides
energy storage in plants and animals
1 glycerol
3 hydrocarbon fatty acid tails
synthesised by ester bond
hydrophobic heads hydrophilic tails
what is the difference between saturated and unsaturated fatty acids
saturated- don’t contain double carbon bonds
unsaturated- have double carbon bonds
structure and function of phospholipids
1 glycerol, 1 phosphate groups 2 fatty acids
found in cell membranes- phospholipid bilayer
heads are hydrophilic
tails hydrophobic
makes centre of bilayer hydrophobic acting as a barrier
structure and function of cholesterol
hydrocarbon ring structure with hydrocarbon tail
has polar group attached
regulate fluidity of membrane
small and flat
at high temps they pack together causing rigidity
what are proteins made from
long chains of amino acids
one or more polypeptides
structure of an amino acid
central c
carboxyl group
amino group
variable group
joined by peptide bonds
what is primary structure
the sequence of amino acids in polypeptide chain
what is secondary structure
coiled alpha helix or folded beta pleated sheet caused by formation of hydrogen bonds
what is tertiary structure
coil of folding of secondary structure forming 3D structure
uses ionic bonds, disulphide bonds, hydrophobic and hydrophilic interactions
hydrogen bonds
what is quaternary structure
several polypeptide chains held together by bonds
final 3D structure
describe globular proteins
soluble so easily transported
round and compact
examples and description of globular proteins
haemoglobin- conducted protein containing iron prosthetic group
insulin- hormone consisting of 2 polypeptide chains
amylase- enzyme that brakes down starch
describe fibrous proteins
insoluble
strong and rope like
unreactive
examples and description of fibrous proteins
collagen- in connective tissue
keratin- in hair, skin, nails
elastin- is elastic connective tissue, recoils
what are inorganic ions
an ion that has electrical charge
positive- cation
negative- anion
don’t contain carbon
test for reducing sugars
Benedict’s
add Benedict’s reagent to sample and heat it in water bath
if positive test goes from blue to green to yellow to orange to brick red
test for non-reducing sugars
add dilute hydrochloric acid to new sample and heat
neutralise with sodium hydrogencarbonate
carry out normal Benedict’s test
test for starch
iodine- if starch present it will turn brown-orange to blue-black
test for proteins
biuret- add sodium hydroxide to sample then copper sulphate
if protein present- blue to purple
test for lipids
emulsion test- shake sample with ethanol and pour into water
if lipid present- clear to milky
