BIOLOGICAL MOLECULES
Monomer Thesmaller units fromwhich largermolecules are made
Polymer molecules made from a largenumber of monomers joined together
POLYMER MONOMER
carbohydrates monosaccharides
proteins aminoacids
construal nucleotides
nucleicacids
condensation reaction where 2 molecules joined together and water is eliminated forming
a chemical bond glycosidic ester peptide phosphodiester
Hydrolysisreaction wherewater is added to break a chemicalbondbetween 2 molecules
Lipidsmade of glycerol 3ft they arenotmonomers as notchainof repeatingmonomers
Carbohydrates
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CHOonly
carbs
simplesugarscarbs complexsugars
anaemia polysaccharides
mmmm
a Bsiucose maltose glycogen
galactose lactose starch
cellulose
MONOSACCHARIDES
monomer of carbohydrates
eg glucose galactose fructose
generalformula Chao n
Glucose 2isomers
CoHiro hexose sugar 6carbons
Alphaglucose o
iHzOH
Es o
on position
Ho
I c'it
94
c at
H OH
2 Beta glucose
is
iHzOH
i o
OHposition
Ho
c
g CI
C c
µ g
Disaccharides
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maltose sucrose lactose
tu catween
formed by condensation of 2 monosaccharides formingglycosidicbond
releasing H2O
formula 1242201 2x C6Hiz06 H2O
monosaccharide polysaccharide
glucose glucose maltose
glucose t galactose lactose
glucose fructose sucrose
eg of condensation
2 glucose x
c
glucoseTi
Q
c
H H a C O
e
formsH2O bindsto C1
onothermolecule
toformglycosidicbond
v
c O
e É o d c o
f
t H2O
l c e e
maltose
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weenaries
glycogen starch cellulose
structure ofglycogen starch x glucose
C o
Hic
Ho c c
d o c
c c
d o d
I 9 city
Starch
plant carb store stored as starchgrains in plastids eg chloroplasts
Amylose
spiral structure less common
ALL 1 4 glycosidic bonds not branched Mr
Amylopectin
more common
I 4 and 1 6 so highlybranched FEI
nose
carbstorage in animals g
I 4 and 1 6 highlybranched same structureas amylopectin mmmmm
but soluble
Glycogen Starch
Insoluble doesnt affect 4 up Insoluble doesntaffect 4
commisact
Compact as branched due to spiralshape
Branched more ends for Large cannot leave cell through Csm
glucoseto be released for respiration bramatiched
more ends for glucose to
be released for respiration
Cellulose
monomer B glucose
Only 1 4 bonds alternate B glucose flipped so chain is straight
o
E o c c
ti on q
structure related to function
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Long straight chains of B glucose
are held to by H bonding which is strong in largenumbers
to form fibrils
these provide strength rigidity I support so eg cell wall wont burst
Carbohydrate Tests
1 Reducing sugars all monosaccharides lactose maltose
semi quantitative subjective as wedeciphercolour
1 Add Benedict's reagant
2 Heat
Low conc stays blue
High conc brickredsolution
2 Non reducing sucrose rest of disaccharides
sugar
1 Do benedict's test t it stays blue
2 Add HCl t boil
3 Add sodium hydrogen carbonate to neutralise
4 Add benedick heat
5 Becomes brickred
NOTE brickred precipitate
tomake it quantitative use colorimeter or filterppt t weigh
3 Starch
1 add iodine solution
2 turns blue black
t using calibration curve to find unknown conc of sugars
carry out benedict's test on sugar solutions of known concentration
measure absorbance of each on colorimeter
plot graph with concentration on x axis and absorbance on y axis
do benedicts on unknown sample find absorbance
use graphto find sugar cone from that absorbance
Lipids
insoluble in H2O soluble in ethanol
Uses
waterproof way cuticles
adiposetissueunderskin reducesheatloss
electricalinsulation myelinsheath
adipose tissuearoundkidneys reduces shock protection
Made of FA t glycerol phosphate group
Structure of fatty acids
Carboxyl group COOH attached to hydrocarbon chain R group
I R or foie
It H
R group can differ in length
R group can contain C C doublebonds
Fatty acid can be mono di poly unsaturated
Structure of glycerol
3 carbons 3 OH rest H
condensation between OH on glycerolt OH on carboxyl phosphategroup
H
H G OH
H
g OH
H C OH
I
Triglycerides
Insoluble hydrophobic non polar has CHO only
Glycerol t 3 Fatty acids
condensation forms esterbond
H
ÉÉÉi
I HI E d
OH R H o d R t 3420
on I R n c o É R
H
Glycerol 37A Triglyceride
Phospholipids
One fatty acid replaced byphosphate group
has CHO t Pgroup Insoluble
polarphosphategroupmakeshydrophilic head
fatty acids make hydrophobic tails
formbilayer in water
P H hydrophilic head
H G
1
My
hydrophobictaels
Differences between triglycerides phospholipids
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Both containesterbonds glycerol FA
FA on both maybe unsaturated or saturated
phospholipids have 2ft and P group triglyceridesonly have 3FA
both have CHO but phospholipids alsohave P
both insoluble
phospholipidsformbilayer in water triglycerides dont
triglycerides are hydrophobic nonpolar lipshave hydrophobict hydrophilic
phospho
regions
Test for lipids lipidemulsiontest
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1 Add ethanol t shake todissolvelipid
2 Add water
3 whiteemulsion forms
Proteins
aminoacidmonomer 20types
Made of C H O N sometimes s
amine group one end Naz carboxyl groupotherend COOH
amino acid dipeptide polypeptide
structure
H
N É E
H OH
R
side chain
determines which AA it is
can contain sulfur eg cysteine
condensation between amine carboxyl groups
forms peptide bond between C N
OH on carboxyl t H on amine form H2O
H
H
N C c N c c
H OH R on
k H
yo
t
n c É it it ca
OH
H R R
peptidebond
Protein Structure
PrimaryStructure
Thespecificnumber sequence of amino acids
If thereis a change
number t sequenceof AA changes
H ionic I disulfidebonds form in different places
30structure changes
Secondary structure
Hydrogenbondsbetween NH in amino acid and c o of another
forms alpha helix or beta pleated sheet
mm
Tertiary structure
The FOLDED 3DSHAPE Of POLYPEPTIDEchain
bonds that form 30structure
WEAK D H bonds
weak strongin largenumbers
2 Ionic bonds
between oppositelycharged side groups
STRONG 3 Disulfide bridges
between 2 sulfuratoms in side groupof cysteine
4 extra Hydrophobicinteractions
Quarternary Structure
The way 2 or more polypeptidechains are assembled together
Prosthetic nonprotein groups can associatew protein tomake conjugated protein
Types of protein
Fibrous proteins
eg collagen Keratin silk
30 tightly wound helix
40 3 of thesechains boundbycrosslinks woundtg in ropelike fashion
Strong hightensilestrength insoluble structural functions
Globular proteins
Spherical t soluble as hydrophilicgroups outside hydrophobic inside
metabolicfunctions eg enzymes transport proteins hg
Test for proteins
1 Add Bioret's
reagant
2 solution turns purple
Enzymes
Biological Catalysts
reduces AE so faster reaction
bystressing bonds explaininduced fit
reaction can happen at lower temp
Specificity of enzymes
enzymes have a specific 30 structure
So active site is complementary only to substrate
onlythe substrate can fit
to form enzyme substrate complex
Induced Fit Model explainshowtheylower AE
before reaction As not complementaryto 1doesnt fit substrate
when substrate binds AS changes shapet mouldsaround substrate
to form enz sub complex
this stresses bonds to lowerAE
Factors affectingenzyme action
I emperature
Atc
hightemp highKE
causesH bonds to break
30structure ofenzymechanges itis denatured
1
rate
µ state no longer fits
no more e s complexes
temp
At A
tempincreases rate 1 optimumtemp
KEof enzyme substrate4 highest KEwithout denaturation
theymove faster mostfrequentcollisions
morefrequentcollisionsbetweenthem comes
morefrequent enzsubcomplexes fastest rate of reaction
more at more
more Oli morealkaline higher pH
a e it B C
C largepH change
breaks Hbonds ionicbonds
rate 30structurechanges shape ofAschanges
substrate no longer fits
no es completes
PH
At A optimumpH BslightpHchange
most frequent collisions alters chargesonactivesite
most frequent escomplexes harder for substrate to fit bind
less es complexes
3 Enzyme concentration
T
rate gradalwaysdecreasing
conc
At A
enzyme conc I rate t
enzyme conc 4 rate stays level
more frequentcollisions notenough substrate to make es completes
more frequent es completes
enzi has no effect rate stays level
rate of reaction 7
limiting factor substrate conc
m
4 Substrate concentration
B
race
grad decreasing
conc
At A At B
sub M rate T sub conch rate level
more frequent collisions as all AS are saturated all in
enzymes
more frequent es completes Acone has no effect on rate
rate A
Inhibitors
prevent binding of substrate to AS
fewer enz sub completes
competitive
Similar shape to substrate
can bind to active site instead of substrate competes
fewer available As less frequent e s completes less product made
can be overcome by adding more substrate outcompeted
Outcompete
comp
no
F
conflowra
non competitive
attaches to enzyme somewhere other than active site
Changes 30 structure shape of AS
As no longer complementary to substrate no binding no es completes
cannot be overcome by adding more substrate
finna.com
changedshape
slowrate
mostlyaskedabt increase
Allosteric effectors canincrease lower rate
binds to allosteric site of enzyme
changes 30 structure and shape of AS
now more frequent es completes lowers AE rate4
End product inhibition
metabolic biochemical reaction pathway many consecutive reactions
where the product of one is the substrate of the next
inhibitor to enzyme at start of pathway
regulates product levels
pH calculations
whylogarithmicscale
so wide range of values can fit on graph
pH log Ht
PH
Ht IO
RPI effect of named variable on enzyme
How to measure rate volume of product formed
substrate used
d
If DU is time rate fine arb units
If Du is volume rate Avolume
time
Graphs
IV DU y axis
x axis
If DV volume Iv time rate gradient of tangent at point on curve
Higher absorbance more opaquesolutionin colorimeter
use opposite colour filter on colour wheel red blue
KeeppHconstant pHbuffer
Keep tempconstant water bath equilibrate t measuretemp throughout
repeats identifyanomaliest calculate reliable mean
when do we not disregard anomaly when studying animal humanbehaviour
DNA deoxyribonucleic acid
nucleotidemonomer holds genetic info
Scientists initiallydoubled DNA carried the genetic code dueto its
relativesimplicity
Scientistswhomadethis model I Watson crick
phosphategroup
Mom base Ac a y
In deotyribose
condensation reaction between p group of one nucleotide and deoxyribose
nucleotidestrand Bond betweennucleotides phosphodieste
ofanotherforms poly
H bonds between complementarybases A T G C hold 2 strands together
to form 1 DNAmolecule doublehelix
2types of bases
1 pyrimidine singlering cytosine thymineC uracil
2 purine double adenine guanine
ring
complementary base pairing
purine is complementary topyrimidine
At T u form 2 H bonds
C G form 3 Hbonds
In one DNAmolecule the abundance of a base is equal to the abundanceof
its complementary base
nucleotidestrands are anti parallel
Two poly
parallelbut run in opposite directions
either 3prime 5prime or Sprime 3prime
as phosphodiesterbondisbetween carbons 3 5
Structure of DNArelated to function
Longmolecule so stores alot of information
Sugar phosphate backboneprovidesstrength protects bases
Doublehelix so compact
Weak H bonds so DNAunzippedeasily forreplication
Double stranded so eachstrandcan act astemplate and replication can occur
semi conservatively
Contains base sequence whichstoresinto codes for aminoacids
Semi conservative replication
S phase of interphase
Semi conservative newmoleculeseachcontainstrand fromoriginal molecule
each strand acts as a template
Fastest in bacteria smallamounts of DNA notpackaged withhistoneproteins
DNAhelicasebreaks H bonds betweencomplementarybases
Eachstrandacts as a template
Freenucleotides attach bycomplementary base pairing
DNA polymerasejoins new nucleotides together on new strand formingphosphodiester bonds
H bonds form betweencomplementarybases
New DNAmolecule contains one old strand t one newstrand
Anti parallel replication
AsDNAantiparallel one newstrand is 3 5 one is 5 3
However nucleotides canonly bejoined in 5 3 direction This is because
DNA polymerase is specific
enzyme
ASonly complementary to 5 end of polynucleotide strand
3 end and S end have different shapes cant bindto 3 end
For the new 3 5 strand
called LAGGING strand
enzyme skips a fewnucleotides thenmoves in opposite S 3 direction
joined DISCONTINUOUSLY 3 s
joined in segments OKAZAKI FRAGMENTS
Evidence of semi conservativereplication
Meselson Stahl experiment
1 DNA grown in N's medium so nitrogenous bases contain N's
N's heavy so whencentrifuged band is at bottom
Y
2 DNA transferred to n medium and allowed to replicate
all freenucleotidebases containv14
3 After replication both first
genmolecules have I N's strand I n strand
middleof centrifugetube movesup
4 2nd 2 molecules with N's v14
gen
2 molecules with w wit
proves semi conservative as each new contains one old new shownby rise in
centrifugetube lessheavy
RNA ribonucleic acid
monomer nucleotides
phosphate group ribose sugar nitrogenous base A V G C
uracil notthymine
Pgroup
P ribose
base
Differences with DNA
about
RNApentose sugar is ribose not deoxyribose
nucleotide
I put contains uracil not thymine
RNA single stranded DNA double stranded
RNA is a smaller shorter molecule
Uses
1
MRNA messenger transfers genetic info from DNA to ribosomes
2 ERNA transfer carries AA to ribosomes in PS
anticodon comp to mRNA codon
VirusDNAdifferenttohumanDNA
unequalamount of Att and Cto
nobasepairing
viralDnasinglestranded
ATP adenosine triphosphate
nucleotide derivative modified form pentosesugar p group nitrogenous base
made of ribose adenine and 3 phosphategroups
bose
hoy adenine
Phosphate
a inorganicphosphate
Hydrolase
ATP
ATP t H2O synthase
App pi t E
Atp
Hydrolysis Housed condensation H2oreleased
ATPase refers to ATPhydrolase ATPsynthase
Resynthesis of ATP
condensationreactionbetween ADP t Pi using ATPsynthase releasingATP H2O
during Puss respiration
ADP Pi ATP
ATPsynthase
3ways to synthesise ATP from ADP
photo
phosphorylation photosynthesis
oxidative phosphorylation respiration
substratelevel phosphorylation
Why is ATP a goodenergy store
only one step reaction needed to hydrolyse ATP to release energy
easily reformed dont saywhenasked 2marker
energy is released in manageableamounts
can phosphorylate addphosphateto othersubstances to makethem more reactive
How the hydrolysis of ATP is used in cells
releases energy to beused in other reactions egactivetransport
phosphorylates othersubstances tomake them more reactive
Water
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st
0
ft
H th
g nos
H H H H
POLAR
Held by H bonding between molecules
Useful properties
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It is a metabolite in condensation hydrolysis photosynthesis respiration
It is a good solvent as polar
metabolic reactions occur faster in solution
allows transport of substances
High SHC so can gain losealot ofheatenergywithout changingtemperature
buffers changes in temperature remains stable enzymes wontdenature
High latentheat of evaporation so alot of heatenergyneeded to evaporate it
provides coolingeffectthroughevaporation with little water loss
Cohesion between molecules due to H bonding
supports columns of water in plants
provides surface tensionwhere watermeets air supports small organisms
Floats when solid ice
maintains aquatichabitatbeneath fish t plantsdontfreeze CANMOVE
Transparent
Allows lightthrough for photosynthesis
Water revision
metabolite
good solvent
why
HighSHC
meaning
whyuseful
high LHofevaporation
cohesion between molecules
floatswhensolid
transparent
