biomolecules - summary
DESCRIPTION
notesTRANSCRIPT
Raffles Junior College Core Syllabus - BioMolecules JC22008
EXAMPLES of CARBOHYDRATES
1 GLUCOSE 2 GALACTOSE 3 FRUCTOSE a-glucose i3-glucose
s CHOHo J o (f)
HOH2Q1C0 8
2 5r ~ Ci 3 4 6CHPHCD (f)
H OH H OH H OH Fructose = C2 contains
Glucose amp Galactose = C1 contains aldo gp (making them aldehydes) keto gp (making it a ketone)
1 MALTOSE (0-1 4 glycosidic bond) a-glucose + a-glucose ~
CHOH CHOH o middot (ii
() () r ~ Ci CD (f)
I I H OH H OH
maltose
-eH~H
+
2 LACTOSE (13-14 glycosidic bond) f3-galactose + a-glucose 3 SUCROSE (0-12 glycosidic bond) a-glucose + f3-fructose
1 STARCH (plant) - a-glucose monomers Amylose Amylopectiin
middotgt middot9 tJ+~ branches of helices tilcfJ linked by 0-16 glycosidic bon~s
d4 ~ middotNall monomers within helix Vt all monomers within helix
linked by 0-14 glycosidic bonds linked by 0-14 glycosidic bondseX) ~
2 CELLULOSE (plant) - f3-glucose monomers 0 o all monomers within chain linked by 13-14 glycosidic bonds-lt(f) ~ making every altemate monomerresidue
() () inverted in orientationr ~ Ci CD straight chains cross-linked by H bonds (interchain)(f)
3 GLYCOGEN (animal) - a-glucose monomers fI ZL branches of helices ~W~~
linked by 0-16 glycosidic bonds ~ ~~~ IltJ all monomers within helixJ linked by 0-14 glycosidic bonds
Last uodated by Mrs Maodatene Tan amp Mrs Jeanne Wan
COMMON FEATURES
1 All are hexoses (6C) 2 All carry one carbonyl gp
(either aldo- or keto- gp) 3 Can exist as 6 or 5shy
membered ring 4 Ring structures exhibit
a- and 13- isomerism (OH grp at C1 a - below
j3 - above) 5 Soluble sweet 6 All are reducing sugars 7 Basic unit of carbohydrates
1 Made up of 2 monomers 2 Monomers link to each other
via condensation reaction to produce a disaccharide and a H20 molecule ~ via various types of glycosidic bonds
3 Splitting of a disaccharide into its component monoshysaccharides via hydrolysis and uses 1 Hp
4 All are reducing sugars except sucrose
1 Made up of 1OOs - 1000s monomers
2 Monomers link to each other via condensation reaction to produce a polysaccharide and H20s ~ via various types of glycosidic bonds
3 Splitting of a polysaccharide into its component monoshysaccharides via hydrolysis and uses H20s
4 Generally categorised based on function into (i) STORAGE Polysaccharide (starch amylose amp amylopectin glycogen) amp (ii) STRUCTURAL polysaccharides (cellulose)
STRUCTURE ~ FUNCTION
1 Small MrSmall in size + many OH groups extending out of the ring ~ readily soluble in water + easily transported in animal and
plant transport systems 2 Carbonyl group ~ possess a reducing property
3 Exhibits isomerism ~ contributes to diversity of monomers ~ diversity of
polymers
1 Small MrSmall in size + many OH groups extending out of the rings ~ readily soluble in water + easily transported in transport
systems (esp in plants sucrose) 2 Some possess a free carbonyl group ~ possess a reducing property (except sucrose)
STARCH (amylose) - Storage 1 Made up of many a-glucose residues ~ large energy store ~ insolubleslightly soluble in water 4J w of cells unaffected
2 Linear chains coiled into helices ~ possibly more compact more molecules per fixed voL
3 0(1 ~4) glycosidic linkages between residues ~ hydrolysis via specific enzymes when needed
CELLULOSE - Structural 1 Made up of many f3-glucose residues ~ large insoluble and will not affect 4Jw of cells
2 i3(1~4) glycosidic linkages ~ hydrolytic enzymes limited to certain organisms so not
commonly hydrolysed (~ source of our dietary fibre) 3 Each residue is rotated 180middot making every altemate
residue inverted in orientation ~ OH groups project outwards in all directions ~
H-bonds with adjacent parallel molecules ~ H-bond cross-linking between cellulose molecules ~ rigid structure with high stability
4 A structural hierarchy present (molecules ~ microfibrils ~ macrofibrils) ~ reinforces structure to give high tensile strength ~ fully permeable mesh of several layers ~
free movement of water and solutes GLYCOGEN - similar to amvlose but more highly branched
AMINO ACIDS AMINO ACIDS (MONOMERS) -7 POlYPEPTIDES (POLYMERS) -7 PROTEINS EXAMPLES OF PROTEINSSTRUCT -7 FN
Properties of amino acids -0 1 Unique sequence and number of amino acids Hierarchy of protein structure 1 Form long chains 1 Basic unit of proteins sect in a polypeptide 2 Stable regular structure
ltQ PGbull lt Primary structure2 20 different aa in cells III 2 Linked by covalent peptide bonds 3 Insoluble in water 3 All possess 1 a carbon atom bonded to -lt 3 Eg of a portion of a primary structure 0 rl r 4 Secondary structure important M)Pdy ~ H H
- 1 carboxyl group ~ - gly - ser - his - val - gly - ala - 1 t~ 1 i V S Usually play structural role - 1 amino group 1i 4 The secondary tertiary and quaternary I)LI ~ ri - 1 H atom ~ structures are hence direct consequences of COLLAGEN ~~7 C=~ - 1 R group varies with different aa and (I) the primary structure t V
can be a hydrophobic hydrophilic
0 5acidic alkaline side group) 1 Intramolecular hydrogen bonds formed at secondary structuret_ 1 Each polypeptide chain is a helix with -1000 o H regular intervals along polypeptide backbonecopy I residues-7 triple helix structure ~l VI I 0 ~ 0 (called tropocollagen) -7 large
N f- C ~ 2
backbone (CO-NH) Bonds only involve atoms
Le atoms of R groups of polypeptide H O
Hence function insoluble in water amino H R OH carboxyl W not involved ~ 2 H bonds between the 3 polypeptides -7 group group 8 4 2 types ALPHA HELIX (fj
l tropocollagen -7 covalent bonds between
R-group a -7H bonds form between Hand 0 staggered tropocollagen molecules -7 l 4 Soluble ampexists as zwitterions (have ~ atoms 4 aa apart (ie H belongs to collagen fibril -7 collagen fibre ~
f3 pleated sheetboth basic and acidic properties) ~ NH of aa1 0 belongs to C=O of aaS) Hence function no weak spot runn ing through in solution 2 -7 H-bonds 11 to longitudinal axis fibril + large bundle produce a rope-like
l of helix structure of great tensile strength ~ -73D helical structure
S Hence act as buffers -7Structure supports its STRUCTURAL function
BETA PLEATED SHEET(resists small changes in
to give firmness and to skinH I -7 H bonds form between segments of
tertiaryH~ the polypeptide which are parallel to structureH R 1 Form spherical compact shapeseach other -7 3D accordion-like sheet (Note secondary
2 less stable less regular structureH structuresH~ 1 4 key intramolecular bonds formed along can be found 3 Soluble in water wl
H
(OH ----J polypeptide (ie bonds formed within the within) 4 Tertiary structure important09OH~ ~ 09Jo- same polypeptide) -7 hydrophobic interaction S Common eg enzymes blood proteins~ ~ ltH bondsltionic bonds ltdisulphide bridges6 Each aa will have its own isoelectric iij
2 Formed at irregular intervals HIV Proteasepoint (pH at which each aa is electrically -lt 3 Bonds involve atoms of R groups only (Le the quaternaryneutral) due to unique R groups ~
hydrophobic R group of (eg ) aa1 will interact structure7 Amino acids undergo condensation 1i with the hydrophobic R group of eg aa 78 and (Note thereaction to form polypeptides The ~ hence pull the 2 aa close together) polypeptide is
Ggtreverse occurs via hydrolysis (I) just one of the subunits)-7 3D irregular contortions of the polypeptide 0 cshyAmlnoAcld NnlnoAdd l 1 Consist of two identical polypeptides (99aa)Bonds making up the tertiarv structure
H 0 H 0 ~ -7 homodimerI II I 11 o Two Arn IhQ H-N-Q--C--QH I 1 Intermolecular bonds formed between 2 orH--N--C-C--OH 0 2 Terminal domain impt for stabilising active
AddS I I III oI I more polypeptides (ie between subunits) HIVenzymeH H R2 CD
l 2 Maintained by 4 key bonds H bonds ---I~vl~pTtt~kshy 5 3 At interface of 2 domains is the active site with III tKkbr~ I1~
Condensation ionic bonds disulphide bonds hydrophobic VI specific 3D conformation - compriSing of 2gtOH -lt-er reverse hydrolysis) VI interactions others (not in your syllabus) lIydwsvn groups of three amino acids (asp-thr-gly) md ) -7 involve in catalysisPeptide bond H 0 i HO I
o I 1 I1 1 Ill -7 allows entry of water and viral polyprotein
~kkB(ltKl eshyH--H--C-+-C-- H-i-C-o--OH Un~a1J for hydrolysis of peptide bondI I i I i I
H RI H R2 -7 enzyme specificityt 3D shape of a protein may be changed by 4 2 flexible flaps guard active sites -7 excludei
a
1 Heat C~tenrnnusHmiddottermIOlS more incoming water molecules -7 this allows ~-- 3 Inorganic chemicals eg heavy metals
2 AcidsAlkalis (pH) catalytic reaction to occur
S ENZYMATIC function to cleave polyproteinsPolyptftld~ H~-~AAI-Mt~AAr-AA~ AA2--AA--AAn- ~t~ 4 Organic chemicals eg ether alcohol into functional viral proteinsS Mechanical forces
2
EXAMPLES OF LlPIDS
1 Each is made up of glycerol and fatty acids 1 glycerol + 3 fatty acids ~ 1 triglyceride (via condensation of components)
H HtOH
I Il- middotCmiddot- Oll
I H MCOIl
I-l H to -lt n lttl
1 glycerol +
~ HmiddotmiddotCmiddotmiddot OH
i r Ile OHtl
o Il If C OH
C Ir Hg Ca
ester linkagesHO M O ~
n bullbull~~ An exan1p~ orj trigyccrkle o o Iii A
HO ~O M ~ -S) v middot V 1I o
HO wO-llI i ltshy6 hydrocarbon tail
a 2 Hence a triglyceride molecule has a hydrophilic headand a hydrophobic tail lttl Il 3 Insoluble in water (exists as micelles) soluble in organic solvent
4 2 types Saturated Fat Unsaturated fat 1 lacks C=C in hydrophobic tails 1 possess 1 or gt1 C=C ~ kinks in tails 2 quite closely packed ~ solid at room temp 2 kinks prevent close packing ~ liquid at room temp 3 usually found in animals 3 usually found in plants and fish 4 eg bacon grease lard butter 4 eg vegetable oil cod liver oil
cc middotCC Cmiddot CJC O C c~O~O~cdeg OC cmiddotCcmiddotcmiddot J~9Jc ~cmiddot~c~cP ~H
1 Each is made up of glycerol fatty acids and phosphate groups 2 fatty acids + 1 phosphate grp
1l0 -OM 1I OH tI I 0 OH- P-OH
1I HO-O ~ 0
clI
phosphoester link 1-
bH
~ 1 phospholipid + 3H20
CH COO~1 ~
lHCOO OH IHJ~P-OH
Il 2 Hence it has a hydrophilic phosphate head (also cos of -ve charge) and a hydrophobic hydrocarbon tail 3 Such a property makes it an amphipathic molecule 4 Insoluble in water (exists as micelles) soluble in organic solvent 5 Exist as a phospholipid bilayer at the cellorganelle surface ie cell membrane 6 May have small variable molecules attached to the phosphate head eg choline
1 Insoluble in water soluble in organic compounds Some reproductive hormones 2 Possess 4 interconnected C rings
progesterone3 Structurally little in common with other lipids (J) 4 eg cholesterol vitamin D steroid hormones Omiddotfcen Q Cl 0 CH
y H)
cmiddotmiddoto ~ ~~~
CH 1 I t~J )
CHH
CH
testosterone (PCrt~J cJ 0-
+ 3HzO
(STRUCTURE~) FUNCTION
1 Higher HO ratlq compared to carbohydrates ~ good energy store (2x that of carbohydrates) ~ Hence animals store more energy with less
weight than plants ~ enables animals to travel around with less
weight 2 Good insulator of heat ~ used by animals to retain body heat
eg blubber subcutaneous fat 3 Good barrier of ions ~ allows saltatory conduction of nerve
impulses ~ hence increase transmission of impulse greatly
4 Protection Able to absorb impact ~ cushions vital organs for protection
5 Less dense than water ~ aquatic animals can stay buoyant in water
6 Releases water as a by-product when oxidised ~ metabolic water is a useful source of water for
desert animals or for dev of avian and retile eggs
1 Bilayers form continuous sheets ~ serve as membranes that enclose
cellorganelles allows compartmentalisation 2 Hydrophobic core selectively permeable membrane ~ allows lipid-soluble molecules to pass through
readily ~ although water is polar it can pass through
occasionally because it is small and weak in charge
~ regulates movement of ions polar molecules into and out of cell
3 Hydrophobic interactions between the molecules ~ self-sealing will reseal quickly if they are
punctured or disrupted
4-ring structure of cholesterol (within membrane) ~ regulatesmodulates membrane fluidity ~ At low temperature prevent phospholipids
from getting too close together and therefore prevents solidification of membrane
~ at high temperature prevent the membrane from being excessively fluid and unstable at higher temperatures through their interaction with phospholipids
1 Structurally similar to fats and oils only that the long-chained fatty acids are linked to long-chained alcohols Insoluble ~ 2 Insoluble in water ~ cutin coats surface of leaves to reduce water lossgtlt lttl 3 Chemically inert ~ similar concept with insectsIl
3
Il
PROCEDURE
1 Place 2 cm3 of test solution in a test tube og (l) J 2 Add equal volume of Benedicts reagent c(l) c c 3 Shake the mixture Q omiddot J ~ 4 Heat it by immersing the tube in boiling water bath for 2 minutes
lt0 ( 5 Observe the contents of the tube (J)-I c (l)
lt0 (JgtIII ~
en Q
z 1 If a negative result for Benedicts test is obtained for test solution o 2 Boil equal volume of test solution with dilute HCI for about 1 minute
to hydrolyse disaccharide to monosaccharides ~-I c (l) 3 Cool the contents of the tube Q ~ J 4 Neutralise the contents with sodium hydrogencarbonate solution
lt0 0 (J) because Benedicts regent only works in alkaline conditions c
lt0 5 Carry out Benedicts test for reducing sugar III 6 Record observations in the same format as that for Benedicts test Ul
1 Add a few drops of potassium iodide solution to 1 cm 3 of 0[ test solution (or a piece of the test specimen) S2 ~ 2 Observe any colour change III -I (l)g~
1 Place 2cm3 of test solution in a test-tube 2 Add equal volume of 5 NaOH solution OOJ cmiddot 3 Shake the mixture well
-0 (l)o ~ 4 Add 1 copper sulphate solution drop by drop shaking well (ii-l_ (l) after each drop J (Jgt(Jgt ~ 5 Observe any colour change
m 1 Place 2cm3 of absolute ethanol in a test-tuibe s III 2 Add 2cm3 of test solution to this test-tube J
0 2 Dissolve the contents by shaking vigorously o shy m 3 Add equal volume (ie 4cm3) of cold water C3 u c 4 Observe any colour change CiiJi omiddot
J
-I (l) ~
OBSERVATIONS
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The mixture turns blue-black in colour 2 The mixture remains yellowish-brown in colour
1 The mixture turns from blue to purpleviolet 2 The mixture remains blue in colour (because of the
copper sulphate solution)
1 The mixture turns a clear solution 2 The mixture turns a cloudy white suspensionan emulsion
is formed
CONCLUSIONS
1 No reducing sugars present in the test solution 2 A small amount of reducing sugars is present in the a
~ test solution
3 A moderate amount of reducing sugars is present in the test solution
4 A moderately large amount of reducing sugars is present in the test solution
5 A large amount of reducing sugars are present in the test solution
1 Non reducing sugars absent in the test solution 2 A small amount of non-reducing sugars is present in the
test solution 3 A moderate amount of non-reducing sugars is present in
the test solution 4 A moderately large amount of non-reducing sugars is
present in the test solution 5 A large amount of non-reducing sugars are present in the
test solution
1 Starch is present in the test solution 2 Starch is absent in the test solution
1 Proteins are present in the test solution 2 Proteins are absent in the test solution
1 Lipids are absent in the test solution 2 Lipids are present in the test solution
AMINO ACIDS AMINO ACIDS (MONOMERS) -7 POlYPEPTIDES (POLYMERS) -7 PROTEINS EXAMPLES OF PROTEINSSTRUCT -7 FN
Properties of amino acids -0 1 Unique sequence and number of amino acids Hierarchy of protein structure 1 Form long chains 1 Basic unit of proteins sect in a polypeptide 2 Stable regular structure
ltQ PGbull lt Primary structure2 20 different aa in cells III 2 Linked by covalent peptide bonds 3 Insoluble in water 3 All possess 1 a carbon atom bonded to -lt 3 Eg of a portion of a primary structure 0 rl r 4 Secondary structure important M)Pdy ~ H H
- 1 carboxyl group ~ - gly - ser - his - val - gly - ala - 1 t~ 1 i V S Usually play structural role - 1 amino group 1i 4 The secondary tertiary and quaternary I)LI ~ ri - 1 H atom ~ structures are hence direct consequences of COLLAGEN ~~7 C=~ - 1 R group varies with different aa and (I) the primary structure t V
can be a hydrophobic hydrophilic
0 5acidic alkaline side group) 1 Intramolecular hydrogen bonds formed at secondary structuret_ 1 Each polypeptide chain is a helix with -1000 o H regular intervals along polypeptide backbonecopy I residues-7 triple helix structure ~l VI I 0 ~ 0 (called tropocollagen) -7 large
N f- C ~ 2
backbone (CO-NH) Bonds only involve atoms
Le atoms of R groups of polypeptide H O
Hence function insoluble in water amino H R OH carboxyl W not involved ~ 2 H bonds between the 3 polypeptides -7 group group 8 4 2 types ALPHA HELIX (fj
l tropocollagen -7 covalent bonds between
R-group a -7H bonds form between Hand 0 staggered tropocollagen molecules -7 l 4 Soluble ampexists as zwitterions (have ~ atoms 4 aa apart (ie H belongs to collagen fibril -7 collagen fibre ~
f3 pleated sheetboth basic and acidic properties) ~ NH of aa1 0 belongs to C=O of aaS) Hence function no weak spot runn ing through in solution 2 -7 H-bonds 11 to longitudinal axis fibril + large bundle produce a rope-like
l of helix structure of great tensile strength ~ -73D helical structure
S Hence act as buffers -7Structure supports its STRUCTURAL function
BETA PLEATED SHEET(resists small changes in
to give firmness and to skinH I -7 H bonds form between segments of
tertiaryH~ the polypeptide which are parallel to structureH R 1 Form spherical compact shapeseach other -7 3D accordion-like sheet (Note secondary
2 less stable less regular structureH structuresH~ 1 4 key intramolecular bonds formed along can be found 3 Soluble in water wl
H
(OH ----J polypeptide (ie bonds formed within the within) 4 Tertiary structure important09OH~ ~ 09Jo- same polypeptide) -7 hydrophobic interaction S Common eg enzymes blood proteins~ ~ ltH bondsltionic bonds ltdisulphide bridges6 Each aa will have its own isoelectric iij
2 Formed at irregular intervals HIV Proteasepoint (pH at which each aa is electrically -lt 3 Bonds involve atoms of R groups only (Le the quaternaryneutral) due to unique R groups ~
hydrophobic R group of (eg ) aa1 will interact structure7 Amino acids undergo condensation 1i with the hydrophobic R group of eg aa 78 and (Note thereaction to form polypeptides The ~ hence pull the 2 aa close together) polypeptide is
Ggtreverse occurs via hydrolysis (I) just one of the subunits)-7 3D irregular contortions of the polypeptide 0 cshyAmlnoAcld NnlnoAdd l 1 Consist of two identical polypeptides (99aa)Bonds making up the tertiarv structure
H 0 H 0 ~ -7 homodimerI II I 11 o Two Arn IhQ H-N-Q--C--QH I 1 Intermolecular bonds formed between 2 orH--N--C-C--OH 0 2 Terminal domain impt for stabilising active
AddS I I III oI I more polypeptides (ie between subunits) HIVenzymeH H R2 CD
l 2 Maintained by 4 key bonds H bonds ---I~vl~pTtt~kshy 5 3 At interface of 2 domains is the active site with III tKkbr~ I1~
Condensation ionic bonds disulphide bonds hydrophobic VI specific 3D conformation - compriSing of 2gtOH -lt-er reverse hydrolysis) VI interactions others (not in your syllabus) lIydwsvn groups of three amino acids (asp-thr-gly) md ) -7 involve in catalysisPeptide bond H 0 i HO I
o I 1 I1 1 Ill -7 allows entry of water and viral polyprotein
~kkB(ltKl eshyH--H--C-+-C-- H-i-C-o--OH Un~a1J for hydrolysis of peptide bondI I i I i I
H RI H R2 -7 enzyme specificityt 3D shape of a protein may be changed by 4 2 flexible flaps guard active sites -7 excludei
a
1 Heat C~tenrnnusHmiddottermIOlS more incoming water molecules -7 this allows ~-- 3 Inorganic chemicals eg heavy metals
2 AcidsAlkalis (pH) catalytic reaction to occur
S ENZYMATIC function to cleave polyproteinsPolyptftld~ H~-~AAI-Mt~AAr-AA~ AA2--AA--AAn- ~t~ 4 Organic chemicals eg ether alcohol into functional viral proteinsS Mechanical forces
2
EXAMPLES OF LlPIDS
1 Each is made up of glycerol and fatty acids 1 glycerol + 3 fatty acids ~ 1 triglyceride (via condensation of components)
H HtOH
I Il- middotCmiddot- Oll
I H MCOIl
I-l H to -lt n lttl
1 glycerol +
~ HmiddotmiddotCmiddotmiddot OH
i r Ile OHtl
o Il If C OH
C Ir Hg Ca
ester linkagesHO M O ~
n bullbull~~ An exan1p~ orj trigyccrkle o o Iii A
HO ~O M ~ -S) v middot V 1I o
HO wO-llI i ltshy6 hydrocarbon tail
a 2 Hence a triglyceride molecule has a hydrophilic headand a hydrophobic tail lttl Il 3 Insoluble in water (exists as micelles) soluble in organic solvent
4 2 types Saturated Fat Unsaturated fat 1 lacks C=C in hydrophobic tails 1 possess 1 or gt1 C=C ~ kinks in tails 2 quite closely packed ~ solid at room temp 2 kinks prevent close packing ~ liquid at room temp 3 usually found in animals 3 usually found in plants and fish 4 eg bacon grease lard butter 4 eg vegetable oil cod liver oil
cc middotCC Cmiddot CJC O C c~O~O~cdeg OC cmiddotCcmiddotcmiddot J~9Jc ~cmiddot~c~cP ~H
1 Each is made up of glycerol fatty acids and phosphate groups 2 fatty acids + 1 phosphate grp
1l0 -OM 1I OH tI I 0 OH- P-OH
1I HO-O ~ 0
clI
phosphoester link 1-
bH
~ 1 phospholipid + 3H20
CH COO~1 ~
lHCOO OH IHJ~P-OH
Il 2 Hence it has a hydrophilic phosphate head (also cos of -ve charge) and a hydrophobic hydrocarbon tail 3 Such a property makes it an amphipathic molecule 4 Insoluble in water (exists as micelles) soluble in organic solvent 5 Exist as a phospholipid bilayer at the cellorganelle surface ie cell membrane 6 May have small variable molecules attached to the phosphate head eg choline
1 Insoluble in water soluble in organic compounds Some reproductive hormones 2 Possess 4 interconnected C rings
progesterone3 Structurally little in common with other lipids (J) 4 eg cholesterol vitamin D steroid hormones Omiddotfcen Q Cl 0 CH
y H)
cmiddotmiddoto ~ ~~~
CH 1 I t~J )
CHH
CH
testosterone (PCrt~J cJ 0-
+ 3HzO
(STRUCTURE~) FUNCTION
1 Higher HO ratlq compared to carbohydrates ~ good energy store (2x that of carbohydrates) ~ Hence animals store more energy with less
weight than plants ~ enables animals to travel around with less
weight 2 Good insulator of heat ~ used by animals to retain body heat
eg blubber subcutaneous fat 3 Good barrier of ions ~ allows saltatory conduction of nerve
impulses ~ hence increase transmission of impulse greatly
4 Protection Able to absorb impact ~ cushions vital organs for protection
5 Less dense than water ~ aquatic animals can stay buoyant in water
6 Releases water as a by-product when oxidised ~ metabolic water is a useful source of water for
desert animals or for dev of avian and retile eggs
1 Bilayers form continuous sheets ~ serve as membranes that enclose
cellorganelles allows compartmentalisation 2 Hydrophobic core selectively permeable membrane ~ allows lipid-soluble molecules to pass through
readily ~ although water is polar it can pass through
occasionally because it is small and weak in charge
~ regulates movement of ions polar molecules into and out of cell
3 Hydrophobic interactions between the molecules ~ self-sealing will reseal quickly if they are
punctured or disrupted
4-ring structure of cholesterol (within membrane) ~ regulatesmodulates membrane fluidity ~ At low temperature prevent phospholipids
from getting too close together and therefore prevents solidification of membrane
~ at high temperature prevent the membrane from being excessively fluid and unstable at higher temperatures through their interaction with phospholipids
1 Structurally similar to fats and oils only that the long-chained fatty acids are linked to long-chained alcohols Insoluble ~ 2 Insoluble in water ~ cutin coats surface of leaves to reduce water lossgtlt lttl 3 Chemically inert ~ similar concept with insectsIl
3
Il
PROCEDURE
1 Place 2 cm3 of test solution in a test tube og (l) J 2 Add equal volume of Benedicts reagent c(l) c c 3 Shake the mixture Q omiddot J ~ 4 Heat it by immersing the tube in boiling water bath for 2 minutes
lt0 ( 5 Observe the contents of the tube (J)-I c (l)
lt0 (JgtIII ~
en Q
z 1 If a negative result for Benedicts test is obtained for test solution o 2 Boil equal volume of test solution with dilute HCI for about 1 minute
to hydrolyse disaccharide to monosaccharides ~-I c (l) 3 Cool the contents of the tube Q ~ J 4 Neutralise the contents with sodium hydrogencarbonate solution
lt0 0 (J) because Benedicts regent only works in alkaline conditions c
lt0 5 Carry out Benedicts test for reducing sugar III 6 Record observations in the same format as that for Benedicts test Ul
1 Add a few drops of potassium iodide solution to 1 cm 3 of 0[ test solution (or a piece of the test specimen) S2 ~ 2 Observe any colour change III -I (l)g~
1 Place 2cm3 of test solution in a test-tube 2 Add equal volume of 5 NaOH solution OOJ cmiddot 3 Shake the mixture well
-0 (l)o ~ 4 Add 1 copper sulphate solution drop by drop shaking well (ii-l_ (l) after each drop J (Jgt(Jgt ~ 5 Observe any colour change
m 1 Place 2cm3 of absolute ethanol in a test-tuibe s III 2 Add 2cm3 of test solution to this test-tube J
0 2 Dissolve the contents by shaking vigorously o shy m 3 Add equal volume (ie 4cm3) of cold water C3 u c 4 Observe any colour change CiiJi omiddot
J
-I (l) ~
OBSERVATIONS
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The mixture turns blue-black in colour 2 The mixture remains yellowish-brown in colour
1 The mixture turns from blue to purpleviolet 2 The mixture remains blue in colour (because of the
copper sulphate solution)
1 The mixture turns a clear solution 2 The mixture turns a cloudy white suspensionan emulsion
is formed
CONCLUSIONS
1 No reducing sugars present in the test solution 2 A small amount of reducing sugars is present in the a
~ test solution
3 A moderate amount of reducing sugars is present in the test solution
4 A moderately large amount of reducing sugars is present in the test solution
5 A large amount of reducing sugars are present in the test solution
1 Non reducing sugars absent in the test solution 2 A small amount of non-reducing sugars is present in the
test solution 3 A moderate amount of non-reducing sugars is present in
the test solution 4 A moderately large amount of non-reducing sugars is
present in the test solution 5 A large amount of non-reducing sugars are present in the
test solution
1 Starch is present in the test solution 2 Starch is absent in the test solution
1 Proteins are present in the test solution 2 Proteins are absent in the test solution
1 Lipids are absent in the test solution 2 Lipids are present in the test solution
EXAMPLES OF LlPIDS
1 Each is made up of glycerol and fatty acids 1 glycerol + 3 fatty acids ~ 1 triglyceride (via condensation of components)
H HtOH
I Il- middotCmiddot- Oll
I H MCOIl
I-l H to -lt n lttl
1 glycerol +
~ HmiddotmiddotCmiddotmiddot OH
i r Ile OHtl
o Il If C OH
C Ir Hg Ca
ester linkagesHO M O ~
n bullbull~~ An exan1p~ orj trigyccrkle o o Iii A
HO ~O M ~ -S) v middot V 1I o
HO wO-llI i ltshy6 hydrocarbon tail
a 2 Hence a triglyceride molecule has a hydrophilic headand a hydrophobic tail lttl Il 3 Insoluble in water (exists as micelles) soluble in organic solvent
4 2 types Saturated Fat Unsaturated fat 1 lacks C=C in hydrophobic tails 1 possess 1 or gt1 C=C ~ kinks in tails 2 quite closely packed ~ solid at room temp 2 kinks prevent close packing ~ liquid at room temp 3 usually found in animals 3 usually found in plants and fish 4 eg bacon grease lard butter 4 eg vegetable oil cod liver oil
cc middotCC Cmiddot CJC O C c~O~O~cdeg OC cmiddotCcmiddotcmiddot J~9Jc ~cmiddot~c~cP ~H
1 Each is made up of glycerol fatty acids and phosphate groups 2 fatty acids + 1 phosphate grp
1l0 -OM 1I OH tI I 0 OH- P-OH
1I HO-O ~ 0
clI
phosphoester link 1-
bH
~ 1 phospholipid + 3H20
CH COO~1 ~
lHCOO OH IHJ~P-OH
Il 2 Hence it has a hydrophilic phosphate head (also cos of -ve charge) and a hydrophobic hydrocarbon tail 3 Such a property makes it an amphipathic molecule 4 Insoluble in water (exists as micelles) soluble in organic solvent 5 Exist as a phospholipid bilayer at the cellorganelle surface ie cell membrane 6 May have small variable molecules attached to the phosphate head eg choline
1 Insoluble in water soluble in organic compounds Some reproductive hormones 2 Possess 4 interconnected C rings
progesterone3 Structurally little in common with other lipids (J) 4 eg cholesterol vitamin D steroid hormones Omiddotfcen Q Cl 0 CH
y H)
cmiddotmiddoto ~ ~~~
CH 1 I t~J )
CHH
CH
testosterone (PCrt~J cJ 0-
+ 3HzO
(STRUCTURE~) FUNCTION
1 Higher HO ratlq compared to carbohydrates ~ good energy store (2x that of carbohydrates) ~ Hence animals store more energy with less
weight than plants ~ enables animals to travel around with less
weight 2 Good insulator of heat ~ used by animals to retain body heat
eg blubber subcutaneous fat 3 Good barrier of ions ~ allows saltatory conduction of nerve
impulses ~ hence increase transmission of impulse greatly
4 Protection Able to absorb impact ~ cushions vital organs for protection
5 Less dense than water ~ aquatic animals can stay buoyant in water
6 Releases water as a by-product when oxidised ~ metabolic water is a useful source of water for
desert animals or for dev of avian and retile eggs
1 Bilayers form continuous sheets ~ serve as membranes that enclose
cellorganelles allows compartmentalisation 2 Hydrophobic core selectively permeable membrane ~ allows lipid-soluble molecules to pass through
readily ~ although water is polar it can pass through
occasionally because it is small and weak in charge
~ regulates movement of ions polar molecules into and out of cell
3 Hydrophobic interactions between the molecules ~ self-sealing will reseal quickly if they are
punctured or disrupted
4-ring structure of cholesterol (within membrane) ~ regulatesmodulates membrane fluidity ~ At low temperature prevent phospholipids
from getting too close together and therefore prevents solidification of membrane
~ at high temperature prevent the membrane from being excessively fluid and unstable at higher temperatures through their interaction with phospholipids
1 Structurally similar to fats and oils only that the long-chained fatty acids are linked to long-chained alcohols Insoluble ~ 2 Insoluble in water ~ cutin coats surface of leaves to reduce water lossgtlt lttl 3 Chemically inert ~ similar concept with insectsIl
3
Il
PROCEDURE
1 Place 2 cm3 of test solution in a test tube og (l) J 2 Add equal volume of Benedicts reagent c(l) c c 3 Shake the mixture Q omiddot J ~ 4 Heat it by immersing the tube in boiling water bath for 2 minutes
lt0 ( 5 Observe the contents of the tube (J)-I c (l)
lt0 (JgtIII ~
en Q
z 1 If a negative result for Benedicts test is obtained for test solution o 2 Boil equal volume of test solution with dilute HCI for about 1 minute
to hydrolyse disaccharide to monosaccharides ~-I c (l) 3 Cool the contents of the tube Q ~ J 4 Neutralise the contents with sodium hydrogencarbonate solution
lt0 0 (J) because Benedicts regent only works in alkaline conditions c
lt0 5 Carry out Benedicts test for reducing sugar III 6 Record observations in the same format as that for Benedicts test Ul
1 Add a few drops of potassium iodide solution to 1 cm 3 of 0[ test solution (or a piece of the test specimen) S2 ~ 2 Observe any colour change III -I (l)g~
1 Place 2cm3 of test solution in a test-tube 2 Add equal volume of 5 NaOH solution OOJ cmiddot 3 Shake the mixture well
-0 (l)o ~ 4 Add 1 copper sulphate solution drop by drop shaking well (ii-l_ (l) after each drop J (Jgt(Jgt ~ 5 Observe any colour change
m 1 Place 2cm3 of absolute ethanol in a test-tuibe s III 2 Add 2cm3 of test solution to this test-tube J
0 2 Dissolve the contents by shaking vigorously o shy m 3 Add equal volume (ie 4cm3) of cold water C3 u c 4 Observe any colour change CiiJi omiddot
J
-I (l) ~
OBSERVATIONS
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The mixture turns blue-black in colour 2 The mixture remains yellowish-brown in colour
1 The mixture turns from blue to purpleviolet 2 The mixture remains blue in colour (because of the
copper sulphate solution)
1 The mixture turns a clear solution 2 The mixture turns a cloudy white suspensionan emulsion
is formed
CONCLUSIONS
1 No reducing sugars present in the test solution 2 A small amount of reducing sugars is present in the a
~ test solution
3 A moderate amount of reducing sugars is present in the test solution
4 A moderately large amount of reducing sugars is present in the test solution
5 A large amount of reducing sugars are present in the test solution
1 Non reducing sugars absent in the test solution 2 A small amount of non-reducing sugars is present in the
test solution 3 A moderate amount of non-reducing sugars is present in
the test solution 4 A moderately large amount of non-reducing sugars is
present in the test solution 5 A large amount of non-reducing sugars are present in the
test solution
1 Starch is present in the test solution 2 Starch is absent in the test solution
1 Proteins are present in the test solution 2 Proteins are absent in the test solution
1 Lipids are absent in the test solution 2 Lipids are present in the test solution
PROCEDURE
1 Place 2 cm3 of test solution in a test tube og (l) J 2 Add equal volume of Benedicts reagent c(l) c c 3 Shake the mixture Q omiddot J ~ 4 Heat it by immersing the tube in boiling water bath for 2 minutes
lt0 ( 5 Observe the contents of the tube (J)-I c (l)
lt0 (JgtIII ~
en Q
z 1 If a negative result for Benedicts test is obtained for test solution o 2 Boil equal volume of test solution with dilute HCI for about 1 minute
to hydrolyse disaccharide to monosaccharides ~-I c (l) 3 Cool the contents of the tube Q ~ J 4 Neutralise the contents with sodium hydrogencarbonate solution
lt0 0 (J) because Benedicts regent only works in alkaline conditions c
lt0 5 Carry out Benedicts test for reducing sugar III 6 Record observations in the same format as that for Benedicts test Ul
1 Add a few drops of potassium iodide solution to 1 cm 3 of 0[ test solution (or a piece of the test specimen) S2 ~ 2 Observe any colour change III -I (l)g~
1 Place 2cm3 of test solution in a test-tube 2 Add equal volume of 5 NaOH solution OOJ cmiddot 3 Shake the mixture well
-0 (l)o ~ 4 Add 1 copper sulphate solution drop by drop shaking well (ii-l_ (l) after each drop J (Jgt(Jgt ~ 5 Observe any colour change
m 1 Place 2cm3 of absolute ethanol in a test-tuibe s III 2 Add 2cm3 of test solution to this test-tube J
0 2 Dissolve the contents by shaking vigorously o shy m 3 Add equal volume (ie 4cm3) of cold water C3 u c 4 Observe any colour change CiiJi omiddot
J
-I (l) ~
OBSERVATIONS
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The contents of the test-tube remains a blue solution 2 A green ppt forms in the contents of the test-tube
3 A yellow ppt forms in the contents of the test-tube
4 A brown ppt forms in the contents of the test-tube
5 A brick-red ppt forms in the contents of the test-tube
1 The mixture turns blue-black in colour 2 The mixture remains yellowish-brown in colour
1 The mixture turns from blue to purpleviolet 2 The mixture remains blue in colour (because of the
copper sulphate solution)
1 The mixture turns a clear solution 2 The mixture turns a cloudy white suspensionan emulsion
is formed
CONCLUSIONS
1 No reducing sugars present in the test solution 2 A small amount of reducing sugars is present in the a
~ test solution
3 A moderate amount of reducing sugars is present in the test solution
4 A moderately large amount of reducing sugars is present in the test solution
5 A large amount of reducing sugars are present in the test solution
1 Non reducing sugars absent in the test solution 2 A small amount of non-reducing sugars is present in the
test solution 3 A moderate amount of non-reducing sugars is present in
the test solution 4 A moderately large amount of non-reducing sugars is
present in the test solution 5 A large amount of non-reducing sugars are present in the
test solution
1 Starch is present in the test solution 2 Starch is absent in the test solution
1 Proteins are present in the test solution 2 Proteins are absent in the test solution
1 Lipids are absent in the test solution 2 Lipids are present in the test solution