Macromolecule Scramble
2 main types of tertiary structuresGlobular form ball-like
structures where hydrophobic parts are towards the centre and
hydrophilic are towards the edgesStructure=water solubleFound in
watery environmentscells, tissue fluid, or in fluids being
transported (blood or phloem)metabolic rolesEx: enzymes in all
organisms, plasma proteins and antibodies in mammalsFibrous form
long fibres mostly consist of repeated sequences of amino acids
which are insoluble in waterusually have structural
rolesEx.Collagen in bone and cartilageKeratin in fingernails and
hair
Special ProteinsGlobularFibrousSpherical 3D shapeEx.
Haemoglobin, insulin, enzymesWater solublePhysiologically
activeMetabolic and transport rolesDo not curl up in 3D ballLong,
thin moleculesMolecules lie side-by-side to form fibresInsoluble in
waterNot physiologically activeSTRUCTURAL roles
Haemoglobin
Water soluble globular protein Structuretwo polypeptide
chainstwo polypeptide chainsHydrophobic R groups face inwards
(toward centre)Helps maintain 3D shapeHydrophilic R groups face
outwardsMaintain solubilityEach beta polypeptide chain has similar
structure to myoglobin4 inorganic prosthetic groupsHaem (heme)
groupContains Iron (Fe2+) ionOxygen is very attracted to Iron
(think rust)Functioncarry oxygen around in the bloodDue to presence
of haem group
One Complete Haemoglobin molecule4 haem groupsEach with one Fe2+
ionCarry 4 oxygen molecules (O2)Total of 8 oxygen atomsHaem group
responsible for color of bloodPurple NO oxygen with the FeRed
oxygen has combined with the Fe ion oxyhaemoglobin
One of the polar AA (glutamic acid) in the beta polypeptide
chain is replaced with AA Valine (has a non-polar R group)Non-polar
R group in the beta polypeptide chain (which is found on outside of
molecule) makes haemoglobin much less solubleCauses clotsRBC
inefficient at delivering OxygenAnemia is when there is a lower
than normal RBC countSickle RBC live only 10-20 day (normal RBCs
live about 120)Bone marrow cannot replace fast enough
Sickle Cell Anemia
Collagen: Fibrous protein StructureThree polypeptide chains
wound around each otherHelical but NOT alpha helix (not tight
enough)Every third AA is a glycineCollagen molecule=3 polypeptide
chains wrapped around each otherHydrogen bonds form between these
coils, which are around 1000 amino acids in length, which gives the
structure strength (tensile strength)Collagen MoleculeWhen 3
collagen peptide chainsCollagen FibrilsWhen collagen molecules wrap
around each otherCollagen FibresWhen many collagen fibrils wrap
around each otherCovalent cross linksForm between R groups of
lysines in the collagen molecules parallel to each other Holds
together collagen fibres
Collagen functionsForm the structure of bonesMakes up cartilage
and connective tissuePrevents blood that is being pumped at high
pressure from bursting the walls of arteriesIs the main component
of tendons, which connect skeletal muscles to bones
Haemoglobin vs. Collagen Haemoglobin may be compared with
Collagen as such: Basic Shape - Haemoglobin is globular while
Collagen is fibrousSolubility - Haemoglobin is soluble in water
while Collagen is insolubleAmino Acid Constituents - Haemoglobin
contains a wide range of amino acids while Collagen has 35% of it
primary structure made up of GlycineProsthetic Group - Haemoglobin
contains a haem prosthetic group while Collagen doesn't possess a
prosthetic groupTertiary Structure - Much of the Haemoglobin
molecule is wound into helices while much of the Collagen molecule
is made up of left handed helix structures
Testing For ProteinsBiuret Test to show the presence of peptide
bondsbasis for the formation ofproteins.Peptide bonds will make
theblueBiuret reagent turnpurple.This color change is dependent on
thenumberofpeptide bondsin the solutionmore protein, the more
intense the change = longer polypeptide chainProceduresCreate a
control for the protein test (water and Biurets reagent)Add 5 mL of
protein solution into test tubeAdd 5 drops of Biurets Reagent (very
basic so do NOT get on hands or clothing)Gently shake/roll test
tube between your handsRecord color changes
DenaturationUnraveling/unfolding of proteinWhy would this be a
problem?When protein loses its 3-D shape and thus its specific
functionCaused by:Unfavorable changes in pH, temperature or other
environmental conditionDisrupts the interactions between side
chains and causes loss of shapeExamples:Frying an eggStraightening
your hair
Denaturationinvolves the disruption and possible destruction of
both the secondary and tertiary structuresnot strong enough to
break the peptide bondsprimary structure (sequence of amino acids)
remains the same after a denaturation Denaturation disrupts the
normal alpha-helix and beta sheets in a proteinUncoils protein into
a random shape= LOSS of FUNCTIONDenaturationOccurs b/c the bonding
interactions responsible for the secondary structure (hydrogen
bonds to amides) and tertiary structure are disruptedtertiary
structure: four types of bonding interactions between "side chains"
that can be disruptedhydrogen bonding, salt bridges, disulfide
bonds, and non-polar hydrophobic interactions Variety of reagents
and conditions can cause denaturation The most common observation
in the denaturation process is the precipitation or coagulation of
the protein
Causes of Denaturation: HEATHeat can be used to disrupt hydrogen
bonds and non-polar hydrophobic interactionsoccurs because heat
increases the kinetic energy and causes the molecules to vibrate so
rapidly and violently that the bonds are disruptedproteins in eggs
denature and coagulate during cookingOther foods are cooked to
denature the proteins to make it easier for enzymes to digest
themMedical supplies and instruments are sterilized by heating to
denature proteins in bacteria and thus destroy the bacteria
Causes of Denaturation: ALCOHOLAlcohol Disrupts Hydrogen
BondingHydrogen bonding occurs between amide groups in the
secondary protein structure Hydrogen bonding between "side chains"
occurs in teriary protein structure in a variety of amino acid
combinationsAll disrupted by the addition of another alcoholA 70%
alcohol solution is used as a disinfectant on the skinpenetrates
the bacterial cell wall and denature the proteins and enzymes
inside of the cellWhy not 95%?95% alcohol solution merely
coagulates the protein on the outside of the cell wall and prevents
any alcohol from entering the cellAlcohol denatures proteins by
disrupting the side chain intramolecular hydrogen bondingNew
hydrogen bonds are formed instead between the new alcohol molecule
and the protein side chains.
Causes of Denaturation: ACIDS/BASES (changing pH)Salt bridges
result from the neutralization of an acid and amine on side
chainsFinal interaction= ionic bond b/t the + ammonium group and
the - acid groupAcids and bases disrupt salt bridges held together
by ionic chargesDouble replacement reaction occurs where the
positive and negative ions in the salt changes partners with the
positive and negative ions in the new acid or base added Occurs in
the digestive system, when the acidic gastric juices cause the
curdling (coagulating) of milk
Causes of Denaturation: Heavy MetalsHeavy metal salts act to
denature proteins in much the same manner as acids and basesHeavy
metal salts usually contain: Hg+2, Pb+2, Ag+1 Tl+1, Cd+2 (and other
metals with high atomic weights)Since salts are ionic they disrupt
saltHeavy metal + protein insoluble metal protein saltUsed for its
disinfectant properties in external applicationsSilver nitrate,
AgNO3used to prevent gonorrhea infections in the eyes of new born
infantsto treat nose and throat infections, cauterize woundsMercury
salts administered as Mercurochrome or Merthiolate have similar
properties in preventing infections in woundsUsed in reverse in
cases of acute heavy metal poisoninga person may have swallowed a
significant quantity of a heavy metal saltAs an antidote, a protein
such as milk or egg whites may be administered to precipitate the
poisonous salt followed by an emetic is given to induce vomiting so
that the precipitated metal protein is discharged from the body
Causes of Denaturation: Heavy Metals
Heavy metals disrupt disulfide bondsThey have high
affinity/attraction for sulfur denaturation of proteinsHave a
positive charge (really want e-)Reducing Agents Disrupt Disulfide
Bonds (things that can accept electrons)Oxidation - involves the
loss of electrons or hydrogen OR gain of oxygenOxidizing agent is
the one thing that LOSES electronsReduction - involves the gain of
electrons or hydrogen OR loss of oxygen Reducing agent is the one
thing that GAINS electronsDisulfide bonds are formed by oxidation
of the sulfhydryl (-SH) groups on cysteineHold together chains or
loops within a single protein chainReducing agents would do the
opposite...break DISUPLHIDE BRIDGES (denaturation)
Denaturation in ACTION!Classification of Proteins According to
biological function.Type:Example:Enzymes- Catalyze biological
reactions-galactosidaseTransport and
StorageHemoglobinMovementActinAnd Myosin in musclesImmune
ProtectionImmunoglobulins (antibodies)Regulatory Function within
cellsTranseription Factors
HormonesInsulinEstrogenStructuralCollagenPath of a Protein in the
BodyCheck out this story!
Inorganic IonsMany important functions in living
systemsInclude:Nerve impulse transmissionExcretion from the
kidneysEnzyme functiontransport
Calcium Ion Ca2++Ions important in:transmission of electrical
impulses across synapsesMuscle contractionCalcium
phosphateStructural component of bones and teeth
Sodium Na+Transmission or nerve impulses along neuronsContribute
to high concentration built up by loop of Henle in medulla of
kidneyEnable concentrated urine to be excreted so water is
conservedSodium-potassium pump in cells
Filtering machines of the bodyAs blood travels through the
kidneys, they remove waste products and excess waterProcess about
200 liters of blood to sift out about 2 liters of waste products
and extra water, everyday.The waste, along with the water is turned
into urine which travels through the remaining components of the
urinary system and is excretedFood consumed provides energy and
helps repair cellsWhatever the cells do not use in this process
must be eliminated from the bodyIt is combined with waste from the
breakdown of normal tissues in the bloodThe kidneys help rid the
body of these materials to prevent accumulation that can damage the
body
Potassium Ions K+Work with sodium ionsInvolved in transmission
of nerve impulses along neuronsContribute to control of turgidity
of cellsThis controls opening and closing of the
stomataSTOMOTA:Tiny openings on the underside of cellsSurrounded by
guard cellsClose up to conserve water
Three sodium ions enter the pump and attach to binding
sites.
ATP binds to the pump.
One phosphate bond in the ATP molecule breaks, releasing its
energy to the pump protein. The pump protein changes shape,
releasing the sodium ions to the outside.The new shape reduces its
ability to bind to sodium ions and it increases its ability to bind
potassium ions. The two potassium binding sites are exposed to the
outside, allowing two potassium ions to enter the pump.
When the phosphate group detaches from the pump, the pump
returns to its original shape.Its ability to bind potassium ions is
decreased and its ability to bind sodium ions is increased. The two
potassium ions leave, three sodium ions enter, and the cycle
repeats itself.Magnesium Ion, Mg2++Chlorophyll molecules contain
magnesiumActive sites of ATP synthases contain Magnesium ionsATP
sythase ASE = enzymeEnzyme that helps add a phosphate group (PO43-)
to an adenosine diphosphate (ADP) molecule to make adenosine
triphosphate (ATP)
Chloride ion Cl-Works with sodium ions Contributes to the high
concentration built up by the loop of Henle in the medulla of the
kidneyEnables concentrated urine to be excreted so water is
conservedHelp balance the positive charge of cations (Na+ and K+)
within and around cellsNitrate ions, NO3-Plants use nitrogen from
nitrate ions to make amino acids and nucleotidesIon is able to be
surrounded by water molecules and pulled up into root hairs into
xylem of plant and carried around the plantThis is why polarity of
water is importantallows plants to pull up important ions
Phosphate Ions, (PO43-) Used in making phospholipids (cell
membrane)Used in the making of nucleotides (phosphate
group)DNARNACombine with calcium to make calcium phosphate, that
gives strength to boneComponent of ATP, energy currency of
cells
Iron, Fe2+Hemoglobin contains this ion to attract oxygen
molecule and carry it to cellsOne hemoglobin contains 4 iron
ions
