Biochemistry 1-4 πΈ Flashcards
proton
positive charge
mass of +1
electrons
negative charge
negligible mass
neutrons
no charge
mass of 1
Covalent bonding
formed when unpaired electrons are shared
strongest type of bond
hydrogen bond
the sharing of H atoms
ionic bond
attraction of opposite charges
hydrophobic interaction
interaction of non-polar substances in the presence of polar substances (especially water)
van der waals interaction
interaction of electrons of non-polar substances
electronegativity
the attractive force that an atomic nucleus exerts on electrons within a bond
phosphorylation/dephosphorylation
the adding/taking away of a phosphoryl group
acylation
addition of an acyl group
features of an acyl group
relatively stable
useful for joining molecules
carboxylation
the addition of a carboxyl group
where do carboxyl groups bind?
usually the end of molecules (reactive centre)
esterification
occurs between acid and alcohol group, producing an ester bond.
water will be released
condensation reaction
water is removed, molecules polymerize
hydrolysis
water is added, molecules depolymerize
oxidation-reduction reactions (redox)
electrons transferred from one molecule to another
oxidation
is loss of electrons
reduction
is gain of electrons
What are the oxidation states of carbon?
vary depending on structure of the molecule and electronegativity differences
what do the charge imbalances of carbon help with?
forming reactive groups on biological molecules
monosaccharide
carbohydrates with a single ring structure
disaccharides
carbohydrates with double ring structure
polysaccharides
long chains of monosaccharides
storage carbohydrates
what enables fast metabolism of glucose?
branching of glycogen
1st law of thermodynamics
energy is neither created nor destroyed
2nd law of thermodynamics
when energy id converted from one form to another, some of that energy is unable to do work
enthalpy
heat of a reaction
entropy
measure of disorder
where does free energy tend towards after many reactions
an unusable state
equation for change in free energy
πG = πH - T πS
free energy is related to?
the point of equilibrium, if its near 0 itβs reversible
Exergonic reations
total free energy of products is less than total free energy of reactants
can occur spontaneously
Endergonic reactions
total free energy of products is more than total free energy of reactants
requires energy input
coupling of reactions
bodily reactions often occur by coupling an unfavourable reaction with a favourable reaction (ATP is widely used because of this)
metabolism
all reactions that are taking place in the body
Catabolism
breaking down complex molecules out of smaller ones and releasing energy
Anabolism
synthesising complex molecules from smaller molecules, requires energy
Properties of water
Polar
molecules form a dipole, tetrahedral shape
molecules are held together with H bonding
Polar (water)
electrons are shared unequally causing a difference in the charge from one side to another
enables water to act as a universal solvent
Amphipathic Molecules
molecules with polar and nonpolar parts which can form the lipid layer of membranes and micelles
Structure of amino acids
βΊ-carbon is bonded to;
amino group (-NH2)
carboxyl group (-COOH)
hydrogen (-H)
side chain (-R)
Classifications of amino acids
non-polar
polar
acidic
basic
peptide bonds
join amino acids
produce condensation reaction
important in folding of proteins
Base
proton acceptors
acid
proton donators
strength determined by how readily is donates protons
equation for acid dissociation
Ka= [H+][A-][HA]
pKa=-log10[Ka]
Henderson-Hasselbalch equation
pH=pKa+log[A]/[HA]
Buffers
a solution used to control the pH of a reaction mixture that resists a change in pH when moderate amounts of acid or base are added
when the acid concentration is equal to the conjugate base (pH=pKa)
What happens when pH changes in a protein?
it can change the ionisation and therefore the structure and function
primary protein structure
sequence of amino acids
Secondary protein structure
localised conformation of the poly peptide bond
hydrogen bonded
three tipes:
- βΊ helix
- Ξ² sheet
- Triple helix
Tertiary protein structure
3D structure of an entire polypeptide
fibrous: mechanically strong, insoluble in water, the chains are parallel
globular: spherical, soluble in water and salt solutions
Quaternary
spatial arrangement of polypeptide chains in a protein with multiple subunits
Two examples of quateranry
haemoglobin or tropocollagen
quaternary haemoglobin
4 subunits, 2 alpha & 2 beta
each subunit has on haem group which binds to oxygen
each oxygen binding changes the affinity of other subunits
Tropocollagen
Structural unit of a collagen fibre
three helical chains twisted around each other to for, a right handed super helix
