lecture 1 Flashcards
covalent and non-covalent bonds
what are the atomic numbers of Carbon, Hydrogen, Oxygen and Nitrogen (protons and electrons)
6, 1, 8, 7
what are the atomic masses of Carbon, Hydrogen, Oxygen and Nitrogen
12, 1, 16, 14 (protons + neutrons)
define a covalent bond
a bond that forms when two atoms share a pair of electrons
define a non-covalent bond
an attraction between positive and negative charges
what is a phosphodiester bond
a covalent bond joining the 3’ hydroxyl group of one nucleotide to the 5’ phosphate group of the next nucleotide
what is electrostatic interaction
attraction between opposite charges (intermolecular and intramolecular)- molecules interact in ways to maximise favourable interactions
what is ionic bonding
electrostatic attraction between oppositely charged ions
give an example of electrostatic repulsion in biomolecules
DNA - negatively charges due to the negative charge on each phosphate group in the sugar-phosphate backbone
describe van der Waals interactions in biomolecules
weak interactions between two dipolar atoms
what is van der Waals distance and what happens when it reduces
the distance at which two molecules are attracted to each other, when it reduces, the electrons of the two molecules may overlap causing repulsion leading to a rigid DNA structure
describe hydrogen bonding in biomolecules
interaction between an electropositive H in one molecule and an electronegative atom (O or N) in another molecule, it is the bond that joins base pairs in DNA
what are hydrophobic interactions
water cannot form hydrogen bonds with non-polar molecules, instead the water molecules form hydrogen bonds around the non-polar molecule like a cage. when non-polar molecules come together (hydrophobic interaction) some of the water molecules from the cage are released
what is a monomeric protein
a protein consisting of a single polypeptide chain
what is an oligomeric protein
two or more polypeptide chains held together by non covalent interactions
how do you calculate molecular weight
mass number x no. of atoms
what is the average weight of an amino acid residue
110 Daltons
what is the mass of a protein that consists of 150 amino acids
150 x 110 Da = 16500 Da (16.5 kDa)
what is an enzyme
a protein that catalyses a biochemical reaction by lowering the activation energy of the reaction
what does the Michaelis mention equation describe
the variation of enzyme activity as a function of the substrate concentration
what happens to the rate of product formation at high substrate concentrations
enzymes are working at maximum capacity, adding substrate no longer affects the rate of product formation
what happens to the rate of product formation at low substrate concentrations
as the substrate concentration increases, so does the rate of product formation
what does an irreversible inhibitor do
binds strongly to an amino acid R group that participates in substrate binding or catalysis - permanently inactivating the enzyme
what is a reversible inhibitor
inhibitory effects can be reversed at least to some extent by the presence of the substrate
