UNIT 3 Section 8 - Amino Acids, Proteins and DNA Flashcards
what is an isoelectric point
the pH at which a molecule has no overall charge
what is the isoelectric point for amino acids
pH 7
what happens at pH 7 with amino acids
there is no charge and a zwitterion is formed as dissociation and dative covalent bonds are happening at the same time
what happens at a low pH in terms of amino acids
the nitrogen forms a dative covalent bond with the H+ ions
what happens at a high pH in terms of amino acids
the H from the carboxyl group dissociates and the COO group becomes negatively charged
how are amino acids joined
in condensation reaction where water is eliminated
what state is a zwitterion in
a solid due to the oppositely charged ions causing ionic bonding which is strong electrostatic forces of attraction meaning a high MP/BP
how do you break proteins down
hydrolysis reactions due to the C=O bond being polar as it can be attacked by nucleophiles and an acid or enzyme is required
what is the primary structure of a protein
the base sequence of amino acids
what is the secondary structure of a protein
the amino acid sequence coils up due to interactions like hydrogen bonding between chains forming either an alpha helices or beta pleated sheets
what is the tertiary structure of a protein
the further folding of the secondary structures held together by side chain reactions forming hydrogen bonds, ionic bonds and covalent bonding
what type of bonding is a disulphide bridge and what bases does it hold together
covalent bonding
cystine bases
how does hydrogen bonding form a secondary structure of a protein
nitrogen and oxygen are both very electronegative
therfore the C=O bond and the N-H bond are polar
resulting in the formation of a hydrogen bond between the O and H due to the lone pair of electrons on the O being strongly attracted to the delta + of the H
what is an enzyme
biological catalyst that reduce the activation energy needed by providing an alternate pathway
what makes enzymes unique and what does this mean for enantiomers
they have active sites that are stereospecific and this means they will only be able to bind to one enantiomer
what are the three components of DNA
phosphate ion, base, 2-deoxyribose sugar
where does the phosphodiester bond form
between the 2 sugars and the phosphate group
out of phosphate and base which is on carbon 1 and which on carbon 5
phosphate is always on carbon 5
base is always on carbon 1
what bases can cisplatin bond to
guanine and adenine bases
what shape and bond does cisplatin form
forms square planar with a bond angle of 90
what does cisplatin do to Gunaine
when cisplatin bonds to guanine and ligand substitution reaction occurs where the chlorines swap with nitrogen from the guanine as the nitrogen co-ordinately bonds to the platinum
what impact does the reaction between guanine and cisplatin have
prevents to DNA from functioning/replicating so the cell dies
why is cisplatin helpful in treating cancer
interferes with the DNA to prevent cancerous cells from replicating
what are the negatives about using cisplatin as a cancer treatment and despite these why do we still use it
can also interfere with the DNA in healthy cells and affect cells like WBC which makes peoples more suceptible to disease
benefits outweigh the risks as curing cancer is better than the side effects of using cisplatin
how can you reduce the impact of cisplatin on healthy cells
lowering the dosage
using delivery systems like injections or carrier molecules
what is the structure of cisplatin
square planar bonding shape
platinum in the middle with 2 Cl molecules and 2 NH3 molecules
