DNA Flashcards
General formula for amino acid
RCH(NH2)COOH
define term zwitterion
an ion which acts as an acid and a base
how do amino acids act as an acid and base
they have an amine and carboxylic acid groups
define isoelectric point
the pH at which a molecule has no charge
zwitterion in acidic conditions
NH3 positively charged
zwitterion in alkaline conditions
COO negatively charged
How are amino acids connected in a chain
condensation polymerisation leads to an Amide linkage
define primary structure in DNA
a sequence of a chain of amino acids
define secondary structure in DNA
Hydrogen bonding between different componants in the same chain causes pleating and helixes
define tertiary structure in DNA
alpha helix + beta pleated sheet, amino acid chain folded into a complex 3D shape
what is an enzyme
a protein which acts as a biological catalyst
define the term ‘stereospecific’
only one enantiomer of the correct molecule will bind to the active site
how drugs affect enzymes
same shape as the protein’s active site, so they block and inhibit the enzyme
name 3 interactions which alter the shape of a protein
hydrogen bonding- between side chains of protein
sulfur-sulfur bonds- between amino acids with sulfur in side chains
van der waals- between side chains
what happens when a protein is hydrolised
the amide linkage breaks to reform the original amino acids
what happens in hydroliysis occurs on the acid in an amino acid
amine forms ion- COOH will form neutral protonated form
equation for Rf
distance substance travels/ distance solvent travels
structure of DNA strands
phosphate-sugar backbone
how cisplatin works as an anti-cancer drug
binds to DNA, preventing DNA being replicated
explain how cisplatin binds to DNA
Cl ligand replaces nitrogen atom in Guanine bases- ligand replacement
pros of cisplatin
potent- stop cells dividing
leaving cancer potentially more dangerous than damage caused to healthy cells by cis-platin
increase recovery rate, reduce chance of death and improve quality of life
cons of cisplatin
doesn’t target specifically cancerous cells, causes damage to any part of body rapidly replicating IE stomach lining, hair follicles and throat cells.
