A2- DNA and anticancer drugs Flashcards
Why is DNA acidic?
phosphate groups have P-O-H which can donate H+ (and form P–O-)
How many H bonds form between A and T?
2
How many H bonds form between C and G?
3
What do H bonds form between?
a H sandwiched between O or N
What 2 groups react (and on which molecules) to form phosphodiester bonds?
OH on Phosphate and OH on sugar
What sugar is found in DNA?
deoxyribose
Draw cisplatin…
H3N Cl
Pt
H3N Cl
How does cisplatin work?
- N on adjacent Guanines forms coordinate bond with Pt, replacing H2O and Cl ligands
- prevents DNA replication
Where does cisplatin bond to DNA?
2 adjacent G bases
How does cisplatin bond to DNA?
- N atom in G bases has lone pair that it donates to Pt
- forming a dative covalent bond
What displaces the Cl in cisplatin?
H2O
What displaces H2O ligands on cisplatin? What type of reaction is this?
N on Guanine bases
Ligand-substitution
What process does cisplatin prevent?
DNA replication
After cisplatin enters a cell, one of the chloride ligands is replaced by a water molecule to form a complex ion
Give the equation for this reaction.
[Pt(NH3)2Cl2] + H2O –> [Pt(NH3)2(H2O)Cl]+ + Cl-