Molecules in a bio envir Flashcards
How do OH electronegative bonds work?
Oxygen distorts the e- density by pulling all the e-s towards it to create dipoles.
What do polar molecules have?
Polar bonds with charged regions, like dissolves in like
Can Glucose and ethanol ionise
NO
Alcohols DO NOT IONISE. O in the don’t does not polarise enough to lose the H, need to do something extreme to lose H+
What kind of molecules are polar molecules?
Hydrophilic
What are NP molecules
No polar bonds or charged areas eg Heptane, Benzene
What kind of molecules are non- polar molecules?
Hydrophobic, like dissolves in like
Why are NP molecules NP?
C bonds aren’t electronegative
What is Hydration?
Adding water to another molecule
The polar nature of water enables electrostatic interactions with other charged molecules
What allows hydration to occur?
H bonding
Why is H bonding a driving force?
It has the right amount of E and is strong in numbers and can be broken when needed eg during ATP cycle, breaking of DNA H bonds during transcription
What is the principal component of cells
H2O, around 78%
What happens when the pH is set externally?
The molecule responds to reach equilibrium and ionises in a way that responds to the pH of the sol
Can molecules/ functional groups exist in charged and uncharged forms?
Yes, eg amine can exist as an anion, zwitterion and a cation
What is ionisation status of a molecule influenced by?
Ph of envir
How easy is it for an ionsable functional group/molecule to ionise
If the pKa is one below the pH
Protonation happens and vice versa
What part of the amino acid is ionised?
The side chains as the alpha amine and Carboxyl group aren’t available for ionisation
Net charge of the molecule depends on the ionisation of the side chains groups (R-, N-, C-termini)
Features of an amide bond
*resistant to attack by nucleophiles and lewis bases
*Dont attack themselves (benign)
*Have partial delocaisation of the lone pair group on N, forms a 1/2 C-N strength bond
How are amide bonds formed?
Condensation between a COOH of one amine and NH2 of another
What does H2O do to NP bonds?
Attempts to hydrate it in an aq environemnt
What are hydration shells?
water molecule orient themselves to maximise the +/- attractions between the ion and the partial charges on the water molecule.
