BCEM 393 STUDY GUIDE WITH VERIFIED
QUESTIONS AND ANSWERS [ GRADED A+]
Hydrogen bonds - ✔✔Partial charges on hydrogen atoms interact with
lone pairs
Hydrophobic interactions - ✔✔Release of ordered water on non-polar
surfaces, often called entropy driven and only occur in aqueous
solution
Ionic interactions - ✔✔Positive charges interact with negative charges,
water molecules around the charges weakens them
©morren2024/2025.Year published 2024.
,Dipole-dipole interactions - ✔✔Dipole on one molecules interacts with
a dipole of another molecule, they align in opposite directions, weaker
when water is present
Van der Waals interactions - ✔✔Caused by temporary dipoles from
shifting e- clouds on two molecules, occur between any types of
molecules
Can two ethanol molecules have a hydrophobic interaction with each
other in solution? - ✔✔Yes because they have non-polar ch3 groups
Why does adding salt to a solution increase the strength of
hydrophobic interactions? - ✔✔It interacts with free H2O molecules
©morren2024/2025.Year published 2024.
,What sign is logP if a molecules is hydrophilic? (In bottom layer) -
✔✔Negative
What amino acids absorb light at 280nm? - ✔✔Tryptophan and
tyrosine
What is blood buffered by? - ✔✔Carbonic acid
Hyperventilation - ✔✔Less CO2 gas, equilibria shift to the left absorbing
H+ which causes the bloods pH to increase
What is the inside of cells buffered by? - ✔✔Phosphate, H2PO4
(pka=6.86)
©morren2024/2025.Year published 2024.
, What must a buffer contain? - ✔✔A weak acid and its conjugate base
3 ways to make buffers - ✔✔1. Add both HA and A- to water
2. Add HA to water and titrate with OH- to desired pH
3. Add B to water and titrate with H+ to desired pH
pH < pka - ✔✔Equilibrium is more to the left; [A-] < [HA]
Can most phosphoglycerolipids help to buffer pH in the cell? - ✔✔No
because the buffer region does not include 7.2
Isoelectric point - ✔✔pH at which a molecule has zero net charge
(mostly zwitterion), to calculate the pI average the two pka values on
either side of the zwitterion
©morren2024/2025.Year published 2024.
QUESTIONS AND ANSWERS [ GRADED A+]
Hydrogen bonds - ✔✔Partial charges on hydrogen atoms interact with
lone pairs
Hydrophobic interactions - ✔✔Release of ordered water on non-polar
surfaces, often called entropy driven and only occur in aqueous
solution
Ionic interactions - ✔✔Positive charges interact with negative charges,
water molecules around the charges weakens them
©morren2024/2025.Year published 2024.
,Dipole-dipole interactions - ✔✔Dipole on one molecules interacts with
a dipole of another molecule, they align in opposite directions, weaker
when water is present
Van der Waals interactions - ✔✔Caused by temporary dipoles from
shifting e- clouds on two molecules, occur between any types of
molecules
Can two ethanol molecules have a hydrophobic interaction with each
other in solution? - ✔✔Yes because they have non-polar ch3 groups
Why does adding salt to a solution increase the strength of
hydrophobic interactions? - ✔✔It interacts with free H2O molecules
©morren2024/2025.Year published 2024.
,What sign is logP if a molecules is hydrophilic? (In bottom layer) -
✔✔Negative
What amino acids absorb light at 280nm? - ✔✔Tryptophan and
tyrosine
What is blood buffered by? - ✔✔Carbonic acid
Hyperventilation - ✔✔Less CO2 gas, equilibria shift to the left absorbing
H+ which causes the bloods pH to increase
What is the inside of cells buffered by? - ✔✔Phosphate, H2PO4
(pka=6.86)
©morren2024/2025.Year published 2024.
, What must a buffer contain? - ✔✔A weak acid and its conjugate base
3 ways to make buffers - ✔✔1. Add both HA and A- to water
2. Add HA to water and titrate with OH- to desired pH
3. Add B to water and titrate with H+ to desired pH
pH < pka - ✔✔Equilibrium is more to the left; [A-] < [HA]
Can most phosphoglycerolipids help to buffer pH in the cell? - ✔✔No
because the buffer region does not include 7.2
Isoelectric point - ✔✔pH at which a molecule has zero net charge
(mostly zwitterion), to calculate the pI average the two pka values on
either side of the zwitterion
©morren2024/2025.Year published 2024.
