BMSC 200 - MODULE 2 QUESTIONS
& ANSWERS(RATED A+)
Electronegativity of water - ANSWERThe different electronegativities of hydrogen
and oxygen make water a polar molecule capable of forming hydrogen bonds. This
makes water a good solute.
Hydrophobic interactions - ANSWERNon-polar hydrophobic compounds dissolve
poorly in water. These compounds minimize their surface area exposed to water by
forming aggregates in which the hydrophobic groups go to the interior through
hydrophobic interactions. Only the more polar portions interact with water.
Stabilization of biomolecular structures - ANSWERWeak non-covalent interactions
influence the formation and stabilization of biomolecular structures. These include
hydrogen bonding, hydrophobic interactions, electrostatic interactions and van der
Waals interactions.
Water ionization - ANSWERWater ionizes slightly. The extent can be described by
the equilibrium constant which the ion product of water (Kw)
pH - ANSWERpH is the concentration of hydrogen ions : pH = -log[H^+] = log
1/[H^+]
pKa - ANSWERThe stronger the acid the lower the pKa. It is determined
experimentally by finding the pH at the midpoint of a titration curve. pKa = -log Ka
Buffer - ANSWERA solution that resists changes in pH by adding acid or base. A
buffer consists of a weak acid and its conjugate base
pH calculation - ANSWERThe henderson-hasselbalch equation : pH = pKa + log
[A-]/[HA]
buffers in cells and tissues - ANSWERPhosphate and bicarbonate buffer systems
maintain intracellular and extracellular fluids at physiological pH
Buffering Region - ANSWERone pH unit on either side of the pKa
Henderson Hasselbalch - ANSWERAn equation relating the pH, the pKa and the
ration of the concentrations of the proton acceptors (A-) and proton donor (HA)
species in a solution.
ph = pKa + log [A^-]/[HA]
Amphipathic - ANSWERA molecule containing both polar and non-polar portions
, Amphoteric - ANSWERA molecule capable of donating and accepting protons, thus
able to serve as an acid or a base
Ionic Interaction - ANSWERAn interaction between electrically charged groups;
attractive between groups of opposite charge, repulsive between groups of the same
charge
hydrogen bond - ANSWERA weak electrostatic attraction between one
electronegative atom (such as oxygen or nitrogen) and a hydrogen atom covalently
linked (donor) to a second electronegative atom that has a free electron pair
(acceptor)
Intramolecular - ANSWERlimited within the structure of a single molecule
Intermolecular - ANSWERlimited within the structures of different molecules. For
example, forces of attraction or repulsion between neighboring, different entities
What is the most abundant molecule in living systems? - ANSWERWater is the most
abundant in living systems. About 70% of the cell.
What roles does water has? - ANSWERHas active and passive roles in biological
systems
Passive role of water - ANSWERThe structures of biomolecules are formed in
response to their interaction with water
Active role of water - ANSWERWater is a participant in any biochemical reactions
Electronegativities of water - ANSWEROxygen and hydrogen differ in their
electronegativities. Oxygen is more electronegative and as a result, water has a
permanent dipole/polarity.
Dipole of water charges - ANSWERWater has a permanent dipole with O having a
partial negative charge and H having a partial positive charge.
Why is the polarity of water essential? - ANSWERIt is essential in its ability to
interact with other water molecules and other biomolecules
Example of an amphipathic molecule - ANSWERfatty acids are composed of
carboxyl groups with hydrocarbon tails; tail doesn't have a charge = hydrophobic;
carboxyl group has electronegative charge (acceptor) and is hydrophilic
What does the exact solubility of molecules depend on? - ANSWERThe solubility of
a molecule in water depends on its ratio of polar to nonpolar groups. The larger the
portion of non-polar groups the less soluble the molecule is in water.
What is an example of the exact solubility of moelcules - ANSWERShorter fatty acids
are more soluble in water than longer fatty acids.
& ANSWERS(RATED A+)
Electronegativity of water - ANSWERThe different electronegativities of hydrogen
and oxygen make water a polar molecule capable of forming hydrogen bonds. This
makes water a good solute.
Hydrophobic interactions - ANSWERNon-polar hydrophobic compounds dissolve
poorly in water. These compounds minimize their surface area exposed to water by
forming aggregates in which the hydrophobic groups go to the interior through
hydrophobic interactions. Only the more polar portions interact with water.
Stabilization of biomolecular structures - ANSWERWeak non-covalent interactions
influence the formation and stabilization of biomolecular structures. These include
hydrogen bonding, hydrophobic interactions, electrostatic interactions and van der
Waals interactions.
Water ionization - ANSWERWater ionizes slightly. The extent can be described by
the equilibrium constant which the ion product of water (Kw)
pH - ANSWERpH is the concentration of hydrogen ions : pH = -log[H^+] = log
1/[H^+]
pKa - ANSWERThe stronger the acid the lower the pKa. It is determined
experimentally by finding the pH at the midpoint of a titration curve. pKa = -log Ka
Buffer - ANSWERA solution that resists changes in pH by adding acid or base. A
buffer consists of a weak acid and its conjugate base
pH calculation - ANSWERThe henderson-hasselbalch equation : pH = pKa + log
[A-]/[HA]
buffers in cells and tissues - ANSWERPhosphate and bicarbonate buffer systems
maintain intracellular and extracellular fluids at physiological pH
Buffering Region - ANSWERone pH unit on either side of the pKa
Henderson Hasselbalch - ANSWERAn equation relating the pH, the pKa and the
ration of the concentrations of the proton acceptors (A-) and proton donor (HA)
species in a solution.
ph = pKa + log [A^-]/[HA]
Amphipathic - ANSWERA molecule containing both polar and non-polar portions
, Amphoteric - ANSWERA molecule capable of donating and accepting protons, thus
able to serve as an acid or a base
Ionic Interaction - ANSWERAn interaction between electrically charged groups;
attractive between groups of opposite charge, repulsive between groups of the same
charge
hydrogen bond - ANSWERA weak electrostatic attraction between one
electronegative atom (such as oxygen or nitrogen) and a hydrogen atom covalently
linked (donor) to a second electronegative atom that has a free electron pair
(acceptor)
Intramolecular - ANSWERlimited within the structure of a single molecule
Intermolecular - ANSWERlimited within the structures of different molecules. For
example, forces of attraction or repulsion between neighboring, different entities
What is the most abundant molecule in living systems? - ANSWERWater is the most
abundant in living systems. About 70% of the cell.
What roles does water has? - ANSWERHas active and passive roles in biological
systems
Passive role of water - ANSWERThe structures of biomolecules are formed in
response to their interaction with water
Active role of water - ANSWERWater is a participant in any biochemical reactions
Electronegativities of water - ANSWEROxygen and hydrogen differ in their
electronegativities. Oxygen is more electronegative and as a result, water has a
permanent dipole/polarity.
Dipole of water charges - ANSWERWater has a permanent dipole with O having a
partial negative charge and H having a partial positive charge.
Why is the polarity of water essential? - ANSWERIt is essential in its ability to
interact with other water molecules and other biomolecules
Example of an amphipathic molecule - ANSWERfatty acids are composed of
carboxyl groups with hydrocarbon tails; tail doesn't have a charge = hydrophobic;
carboxyl group has electronegative charge (acceptor) and is hydrophilic
What does the exact solubility of molecules depend on? - ANSWERThe solubility of
a molecule in water depends on its ratio of polar to nonpolar groups. The larger the
portion of non-polar groups the less soluble the molecule is in water.
What is an example of the exact solubility of moelcules - ANSWERShorter fatty acids
are more soluble in water than longer fatty acids.
