UNE Biochem Unit 1 Exam 2025 Questions and Answers
100% Solved
True or False: a decrease in pH will cause hemoglobin to bind more oxygen more tightly -
answers-False
When does Km = [s] - answers-when v0 = 1/2 Vmax
the michaelis constant (Km) is equal to the substrate concentration at half maximal velocity
E coli - answers-At lower temperatures the cells will produce membranes with the highest ratio
of unsaturated/saturated fatty
Cell organization - answers-monomeric units -> Macromolecules -> supra molecular complexes
Gibbs Free Energy - answers-- Negative delta G means a reaction is energetically favorable
(exergonic)
RNA World Hypothesis - answers-- Life may have started with a self-replicating ENA
- RNA is both a carrier of genetic information and a catalyst
Hydrogen bond vs covalent bond - answers-Hydrogen bonds are longer and weaker
max of 4 hydrogen bonds
water molecules are perfect hydrogen bond donors and acceptors
,Hydrogen bonding in ice - answers-water molecules form a H-bonded network that fully
satisfied the H-bonding potential (4 per molecule)
In liquid water there are about 3.4 H bonds per molecule. This makes water denser than ice due
to increase of entropy
a cup of water has been frozen such that the ice level is exactly at the top of the cup. What will
happen when the ice melts? - answers-The water level is below the rim (hexagonal structure
collapses)
Strength of hydrogen bonds - answers-stronger hydrogen bonds at 180 degrees versus a 120
degree angle
The hydrophobic effect - answers-- hydrophobic compounds interfere with the structure of
water
- water molecules ordered around a hydrophobic molecule reduce the entropy of water, which
is thermodynamically unfavorable
- clustered lipids release water, which is entropically favorable, which is the hydrophobic effect
- Spontaneous clustering of non-polar groups maximizes entropy of water
Water as a reactant - answers-in hydrolysis and condensation reactions water is a reactant.
ATP hydrolysis releases energy because in forms new bonds and creates products that are more
stable than reactants
Ionization of water - answers-Kw= [H+] [OH-] = 1 x 10 ^-14
, ex. 0.1M HCl = [OH-] = 10^-13 M
pH - answers--log [H+]
pKa - answers-smaller pka = stronger acid
pKa = -log [Ka]
Ka = [H+][A-] / [HA]
Buffers - answers-pH = pKa
buffer region + or - 1
- phosphate and bicarbonate are important buffers in blood
Amino Acid Structure - answers-
Stereochemistry of amino acids - answers-All amino acids in proteins are L-stereoisomers
(except glycine)
glycine - answers-nonpolar, aliphatic
Alanine - answers-nonpolar, aliphatic
Proline - answers-nonpolar, aliphatic
Valine - answers-nonpolar, aliphatic
100% Solved
True or False: a decrease in pH will cause hemoglobin to bind more oxygen more tightly -
answers-False
When does Km = [s] - answers-when v0 = 1/2 Vmax
the michaelis constant (Km) is equal to the substrate concentration at half maximal velocity
E coli - answers-At lower temperatures the cells will produce membranes with the highest ratio
of unsaturated/saturated fatty
Cell organization - answers-monomeric units -> Macromolecules -> supra molecular complexes
Gibbs Free Energy - answers-- Negative delta G means a reaction is energetically favorable
(exergonic)
RNA World Hypothesis - answers-- Life may have started with a self-replicating ENA
- RNA is both a carrier of genetic information and a catalyst
Hydrogen bond vs covalent bond - answers-Hydrogen bonds are longer and weaker
max of 4 hydrogen bonds
water molecules are perfect hydrogen bond donors and acceptors
,Hydrogen bonding in ice - answers-water molecules form a H-bonded network that fully
satisfied the H-bonding potential (4 per molecule)
In liquid water there are about 3.4 H bonds per molecule. This makes water denser than ice due
to increase of entropy
a cup of water has been frozen such that the ice level is exactly at the top of the cup. What will
happen when the ice melts? - answers-The water level is below the rim (hexagonal structure
collapses)
Strength of hydrogen bonds - answers-stronger hydrogen bonds at 180 degrees versus a 120
degree angle
The hydrophobic effect - answers-- hydrophobic compounds interfere with the structure of
water
- water molecules ordered around a hydrophobic molecule reduce the entropy of water, which
is thermodynamically unfavorable
- clustered lipids release water, which is entropically favorable, which is the hydrophobic effect
- Spontaneous clustering of non-polar groups maximizes entropy of water
Water as a reactant - answers-in hydrolysis and condensation reactions water is a reactant.
ATP hydrolysis releases energy because in forms new bonds and creates products that are more
stable than reactants
Ionization of water - answers-Kw= [H+] [OH-] = 1 x 10 ^-14
, ex. 0.1M HCl = [OH-] = 10^-13 M
pH - answers--log [H+]
pKa - answers-smaller pka = stronger acid
pKa = -log [Ka]
Ka = [H+][A-] / [HA]
Buffers - answers-pH = pKa
buffer region + or - 1
- phosphate and bicarbonate are important buffers in blood
Amino Acid Structure - answers-
Stereochemistry of amino acids - answers-All amino acids in proteins are L-stereoisomers
(except glycine)
glycine - answers-nonpolar, aliphatic
Alanine - answers-nonpolar, aliphatic
Proline - answers-nonpolar, aliphatic
Valine - answers-nonpolar, aliphatic
