©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
BIOC 3021 EXAM 1 REVIEW SHEETS.
Exam Questions And Answers (Guaranteed
A+)
What are the six most common elements present as covalent components of bioorganic
compounds? - answer✔H, O, N, C, S, P, Cl
What are covalent bonds, and how strong and permanent are they relative to other bonds in
living organisms? - answer✔Covalent bonds are the sharing of electrons between two species.
Non polar covalent bonds are the strongest
What is the difference between polar and nonpolar covalent bonds? What combinations of
atoms are involved in these two kinds of covalent bonds? - answer✔Polar covalent bonds: The
EN differs (C-O bonds)
Non-polar covalent bonds: En is identical or is very similar (H-H bonds)
What are common ionic elements in biological systems? What happens to ionic substances in
the aqueous environment of living organisms? What are the properties of the ionic bonds that
occur between inorganic ions or between organic ions? - answer✔Common ionic elements: Na
and Cl
In aqueous environments ionic substances dissociate
Inorganic compounds form ionic bonds that have high melting points that are made up of a
single element or compound that does not include carbon or hydrogen.
What are hydrogen bonds? What organic structures are involved in hydrogen bonding? What is
the importance of hydrogen bonding in living organisms? - answer✔Hydrogen bonds are polar
bonds that have a partially positive H interacting with a partially negative element (like O or N).
Important because they are essential for protein structure, binding of enzymes to substrate and
they hold the DNA helixx together.
What are two types of nonpolar bonds? Why do nonpolar molecules aggregate together in
water? - answer✔Van der waals forces and hydrophobic interactions
1|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
Van der Waals forcesCaused by induced electrical interactions between closely approaching
atoms
E clouds fluctuate together to "fit together"
Strength depends on size of atoms and the distance
Bigger e- clouds from stronger interactions
Strength is inversely proportional to the 6th power of distance
Atoms need to be 2nm apart
Hydrophobic Interactions
These bonds form due to exclusion of water from groups of non polar molecules
Water molecules prefer each other (strongest interactions)
Forces nonpolar molecules together
Hydrophobic molecules are not really attracted to each other, they just herded together by
water so that the maximum number of water-water interactions can form
Water molecules push hydrophobic molecules together so that fewer water molecules need to
be near hydrophobic molecules, water water H bonding can be maximized
What is pH and how does it relate to the molarity of hydrogen ions in solution? - answer✔pH is
the numerical value of -log[H+]. It describes the solutions acidity It is inversely related to the
hydrogen ion concentration. So if pH decreases then H ion increases tenfold.
What is a strong acid? What is the percent dissociation of a strong acid in water? When a strong
acid is present in water, why are the molarity of the strong acid and the molarity of the
hydrogen ion the same? - answer✔A strong Acid completely dissociates in water. The
concentrations of Hydrogen ion and acid are equal since it dissociates completely in an aqueous
environment.
What is a weak acid, and why are weak acids not completely dissociated? Why are the molarity
of the weak acid and the molarity of the hydrogen ion not the same? If a 0.1 M solution of a
weak acid is 10% dissociated, what is the molarity of hydrogen ions? - answer✔Weak Acid does
not dissociate completely in water. Molarities are not the same due to the lack of complete
dissociation.
0.1M x (10/100)= 0.01 M
What is a buffer solution? Why is a mixture of a weak acid and its conjugate base needed to
give good buffering? Why doesn't a solution containing just a weak acid serve as a buffer? Why
2|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
don't strong acids serve as buffers? - answer✔A buffer solution consists of a weak acid and its
conjugate base equilibrium in an aqueous solvent. It can resist changes in pH when a strong
acid or strong base is added. Can't have just one because then the equation would only go one
way. A strong acid can't be a buffer because it ionizes completely.
Write the Henderson-Hasselbach equation. What are the definitions of pH, pKa and log A-/HA?
Why do all weak acids give the same shaped titration curve? At what pH does a weak acid and
conjugate base combination give the best buffering? If a weak acid has a pKa of 5 what is the
pHwhen the weak acid is 10%, 50% and 90% titrated with NaOH? - answer✔pH=pKA+log[A-
]/[HA]. pH describes the solution acidity as it is the numerical value of -log[H+].pKa is the
strength of an acid. Log a-/HA is the molar concentration of the conjugate base. All have the
same titration curve because it has the same flat region +/- 1 unit from pKa, give the best
buffering at pH that is -/+1 from pKa
PH=4.05, 5, 5.95
If the pKa is 6 and the ratio of A-/HA is 1 what is the pH? If the pKa is 6 and the ratio of A-/HA is
10 what is the pH? If the pKa is 6 and the pH is 6 what is the ratio of A-/HA? If the pKa is 6 and
the pH is 5 what is the ratio A-/HA? - answer✔6,7,1,0.01
What are the most common oxidation and reduction reactions in living organisms? -
answer✔The most common oxidation and reduction reactions in living organism are
metabolism reactions
Starting with methane and ending with carbon dioxide, what are the intermediates in an
oxidation pathway in which additional bonds to oxygen are added at each stage? -
answer✔Alkane ---> Alcohol ---> Aldehyde/Ketone ---> Carboxylic Acid ---> Carbon Dioxide
Intermediate = NAD+ reduced to NADH with MDH
Starting with ethane and ending with ethyne (aka acetylene) what are the stages of oxidation in
which hydrogen is removed but oxygen is not added to the compound? - answer✔Ethane
Oxidation takes 2e- and 2H to make ethene
Oxidation takes 2e- and 2H to make Ethyne
Why are oxidation-reduction reactions so important in human metabolism? What role do highly
reduced organic compounds and oxygen play as the major electron donors and acceptors in the
production of energy in this process? - answer✔All metabolism involves carbon redox
reactions.
Reduce carbon atoms contain energy that the cell can capture. For example, methane is fully
reduced and we harvest energy by oxidizing (burning) it using oxygen as the oxidizing agent.
3|Page
ALL RIGHTS RESERVED.
BIOC 3021 EXAM 1 REVIEW SHEETS.
Exam Questions And Answers (Guaranteed
A+)
What are the six most common elements present as covalent components of bioorganic
compounds? - answer✔H, O, N, C, S, P, Cl
What are covalent bonds, and how strong and permanent are they relative to other bonds in
living organisms? - answer✔Covalent bonds are the sharing of electrons between two species.
Non polar covalent bonds are the strongest
What is the difference between polar and nonpolar covalent bonds? What combinations of
atoms are involved in these two kinds of covalent bonds? - answer✔Polar covalent bonds: The
EN differs (C-O bonds)
Non-polar covalent bonds: En is identical or is very similar (H-H bonds)
What are common ionic elements in biological systems? What happens to ionic substances in
the aqueous environment of living organisms? What are the properties of the ionic bonds that
occur between inorganic ions or between organic ions? - answer✔Common ionic elements: Na
and Cl
In aqueous environments ionic substances dissociate
Inorganic compounds form ionic bonds that have high melting points that are made up of a
single element or compound that does not include carbon or hydrogen.
What are hydrogen bonds? What organic structures are involved in hydrogen bonding? What is
the importance of hydrogen bonding in living organisms? - answer✔Hydrogen bonds are polar
bonds that have a partially positive H interacting with a partially negative element (like O or N).
Important because they are essential for protein structure, binding of enzymes to substrate and
they hold the DNA helixx together.
What are two types of nonpolar bonds? Why do nonpolar molecules aggregate together in
water? - answer✔Van der waals forces and hydrophobic interactions
1|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
Van der Waals forcesCaused by induced electrical interactions between closely approaching
atoms
E clouds fluctuate together to "fit together"
Strength depends on size of atoms and the distance
Bigger e- clouds from stronger interactions
Strength is inversely proportional to the 6th power of distance
Atoms need to be 2nm apart
Hydrophobic Interactions
These bonds form due to exclusion of water from groups of non polar molecules
Water molecules prefer each other (strongest interactions)
Forces nonpolar molecules together
Hydrophobic molecules are not really attracted to each other, they just herded together by
water so that the maximum number of water-water interactions can form
Water molecules push hydrophobic molecules together so that fewer water molecules need to
be near hydrophobic molecules, water water H bonding can be maximized
What is pH and how does it relate to the molarity of hydrogen ions in solution? - answer✔pH is
the numerical value of -log[H+]. It describes the solutions acidity It is inversely related to the
hydrogen ion concentration. So if pH decreases then H ion increases tenfold.
What is a strong acid? What is the percent dissociation of a strong acid in water? When a strong
acid is present in water, why are the molarity of the strong acid and the molarity of the
hydrogen ion the same? - answer✔A strong Acid completely dissociates in water. The
concentrations of Hydrogen ion and acid are equal since it dissociates completely in an aqueous
environment.
What is a weak acid, and why are weak acids not completely dissociated? Why are the molarity
of the weak acid and the molarity of the hydrogen ion not the same? If a 0.1 M solution of a
weak acid is 10% dissociated, what is the molarity of hydrogen ions? - answer✔Weak Acid does
not dissociate completely in water. Molarities are not the same due to the lack of complete
dissociation.
0.1M x (10/100)= 0.01 M
What is a buffer solution? Why is a mixture of a weak acid and its conjugate base needed to
give good buffering? Why doesn't a solution containing just a weak acid serve as a buffer? Why
2|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
don't strong acids serve as buffers? - answer✔A buffer solution consists of a weak acid and its
conjugate base equilibrium in an aqueous solvent. It can resist changes in pH when a strong
acid or strong base is added. Can't have just one because then the equation would only go one
way. A strong acid can't be a buffer because it ionizes completely.
Write the Henderson-Hasselbach equation. What are the definitions of pH, pKa and log A-/HA?
Why do all weak acids give the same shaped titration curve? At what pH does a weak acid and
conjugate base combination give the best buffering? If a weak acid has a pKa of 5 what is the
pHwhen the weak acid is 10%, 50% and 90% titrated with NaOH? - answer✔pH=pKA+log[A-
]/[HA]. pH describes the solution acidity as it is the numerical value of -log[H+].pKa is the
strength of an acid. Log a-/HA is the molar concentration of the conjugate base. All have the
same titration curve because it has the same flat region +/- 1 unit from pKa, give the best
buffering at pH that is -/+1 from pKa
PH=4.05, 5, 5.95
If the pKa is 6 and the ratio of A-/HA is 1 what is the pH? If the pKa is 6 and the ratio of A-/HA is
10 what is the pH? If the pKa is 6 and the pH is 6 what is the ratio of A-/HA? If the pKa is 6 and
the pH is 5 what is the ratio A-/HA? - answer✔6,7,1,0.01
What are the most common oxidation and reduction reactions in living organisms? -
answer✔The most common oxidation and reduction reactions in living organism are
metabolism reactions
Starting with methane and ending with carbon dioxide, what are the intermediates in an
oxidation pathway in which additional bonds to oxygen are added at each stage? -
answer✔Alkane ---> Alcohol ---> Aldehyde/Ketone ---> Carboxylic Acid ---> Carbon Dioxide
Intermediate = NAD+ reduced to NADH with MDH
Starting with ethane and ending with ethyne (aka acetylene) what are the stages of oxidation in
which hydrogen is removed but oxygen is not added to the compound? - answer✔Ethane
Oxidation takes 2e- and 2H to make ethene
Oxidation takes 2e- and 2H to make Ethyne
Why are oxidation-reduction reactions so important in human metabolism? What role do highly
reduced organic compounds and oxygen play as the major electron donors and acceptors in the
production of energy in this process? - answer✔All metabolism involves carbon redox
reactions.
Reduce carbon atoms contain energy that the cell can capture. For example, methane is fully
reduced and we harvest energy by oxidizing (burning) it using oxygen as the oxidizing agent.
3|Page
