Titration
What ions form when two water molecules exchange a hydrogen atom?
hydronium (H3O+) and hydroxide (OH-)
structure of phospholipids
glycerol with 2 fatty acids and a phosphate group attatched to the glycerol
What is the main difference between competitive and noncompetitive inhibition?
Competitive inhibitors bind to the active site, whereas noncompetitive inhibitors bind elsewhere and alter the enzyme's shape.
What is the primary structure of a protein
the sequence of amino acids.
what does entropy measure in a system?
disorder or randomness
what does [A-] represent in the Henderson-Hasselbalch equation?
concentration of conjugate base
3 important types of lipids to biological life
fats, phospholipids, and steroids
explain how competitive inhibition decreases enzymatic activity
The inhibitor competes with the substrate for access to the active site.
Two examples of intermolecular forces that can keep R groups of different polarities together.
Hydrogen bonding and other van der Waals forces.
According to the second law of thermodynamics, how does the entropy of a system tend to change over time?
entropy tends to increase over time
What defines an acid versus a base under the Bronsted-Lowry definition?
An acid donates protons while bases accept protons.
structure of steroids
4 interconnected carbon rings
A substrate can act as an allosteric regulator.
Substrates and proteins can have different levels of cooperativity. These degrees of cooperativity are quantified by a value known as the Hill coefficient, or nHill.
• Molecules that exhibit positive cooperativity have nHill > 1.
• Molecules that exhibit negative cooperativity have nHill < 1.
• Molecules that exhibit no cooperativity have nHill of 1.
what are hydrophobic interactions
Polar amino acids have R groups with partial charges, which can interact and bond with the water molecules in the aqueous solution surrounding and inside a cell, making them hydrophilic. Nonpolar amino acids have R groups without partial charges and cannot interact or bond with the water molecules in the aqueous solution surrounding and inside a cell, making them hydrophobic.
when energy is transformed, some of it always becomes what type of energy due to entropy?
heat or thermal energy
What is a buffer solution
a solution that resists changes in pH
explain the difference between saturated and unsaturated fatty acid tails.
Saturated fatty acids:
Have no double bonds between carbon atoms — all carbons are “saturated” with hydrogen atoms.
→ Example: stearic acid (found in butter).
Unsaturated fatty acids:
Have one or more double bonds (C=C) between carbons.
→ Example: oleic acid (in olive oil).
explain feedback inhibition
The products of an enzyme-controlled reaction eventually go back and inhibit its creation.
Explain the structure of beta strands and alpha helices. Explain which parts of the amino acid form hydrogen bonds. How do backbone constituents relate? (no partial credit)
α helices are such a structure that can arise from this hydrogen bonding. These helices appear as coils in a polypeptide’s conformation. The helix is held in place by bonding between every fourth amino acid’s backbone constituents in a chain.
β pleated sheets are the second major type of secondary structure. β pleated sheets form when parallel parts of a polypeptide chain form hydrogen bonds between each other. The parts of an apolypeptide that line up to form β pleated sheets are known as β strands. Note that β strands refer to parts of a single polypeptide, not separate polypeptides.
explain what Gibbs free energy is, the equation to find the change in Gibbs energy of a chemical reaction, and what the variables in the equation mean.
∆G = ∆H − T∆S
where ∆G represents the change in Gibbs free energy, ∆H represents the change in enthalpy, or the total energy of a system, T represents temperature in Kelvin, and ∆S represents the change in entropy.
What is the conjugate base to NH3
NH2-
what are the 2 nitrogenous bases that are purines?
adenine and guanine
What do the Vmax and a mean in the Michaelis-Menten equation?
Vmax represents the maximum rate of the reaction, while a represents the concentration of the substrate.
Explain what a helix breaker/disruptor is and provide two examples. Extra 200 pts if you can explain how each helix breaker functions as a helix breaker.
Proline has a unique structure in which its R group is incorporated into its backbone chemical groups (technically making it an imine), rendering it unable to bend into the correct conformations to form hydrogen bonds with other amino acids and thus unable to form an α helix.
Glycine has a less pronounced effect on α helices compared to proline; however, it can still disrupt the overall structure. Glycine, with a very small R group, has a large amount of conformational freedom and is very flexible. This flexibility causes instability when incorporated in a polypeptide with an α helix.
what does a positive or negative ∆G value tell you about the chemical reaction?
A chemical reaction with a positive ∆G value is non-spontaneous. As the chemical reaction progresses, the amount of energy in the molecules increases, meaning that energy must be input; it does not occur spontaneously. These chemical reactions, which use energy, are known as endergonic.
A chemical reaction with a negative ∆G value is spontaneous. As the chemical reaction progresses, the amount of energy in the molecules decreases, meaning that energy is released and the reaction can occur on its own. These chemical reactions, which release energy, are known as exergonic.