L2: Water, pH and Buffers Flashcards
What are logs in biochemisty?
Logarithms. They are used to measure very large or small amounts.
What are buffers?
They help maintain a stable pH level by resisting changes when small amounts of acid or base are added.
Unusual properties of water: High Heat capacity
Water can absorb and store a significant amount of heat without a large change in temperature. Heat first breaks the bonds and then the increase in kinetic energy increases the movement of the particles.
Unusual properties of water: Solvency
Oxygen is more electronegative than hydrogen, which creates a polar molecule. This allows water to interact with other polar molecules. Like dissolves like through solvation or hydration.
Unusual properties of water: Hydrogen bonding
Leads to cohesion of water molecules and gives water it’s high surface tension.
What is an angstrom?
Measures the length of extremely small distances. It’s equal to 0.1 nanometers.
What is Gibbs Free energy?
It is a measurement of the maximum reversible work that can be performed by a system at constant temperature and pressure.
e.g The oxidation of glucose and the production of ATP in humans results in the storage of large amounts of Gibbs free energy in the phosphate bonds of ATP
What is the hydrophobic effect?
The tendency of nonpolar molecules or regions within a molecule to aggregate or avoid contact with water molecules due to the unique properties of water and the desire to minimise the disruption of water’s hydrogen bonding nextwork.
What is an ordered shell?
The structured arrangement of water molecules around a solute molecule such as an ion or biomolecule.
How does water dissociate?
Through self or auto-ionisation.
What is the concentration of water?
The amount of water molecules present in a particular system.
What are equilibrium constants?
Values describing the balance between reactants and products in a chemical reaction at equilibrium.
Define: acid
proton donor.
Define: bases
proton acceptor.
What is denaturing?
Change of shape and thus the function of biomolecule ie a protein or nucleic acid.
What is the henderson-hasslebach equation?
An equation used to calculate pH of the solution containing a weak acid and its conjugate base when the concentrations of both are known. pH = pKa + log ([A-]/[HA])
When do I use the henderson-hasslebach equation?
When the concentrations of both the weak acid and conjugate base are known. pH = pKa + log ([A-]/[HA])
How do i apply the henderson-hasslebach equation?
When the concentrations of both the weak acid and conjugate base are known. pH = pKa + log ([A-]/[HA])
What is Le Chateliers principle?
If a system at equilibrium is subjected to a change in temperature, pressure, or concentration of reactants of products, the system will adjust itself in order to counteract the affect of the change and restore equilibrium.
What are buffers in the blood?
Chemical systems that help maintain pH balance of the blood within a narrow range. ie proteins such as hemoglobin can accept or donate protons to help maintain pH balance.
How do amino acids act as buffers?
by accepting or donating protons, amino acids can resist changed in ph and maintain a relatively constant pH level - amoni groups and carboxyl groups.
What does glycine do as a buffer?
Glycine helps maintain the pH balance by accepting or donating protons in response to changes in acidity or alkalinity.
what is a bicarbonate buffer system
involves the equilibrium between carbonic acid and bicarbonate which helps prevent a significant decrease or increase in pH.
what is the phosphate buffer system?
Phosphate ions act as buffers in the blood.
