L2: Water, pH and Buffers

Question 1

What are logs in biochemisty?

Answer 1

Logarithms. They are used to measure very large or small amounts.

Question 2

What are buffers?

Answer 2

They help maintain a stable pH level by resisting changes when small amounts of acid or base are added.

Question 3

Unusual properties of water: High Heat capacity

Answer 3

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.

Question 4

Unusual properties of water: Solvency

Answer 4

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.

Question 5

Unusual properties of water: Hydrogen bonding

Answer 5

Leads to cohesion of water molecules and gives water it’s high surface tension.

Question 6

What is an angstrom?

Answer 6

Measures the length of extremely small distances. It’s equal to 0.1 nanometers.

Question 7

What is Gibbs Free energy?

Answer 7

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

Question 8

What is the hydrophobic effect?

Answer 8

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.

Question 9

What is an ordered shell?

Answer 9

The structured arrangement of water molecules around a solute molecule such as an ion or biomolecule.

Question 10

How does water dissociate?

Answer 10

Through self or auto-ionisation.

Question 11

What is the concentration of water?

Answer 11

The amount of water molecules present in a particular system.

Question 12

What are equilibrium constants?

Answer 12

Values describing the balance between reactants and products in a chemical reaction at equilibrium.

Question 13

Define: acid

Answer 13

proton donor.

Question 14

Define: bases

Answer 14

proton acceptor.

Question 15

What is denaturing?

Answer 15

Change of shape and thus the function of biomolecule ie a protein or nucleic acid.

Question 16

What is the henderson-hasslebach equation?

Answer 16

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])

Question 17

When do I use the henderson-hasslebach equation?

Answer 17

When the concentrations of both the weak acid and conjugate base are known. pH = pKa + log ([A-]/[HA])

Question 18

How do i apply the henderson-hasslebach equation?

Answer 18

When the concentrations of both the weak acid and conjugate base are known. pH = pKa + log ([A-]/[HA])

Question 19

What is Le Chateliers principle?

Answer 19

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.

Question 20

What are buffers in the blood?

Answer 20

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.

Question 21

How do amino acids act as buffers?

Answer 21

by accepting or donating protons, amino acids can resist changed in ph and maintain a relatively constant pH level - amoni groups and carboxyl groups.

Question 22

What does glycine do as a buffer?

Answer 22

Glycine helps maintain the pH balance by accepting or donating protons in response to changes in acidity or alkalinity.

Question 23

what is a bicarbonate buffer system

Answer 23

involves the equilibrium between carbonic acid and bicarbonate which helps prevent a significant decrease or increase in pH.

Question 24

what is the phosphate buffer system?

Answer 24

Phosphate ions act as buffers in the blood.