Amino Acids

Question 1

Non-covalent Intermolecular reaction

Answer 1

Electrostatics (ion-ion, ion-dipole, dipole-dipole)

Hydrogen bonding

Van Der Waals

Hydrophobic affect

Question 2

Amino Acids structure

Answer 2

Possess both a carboxyl (-COOH) and an amino acid (-NH^2) group.

Question 3

Alpha Amino Acids structure

Answer 3

Both carboxyl (-COOH) and amino (-NH^2) groups attached to a central carbon atom known as the alpha carbon atom.

Question 4

What is the R in the structure of an amino acid?

Answer 4

A hydrogen atom

Or

Organic group (polar, non-polar, basic or acidic).

R determines the properties for the amino acid.

Question 5

Basicity

Answer 5

Most commmonly measured using pKa of conjugate acid.

Less acidic conjugate acid < stable
Lower Ka < higher the pKa
= < basic the original base.

Question 6

Sources of amino acids

Answer 6

Plants And Microorganisms

(Synthesised from simple inorganic molecules)

Question 7

Bronsted-Lowry

Answer 7

(Remember Bronsted-Lowry has a strike through the first ‘o’)

Acid - proton (hydrogen ion) donor

Base - proton (hydrogen ion) acceptor

Question 8

Simple Acid and Base equation/formula

Answer 8

H-A + H2O —K—>(<-a- underneath) A- + H30+

Acid 1 + Base 1 —> conjugated base of acid 1 + conjugated acid of base 1

(arrow from joining hyphen to other side of A)

Question 9

Equation for Ka

Answer 9

Ka = [Conjugated base of acid 1][H30+]/[Acid 1]

Or

Ka = [A-][H3O+]/[HA]

Question 10

Equation for pKa

Answer 10

PKa = -log10 Ka