Cellular biochemistry summary
L1 Interactions in aqueous systems
Hydrophobic = non-polar = not easily dissolved in water
Hydrophilic = polar = easily dissolved in water
Amphipathic = some parts hydrophilic, some parts hydrophobic
-
+ +
Hydrogen bonds = electrostatic attraction between O and H
- 4 bonds per molecule when in solid phase, 3.4 bonds when in liquid phase
- Relatively weak, strongest when donor and acceptor are in straight line
Van der Waals interactions = to uncharged molecules pull on each other
- Very weak
Ions: hydration makes them stable
Amphipathic molecules -> non polar sides together -> form membranes/ micelles
Acid = can give off H+ (COOH)
Base = can take up H+ (COO-)
Tendency to lose/take up big: strong acid/base, tendency weak: weak acid/base
[𝐶][𝐷]
For weak acids/bases goes: 𝐴 + 𝐵 ⇌ 𝐶 + 𝐷 gives 𝐾𝑒𝑞 = [𝐴][𝐵]
𝑝𝐻 = −log [𝐻 + ] and [𝐻 + ] = 10−𝑝𝐻
pH is important for:
- Effects of proteins
- Diagnostic markers
,Titrations:
Midpoint: [original product] = [formed product] -> pH = pK
[𝑏𝑎𝑠𝑒]
Henderson-Hasselbach equation: 𝑝𝐻 = 𝑝𝐾𝑎 + log ( [𝑎𝑐𝑖𝑑] )
L2 Amino acids & proteins
Basic structure amino acid:
, with 20 different groups in the place of the red H
Classification:
- Non-polar (aliphatic)
Hydrophobic side group -> point groups towards each other -> form protein
- Aromatic groups (ring structures)
Can absorb UV-light
- Polar, uncharged
Can form hydrogen bonds, are on outside of protein
Some form sulphate bridges
- Polar, positively charged
Hydrophilic
- Polar, negatively charged
Hydrophilic
, Amino acids can give away 2 H+ ions: from -COO- and -NH3+ -> zwitter ion
-> 2 pK’s and 2 buffering regions: middle is PI = net electric charge is 0
1 amino acid = 110 dalton
1 dalton = 1.66 * 10-24 g
1 amino acid = 110 * (1.66 * 10-24) g
Peptide = chain of amino acids,
- Hormones, neuropeptides, antibiotics, protection
Protein = polymer of amino acids (way longer)
L1 Interactions in aqueous systems
Hydrophobic = non-polar = not easily dissolved in water
Hydrophilic = polar = easily dissolved in water
Amphipathic = some parts hydrophilic, some parts hydrophobic
-
+ +
Hydrogen bonds = electrostatic attraction between O and H
- 4 bonds per molecule when in solid phase, 3.4 bonds when in liquid phase
- Relatively weak, strongest when donor and acceptor are in straight line
Van der Waals interactions = to uncharged molecules pull on each other
- Very weak
Ions: hydration makes them stable
Amphipathic molecules -> non polar sides together -> form membranes/ micelles
Acid = can give off H+ (COOH)
Base = can take up H+ (COO-)
Tendency to lose/take up big: strong acid/base, tendency weak: weak acid/base
[𝐶][𝐷]
For weak acids/bases goes: 𝐴 + 𝐵 ⇌ 𝐶 + 𝐷 gives 𝐾𝑒𝑞 = [𝐴][𝐵]
𝑝𝐻 = −log [𝐻 + ] and [𝐻 + ] = 10−𝑝𝐻
pH is important for:
- Effects of proteins
- Diagnostic markers
,Titrations:
Midpoint: [original product] = [formed product] -> pH = pK
[𝑏𝑎𝑠𝑒]
Henderson-Hasselbach equation: 𝑝𝐻 = 𝑝𝐾𝑎 + log ( [𝑎𝑐𝑖𝑑] )
L2 Amino acids & proteins
Basic structure amino acid:
, with 20 different groups in the place of the red H
Classification:
- Non-polar (aliphatic)
Hydrophobic side group -> point groups towards each other -> form protein
- Aromatic groups (ring structures)
Can absorb UV-light
- Polar, uncharged
Can form hydrogen bonds, are on outside of protein
Some form sulphate bridges
- Polar, positively charged
Hydrophilic
- Polar, negatively charged
Hydrophilic
, Amino acids can give away 2 H+ ions: from -COO- and -NH3+ -> zwitter ion
-> 2 pK’s and 2 buffering regions: middle is PI = net electric charge is 0
1 amino acid = 110 dalton
1 dalton = 1.66 * 10-24 g
1 amino acid = 110 * (1.66 * 10-24) g
Peptide = chain of amino acids,
- Hormones, neuropeptides, antibiotics, protection
Protein = polymer of amino acids (way longer)
