Summary Biochemistry : Introduction to Molecules of life, carbohydrates, proteins, lipids, enzymes

Molecules of life
Wednesday, 20 April 2022 10:21


Carbon
• Central atom
• 4 valence electrons; 4 bonding sites




Biological Macromolecules



Carbohydrate Protein Lipid Nucleotide
Glucose Amino acid Fats Pyrimidines & Purines
_________________________________monomers____________________________________

Function of macromolecules is dictated by its shape (water gives shape)


Water
• Cells = Water + Macromolecules
• Tight regulated by hypothalamus & kidney function
• Fluid compartments:
1/3
60%=42l




2/3
-Ions provide electrolytes required by our body




-Bicarbonates ions (HCO3-) & Cl- interchange between RBC + plasma to preserve electroneutrality in plasma - important in buffering
-In interstitial fluid [anions] = [cations]
-Intracellular ions demonstrate buffering
-HCO3- + K+ = major buffers
• Structure of water:


► Polarised ∴ electric dipoles
► Asymmetrical (104.5o)




• How water bonds:
-Hydrogen bonding using cohesion or adhesion forces
-Occurs when H+ bonds to lone pairs of electronegative atoms (O, N, F)
-H bonds weaker than covalent bonds
-Require less energy than covalent bonds to break H-bonds

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, -Hydrogen bonding using cohesion or adhesion forces
-Occurs when H+ bonds to lone pairs of electronegative atoms (O, N, F)
-H bonds weaker than covalent bonds
-Require less energy than covalent bonds to break H-bonds
-Bonds with 3.4 water molecules (ambient temp.)
-Bonds with 4 water molecules (freeze temp.)




• Properties of water:




-energetic driving force (folding of proteins, formation of membranes using polarity
-chemical reagent
Hydrolysis : Compound + Water → Building Blocks A.K.A monomers (important in digestive reactions)
Dehydration : Building macromolecules
-pure water ionises to some degree in cells
Release of H+ into solution
Ionisation is very small e.g. only 1 out of 107 water molecules are ionised
Begins concept of pH




Explain law of mass action
Explain working out; [OH ions] = [H ions] because of
ratio, [H] squared




- Pure water is neutral


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, Acidic pH < 7, [H+] > [OH-]
Basic/alkaline solution pH > 7, [H+] < [OH-]
Neutral pH 7, [H+] = [OH-]
• pH is important




• Various physiological buffers to maintain body compartments' physiological pH i.e. resists changes in pH




Interstitial fluid Blood Urine Intracellular fluid Bone
Bicarbonate Bicarbonate Phosphate Phosphate Calcium carbonate
Protein Haemoglobin Ammonia Phospo-compounds
Phosphate Phosphate Proteins
Plasma proteins Histidine





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