Topic 2: Molecular Biology

2.1 Molecules to metabolism
Living processes involve multiple chemical substances. These are based upon carbon compounds such as carbohydrates, lipids, proteins and nucleic acids.

Application: Urea is produced naturally by living organisms as excrement but it can also be artificially synthesized.

NOS: 

• People believed that organic compounds can only be made using a 'vital principle' - this was vitalism.

• This theory was falsified after it was discovered that urea could be artificially synthesized.

• This falsification does not cause all scientists to abandon the theory, however, it does create controversies.

Carbon can form four bonds allowing a wide range of different molecules to be made. They form covalent bonds with hydrogen, oxygen, nitrogen and phosphorus.

Living organisms are based upon carbon compounds such as carbohydrates, lipids, proteins and nucleic acids which are made up of the elements carbon (C), hydrogen (H), oxygen (O) and nitrogen (N).

Metabolism is the process of chemical reactions, that are catalyzed by enzymes, occurring in a cell or various living organisms. It can be separated into two types:

Anabolism - An endothermic reaction that forms larger molecules from smaller molecules. This processes requires energy (ATP). Examples are condensation reactions, photosynthesis, DNA synthesis and synthesis of complex carbohydrates and polypeptides.

Catabolism - An exothermic reaction breaking down larger molecules into smaller molecules. This process releases energy. Examples are hydrolysis, cellular respiration, digestion.

(REMEMBER -> EXO breaks CATS -> Catabolism is exothermic and breaks down larger into smaller)

2.2 Water

2.3 Carbohydrates and lipids

2.4 Proteins

2.5 Enzymes