Molecular Biology

Molecular Biology

2.1 Molecules to Metabolism

Molecular biology explains living processes in terms of the chemical substances involved.

Molecular biology = branch focused on structures and functions at a molecular level.

Carbon atoms can form four covalent bonds allowing a diversity of stable compounds to exist.

Atom = a single particle of an element, consisting of a positively charged nucleus surrounded by a cloud of negatively charged electrons.

Molecule = a group of two or more atoms held together by covalent bonds.

Organic compound = consists of carbon and is found in living things.

Forms diversity by:

Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids.

Carbohydrate = organic compound composed of carbon, hydrogen and oxygen atoms, with a ratio of two hydrogens to one oxygen.

Lipids = class of non-polar, hydrophobic molecules that are insoluble in water, and may come in a variety of forms, namely simple, complex or derived.

Proteins = large, complex molecules, composed of carbon, hydrogen, oxygen and nitrogen.

Nucleic Acids = chains of subunits called nucleotides, which contain carbon, hydrogen, oxygen, nitrogen and phosphorus, and are found in the form of either ribonucleic acid (RNA), or deoxyribonucleic acid (DNA).

Metabolism is the web of all the enzyme-catalysed reactions in a cell or organism.

Metabolism = integrated network of all the biochemical reactions of life.

Functions of metabolic pathways:

  1. Providing a source of energy for cellular processes.
  2. Enabling the synthesis and assimilation of new materials for use in the cell.

Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.

Anabolism = the building up of complex molecules from smaller ones.

Condensation reaction = formation of larger molecules involving the removal of water from smaller component molecules.

Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers.

Catabolism = the breaking down of complex molecules in the biochemistry of cells.


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