Elements of Life:
- Living matter is mainly composed of carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
- These elements constitute about 90% of the body's dry weight.
- Other important elements like calcium, potassium, sodium, chlorine, magnesium, iron, copper, cobalt, iodine, zinc, fluorine, molybdenum, and selenium are also found in cells.
Carbon - the Unique Element of Life:
- Carbon is the most versatile element of life.
- It forms an infinite number of compounds due to its ability to form stable covalent bonds and C-C chains.
- About 90% of compounds in living systems contain carbon.
Chemical Molecules of Life:
- Life is composed of chemical molecules.
- A single bacterium cell may contain around 6,000 different organic compounds.
- Humans may have around 100,000 different types of molecules.
Complex Biomolecules:
- Organic compounds like amino acids, nucleotides, and monosaccharides are building blocks of complex biomolecules.
- Examples of complex biomolecules include proteins, nucleic acids (DNA and RNA), and polysaccharides.
- Lipids, although not considered biopolymers, are important biomolecules containing fatty acids.
Structural Hierarchy of an Organism:
- Macromolecules (proteins, lipids, nucleic acids, and polysaccharides) form supramolecular assemblies like membranes.
- Membranes further organize into organelles, cells, tissues, organs, and the whole organism.
