Molecular Components of Cells

Molecular Components of Cells

• Cells contain thousands of different molecules
• Many chemical elements are found in cells
• The four most abundant atoms are C, H, O, and N, representing about 96% of the atoms in most living organisms
• Other elements like P, Ca, S, Cl, Na, K, Mg comprise about 4% of the atoms.
• Trace elements (like Cu, Zn, Se, I, Mo) exist in very low concentrations.
• Water (H₂O) makes up about 70% of a bacterium's weight

Inorganic Compounds

• Water: The most abundant component in cells, comprising 65% to 80% of animal or plant cells respectively.
• Water's polarity allows it to form hydrogen bonds with other molecules
• These hydrogen bonds are crucial for many cellular processes including hydrolysis, photosynthesis, thermal regulation.
• Mineral Salts: Dissolved in water, they dissociate into ions (e.g., sodium chloride, potassium chloride, magnesium sulfate).
• lons' balance is crucial for many cellular functions including membrane permeability, cell division, enzyme activity and muscle contraction
• Important roles in nerve signaling, muscle contraction, and enzyme activity.

Organic Compounds

• Organic compounds are composed of C, H, O, N, and sometimes S, P.
• There are four main classes: proteins, carbohydrates, lipids, and nucleic acids.
• Vitamins are also organic compounds.
• Many organic molecules are involved in major cellular processes
• These molecules are named metabolites, and the collection of them is the metabolome

Proteins

• Proteins are the largest and most diverse molecules in cells, composing 55-85% of the cell's dry weight

• Proteins are made up of amino acids linked together by peptide bonds

• There are 20 different amino acids

• Diverse sequences of amino acids result in varied functions

• Proteins perform diverse functions: structure, catalysis, transport, etc.

• Proteins also play crucial roles in communication between cells, immune responses, and energy conversion in muscle activities.

Importance of Proteins

• Proteins play important roles in communication between cells, immune responses, and energy conversion in muscle activities.
• Proteins are crucial for almost all functions in cells and organisms.