B3

• Carbon, oxygen, hydrogen and sometimes nitrogen in biological molecules

• Carbon atoms join together -> form chains/ring structures

  • Can be very large (macromolecules)

    • Often constructed of repeating sub-units (monomers)

  • Polymers:

    • Def: macromolecules mode of long chains of monomers held together by chemical bonds

    • Polysaccharides

      • Chains of single units like glucose

    • Proteins

      • Amino acid chains

    • Molecules made of many small units -> often have different properties than sub-units -> makes them suitable for specific functions in living organisms

      • Glucose = weak & very soluble

        • Cellulose (macromolecule of glucose) = insoluble + tough

          • Good for cell wall formation around plant cells

        • Cells need chemical substances

          • Make new cytoplasm + produce energy

          • Organisms need food -> supply cells with substances

          • Most cells = specialised cells -> specific needs

          • All cells need

            • Water

            • Oxygen

            • Salts

            • Food

          • All cells consist of

            • Water

            • Protein

            • Lipids

            • Carbs

            • Salts

            • Vitamins

            • Or their derivatives

Carbohydrates

• Simple, soluble sugars or complex materials (ex. Starch or cellulose)

• All only have:

  • Carbon

  • Hydrogen

  • Oxygen

• Common simple sugar = glucose (C6H12O6)

• Many glucose molecules joined together -> large carb

• Glycogen

  • Polysaccharide

  • Forms food storage substances in animal cells

• Starch

  • 100s of glucose in chain

  • Important storage substance in plant cells

Fats

• Solid form of lipids (liquids lipids = oil)

• Fats & oils

  • Only made of:

    • Carbon

    • Hydrogen

    • Oxygen

  • Three molecules of fatty acid + 1 molecule of glyercol

Protein

• Chain of amino acids

Structural protein: help structure of cell

• - Cell membrane

• - Mitochondria

• - Ribosomes

• - Chromosomes

  • Enzymes: control chemical reactions that keep cell alive

    • Where:

      • Membrane system

        • Mitochondria

        • Special vacuoles

        • Fluid part of cytoplasm

      • All proteins have

        • Carbon

        • Hydrogen

        • Oxygen

        • Nitrogen

        • Many: sulfur

Water

• Cells = 75% water otherwise die

• Good solvent

• Substances in cells move in water solution