Lipidy - složené lipidy - struktura, význam zástupci - handout

Lipids

  • Sloné lipidy: Key structures and functions discussed in a general medicine lecture by Lenka Fialová.

Selected Categories of Lipids

  • Different categories include:

    • Acyly mastných kyselin (Fatty Acids)

    • Glycerolipidy (Glycerolipids)

    • Glycerofosfolipidy (Glycerophospholipids)

    • Sfingolipidy (Sphingolipids)

    • Sterolové lipidy (Sterol Lipids)

    • Prenolové lipidy (Prenol Lipids)

Glycerophospholipids (GP)

  • Defined as glycerol esters with fatty acids.

  • On the third carbon of the glycerol backbone, phosphoric acid is attached.

  • The phosphoric acid in GP is further esterified with small polar molecules, often containing –OH groups.

Structural Basis of Glycerophospholipids

  • Kyselina fosfatidová (Phosphatidic Acid):

    • Triester of glycerol.

    • Fatty acids are esterified at positions 1 and 2.

    • At position 3, phosphoric acid (negatively charged) is esterified.

Acyl Groups in Glycerophospholipids

  • Presence of saturated and unsaturated fatty acids in the structure.

  • Display the properties of hydrophobic (water-repelling) and hydrophilic (water-attracting) groups.

Categories of Glycerophospholipids based on Hydrophilic Component

  • Differences emerge based on the nature of the hydrophilic components esterified with phosphoric acid.

  • Example groups include:

    • Fosfatidylcholin (Phosphatidylcholine)

    • Fosfatidylserin (Phosphatidylserine)

    • Fosfatidylethanolamin (Phosphatidylethanolamine)

    • Fosfatidylinositol (Phosphatidylinositol)

Importance of Glycerophospholipids

  • Structural components of cell membranes.

  • Possess emulsion properties and act as surfactants to reduce surface tension.

  • Participate in cellular information transfer and signaling.

Notable Glycerophospholipids

  • Fosfatidylcholin (Lecithin):

    • Most abundant phospholipid in cell membranes (especially external membrane layers).

    • Serves as a reservoir of choline for acetylcholine synthesis (neurotransmitter).

  • Dipalmitoylfosfatidylcholin:

    • Component of lung surfactant, reducing surface tension in alveoli.

Phosphatidylinositol Role in Cell Signaling

  • Acts as a precursor for second messengers, influencing cell signaling pathways.

Kardolipin (Diphosphatidylglycerol)

  • Two phosphatidic acid molecules linked via glycerol.

  • Key phospholipid in mitochondrial inner membranes.

Glycosphingolipids

  • Comprised of carbohydrate components, lacking phosphoric acid.

  • Structural categorization into neutral and acidic types:

    • Cerebrosides: Compiled of ceramide and sugar (galactose/glucose).

    • Gangliosides: Complex structures with multiple sialic acids locations.

Summary of Functions

  • Glycerophospholipids: Built for cellular structure, interactivity, and signaling.

  • Sphingolipids: Key in membrane biology, cellular interactions, and communicating signals.

  • Gangliosides: Known for their abundance in brain tissue and role in cellular signaling and receptor activity.