Lipids

Referred as fats, composed mostly of carbon-hydrogen bonds

Primary sources of fuel → provide stability to cell membrane and allow for transmembrane transport.

Requires special transport mechanisms (lipoproteins) for circulation in the blood

Major lipids: (5)

diverse group of compounds, insoluble in water but soluble in non-polar solvents (e.g., ether, chloroform).

They are not chemically related like carbohydrates or proteins, but physically related by solubility

Lipids are _ polymers.

Carbohydrates → polymers of

Proteins → polymers of

Functions of Lipids (4)

Most abundant lipids from phosphatidic acid, made in liver & intestine

Formed by 2 fatty acids + phosphorylated glycerol

Amphipathic lipid:

Phospholipid High saturated fatty acid content is a risk factor for

Phospholipid Structure: like triglycerides but with _

Phospholipid In the lungs, it is made by type II pneumocytes as

Phospholipid Serum reference value:

Act as surfactants, reducing alveolar surface tension → aids gas exchange and prevents alveolar collapse

Involved in cell metabolism and blood coagulation

Serve as substrates for enzymes like LCAT and LPL → composition changes can affect enzyme function

Surfactant deficiency → leads to neonatal respiratory distress syndrome (RDS)

Forms of Phospholipids (3)

Forms of Phospholipids Only membrane phospholipid not derived from glycerol, but from sphingosine (an amino alcohol)

Forms of Phospholipids Key component of RBC membranes and nerve sheaths