Triglycerides

Structural & functional differences between different types of lipids

Lipids are hydrophobic molecules.

Triglycerides are an energy storage lipid

• Composed of glycerol joined to 3 fatty acid molecules.

• By condensation reaction

• Forming ester bonds

• They are transported in the blood in HDLs or LDLs

• If any of the fatty acids contains 1 or more carbon-carbon double bonds it is an unsaturated fat

Triglycerides can be hydrolysed to release the fatty acid chains, which can be used in respiration.

Saturated fatty acids are straight molecules, can pack more closely together & are associated with high risk of CVD

Cholesterol is a planar molecule found in cell membranes & it regulates membrane fluidity

How are lipids transported in the body?

• Lipoproteins are triglycerides surrounded by a layer of phospholipid, protein & cholesterol.

• Lipoproteins are how triglycerides are transported in the blood.

• Excess energy in diet is converted to LDLs by liver for fat to be transported to adipose tissues for long term storage.

• LDLs contain more saturated fats, more cholesterol & less protein.

• When energy stores are used up, fat is released by adipose back into the blood as HDL

• HDLs contain more unsaturated fats, less cholesterol & more protein.

What is the relationship between blood cholesterol levels & CVD?

• The ratio of HDL to LDL is correlated to CVD

• A low HDL : LDL is a risk factor for CVD

• Because WBC can absorb their saturated fats & cholesterol to become foam cells.

• A high HDL : LDL is thought to have protective effects against CVD

• Genetic variation of apolipoprotein genes affects genetic part of CVD risk

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