Lipids Flashcards
what are Lipids properties
- Large biomolecules
- Formed from carbon, hydrogen, oxygen and sometimes phosphorus
- Largely non-polar (mostly C-H and C-C bonds)
- Largely insoluble in water
- Soluble in non-polar solvents (e.g. hexane)
- Lipids are not polymers
- Hydrophobic interactions cause lipids to group together in water
give examples of lipids
- Fats
- Oil
- Waxes
- Phospholipids
- Steroids
what is the structure of lipids?
Two different subunits make a triglyceride (a type of lipid):
- Glycerol forms the backbone and has 3 side attachment sites for fatty acids
- 3 fatty acid side chains attach to the glycerol backbone to form a triglyceride
Formation of Triglycerides
• Dehydration synthesis (condensation reaction)
Triglyceride Digestion
- Triglycerides can be broken down by hydrolysis
- Digestion of triglycerides requires intestinal enzyme lipase and water
- Fatty acids are more easily absorbed and transported
glyceral,monoglyceride, diglyceride, fatty acids
what are the two classes of Fatty Acids
- Triglycerides are composed from a large variety of fatty acids added to glycerol
- Two classes of fatty acids form triglycerides:
- Saturated with single C-C bonds
- Unsaturated with numbers of double C=C bonds
give an example of a saturated fatty acid (SFA)
palmitate
give an example of • Unsaturated Fatty Acid (UFA)
Oleate
what are FFAs
give exaples of fats that cant be produced by the body.
- When not part of a triglyceride: free fatty acids (FFAs)
- Some FFAs are essential
- Cannot be synthesised in the body
- Omega-3 (-3) fatty acids (e.g. α-linolenic acid)
- Omega-6 (-6) fatty acids (e.g linoleic acid)
Dietary Fatty Acids
describe
SFAs and UFAs
- SFAs form compact, closely packed triglycerides, solid at room temperature
- UFAs form loosely packed triglycerides, liquid at room temperature
Steroids are lipids:
describe the structure and compounds involved in creating it
- Basic structure is four fused carbon rings with various side groups attached
- Lanosterol is the building block for other steroids
- Lanosterol is formed by the cyclization of squalene
give an examples of steroids
- Cholesterol
- Sex hormones
- Corticosteroids (produced in adrenal cortex)
- Vitamin D
examples of sex hormones
- Oestrogen
- Progesterone
- Testosterone
where are Corticosteroids found and give an example of this?
• Corticosteroids (produced in adrenal cortex)
Aldosterone (mineralocorticoid)
Cortisol (glucocorticoid)
whats the real name of vitamin D? give an example
• Vitamin D (cholecalciferol) – a secosteroid
what is a Phospholipids
• Some lipids have a phosphate group (PO42-) bonded to the glycerol in place of a fatty acid
what are the properties of phosphate group on phospholipids
- Polar
- Soluble in water (hydrophilic)
- Head
what are the properties of fatty acid groups on phospholipids
- Non-polar
- Insoluble in water (hydrophobic)
- Tail
describe the structure of Phosphatidylcholine
choline is attached to phosphate group on a phospholipid