Lecture 8 Flashcards
Review the grouping of lipids (Fatty acids, triacylglycerols, phospholipids, sphingolipids, steroids)
Simple Lipid: triacylglycerol
Complex Lipid: phospholipid + glycolipid
glycerophospholipid cerebrosides
spinghophosopholipid sulfatide
globoside
ganglioside
Derived Lipid: FA
Discuss the structure and the biomedical importance of fatty acids and cholesterol
FA: components of complex and simple lipids
Cholesterol:
Polar head: likes polar head of phospholipid bilayer
Non polar ring: during hot temp reduced mobility and during cold temp it stabilizes the phospholipid tails
Describe fatty acid structure and discuss the melting points related to chain length and desaturation and relate its significance in humans
FA can be saturated or unsaturated
Unsaturated have double bonds + cis = kinks so they are more fluid. Increase kinks = decrease melting temp
Note: higher chain length = higher melting point
Discuss the biological importance of dietary essential fatty acids and describe in detail the structures of linoleic acid (ω6) and α-linolenic acid (ω3
Cannot synthesis linoleum acid and alpha linolenic acid
Discuss the grouping of fatty acids into the ω-6 and ω-3 families and describe in general the synthesis of arachidonic acid and of docosahexaenoic acid (DHA)
Can make arachidonic acid from w-6 linoleic acid
Humans cannot make enzymes beyond C-9 so add linoleic acid to create arachidonic acid which is C20.
a: desaturate: add double bond
b: elongate: add 2 c
c: desaturate: add double bond
Cannot make alpha linolenic acid but we can make eicosapentaenoic acid (EPA)- c20 and further modify to make docosahexaenoic acid (DHA) - c22
Describe the structures and functions of triacylglycerols.
TAG:
Glycerol backbone + 3 FA + ester bond
Storage form of lipid- used during starvation/ ketone bodies
Distinguish between phospholipids (Sphingophospholipid and glycerophospholipids) and glycolipids with examples for each
Complex Lipids:
1: Phospholipids- phosphate
a: glycerophospholipid - glycerol
b: sphingophospholipid - sphingosine
2: Glycolipids - carb
- cerebroside
- sulfatide
- globoside
- ganglioside
Classify complex lipids:
- Phospholipids which can be further classified based on the alcohol as
• Sphingophospholipid (Eg: Sphingomyelin)
• Glycerophospholipids (Eg: Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine,
phosphatidylinositol, cardiolipin) - Glycolipids (or Sphingoglycolipids or Glycosphingolipids) – Contain a carbohydrate
group: Examples: Cerebrosides, Globosides, Gangliosides and sulfatides
Indicate the composition and functions of:
1. Glycerophospholipids: Phosphatidylcholine, phosphatidylethanolamine, plasmalogens,
phosphatidylserine, phosphatidylinositol, cardiolipin
2. Sphingophospholipid: Sphingomyelin
3. Glycolipids (or Sphingoglycolipids or Glycosphingolipids): Cerebrosides, globosides and
gangliosides
- Glycerophospholipids: have glycerol + 2 FA (nonpolar) + phosphate (N containing group) (polar/hydrophilic)
- phosphatidylcholine: choline (outer MT)
- phosphatidylethanolamine: ethanolamine (inner MT)
- plasmalogens: ether bond instead of ester
- phosphatidylserine: serine (INNER MT)***
- phosphatidylinositol: polyol inositol (inner MT)
PIP2 - IP3 + DAG - cardiolipin: diphosphatidylglycerol/ INNER MT***
- Sphingophospholipid:
- Sphingomyelin - Glycolipids (or Sphingoglycolipids or Glycosphingolipids):
- Cerebrosides
- globosides
- gangliosides
Discuss role of lung surfactant (Dipalmitoyl phosphatidylcholine/ DPPC) in respiratory distress syndrome
Surfactant means to decrease surface tension of alveolar fluid so the alveolus does not collapse when expiration occurs.
Neonates (premature) that have low levels of DPPC = high risk for respiratory syndrome (RDS) due to collapse of alveoli
L/S (lecithin-sphingomyelin) ratio is measures to determine fetal lung maturation
>2 : low risk for RDS, lung is mature
