Lipids Flashcards
Lipids
-Large molecules
-hydrophobic
-varied functions and forms
4 types of lipids
Neutral
Phospholipids
Steroids
Waxes
Neutral lipids
fats and oils (simple lipids)
Phospholipids
glycolipids (complex lipids)
Neutral lipids information
• Often called a triacylglycerol
• Made from two components, glycerol ( a
simple alcohol) and fatty acids
• The fatty acid joins to the alcohol by an ester link
• Are the main storage form of fat in cells (adipose cells)
How is triacylglycerol made
Removal of water between glycerol ans fatty axis forming a glycosidic bond
Normal levels of triglycerides
- normal level: <150 mg/dL
- border line: 150-199 mg/dL
- high: >200mg/dL
Properties of fatty acids
• May be saturated (no double bonds) or unsaturated (1-4 double bonds)
• Double bonds are in cis conformation increasing area of lipid
• Have an even number of carbon atoms (commonly 12-24)
• Have a single carboxyl (acid) group (-COOH)
• Become more hydrophobic with increasing carbon number
Melting points of fatty acids
• Unsaturated fatty acids have lower melting points than saturated fatty acids.
• Unsaturated fatty acids maintain fluidity of cell membranes.
Advantages of low melting points of unsaturated fatty acids
The hooves contain a larger proportion of unsaturated fatty acids than the upper leg.
What type of isomers does oleic acid show
Cis trans
Why are fatty acids essential
required for normal growth, and thought to provide protection against cardiovascular disease e.g. ω-6 fatty acids (linoleic acid), ω-3 fatty acids (linolenic acid)
Role of arachidonic acid
• Present in the cell membrane
• A key inflammatory intermediate
In spiders
Role of omega 3 fatty acids
Fetal developmenyt
Cardiovascular function
Alzheimer’s disease
What type of fat is plant fat and fish fat
Unsaturated
What is the process called of converting unsaturated fats to Saturated
Hydrogenation by adding hydrogen
Side effect of hydrogenation
Double bond in the trans configuration
Phospholipids
In a phospholipid, two fatty acids and a
phosphate group are attached to glycerol
• The two fatty acid tails are hydrophobic, but the phosphate group and its attachments form a hydrophilic head
• Phospholipids make up cell membranes
Phospholipid bilayer
Hydrophilic head
Hydrophobic tail
What is sphingomyelin
Found in myelin sheath
Made from sphinohosine+fatty acids+phosphate group+choline
Niemann-Pick disease
• A genetically-inherited disese.
• Type A and B: Sphingomyelinase deficiency
• Type C:
Defective cholesterol transport NPC-1 gene
• Characterized by
✓ progressive neurologic damage
✓ enlarged live and spleen
✓ jaundice
What is cerebroside
Contain sugar residues
Krabbe’s disease
-Mutations in the GALC gene (galactocerebrosidase gene)
-no myelin in the white matter
What are Steroids characterised by
characterized by a carbon
skeleton consisting of four fused rings
Cholesterol
an important steroid, is a component in animal cell membranes
Normal levels of cholesterol
5mmo\L or less
What is Atherosclerosis
Plaque in the artery wall which causes blood clots
Examples of steroid hormones
Testosterone
Estradiol
Biological functions of lipids
• Structural components of cell membranes
• Energy storage
• Adipose tissue also cushions vital organs and insulates the body
• Regulate cellular activities as hormones
Function of glycerol
Energy source
Function of steroid backbone
-component of cell membranes
-hormones
