Lecture 19. Lipids Flashcards
Where are fatty acids stored and sythesised ?
Fatty acids are stored as triacylglycerides in adipocytes and synthesised in the liver
What are lipins ?
Proteins with roles in lipid metabolism and disease
What is k1
Precursor of most vitamin k in nature and is a steroisomer of phyllquinone
What is phylloquinone ?
An electron acceptor in photosynthesis
What are the five major classes of steroid hormones ?
- progestogens
- glucocorticoids
- mineralocorticoids
- androgens
- estrogens
What is cholesterol a precursor to ?
Steroid hormones, bile salts and vitamin D
What is nieman pick disease ?
Genetic dificiency of sphinomyelinase
What is the structure of sphingosine ?
18 carbon amino alcohol with unsaturated hydrocarbon chains
What is the function of sphingomyelin ?
Coats axons of neurons, allows nerve transmission over distances
What is sphingosine ?
An alternative to glycerol in some complex lipids
What are some functions of sphingoids ?
- Very abundant in brain extracts
2. Important in signal transmission and cell recognition
What are sphingolipids ?
A class of lipids containing a backbone of sphingoid bases and aliphatic aminoalcohol
What are PC-lecithins?
Emulsifying agents
What are glycerophospholipids ?
Are glycerol based phospholipids, where 2 fatty acids and a phosphoric acid are attached
Where do triglycerides and glycogen store energy ?
In the form of covalent bonds
What happens in a beta oxidation catabolic process ?
A fatty acid is broken down in the mitochondria to generate CoA
Where is rhodopsin attached and by what ?
The eye by a palmitoyl CoA fatty acid
What is a fatty acid ?
A carboxylic acid with a long aliphatic tail
What is the function of waxes ?
Provide surface coverings which prevent water loss
What are adipocytes ?
They are fat cells. Continuous site of synthesis and breakdown of triglycerides. Oxidation provides caloric content
What are triglycerides ?
Stored in adipose tissue, and is a major form of energy in plants and animals
What are the three main functions of lipids ?
- Energy storage and supply
- Membrane components/surface coverings
- Signals, messages, cofactors and pigments
What are the classes of lipids ?
- Simple lipids
- Compound lipids
- Derived lipids
What are prostaglandins ?
Are diverse biological lipid molecules with many functions
What are steroids ?
Organic compounds with 4 rings arranged in a specific orientation eg. cholesterol and sex hormones
What are complex lipids ?
Consist of 2 or more structural moieties such as phospholipids, glycolipids
What are waxes ?
Esters of long chain alcohols and fatty acids
How is the charge spread in a non-polar molecule ?
Symmetrical
In a polar molecule how is the charge distributed ?
Unequally
What molecules are fat soluble ?
Non-polar
Which molecules are water soluble ?
Polar molecules
What do polar molecules have ?
One positive charge and the other end has a negative charge
What have lipids got in common ?
- They are mostly insoluble in water
2. They are soluble in solvents that have low polarity or are non-polar
