Lipids Flashcards
What do lipids use to store energy?
Glucose converted to Glucose6P, goes through glycosis to produce pyruvate and then with PDH forms TCA, which then forms citrate and you have fatty acid synthesis.
What are the useful benefits of lipids?
Fats and oils for energy storage.
Insulation from environment- heat and shock absorber.
Water repellent,e.g. birds, sheep.
Prevents evaporation in plants.
How are lipids good biological membranes?
They are a barrier between cells and the environment. They are essential for generating electrochemical gradients.
Lipids are light absorbing _________.
pigments
Lipids are anchors for ________.
proteins
What additionally are lipids good for?
Vitamins
Hormone production
Give the 4 ways lipids are building blocks and a description?
Lipids- Chemically diverse
Oils- Viscous liquid immiscible in water.
Fats- Soft greasy substance, composed of lipid mixtures.
Wax- Harder and less greasy than fats. Form solids at ambient temperatures.
What is a fatty acid made up of?
Carboxyl group- Called the ‘head group’, anionic, POLAR.
Hydrocarbon chain- (4-36) carbons, almost always even, HYDROPHOBIC.
Are there many types of lipids?
100 fatty acids known- differ in chain length and saturation.
What is the difference between a saturated and unsaturated fatty acids?
In the hydrocarbon chain of the fatty acid in saturated fats all the bonds are C-C= saturation.
However in unsaturated fats the hydrocarbon chain has >1 C=C bonds= unsaturation.
Does the C=C bond rotate?
It does not rotate.
What does cis mean in relation to fatty acids.
An unsaturated fatty acid where the hydrogen atoms bonded to double-bonded carbon atoms are on the same side, resulting in a kinked shape of the carbon chain.
C=C in most natural fatty acids are ___
Cis
What is the nomenclature of fatty acids?
The last C in chain is always ⍵.
No C=C is saturated
≥C=C is unsaturated
1 C=C is monounsaturated
>1 C=C is polyunsaturated.
What is the omega nomeclature for polyunsaturated fatty acids?
Counting for C=C bond goes up from the omega carbon.
This is because they are important for human nutrition.
If there is a C=C at the 3rd C from the omega this becomes an omega 3 fatty acid.
If there is a C=C at the 6th C from the omega this becomes an omega 6 fatty acid.
What happens when chain length increases of the fatty acid?
Solubility decreases
Melting point increases.
What happens when the saturation level of a fatty acid increases?
the melting point decreases.
What type of C=C bonds do natural fats have?
Cis C=C bonds.
Describe the nature of trans C=C bonds?
Extended and increase melting point.
How do trans fats have increased shelf-life?
Fats are partially hydrogenated for C=C to C-C which stops the double bonds from oxidising.
What is the unwanted side affect of Cis C=C bonds?
Cis C=C become trans C=C and the intake of trans fats increases risk of cardiovascular disease.
What are the two broad families of lipids?
Storage lipids are NEUTRAL
Membrane lipids are POLAR
What is the simplest lipid constructed from fatty acids?
Triacylglycerol. Neutral lipids.
What does tracylglycerol consist of?
-Glycerol
-3 ester linked fatty acids.
What affects the complexity of a triacylglycerol?
Whether the fatty acids that make up triglycerides are the same or mixed. If they are the same then it is simple but if mixed then complex.
Are triglycerides soluble or insoluble?
Insoluble.
What is the function of triacylgylerols?
Provide energy and insulation.
What is the structure of storage lipids?
An adipocyte cross section.
Large fat droplets.
What do lipase enzymes do?
Release fatty acids that are used for energy production.
They store twice the energy than carbohydrates and weigh less because of the no hydration water.
What does amphipathic mean?
A molecule or protein having both hydrophilic and hydrophobic parts.
How are membrane bilayer formed from?
Amphipathic parts: hydrophilic head and hydrophobic tail.
What are the 3 major types of membrane lipids?
- Glycerophospholipids
- Sphingolipids
- Sterols(cholesterol)
What are glycerophospholipids composed of?
- Glycerol
- 2 fatty acids
- phosphate with alcohol attached
Give some structural points of glycerophospholipids?
Phosphate group is negatively charged.
Fatty acids tails vary widely.
One type of glycerophospholipid may consist of several different species with unique combination fatty acids.
Varies per species and tissue within an organism.
What part from a glycerophospholipid affects its name?
The phosphate group.
E.g. Phophatidylcholine
Name of head group is choline.
Describe the structure of sphingolipids?
Polar head
2 non-polar tails
Doesn’t have a glycerol, sphingsine attaches to a long chain fatty acid.
Sphingosine is a long aiphatic chain amino alcohol.
End group similar to glycerol.
What is the structure->function relation of sphingolpids?
The phosphate group modifies function.
There are proteins found on plasma membrane.
Sphingolipids are present in myelin sheath.
The carbohydrate head groups lead to cell-cell recognition e.g ABO blood groups.
Where are gangliosides found?
Eukaryotic cells.
What does the glycolpid ganglioside do?
Determine blood group types.
What do the subtle differences in oligosaccharide group lead to?
Changes in blood type recognition by the immune system.
What is the major sterol in animals?
Cholesterol
It plays a structural role in membranes and also precursor of steroids.
What apart from storage and structural do lipids do?
They signal HORMONES and INTRACELLULAR MESSENGERS carried in blood between tissues in response to stimuli.
They signal PIGMENTS for photosynthesis and vision.
They signal plants to produce volatile lipids to COMMUNICATE from a distance and DETER PREDATORS.
Give a description of steroids?
Don’t have the alkyl chain attached to D ring(as in cholesterol)
More polar than cholesterol
Steroid hormones travel in bloodstream.
Steroids bind receptor and change gene expression.
What are two common steroids derived from cholesterol?
Testosterone(male sex hormone)
Cortisol(regulates glucose metabolism)
What are the two types of vitamin?
Water soluble
Fat soluble
What does vitamin D do?
Regulate metabolism of Calcium in the liver, intestine and bone.
What is the structure of waxes?
Long chain fatty acids+long chain alcohols.
High melting temperatures, Solid at room temperature.
What is the function of waxes?
Energy stores for plankton.
Water repellent for birds
Prevent evaporation in waxy plants, e.g holly.
How are waxes used industrially?
Soaps and leather production
Polish
Food additive
Waterproofing of clothing(most memorable)
