Lipids Flashcards
Lipids : elements, monomer, function
CHO, glycerol and fatty acids, provides energy, cell membranes, hormones
Triglyceride functions
- Energy storage in animals and plants due to long fatty acid chains which contain ester bonds that release energy when hydrolysed
- Energy source for respiration
- Protection packing around vital organs
- Thermal insulation - reduces energy loss
- electrical insulation around neurons help speed up conduction of action potentials
- Helps buoyancy in aquatic mammal
- source of water - when fat is being condensed Ester bonds are made so water is released
E.g. used for survival for camels (in humps) - absorption of fat soluble vitamins ADEK
Why are triglycerides a better energy storage molecule than carbohydrates?
because they are vey long so they store more ATP that they can release
Why do camels store fat?
When fat is condensed, Ester bonds are made therefore water is released. This is used to survive in dry conditions.
Are lipids polar or nonpolar?
Nonpolar so they don’t dissolve in water, but they do dissolve in ethanol
How do you test for lipids?
Add ethanol into the mixture for the lipids to be dissolved in the ethanol then water for it to separate a positive test can be indicated through a cloudy white emulsion forming on top
What are lipids: polymers or macromolecules? And why
Macromolecules they are made of different molecules bonded together
Triglyceride structure
Glycerol attached with Ester bonds to 3 fatty acid chains
What is the condensation of lipids also known as?
Esterification
Triglyceride sources
- Lipids from animals (butter lard meat) are saturated.
They are solid at room temperature - Lipids from plants (oil nuts seeds) are unsaturated. contain double bonds so the chain can be kinked. They are liquid at room temperature
Phospholipids structure
Hydrophilic Phosphate head attached to glycerol and two hydrophobic fatty acids tails
Phospholipid functions
Component in cell membranes control what goes in and out of the cell by acting as a barrier to polar (water soluble) molecules
Suggest two medical conditions that may be associated with increased blood cholesterol levels
Heart attacks/plague/ strokes
Cholesterol structure
Hydrocarbon rings attached to hydrocarbon tail and a hydroxyl group
Give two reasons why triglycerides are used as energy storage molecules
They are insoluble and contain lots of chemical energy in the long fatty acid chains
Explain how the structure of phospholipids make them suited to their function
PhosphoLipid heads are hydrophilic and their tails are hydrophobic. so they form a double layer (the bilayer of the cell membranes) with their heads facing outwards towards the water on either side. The centre of the bilayer is the hydrophobic so water soluble substances can’t easily pass through.
Why might PH fall During the hydrolysis of lipids
Fatty acids are released
Lipids are used for energy storage in the form of
Triglycerides
what is there a lot of in the fatty acid tails
hydrogen
in a triglyceride where does the Ester Bond form between glycerol and fatty acid
The OH from the carboxylic acid group of the fatty acid and a H from the OH group on the glycerol is lost as a water molecule.
single bond is formed between the C left from carboxyl group and the O from OH group
How are lipid molecules suited to their role in animals
- insoluble - doesn’t affect water potential of cell
- fatty acid Have long carbon chains which are energy rich so contain more energy in less space which can be broken down to release more energy to meet high demands
- Animal fats are harder because they are saturated and are solid at room temperature so a more suited to their role as protection for vital organs or thermal insulation
why will triglycerides With less hydrogens Have a lower melting point
Less hydrogen means more double bonds Meaning more kinked chains which are less uniformly packed these take up more space resulting in less triglycerides to be stored resulting in less energy needed to break the ester bonds in these triglycerides
