Lipids Flashcards
What are 2 main groups of lipids?
Triglycerides
Phospholipids
What are the 3 elements lipids are made up of?
Carbon
Hydrogen
Oxygen
Do lipids contain a lower proportion of oxygen compared to carbohydrates?
Yes
What are triglycerides made up of?
1 glycerol
3 fatty acids
Why are triglycerides not considered to be polymers?
Made up of 2 different types of subunit (glycerol and fatty acids)
Have different structures
Are not made from identical monomers
What is the general formula for glycerol?
C3H8O3
Is glycerol constant in both triglycerides and phospholipids?
Yes
What are the 3 main components of fatty acids?
Methyl group (CH3)
Long hydrocarbon chain (CH2)
Carboxyl group (COOH)
What are constant and what is the variable in fatty acids?
Methyl group - constant
Hydrocarbon chain - variable
Carboxyl group - constant
What are the properties of saturated fatty acids?
Are solid at room temperature
Contain no carbon to carbon double bonds
Has a straight chain hydrocarbon chain
Has the maximum number of hydrogen atoms bound to the carbon atoms in the hydrocarbon chain
What are the properties of unsaturated fatty acids?
Oils at room temperature
1 or more carbon to carbon double bonds
Does not contain the maximum number of hydrogen atoms
How is a triglyceride formed?
1 glycerol + 3 fatty acids = triglyceride
Each fatty acid is bonded to the glycerol by an ester bonds
Has 3 ester bonds in total
What can a high intake of fat lead to?
Damages heart and coronary arteries
Contributes to heart disease
What are low density lipoproteins (ldl’s)?
Contain and transport saturated fats and cause harm
Fatty material can block major arteries (plaque)
Cause a myocardial
Infarction (heart attack)
Stick to the lining of the vessel
What are high density lipoproteins (hdl’s)?
Contain and transport unsaturated fats
Carry harmful fats away to the liver for disposal
Higher proportion of HDL in the blood lowers the risk of heart disease
Removes ldl’s from blood to the liver
What health implication can occur because of a high fat intake?
Atherosclerosis
Aneurysm
Myocardial infarction
Are lipids soluble or insoluble in water?
Insoluble in water
Soluble in organic solvents (acetone/ethanol)
What are the main 6 functions of lipids?
Energy storage
Protection of vital organs
Thermal insulation
Buoyancy
Metabolic water
Waterproofing
How does energy storage help with the function of lipids?
Used as an energy storage in seeds and animals
Release a lot more energy than carbohydrates
Used as alternative respiratory substrates
How does the protection of vital organs help with the function of lipids?
Used as ‘shock absorption’
Prevent physical damage to internal organs
How does thermal insulation help with the function of lipids?
Slow conductor of heat
Examples - blubber in whales, seals and polar bears
Lipids reduces heat loss
How does buoyancy help with the function of lipids?
Lipids are less dense than water
Float and have a role in maintaining buoyancy in organisms
Examples - fish
How does metabolic water help with the function of lipids?
Production of metabolic water occurs when lipids are oxidised by respiration
Important to desert animals
Example - camels whose hump is made of fat
How does waterproofing help with the function of lipids?
Waxes are hydrophobic
Cover the exoskeleton of insects and cuticle of plant leaves
Provide a waterproofing property
Reduce water loss
What are phospholipids?
Has 1 glycerol, 2 fatty acids and a phosphate group attached to the glycerol
Which part of the phospholipids is hydrophobic and hydrophilic?
Fatty acid tail - hydrophobic
Polar head group - hydrophilic
What is the main function of phospholipids?
Important component of cell membranes
Helps control the inflow and outflow of substances
Due to the presence of hydrophobic fatty acid tails, a hydrophobic core is created when a phospholipid bilayer forms
Acts as a barrier to water-soluble molecules
Describe the structure of phospholipids
Are amphipathic (both hydrophobic & hydrophilic)
Phospholipids form monolayers/bilayers in water
