Biochemistry Lipids Flashcards
(14 cards)
What elements are lipids made up from?
Carbon, hydrogen, and oxygen, but less oxygen and more hydrogen than carbohydrates
Lipids typically have a higher hydrogen-to-oxygen ratio compared to carbohydrates.
What are the main types of lipid?
The 2 main types are triglycerides and phospholipids, but they also include waxes and steroids
Each type of lipid has distinct functions and structures.
What are the main jobs of triglycerides?
- They act as energy stores (release more kJ/g than carbs when hydrolysed)
- They are excellent for insulation purposes as they are non-conductive
- They protect many major organs in the body
Triglycerides are stored as sub-cutaneous fat beneath the skin, contributing to insulation and organ protection.
How are triglycerides formed?
They are formed when one glycerol molecule combines with 3 fatty acids via 3 condensation reactions (water removed)
This process is essential for creating the triglyceride structure.
What type of bond is found in triglycerides and where is it found?
ESTER BONDS are formed between the hydroxyl, -OH groups of the glycerol and the carboxyl, -COOH, groups of the 3 fatty acid chains
Ester bonds are crucial for the stability and function of triglycerides.
How is energy released from a triglyceride?
During digestion, hydrolysis occurs, breaking the ester bonds and releasing energy (forming the glycerol and 3 fatty acids once more)
The hydrolysis process is key to utilizing triglyceride energy.
What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids contain the maximum number of hydrogen atoms and therefore no C=C double bonds; unsaturated fatty acids do not have the maximum number of hydrogen atoms and so DO HAVE C=C double bonds
This distinction affects the physical properties and health implications of the fatty acids.
What are mono and polyunsaturated fats?
Monounsaturates have ONE C=C bond; polyunsaturates have more than one C=C bond
The number of double bonds influences the fat’s characteristics and health effects.
What is the difference between fats and oils?
Fats tend to be solid at room temperature and are often made from saturated fatty acids; oils tend to be liquid at room temperature and are made from unsaturated fatty acids.
Saturated fatty acids have no double bonds, whereas unsaturated fatty acids contain one or more double bonds.
How is a phospholipid different from a triglyceride?
Triglycerides are made up of one glycerol molecule and 3 fatty acids; phospholipids are made up of one glycerol molecule attached to 2 fatty acids and one phosphate group.
In phospholipids, one of the fatty acid chains is replaced by a phosphate group.
Define hydrophobic in relation to phospholipids.
The tail end of the phospholipid, containing the fatty acid chains, is hydrophobic and repels water.
Hydrophobic means ‘water-hating’ and is non-polar.
Define hydrophilic in relation to phospholipids.
The head end of the phospholipid, containing the glycerol and phosphate group, is hydrophilic, meaning it is attracted to water and is ‘water-loving’.
Hydrophilic means it is polar (or charged).
What is the job of phospholipids in the body?
They form the phospholipid bilayer, which is what cell membranes are made from, and they are found in a fluid in the lungs called surfactant, which prevents the lungs from collapsing.
In what different ways do phospholipids arrange themselves when exposed to water?
Phospholipids can arrange themselves in the following ways:
* They form a monolayer on the surface of water
* They form micelles when mixed with water
* They form a bilayer when creating cell membranes.
A bilayer membrane is essential for cell structure and function.
