Lipids Flashcards
What are Lipids and what Two groups are they broken into
Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and functions of living cells. It acts as a energy storage system in plants and animals. It is compact so a lot of energy is stored in a small volume. They are divided into 2 groups
(Triglycerides and Phospholipids)
Describe the structure of triglycerides
A glycerol molecule with 3 fatty acids attached via an ester bond (C=O). The 3 fatty acids can either be identical or different and the difference in them will determine the properties of different fats and oils
What is the difference between fats and oils
Although they are both made up of triglycerides fats are solid at room temperature and oils are liquid at room temperature
What are the 2 types of fatty acids
Saturated and Unsaturated
Describe Saturated and Unsaturated fatty acids
Saturated Fatty acids have the full number of hydrogen atoms bonded to the carbon chain and therefore have no double bonds in the carbon chain
Unsaturated Fatty Acids have at least one carbon to carbon double bond in the structure and therefore fewer hydrogens
Why are Lipids not polar
Because they have more -CH than -OH bonds
How does the non polarity of lipids affect it as a storage molecule. How are they stored in plants and animals
Because it is non polar lipids can not dissolve in water making them good storage molecules in Plants and animals. When stored in cells it does not affect the water potential of the cell as it is insoluble. In plants they are stored as oils in seeds and in animals they are stored as adipose tissue
How does the increased number of hydrogens in them affect lipids
It makes lipids highly reduced and when oxidized during respiration they release more energy for the same mass of carbohydrates and proteins. They also release water when oxidised which is used to support organisms in dry conditions (hump of camels )
What is the structure of phospholipids
Phospholipids have a similar structure to triglycerides but one of the fatty acids is replaced by a phosphate molecule. The phosphate group often has a nitrogen containing group like chlorine.
What are phospholipids
Phospholipids are a key component is the make up of cells. They form the phospholipid bi layer within the cell membrane where the hydrophilic phospholipid heads face the aqueous regions within and without of the cell and the hydrophobic fatty acid tails face within the layer. The phospholipid bi layer acts as a hydrophobic region that allows lipid soluble substances to easily diffuse across the cell membranes whereas water soluble ones cannot.
