Lipids Flashcards
What are triglycerides?
Triglycerides are a type of lipid consumed in our diet that we use as an energy source. The triglycerides are digested in our small intestines into fatty acids and glycerol.
These products are used by the body’s cells to produce phospholipids- a part of a cell’s plasma membrane. They can also be used to store fat in the body as triglycerides.
How do you form a triglyceride?
A condensation reaction between glycerol and 3 fatty acids.
What are the properties of a lipid?
Lipids are:
- Large, organic molecules
- non-polar
- insoluble in water
- soluble in alcohol
What are 5 uses of triglycerides?
Energy source- triglycerides can be used by prokaryotes and eukaryotes in respiration to produce ATP.
Energy storage- Mammals store triglycerides in adipose tissue.
Protection- Body organs are surrounded by fat, which protects them from sudden body movement.
Insulation- Animals that live in cold climates have a layer of adipose tissue called “blubber” that insulates them from the cold.
Buoyancy- Aquatic animals use their blubber to help them to float, as triglycerides are less dense than water.
What are the uses of phospholipids?
Phospholipids are the main component of plasma membranes, where they form a bilayer.
This is because the phosphate head is hydrophilic and attracts water, whereas the lipid tail is hydrophobic and repels water.
Phospholipid bilayers act as a partially permeable membrane, allowing only small or non-polar molecules into the cell.
What is the purpose of cholesterol?
Cholesterol adds stability to plasma membranes. Animals that live in cold regions have more cholesterol in their membranes to prevent them from freezing.
What is the purpose of steroids?
Steroids are hormones such as oestrogen and testosterone. Although they are large, because they are non-polar they can cross the plasma membrane easily.
