1.7 Lipids: Triglycerides & Phospholipids Flashcards
The structure and function of triglycerides The synthesis and breakdown of triglycerides The structure and function of phospholipids The similarities and differences between triglycerides and phospholipids (22 cards)
What is a triglyceride?
i.e what is it used for? and in what?
- A lipid
- used to store energy
- animals, plants, and some bacteria
What is the structure of a triglyceride?
Glycerol backbone and three fatty acid tails
What type of bonds are in a triglyceride?
Ester bonds
What are 4 reasons why triglycerides good for energy storage?
- Long hydrocarbon tails - Many carbon-hydrogen bonds can be broken to release energy
- low mass to energy ratio - Lots of energy can be stored in a small volume
- Insoluble - Do not affect water potential of cells as they are large and non-polar
- High ratio of hydrogen to oxygen atoms - will release water when oxidised
How are triglycerides formed?
By condensation reactions
How are triglycerides broken down?
Not by what enzymes but by what type of reaction
By hydrolysis reactions
What is a phospholipid?
A lipid used as a structural component of cell membranes
How does a phospholipid differ from a triglyceride?
One fatty acid tail is replaced by a phosphate group
What are the two parts of a phospholipid?
Hydrophilic head and hydrophobic tail
Why is the phospholipid head hydrophilic?
It contains a polar phosphate group
Why is the phospholipid tail hydrophobic?
It contains non-polar fatty acids
What is a phospholipid bilayer?
A double layer of phospholipids in water
How do phospholipids arrange in a bilayer?
Hydrophilic heads face outwards
Why does a phospholipid bilayer form a barrier?
The hydrophobic center repels water-soluble substances
What is the function of triglycerides?
Energy store
What is the function of phospholipids?
Structural component of membrane
How many fatty acid tails do triglycerides have?
3
How many fatty acid tails do phospholipids have?
2
Do triglycerides contain phosphate?
No
Do phospholipids contain phosphate?
Yes
Are triglycerides polar or nonpolar?
Non-polar
Are phospholipids polar or nonpolar?
Polar
