Chapter 3: 3.5 Flashcards
Lipids (26 cards)
What is a lipid?
carbon, hydrogen and oxygen
What are the 2 types of lipids? What are they at room temperature?
Fats, Oils
What is a triglyceride made up of?
1 glycerol molecule + 3 fatty acids
What are fatty acids made up of?
A carboxyl group
What groups do fatty acids and glycerol molecules contain?
Hydroxyl groups
What do the hydroxyl groups do?
Forming 3 water molecules and bonds between the fatty acids and glycerol
What are the bonds between fatty acids and glycerol called?
Ester bonds
What is the structure of saturated fatty acid chains?
> Double bonds between the carbon atoms
All carbon atoms form the maximum amount of bonds with hydrogen atoms
Chains are bent
What are unsaturated fatty acid chains?
Contain single bonds between some carbon atoms
What are monounsaturated fatty acid chains?
Contain double bonds
What is the effect of a double bond?
Causes the molecule to bend, therefore the molecule can’t be packed closely together
What triglycerides do plants contain? Elaborate on it
Unsaturated triglycerides
- Occur as oils
- Healthier than saturated fats
What are phospholipids and what do they contain>
- Modified triglycerides
2. Contain phosphorus, carbon, hydrogen and oxygen
Where are inorganic phosphate ions found?
In the cytoplasm of every cell in prokaryotes and eukaryotes
What are chemical properties of a phosphate ion?
Have extra electrons so are negatively charged, making them insoluble
How is a triglyceride made into a phospholipid? (*Refer to Figure 3 on p.g.55)
One fatty acid chain in the triglyceride is replaced with a phosphate group to form a phospholipid
Describe the structure of a phospholipid
Polar
Fatty chains
They have a phosphate group
Describe the non-polar tails
- Repelled by water so are hydrophobic
- Mix easily with fat
Describe the charged heads
-Attracted by water
What happens when phospholipids mix with water?
- Form a layer on the water’s surface with phosphate heads in the water and fatty acid tails sticking out of the water
Explain what sterols are
- Also known as steroid alcohols
- Another type of lipid found in cells
- Not fats or oils
- Complex alcohol molecules
- Made of a 4 carbon ring structure with a hydroxyl (OH) group at one end
- Have hydrophilic+hydrophobic properties (OH group = hydrophilic, rest of molecule - hydrophobic)
What role does cholesterol have?
What is the result of this?
- Cholesterol has an important role in the formation of membranes, where cholesterol becomes positioned between the phospholipids with hydroxyl groups on the outside of the membrane
- cholesterol adds stability to membranes
- regulates membrane fluidity by keeping membrane fluids at low temperatures + stopping them become too fluid at high temperatures
What roles do lipids play?
- Membrane formation + creation of hydrophilic barriers
- Chemical production
- Impulse transmission
- Waterproof
Where else are lipids stored? What does this provide?
- In skin
- In vital organs
Provides: - Blocks heat loss
- stability to protect vital organs e.g. heart and kidneys
- Buoyancy for aquatic animals e.g. whales
