Module 2 Section 2 - Lipids Flashcards
What are the three types of lipids we need to know
Triglycerides
Phospholipids
Cholesterol
What are triglycerides
Macromolecules
What is a macromolecule
Complex molecules with a relatively large molecular mass
What do all lipids contain
Carbon
Hydrogen
Oxygen
What is the structure of triglycerides
1 molecule of glycerol with 3 fatty acids attached to it
What are the structure of the fatty acids molecules
-Made of hydrocarbons
-long tails
-hydrophobic
What bonds do triglycerides contain
Ester bonds
Triglycerides are synthesised by the formation of ….
An ester bond between each fatty acid and the glycerol molecule
How did each ester bond formed
Condensation reaction
What happens in a condensation reaction
A water molecule is released
What is the process in which triglycerides are synthesised called
Esterification
How are ester bonds broken
Hydrolysis reaction (water molecule is used up)
What are the 2 types of fatty acids
Saturated
Unsaturated
What is the difference between saturated and unsaturated fatty acids
Their hydrocarbon tails
Saturated fatty acids don’t have any ….
Double bonds between carbon atoms - fatty acids is saturated with hydrogen
Unsaturated fatty acids have at least …
One double bond between carbon atoms which cause the chain to kink
What are triglycerides mainly used for in animals and plants
energy storage molecules
What do some bacteria use triglycerides as
To store energy and carbon
Why are bacteria good for storage
Long hydrocarbon tails that contain lots of chemical energy
They are insoluble so water doesn’t enter the cells by osmosis
What do the long tails of triglycerides allow
It allows lipids to contain about twice as much energy per gram as carbohydrates
How does triglycerides repel/deter water from entering cells
They act as insoluble droplets in cells because fatty acid tails are hydrophobic - the tails face inward, shielding themselves from water with their glycerol heads
Where are phospholipids found
Cell membranes of all eukaryotes and prokaryotes
Phospholipids make up what in cell membranes
Phospholipid Bilayer
Cell membranes control what enters and exits a cell how does a phospholipid do this
The head is phospholipids are hydrophilic and their tails are hydrophobic - they form a double layer with their heads facing out toward the water on either side
How does the phospholipid bilayer allow the membrane to act as a barrier
The centre of the bilayer is hydrophobic meaning water-soluble substances can’t easily pass through
What is the structure of cholesterol
It has a hydrocarbon ring attached to a hydrocarbon tail
What is attached to the ring structure
A polar Hydroxyl group
What does cholesterol do to eukaryotic cells
They help strengthen the cell membrane by interacting with the phospholipid bilyaer
Phospholipids are also….
Macromolecules
What is the structure of a phospholipid
1 molecule of Glycerol
2 Fatty acids attached to the glycerol
1 phosphate group attached to the glycerol
The phosphate group is….
Hydrophilic
The fatty acid tails are….
Hydrophobic
What is said about cholesterols size and shape
Small size and flat shape
What is the significance of the size and shape of cholesterol
The size and shape allows cholesterol to fit in between the phospholipid molecules in the membrane
How does cholesterol help to make membranes less fluid and more rigid
They bind hydrophobic tails of the phospholipids, causing them to pack more closely.
