Unit 1 Biological Molecules (Lipids) Flashcards
What are triglycerides?
Triglycerides are a type of lipid that are mainly used as energy strorage molecules.
How are triglycerides formed?
Triglycerides are formed from the condensation of 1 molecule of glycerol and 3 molecules of fatty acids.
What is formed between the glycerol and fatty acids chains?
An ester bond is formed between the glycerol and fatty acid chains.
What is released per ester bond made?
Per ester bond made,1 molecule of water is released.
How many molecules of water are released, per triglyceride?
3 molecules of water are released per triglyceride formed.
Describe the structure of fatty acids?
Fatty acids have long ‘tails’.
What are the tails of fatty acids made of?
Fatty acids have tails made of a chain of hydrocarbons containing 4-36 carbon atoms.
Describe the Hydrocabon tails of fatty acids?
The hydrocarbon tail is variable but most fatty acids have a hydrocarbon tail that contains 12-18 carbon atoms.
Where does Glycerol link to with the fatty acids?
Glycerol links to the central carbon atom on fatty acids.
What are the 2 main points about the fatty acids in a triglyceride? step 1
1) The fatty acids in a triglyceride can be similar or dissimilar to each other.
What are the 2 main points about the fatty acids in a triglyceride? step 2
2) The fatty acids can be saturated or unsaturated.
What is stored in the fatty acid tails?
Chemical energy is stored in the fatty acid tails.
What happens as a result of triglycerides breaking down?
As triglycerides break down, lots of energy is released.
What is the fact about the amount of energy in lipids compared to carbohydrates?
Carbohydrates contain half the amount of energy per gram compared to lipids
What is the relation between triglycerides in comparison to water?
Triglycerides are insoluble in water due to the fatty acid tails being hydrophobic.
Since triglycerides are insoluble in water what is this in relation to the water potential?
The cell’s water potential is not changed in relation to the fatty acids tails being hydrophobic.
Why is it important that the cell’s water potential in relation to triglycerides?
This means that the cell’s water potential is not affected by the triglycerides as a result the water being unable to enter the cell via osmosis.
What would happen if too much water entered the cell?
The cell would become swollen and would burst.
Too much water entering the cell is also known as?
Osmotic Shock
Why are the insoluble triglycerides formed as droplets?
The hydrophobic fatty acid tails face inwards which forms a droplet.
What type of energy do triglycerides store?
Chemical energy
What is the similarity between Phospholipids and Triglycerides?
They are both composed of a one glycerol molecule attached to 3 molecules of fatty acids.
What is the difference between Phospholipids and Triglycerides?
Phospholipid has 2 molecules of fatty acids with the third molecule of fatty acid being replaced with a hydrophilic phosphate group.
What is the term used when the phospholipid has an hydrophobic and hydrophilic part?
An amphipathic molecule
In phospholipids where do the hydrophobic tails face?
In Phospholipids the hydrophobic tails faces inwards in the bilayer within a membrane.
What type of substances can’t easily pass through the membrane within the bilayer of the phospholipid?
Water-soluble substances can’t pass through the membrane.
Which way does the hydrophilic phosphate head face?
Outwards
What state are saturated fatty acids at room temperature?
Solids
What negative impact can saturated fats have on humans?
There is an increased risk of heart failure as well as cardiovascular disease.
Give 3 foods with large proportion of saturated fats?
Butter, cheese and creams
What feature do saturated fats have in a chain?
The fatty acids are joined together in single bonds within a chain.
What feature do unsaturated fats have in a chain?
The fatty acids are joined together in at least one double bond with other single bonds.
Give an example of an unsaturated fats?
Cooking Oils
What are phospholipids?
A type of lipid that forms a bilayer.
What are the main component of cell membranes?
Phospholipids
What is the role of a phospholipid?
They are responsible for what goes in and out of a cell
What feature is only present within a saturated fatty acid chain?
There are only single carbon atoms bonded together to form a chain.
What is the test for lipids called?
The emulsion test
What is an emulsion?
Small droplets of a substance are suspended within a solution.
What are the steps within the emulsion test?
1) Place the sample in a boiling with ethanol.
2) Shake well and leave the test tube upright for 2-3 mins.
3) Pour the solution into a boiling tube containing distilled water.
If a lipid is present within the test tube what forms?
A distinct white and milky layer forms.
Describe how triglycrides are formed? (3 steps)
1) Triglyceride is formed from the condensation reaction between the hydroxyl group on the glycerol and the carboxyl group on the fatty acids.
Describe how triglycerides are formed (2nd step)?
2) An ester bond between the hydroxyl groupa nd the carboxyl bond forms.
Describe how triglycerides are formed (3rd step)?
3) For each ester bond made there are 3 molecules of water produced.
How do phospholipids interact with water? (1st step)
1) The phosphate group of the phospholipid is water-soluble so its is hydrophylic.
How do phospholipids interact with water? (2nd step)
2) Therefore the phospholipids have only the phosphate group as hydrophilic which means the rest of the phospholipid is hydrophobic.
How do phospholipids interact with water?
3) This means that phospholipids can interact with water as water is a polar molecule which can interact with the negative charged phosphate head.
Compare saturated and unsaturated fatty acids in their structure? (1st step)
1) Both saturated and unsaturated fatty acid chains are made up of hydocarbon chains.
Compare saturated and unsaturated fatty acids in their structure? (2nd step)
2) The saturated fatty acid chains are made up of one or more double bonds along with the other single bonds.
Compare satturated and unsaturated fatty acids in their structure? (3rd step)
3) The unsaturated fatty acid chains are made up of just single bonds.
Compare satturated and unsaturatted fatty acids in their structure? (4th step)
4) The double bonds in the saturated fatty acids cause the carbon atoms to kink which means unsaturated fatty acids are unable to pack close and tightly together.
