1.2 Lipids

Tania Parvaiz
Flashcards by Tania Parvaiz, updated more than 1 year ago


AS level AS Biology (Unit 1 - Biological Molecules) Flashcards on 1.2 Lipids, created by Tania Parvaiz on 03/01/2017.
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Question Answer
How do lipids react in water and why? Insoluble in water because fatty acid tails are hydrophobic
How do lipids react in organic solvents such as alcohol and acetone? Soluble in organic solvents
What elements do lipids contain and how to the proportions compare to the proportions in carbohydrates? •Carbon hydrogen and oxygen •Proportion of oxygen to carbon and hydrogen is smaller in lipids
Are lipids polymers? No
Name the 2 types of lipids and their biological roles? •Triglycerides - store energy and provide insulation •Phospholipids - form cell membranes
What is a triglyceride molecule made up of? A glycerol molecule and 3 fatty acid chains
What do fatty acid molecules have? Long hydrocarbon tails
How is a triglyceride formed? (Diagram) a591403c-0bc9-4573-8cec-936e41226997.jpg (image/jpg)
2 differences between saturated fatty acids and unsaturated fatty acids? •Saturated = only single C-C bonds. Unsaturated = 1 double bond •Saturated are solid at room temp, unsaturated are usually liquids at room temp
4 roles of lipids? •Provide energy •Waterproofing - insoluble in water •Insulation - slow conductors of heat. •Protection - fat stored around delicate organs such as kidney and heart
Why are triglycerides good storage molecules? Low mass to energy ratio - more energy can be stored in a small volume.
What does the structure of a phospholipid look like? 546dded6-7609-44cf-8cb0-6365e1e4dc55.jpg (image/jpg)
Phospholipids are polar molecules. What does this mean? Have 2 ends (poles) with different electrical charges which behave differently
What is the head of phosphates? Hydrophilic
What is the tail of phosphates? Hydrophobic
What is a phospholipid bilayer? 2 layers of phospholipids back to back. Arrange themselves into this when in an aqueous environment (cell membrane)
What is a micelle? 2e6b6151-6f01-42dd-8a93-ca257562c955.png (image/png)
Why are triglycerides not polymers? Because they are not in a chain
Explain the meaning of saturated? Contains only single C-C bonds
Explain the meaning of unsaturated? Has one or more double C=C bonds.
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