4819666
Description
Flashcards by Bee Brittain, updated more than 1 year ago
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Created by Bee Brittain
over 8 years ago
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| Question | Answer |
| What elements make up Lipids? | Carbon, Hydrogen and Oxygen |
| Lipids have a characteristic that means they wont effect water potential, what is this characteristic? | They are Insoluble |
| Lipids are soluble in two substances though! Name them. | Alcohol and Acetone |
| Lipids are a useful source of energy, why? | when oxidised, lipids provide over 2x the energy of carbohydrates |
| Lipids make a good waxy cuticle on plants and insects, why? | Lipids are insoluble, so this means they are waterproof and provide a good waterproof coating for most organisms |
| Why are lipids good insulators? | Lipids are slow conductors of heat, meaning when stored, they help retain body heat. They also act as electrical insulators in the myelin sheath around nerve cells |
| Lipids can be found around vital organs, why? | Fat is often stored around delicate organs as it provides a form of protection |
| Name two types of lipid | Triglyceride and Phospholipid |
| What does it mean if a fatty acid is: 1) Monounsaturated? 2) Polyunsaturated? 3) Saturated? | 1) Monounsaturated = 1 Double Bond 2) Polyunsaturated = Many Double Bonds 3) Saturated = No Double Bonds |
| What makes triglycerides an excellent source of energy? | They have a high ration of C-H bonds compared to C atoms |
| What feature of triglycerides makes a good storage molecule? | They have a low mass to energy ratio, so you don't need much to have enough energy so they store well. This is beneficial to many animals |
| Are triglycerides polar or non-polar? | They are non-polar (this is also why they are insoluble!) |
| When oxidised, what do triglycerides release? | They release water, this makes them useful to animals as they provide a source of water for organisms who live in hotter/dryer enviroments |
| Are phospholipids polar or non-polar? | Polar |
| What feature of a cell do phospholipids make up? How come they are suited to this feature? | They make up the phospholipid bi-layer. They are suited to this because phospholipids have a hydrophobic 'tail' (the fatty acids) and a hydrophilic 'head' (the phosphorus group) so they form a double layer with the 'heads' facing out and the 'tails' facing in. |
| Name two differences between the structure of a triglyceride and a phospholipid? | A triglyceride has 3 fatty acids, and a glycerol molecule. On the other hand, a phospholipid has only 2 fatty acids, a glycerol and a phosphate group. |
| Describe the steps in the test for a lipid. | - Add ethanol to the test tube containing the sample - Shake tube throughly, dissolving the sample in the ethanol - Add Water and shake gently |
| If there is a lipid present, what will happen to the solution in the test? | It will turn cloudy white as an emulsion has been formed. |
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