Biological Molecules - Lipids Flashcards Preview

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Flashcards in Biological Molecules - Lipids Deck (16)
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1

What do all Lipids contain?

Hydrocarbons

2

What are the 2 groups of lipids?

1. Triglycerides
2. Phospholipids

3

How are Triglycerides formed?

Condensation of one molecule of glycerol and three molecules of fatty acid

4

Describe one feature of Fatty Acids and explain how it aids its function.

The tails are hydrophobic, making lipids insoluble in water

5

Draw out the structure of a Triglyceride.

Refer to textbook.

6

Draw out the structure of a Fatty Acid

Refer to textbook.

7

What are the 2 types of Fatty Acids?

1. Saturated
2. Unsaturated

8

`What type of fatty acid doesn't have any double bonds between their carbon atoms?

Saturated

9

What type of fatty acid has double bonds between their carbon atoms?

Unsaturated

10

What bond is formed between glycerol and a fatty acid?

Ester Bond

11

How many times does a condensation reaction between glycerol and a fatty acid happen to form a triglyceride?

3

12

What lipids are found in cell membranes?

Phospholipids

13

What is the difference between a Phospholipid and a Triglyceride?

In a phospholipid, one of the fatty acid molecules is replaced by a phosphate-containing group

14

Describe 3 features of Triglycerides and explain how it aids its function.

1. Triglycerides are mainly used as energy storage molecules. They're good for this because the long hydrocarbon tails of the fatty acids, contain lots of chemical energy

2. They're insoluble in water, so they don't affect the water potential of the cell and cause water to enter the cell by osmosis, which would cause the cell to swell

3. The triglycerides bundle together as insoluble droplets in cells because the fatty acid tails are hydrophobic

15

Describe one feature of Phospholipids and explain how it aids its function.

Phospholipid heads are hydrophilic and their tails are hydrophobic, so they form a double layer with their heads facing out towards the water on either side. The centre of the bilayer is hydrophobic, so water-soluble substances can't easily pass through it - the membrane acts as a barrier to those substances

16

Describe the Emulsion Test for Lipids.

1. Shake the test substance with Ethanol for about 1 minute

2. Pour the solution into water

3. +ve= Milky emulsion