Lipid structure and function

Question 1

What are the lipids definitions and examples (3)

Answer 1

• Small, naturally occurring molecules
• Some contain ester linkages therefore can be hydrolysed (e.g. fats, waxes) and others so not contain ester linkages therefore cannot be hydrolysed (e.g. cholesterol, steroids)
• Examples: fats, oils, waxes, vitamins, hormones, cell membrane components

Question 2

What is the lipid structure of triacylglycerols (3)

Answer 2

1. Glycerol group - A three-carbon sugar that acts as the backbone of a lipid molecule
2. Fatty acids chain - long chains made up of hydrocarbons (carbons and hydrogens) hydrophobic (repel water)
3. Phosphate group - A hydrophilic group (soluble in water)

Question 3

What is the lipid structure of Glycerophospholipids (4)

Answer 3

1. glycerol linked to 2 fatty acids and 1 phosphoric acid
2. C1 fatty acid - saturated
3. C2 fatty acid - unsaturated
4. C3 phosphate bonded to an amino alcohol

Question 4

What is the lipid structure of Sphingolipids (3)

Answer 4

1. Sphingosine backbone
2. fatty acid chain (hydrophobic)
3. phosphate group (hydrophillic)

Question 5

What are the fatty acids structure and properties (5)

Answer 5

• Generally unbranched
• Contain even number of carbon atoms
• Double bonds usually have cis geometry
• More than 100 different fatty acids
• Fatty acids exist as anion (negatively charged)

Question 6

what is Membrane lipid composed of (3)

Answer 6

1. Glycerol backbone
2. Fatty acid tails (hydrophobic)
3. Phosphate group (hydrophilic)