Topic 16: Lipids

What is the primary structural component of phospholipids?

• Glycerol backbone

• Steroid ring

• Terpene unit

• Amino acid chain

Which part of the phospholipid is hydrophilic?

• Fatty acid tails

• Phosphate group

• Steroid core

• Terpene chain

What is the role of phospholipase enzymes?

• Synthesise phospholipids

• Break down phospholipids

• Transport phospholipids

• Convert phospholipids into proteins

Which of the following is a characteristic of the mosaic model of cell membranes?

• Uniform distribution of proteins

• Random distribution of lipids

• Fluid combination of lipids and proteins

• Rigid structure with fixed components

In the mosaic model, what is the function of cholesterol?

• Increase membrane fluidity

• Decrease membrane fluidity

• Act as a protein anchor

• Serve as a carbohydrate source

What are terpenes primarily composed of?

• Amino acids

• Isoprene units

• Fatty acids

• Nucleotides

What is the role of phospholipids in cell membranes?

• Provide energy

• Act as enzymes

• Form a bilayer structure

• Store genetic information

Which method could you use to distinguish two chemically distinct phospholipids by chemical, physical or enzymatic tests?

• Treat samples with a phospholipase and detect free fatty acid release by gas chromatography

• Detect their polar headgroups by gas chromatography and compare with standards

• Combine hydrolysates with 1-Fluoro-2,4-dinitrobenzene (FDNB) to check for the formation of a coloured product

• Confirm the melting point of phospholipids are different

What is the significance of the fluidity in cell membranes?

• It allows for the rigid structure of the cell

• It enables the movement of proteins and lipids

• It prevents the entry of water

• It stabilises the cell membrane

Which of the following is NOT a function of terpenes?

• Pigmentation

• Photosynthesis

• Structural support

• Antioxidant activity