Lipids Flashcards
What is the structure of a fatty acid?
Fatty acids are long hydrocarbon chains with a carboxyl group (-COOH) at one end.
What is saturation in reference to fatty acids?
Saturated fatty acids: Have no double bonds (Solid at room temp)
Unsaturated fatty acids: Have one or more double bonds (Liquid at room temp)
What are the two types of unsaturation that a fatty acid can face?
Monounsaturated: One double bond.
Polyunsaturated: More than one double bond.
How does cis vs trans configuration affect the fatty acid?
Cis fatty acids cause a kink in the chain, making them liquid at room temperature.
Trans fatty acids have a straighter chain and often being solid at room temperature.
What is hydrophobicity?
Fatty acids are nonpolar, making them insoluble in water but soluble in organic solvents like chloroform or ethanol.
What are the six major subclasses of lipids?
Fatty Acids
Triacylglycerols (Triglycerides)
Phospholipids
Steroids
Glycolipids
Sphingolipids
What is the structure of Triacylglycerols (Triglycerides)?
Consists of three fatty acid molecules attached to a glycerol backbone. (Major form of energy storage)
What is the structure of Phospholipids?
Structure: Made up of two fatty acids and a phosphate group attached to a glycerol backbone. The phosphate group gives phospholipids their amphipathic nature. (Key for cell membranes)
What is the structure of steroids?
Have a characteristic four-ring structure (steroid nucleus). Cholesterol is the most common example.
What is the structure of Glycolipids?
Composed of a sugar molecule attached to a lipid, often a phospholipid.
What are the main biological functions of lipids?
Energy Storage (Triglycerides)
Cell Membrane Structure (Phospholipids and cholesterol)
Signaling Molecules (Lipids like steroid hormones)
Insulation and Protection
What are the physical properties of the phospholipid bilayer?
Amphipathic Nature (Hydrophilic heads/Hydrophobic tails)
Fluidity (The membrane isn’t ridged)
Self-Sealing
Selective Barrier
What are the three different types of membranal proteins?
Integral Membrane Proteins: These proteins are embedded in the lipid bilayer.
Peripheral Membrane Proteins: These proteins are attached to the surface of the membrane
Lipid-Anchored Proteins: Some proteins are covalently attached to lipids in the membrane.
What are the three key points of the fluid mosaic model?
Fluidity (The lipids and proteins within the bilayer can move sideways)
Mosaic of Proteins (Membranes are not just made of lipids but also contain a variety of proteins scattered throughout the bilayer)
Asymmetry (The two layers of the lipid bilayer are not identical
Why Are Membranes Impermeable to Most Substances?
The hydrophobic interior of the lipid bilayer makes membranes impermeable to most substances, especially those that are hydrophilic or polar, such as ions, sugars, and amino acids.
