Lipids Structure and Properties Quiz

Lipids are a diverse group of biological molecules that share a common feature: they are largely hydrophobic (water-repelling).

Lipids are essential for various functions in living organisms, including energy storage, cell membrane formation, insulation, and hormone production.

A fatty acid is a long chain of carbon atoms with a carboxyl group (COOH) at one end. This structure makes them amphipathic, meaning they have both hydrophilic (water-loving) and hydrophobic (water-fearing) regions.

Saturated fatty acids have no double bonds between carbon atoms in their hydrocarbon chain, making them very stable.

Unsaturated fatty acids have at least one double bond between carbon atoms in their hydrocarbon chain, making them less stable and more reactive.

The position of double bonds is indicated by the number of the carbon atom where the double bond starts.

Glycerophospholipids are complex lipids composed of glycerol, two fatty acid chains, and a phosphate group. They are the major constituents of cell membranes.

Steroids are lipids with a characteristic four-ring structure. They include vital molecules like cholesterol, which is a precursor to many hormones and is essential for cell membrane structure.

A type of lipid primarily found in the central nervous system. Its structure differs from other lipids by having a sphingosine backbone instead of glycerol.

A type of sphingolipid with a phosphate group attached to a head group. A major component of cell membranes, particularly in the central nervous system.

A type of lipid characterized by having a sugar molecule attached to the backbone of the lipid through a glycosidic bond, without phosphate involved.

A type of lipid found in archaea, with a unique structure allowing them to survive extreme conditions.

A type of lipid that has a complex structure with four fused rings, including three cyclohexane and one cyclopentane ring. They are involved in vital functions like hormonal regulation and membrane structure.

Fatty acids are typically synthesized using two-carbon units, resulting in an even number of carbon atoms in their structure.

The first double bond in most fatty acids is typically located between the 9th and 10th carbon atoms. This is often denoted as Δ9.

Polyunsaturated fatty acids have additional double bonds at positions Δ12 and Δ15, in addition to the Δ9 double bond.

The 'omega' designation refers to the position of the last double bond in a polyunsaturated fatty acid chain.

The length of a fatty acid chain and its degree of saturation (number of double bonds) influence its melting point and fluidity.

Saturated fatty acid chains can pack more tightly together due to the absence of kinks caused by double bonds. This leads to higher melting points and a firmer state.

Unsaturated fatty acids with cis double bonds have a kink in their hydrocarbon tail, disrupting hydrophobic interactions and lowering their melting point.

Hydrogenation is a process that adds hydrogen across double bonds in unsaturated fatty acids, converting them into saturated fats. This process can produce trans fats as a byproduct.

A type of phospholipid where the phosphate group is attached to choline.

A phospholipid with a serine group attached to the phosphate.

A phospholipid with an ethanolamine group linked to the phosphate.

A phospholipid with an inositol group attached to the phosphate.

A type of lipid that forms the basis of cell membranes, comprised of a glycerol backbone, two fatty acid chains, and a phosphate group.

A chemical bond formed when a phosphate group is attached to another molecule.

A chemical bond formed between a carboxyl group and an alcohol group.

The process of forming triglycerides involves attaching three fatty acid molecules to a glycerol backbone through ester linkages. Each fatty acid molecule reacts with a hydroxyl group on the glycerol molecule, releasing a water molecule and forming an ester bond.

A group of molecules with a polar head and a nonpolar tail. They are essential components of cell membranes.

Monoglycerides contain one fatty acid attached to glycerol, while diglycerides have two fatty acid chains attached.

Triglycerides are more hydrophobic compared to free fatty acids, meaning they repel water.

Triglycerides are more energy dense than sugars, meaning they store more energy per gram.

Triglycerides are stored as fat droplets within adipose cells, and they are unhydrated; they don't contain water molecules.

Hydrolysis is the process of breaking down a molecule by adding water. In the case of triglycerides, hydrolysis breaks the ester bonds, releasing fatty acids.

Enzymes are biological catalysts that speed up chemical reactions. Lipases are enzymes that specifically break down triglycerides by adding water across the ester bond.