Lipids, Membranes & Transport in Biochemistry

These flashcards cover key concepts related to lipids, their properties, functions, and the transport mechanisms in biological membranes.

What are lipids characterized by?

High solubility in non-polar solvents and low solubility in water.

What is the building block for complex lipids?

Fatty acids.

What are triacylglycerols known for?

They are membrane precursors and energy storage.

What distinguishes saturated fatty acids from unsaturated fatty acids?

Saturated fatty acids have no double bonds, while unsaturated fatty acids contain one or more double bonds.

What are essential fatty acids mentioned in the notes?

Linoleic (18:2n-6) and α-linolenic (18:3n-3) fatty acids, which cannot be synthesized by humans.

What is the primary function of cholesterol in membranes?

It regulates membrane fluidity.

What are glycerophospholipids?

They are essential components of cell membranes, containing a diacylglycerol with a phosphate group.

What are the two types of mediated transport across membranes?

Passive (facilitated diffusion) and Active transport.

What does the Na+/K+ ATPase do?

It is a primary active transporter that pumps 3 Na+ out of the cell and 2 K+ into the cell.

What is a liposome?

Phospholipid suspensions in water that can form uni- and multilamellar vesicles.

What is the Fluid Mosaic Model?

It describes the dynamic structure of membranes where lipids and proteins can move freely in the bilayer.

What happens to membrane fluidity below the transition temperature?

Membranes lose their fluidity and become gel-like.

What role do integral membrane proteins play?

They are tightly bound to the membrane and can be transmembrane or embedded.

What are the characteristics of trans fatty acids?

They are formed from partial hydrogenation of vegetable oils and are difficult to metabolize.

What impact does temperature have on membrane fluidity?

Lower temperatures lead to decreased fluidity due to tighter packing of hydrocarbon tails.