Module 3/ Lipids and membrane fluidity

Question 1

Lipids

Answer 1

Large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.

Question 2

Fatty acids

Answer 2

Carboxylic acid with a long carbon chain. Can vary in length and in the number and location of double bonds. The hydrocarbon chains of the fatty acids act as non-polar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head.

Question 3

Plasma membrane

Answer 3

Membrane at he boundary of every cell that acts as a selective barrier, regulating the cell’s chemical composition; bilayers of phospholipids

Question 4

Role of the plasma membrane

Answer 4

-Compartmentalization

-Site for biochemical activities

-Providing a selective permeable barrier

-Transporting solute

-Responding to external stimuli (signal transduction)

-Intercellular interaction

-Energy transduction

Question 5

Phospholipids

Answer 5

Lipid made up of glycerol joined to two fatty acids and a phosphate group. It is amphipathic (with both a hydrophilic region and a hydrophobic region).

Question 6

Phospholipids can differ based on 3 thing

Answer 6

-Fatty acid chains (length, number and position of double bond)

-Fatty acid linkage (ester versus ether)

-Head group (phophatidyl-choline,-ethanolamine, -serine, -inositol…)

Question 7

Membrane fluidity

Answer 7

Phospholipids and proteins can move sideways (fluid mosaic)

-Increased fluidity increases the membrane permeability and protein functions.