LIPIDS Flashcards
What makes lipids insoluble in water?
Hydrophobic properties
Lipids charge
Neutral, no electrical charge = nonpolar
Lipids cannot form what type of bonds with water?
Hydrogen bonds
The nonpolar nature of lipids:
Enables them to interact among themselves to assemble into fat droplets or the lipid bilayer of the cell membrane
3 major groups of lipids
-Phospholipids
-Steroids
-Triglycerides
Phospholipids
-Essential components of cell membranes
-Hydrophilic head, hydrophobic tail→ forms bilayer that separates the inside of the cell from its external surroundings
-The lipid bilayer acts as a barrier and facilitates the regulated movement of substances in and out of the cell
Steroids
-Four ring structure
-Regulation (sex + stress hormones)
-Medical use: reducing inflammation, suppressing immunity to prevent the rejection of transplanted organs
Triglycerides
-3 fatty acid chains attached to a glycerol molecule
-Compact, energy rich
-Insulation to retain body heat
-Physical protection of organs
Hydrogen bonding
Weak bond between a hydrogen atom and another electronegative atom
What prevents nonpolar lipids from interacting with polar water molecules?
-Lipids lack charges or polar groups to form hydrogen bonds with water
-Water prefers interacting with other polar molecules
What is the hydrophobic effect?
-Due to the physical repulsion among hydrophobic molecules and polar molecules like water
-The tendency of nonpolar molecules to clump together in water, minimizing their surface area exposed to water
What is the biological relevance of the hydrophobic effect?
-Enables phospholipid molecules to form the lipid bilayer
-Contributes to proteins folding into their functional 3D form
Why does life require hydrophobic biological molecules?
Help form cell membranes, provide insulation, store energy efficiently
Functions of lipids in animals:
-Retain body heat
-Reduces waterlogging of feathers/fur
-Maintains fur/feather integrity
-Reduces colonization by microbes/small pests to reduce risk of infection
Functions of lipids in plants:
-A waterproof layer of lipids covers the surface of plant organs (leaves, fruits, stems, roots)
-The waterproof cuticle layer reduces the risk of dehydration + infection
Which four vitamins are lipids?
A, D, E, K
Stored primarily in liver and fat cells
What vitamins regulate transcription?
A, D, E
What vitamin is a cofactor that activates enzymes?
K
Vitamin A
Vision, skin rejuvenation, bone & tooth growth, reproduction, immunity
Vitamin D
Mineralization of bones (strong bones), immune & neuromuscular function
Vitamin E
-Antioxidant, stabilization of cell membranes (healthy cells = healthy body)
-Reduces risk of mutation, alteration
Vitamin K
-Synthesis of blood clotting proteins and bone proteins
-Bind to enzymes, activates the enzymes
-Microbiome secretes K
Which disorders are due to the insufficient intake of lipid soluble vitamins?
-A: night blindness
-D: rickets
-K: clotting problems
Two branches of triglycerides
Fats, oils
