Basics from Cell Bio Flashcards
What are the three essential lipids in biology?
fats, phospholipids, and steroids
How are fats constructed?
dehydration reaction between glycerol and fatty acids
What is glycerol?
3 carbons with hydroxyl groups attached to each carbon (an alcohol)
What is a fatty acid?
long hydrocarbon with a carboxyl group at one end
Definition of hydrophobic
does not like water, includes nonpolar molecules
definition of hydrophilic
likes water, includes polar molecules
What is an ester linkage
a covalent bond between a hydroxyl group and a carboxyl group, which joins the fatty acid tails to the glycerol
What is a saturated fatty acid?
A carbon chain with no double bonds, completely filled with hydrogens; no “kinks”; solid at room temperature; more viscous
What is an unsaturated fatty acid?
Carbon chain with one or more double bonds, forming “kinks”, resulting in a more fluid substance; liquid at room temperature.
What is the main function of fats?
energy storage; stores twice as much energy per gram as a polysaccharide
What is the primary molecule that forms membranes?
Phospholipids
What is a phopholipid?
2 fatty acid tails attached to a glycerol backbone
What gives the phospholipid head a negative charge?
The phosphate group
What is a steroid?
Lipids that have a 4 ring carbon skeleton with a hydrophobic tail and a small hydrophilic head.
What does amphipathic mean?
It has both a hydrophilic and hydrophobic region
In the term “fluid mosaic model”, what does “fluid” mean?
The membrane undulates and moves, changing constantly
In the term “fluid mosaic model”, what does “mosaic” mean?
The membrane is made up of a myriad of molecules, including phospholipids, proteins, cholesterol, and glycoproteins.
What significant quality of a membrane, other than fluidity, changes when a membrane freezes?
its permeability
What interactions hold the bilayer together?
hydrophobic, or Van der Waals interactions
“Like remains with like”. What does this mean in the context of membranes in the cell.
Compounds that are polar and hydrophilic tend to be near or facing other polar and hydrophilic compounds all the time. The opposite is true with nonpolar and hydrophobic compounds.
What compound hinders the close packing of phospholipids, lowering the freezing temperature of the membrane?
Cholesterol
What determines a membranes function?
The proteins embedded within it.
What are the two types of membrane proteins?
Integral and peripheral proteins.
What kind of protein extends all the way through the lipid bilayer?
A transmembrane protein
Where are membrane proteins and phospholipids synthesized and organized?
endoplasmic reticulum
Where do glycoproteins undergo further carbohydrate modification, and lipids acquire carbohydrates to form glycolipids?
Golgi apparatus
