2.1 Flashcards
cell theory
cells are the fundamental unit of life
all living organisms are composed of cells
all cells come from pre-existing cells
modern cells evolved from a common ancestor
volume
internal region of the cell
cell reaction and activities
surface area
cell membrane makes up the surface area
movement of materials in and out the cell
surface area-volume ratio
as cells grow larger, its volume increases more rapidly than its surface area
surface area-volume ratio decreases as cell grows later
so, large organisms consist of many small cells to account for a large enough ratio (surface area increases while volume remains constant)
all cells have…
similar biological molecules (nucleic acids, carbohydrates, proteins)
cell membrane: phospholipid bilayer and membrane proteins
cytoplasm: everything in the cell bu the nucleus
ribosomes: complexes of RNA and protein
cell membranes
form the outer boundary of every cell
act as a selectively permeable barrier
important in communication and receiving signals
has proteins for binding and adhering to adjacent cells
phospholipid bilayer
have selective permeability
small nonpolar molecules can pass through
small polar molecules pass through slowly
charged or large polar molecules cannot pass through
membrane fluidity factors (4)
degree of unsaturated fatty acids (more unsaturated = higher fluidity)
length of hydrocarbon tails in fatty acids (longer = more fluid)
number of cholesterol molecules (more cholesterol = less fluid)
temperature (higher temp = higher fluidity)
fluid mosaic model
describes biological membranes as a dynamic phospholipid bilayer where proteins can move freely
integral membrane proteins
at least partly embedded in the hydrophobic interior of the bilayer
hydrophobic domain
-nonpolar region
-interact with fatty acids
hydrophilic domain
-polar region
-aqueous environment
transmembrane proteins
integral proteins that span the entire membrane and have hydrophilic segments on both sides
peripheral membrane proteins
lack hydrophobic domains and are not embedded in the membrane
bind to the membrane or integral proteins through noncovalent interactions
anchored membrane proteins
covalently linked to lipids
carbohydrates
covalently bonded to the outer surface of proteins or lipids and serve as recognition sites
glycoprotein = carb + protein
glycolipid = carb + lipid
