plasma membrane

plasma membrane 3 main componenets

lipids, proteins, carbohydrates

fluid mosaic model

mosaic refers to the phospholipids, proteins, carbohydrate chains, cholesterol in the lipid bilayer

phospholipids

two fatty acids attached to glycerol, third hydroxyl group of the glycerol is attached to a phosphate group, form bilayer

Amphipathic

both polar and non polar end

integral membrane protein

span the membrane

carbohydrates

Short chains of carbohydrates (sugars) attach to the lipids and proteins on the outside of the membrane, form a cellular finger print (blood type)

glycolipids

sugar chains attached to a lipid

glycoproteins

sugar chains attached to a protein

fluidity of membranes ______ as temperature drops

decreases

how does cholesterol buffer the fluidity of the plasma membrane

makes it thicker at high temperatures

selective permeability

plasma membranes allow some substances to cross more easily than others

passive transport

diffusion, osmosis, facilitated diffusion, no energy needed

active transport

moves against gradient, requires ATP

hypertonic

higher solute concentration than inside the cell, cell shrivels, water diffuses out

Hypotonic

lower solute concentration than inside the cell, water diffuses in, cell swells

Isotonic

equal concentration inside and outside the cell

animal cells like _______ conditions

isotonic

plant cells like ________ conditions

hypotonic

normal pressure state for plant cells

turgid

plasmolysis

in hypertonic environment, water leaves the cell causing shriveling

osmoregulation

regulation of solute concentrations and water balance by a cell or
organism

contractile vacuole

organelle that functions as a pump to force water out of the cell as fast as it enters by osmosis

channel protiens

hydrophilic channel that molecules pass through

aquaporins

allow 3 billion water molecules to pass through the plasma membrane per second

carrier protein

protein binds to specific molecules and changes shape allowing the molecules to transport

Antiporter

membrane protein that moves at least two different molecules in opposite directions across the cell membrane

Na+/K+ pump

antiporter that uses energy to move Na+ and K+ ions across plasma membrane against concentration gradient

The sodium potassium pump moves ___ positively charged Na+ ions
out of the cell and only ____ positively charged K+ ions into the cell, this creates a net ________ charge on the outside of the cell

3, 2, positive

Electrochemical gradient

diffusion gradient of an ion, affected by concentration gradient and membrane potential

exocytosis

secretion of biological molecules by the fusion of vesicles containing them
with the plasma membrane, mediated by transport vesicles moving from the golgi along microtubules

Endocytosis

Cellular uptake of biological molecules
and particulate matter via formation of vesicles from
the plasma membrane

types of endocytosis

phagocytosis, pinocytosis, receptor mediated

phagocytosis

cell absorbs substances, (cell eating)

Pinocytosis

when a cell ingests extracellular fluid and its dissolved solutes (cell drinking)

receptor mediated endocytosis

engulfment using receptor sites