cells structure and function Flashcards
what does a plasma membrane have
has a outer lipid layer
covers and contains all contents of the cells
what does the cytoplasm do
contains all the dissolved nutrients
what does the nucleus do
brain of the cell
contains all DNA
round or oval shape
what is in the cell membrane
Phospholipid bilayer
Cholesterol
Proteins
Attached carbohydrates
name some membrane functions
barrier between inside and out
controls material
receives signals
transmits signals
name the body fluid pools
Intracellular (ICF)
2/3 of total
Extracellular (ECF) ->
Between cells = Interstitial
In blood vessels = Plasma
In lymphatic vessels = Lymphatic
name some membrane transport mechanisms
Simple Diffusion
Facilitated Diffusion
Osmosis
Active Transport
Transport in vesicles
requirements for simple diffusion
conc gradient of solute
can diffuse across a membrane
if charged must go through channels (gated channels)
what happens in facilitated diffusion
Requires a carrier in membrane
Only goes down concentration gradient
Saturates = maximum speed
Maximum speed dependent on carrier number
what is osmosis
Diffusion of water
Must have a semi-permeable membrane
what is active transport
Requires a carrier
Requires energy (ATP)
Can transport up a concentration gradient (low to high)
Critical for moving important ions
Major active transport in most cells =
Sodium-potassium (Na+/K+) pump
what is transport in vesicles
Requires energy
Involves small membrane sac
Endocytosis - importing materials
Exocytosis- exporting materials
what is a cytoplams
Cell contents
Includes organelles and cytosol
Excludes nucleus
what is a cytoskeleton
Maintains the shape of cell
Locates and transports organelles
Changes cell shape
Includes: microfilaments, intermediate filaments, microtubules
what is a centrosome
Centriole
Pericentriolar material
