1 Flashcards
What is a cell
Basic unit of life Smallest unit able to
reproduce
Eukaryotic cells
Everything except bacteria
Prokaryotic cells
bacteria cells
What is a tissue
Group of cells plus matrix that have a specific
function
Four main types of tissue
epithelial
connective
muscle
nervous
what is the Extracellular matrix
3D matrix surrounding the cell :
• provides support and structure for cells
• regulates cell function
Van’t Hoff equation -osmotic pressure
tells us that osmotic pressure is proportional to concentration : Π=𝑐𝑅𝑇
Polyelectrolyte
polymer with groups that
dissociate in solvent leaving
charged regions
Proteoglycan function in ecm and how its achieved
Proteoglycans attract and retain water in the ECM
Important for
• filling space
• allowing transport of solutes
• mechanical properties
achieve this by exerting an osmotic pressure
what is a Proteoglycan
core protein chain with GAG “hairs” bonded to it 2 types decorin and aggrecan
Glycosaminoglycans (GAGs)
Polysaccharide chains • Four main groups • Hyaluronan • Chondroitin sulphate & dermatan sulphate • Heparan sulphate • Keratan sulphate
Decorin
A few GAG chains
• Chondroitin and dermatan sulphate
• Role in developing collagen fibres
“decorates” collagen fibers
Aggrecan
100s of GAG chains
Chondroitin and keratan sulphate
Role in providing structure to extracellular matrix
issues with the Van’t Hoff equation
bad for high concentrations and doesnt account for charged molecules
Donnan model - cocentration
semi permeable membrane in a in a jar of solution so some molecules cant make it through impacting the concentration of ions / final distribution of solutes
cell model - concentration
tba
What do aggrecan molecules attach to when they form an aggrecan aggregate
Hyaluronan
which distribution can be used to model the charge density in the rod-in-cell model
Boltzmann
What is the term that describes the contents of a cell (fluid plus organelles)?
Cytoplasm
Why are glycosaminoglycans good at attracting and retaining water in the extracellular matrix?
They have a negative charge
They are fixed in the matrix
Poisson’s equation for electrostatics
𝛻^2𝜓( 𝑟) =−𝜌 (𝑟)/𝜀 𝜌 (𝑟) =𝑧𝑒𝑐 (𝑟) 𝜓 𝑟 Mean electric potential at r 𝜌 𝑟 Mean charge density at r 𝜀 Permittivity of the solution c(r) Ion concentration at r
Diffusivity definition
A measure of how easily a solute diffuses through a medium - diffusion coefficient
Diffusivity equation
⟨ 𝑥^2⟩ =2𝑑𝐷t
𝑑 Number of dimensions
𝐷 Diffusivity
𝑡 Time
Stokes-Einstein equation -diffusivity
𝐷 = 𝑘𝑇/6𝜋𝜇𝑅 𝐷 Diffusivity 𝑘 Boltzmann’s constant 𝑇 Temperature 𝜇 Fluid viscosity 𝑅 Radius of sphere