Topic 2.5 - Membrane Permeability 𖦹⋆｡°✩ Flashcards
what is the Fluid Mosaic Model
a moving phospholipid bilayer composed of varying types of molecules
what is a direct consequence of membrane structure
selective permeability
what molecules can freely pass through the selectively permeable cell membrane
small nonpolar molecules such as N2, O2, and CO2
what molecules and ions cannot freely move across the membrane
hydrophilic substances such as large polar molecules and ions
what substances move through transport proteins
hydrophilic substances
what are channel proteins
a hydrophilic tunnel spanning the membrane that allow specific target molecules to pass through
what are carrier proteins
spans the membrane and change shape to move a target molecule from one side of the membrane to the other
what polar molecules can pass through the membrane
small polar molecules can pass directly through the membrane in minimal amounts
༻ ex. H2O
the cell wall is a ____ and ____
the cell wall is a structural boundary and permeable barrier
as a cell boundary, what does the cell wall do
༻ protects and maintains the shape of the cell
༻ prevents against cellular rupture when internal water pressure is high
༻ helps plants stand up against the force of gravity
as a permeable barrier, what does the cell wall do
༻ plasmodesmata: small holes between plant cells that allow the transfer of nutrients, waste, and ions
what do plant cells have that animal cells don’t have
animal cells don’t have cell walls
what is a cell wall made of
complex carbohydrates
༻ plants - cellulose (polysaccharide)
༻ fungi - chitin (polysaccharide)
༻ prokaryotes - peptidoglycan (polymer consisting of sugar and amino acids)
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