3 Boundaries & membranes Flashcards
Eukaryotic cells have _________________ boundaires.
Internal
________ cells have bounaries.
All
Internal boundaires allows formation of specialised ____________________. with paticular ____________ and ________ processes and segregation of harmful _____________.
Microenvironments
solutes
cell
activities
The __________ boundary is the plasma membrane.
Principle.
Membranes are ____________ like, composed of ___________, ______________ and carbohydrates.
Sheet-like.
Lipids.
Proteins.
Thickness of lipid bilayer:
5-8nm.
Mmebranes are ______________ with hydrophillic ____________ and hydrophobic _____________.
Amphipathic.
Head.
Tail.
Name of model with integral proteins in lipid bilayer and peripheral proteins sticking out and covalently bound lipid-anchored proteins on surface.
Fluid Mosaic Model.
______ face outside because they’re ___________
Heads.
Hydrophilic
__________ face inside because they’re ____________
Tails.
Hydrophobic.
4 Key structual features of membranes:
1 Self assembling.
2 Lipids are fluid. Proteins are restricted.
3 Assymetrical
4 Integral proteins pass through bilayer.
7 Components of membranes:
Carbohydrate. Glycolipid. Transmembrane protein. Glycoprotein. Peripheral protein. Cholesterol. Fillaments of cytoskeleton.
Membrane functions:
1 Semi-permeable. Small uncharged or hydrophobic molecules pass through. Large polar molecules or ions cannot. H2O can pass through, can be assited by aquaporin channels.
2 Transporting solutes. Integral proteins can passage or actively transport or act as transport channels.
3 Flexibility for cell movement/divsion.
4 Responds to externalsignals via receptors.
5 Intercellular communication via surface carbohydrates conferring cell identity.
2 Example of small uncharged or hydrophobic molecules:
O2. CO2. N2. Benzene. H2O. Glycerol. Ethanol.
2 Examples of large nonpolar molecules or ions:
Amino acids. Glucose. Nucleotides. H+. NA+. Cl-.
Mmebrane fluidity can be adjusing by altering _____ conent.
Lipid.
The thin plasma membrane often needs aditional ________ and ________________.
Support. Proetection.
Bacteria have _____________ cell wall for _____________.
Peptidoglycan. Rigidity.
Fungi have ________ cell wall.
Chitin.
Plants have _____________ cell wall for _________ and _________.
Cellulose.
Strength.
Support.
Cell walls have means to be ________________.
Permeable.
Animals have a protein network called __________ ____________ under plasma membrane.
Cell Cortex.
Erythrocyte’s cell cortex is _____ ______ attached to plasma membrane via _____________ proteins.
Spectrin meshwork.
Anchor
Some cells have a _________ exterior coating based on sugar molecules.
Glycolax.
