Lecture 3 - Chapter 3 - cellular level of organization.pdf...

This preview shows page 1 - 12 out of 36 pages.

BIOL 1190: Human anatomy and physiology ILecture 3 (15-Sept-2021)Chapter 3: The cellular level of organizationHuman lung fibroblast,Zeiss Microscopy
This lectureParts of a cell (3.1)The plasma membrane (3.2)Transport across the plasma membrane (3.3)Cytoplasm (3.4)
Cells are diverseThere are many different types of cells in the human bodyEach cell has astructurethat reflects isfunction
Cells are diverseCells are the basic unit of lifeThree major parts:Plasma membraneFlexible barrier that separates thecell’s internal environment fromthe external environmentRegulates exchange of materialswith environmentCytoplasmIncludes the cytosol (fluidand solutes) and organelles(subcellular structures withspecific functions)NucleusContains the nucleolus andDNANucleusPlasma MembraneCytoplasm
Plasma membraneFlexible, sturdy barrier that surrounds and contains thecytoplasm of the cellRegulates bidirectional transport of moleculesFacilitates communication between cells
The plasma membrane is a fluid mosaicThe fluid mosaic model describes how lipids and proteinsare arranged within the plasma membraneMosaicmembrane contains many different componentsFluidlipids and some proteins flow freely
Lipids of the cell membraneThe plasma membrane is formed by a phospholipid bilayer75% of membrane lipids are phospholipids20% is cholesterol (fluidity buffer)5% is glycolipids (carbohydrate + lipid)Why do phospholipids form a stable bilayer in aqueoussolutions?
Proteins of the cell membraneIntegral membrane proteinsare anchored to thehydrophobic core of the lipid bilayerTransmembrane proteinsare a subtype of integral membraneproteins that span the entire membranePeripheral membrane proteinsare bound to the surfaceof the membrane by electrostatic interactions
Proteins of the cell membraneGlycoproteinsare membrane proteins bound tosaccharidesExclusively found on extracellular face of the membraneThe saccharides on glycoproteins and glycolipids together formtheglycocalyx; important for cell-cell interactions
Proteins of the cell membraneProteins determine most ofthe membrane’s specificfunctionsIon channels and carriersTransport substances acrossthe membraneE.g. Na+, glucoseReceptorsBind specific molecules andsend a signal to the inside ofthe cell to change cellbehaviourE.g. insulin receptor
Proteins of the cell membraneEnzymesCatalyze chemical reactionsE.g. lactase splits lactose intoglucose and galactoseLinker proteinsConnect cells and facilitatelocomotionE.g. integrinsCell identity markersUsually glycoproteins that helpbody distinguish between cellsE.g. MHC proteins

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 36 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Fall
Professor
N/A
Tags

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture