Presentation on theme: "Structure and function of cell components"— Presentation transcript:
1Structure and function of cell components CarbohydratesLipidsProteinsNucleic AcidsMembranesCytoskeleton
2Cell membranesMany organelles contain or are enclosed by membranes, includingPlasma membraneMitochondriaChloroplastsNuclear envelopeEndoplasmic reticulumGolgi apparatusLysosomesMicrobodies (aka perioxisomes)Remind selves of what all of these cell parts do. ER = phospholipid synthesis and protein synthesis. Golgi = modify, store and transport proteins and other secretory substances. Lysosomes = digest foreign invaders and unwanted organelles. Microbodies = contain enzymes that need to be kept separate from the rest of the cytosol. The functions of each of these also lead to some of the roles of the membranes in cells
3Role of Cell MembranesBased on the functions of the above organelles / membranes write down some of the roles of the membranes in the cells(Leave some space as we will be adding to this list)
4Structure of Cell membranes Fluid Mosaic ModelStudy the diagram – What features do the students already know about. Which are new? What isn’t shown in this diagram? (how saturated the fatty acids in the chains are and the movement of the lipids). Note the phospholipids can move around the circumference of an average cell in a few seconds.
6Structure of Cell membranes LipidsRemember lipids have hydrophilic head and hydrophobic tailsTo avoid the hydrophobic tails coming in contact with water a continuous bilayer sphere is formed.Therefore hydrophobic interactions hold membranes together
7Structure of Cell Membranes ProteinsIntegral proteins (intrinsic)Proteins that are embedded in the membraneThey are held in place by hydrophobic interactions (integral proteins have hydrophobic groups on their outer surface)Peripheral proteins (extrinsic)Proteins attached to the surface of the membrane (often forming non-covalent bonds with integral proteins)
9Function of Membrane Proteins AttachmentCytoskeletonExtracellular matrixIntercellular JunctionsPlasmodesmataTight JunctionsGap JunctionsDesmosomesPlasmodesmata – between plant cells. Tight junctions = 2 membranes fused together to produce a water tight seal to prevent fluid leaking into or out of extracellular space. Gap junctions – areas where cells have a low blood supply and therefore they rely on links (via channel proteins) to get nutrients they require. Desmosomes ‘tie’ cells together to keep them in place.
10Function of Membrane Proteins TransportCarrier ProteinsChannel ProteinsReceptorsEnzymesCell to Cell recognitionReceptors – binding of regulatory protein e.g. a hormone, which can stimulate or inhibit molecular events in the cell. Cell to cell recognition – glycoproteins provide markers for an organism to recognise self and organise tissues. Proteins on non-self cells act as antigens and stimulate the production of antibodies.
11Learning ActivitiesUse all resources to find out more about the functions of membrane proteins.Based on the functions of proteins, add to your list on the role of membranes in cellsRead DART pgs 54 – 56Scholar 5.1 (of interest, but you aren’t required to know it, may be the history of understanding the cell membrane structure)The Structure of Membranes worksheetThe Role of Membranes worksheetAdvanced Higher Questions