Cell Structure & Function

Cell Structure & FunctionOrganizing PrinciplesSupramolecular Structures: All found in prokaryotic cells & eukaryotic cells, not membrane bound

Cell Membrane or Plasma MembraneSelective permeabilityCommunication with the external environmentRecognition of self vs. non-self

RibosomesSite of protein synthesisFormed from two sub-units (large & small)Free in cytosol or bound to endoplasmic reticulum

Cell WallFound in all organisms except animals & a few protistaMade of different macromolecules in different kingdomsProtects cell, maintains cell shape, & prevents excessive water uptakeAllows turgor pressure to develop

Double Membrane Bound Organelles

These are all prokaryotic in origin.They have their own DNA and ribosomesReproduce by binary fissionAre killed by antibioticsAll easily seen in the light microscope

MitochondriaSite of cellular respiration

ChloroplastSite of photosynthesis

NucleusHolds DNAMakes ribosomes in a specialized region called the nucleolusTranscribes DNAReplicates DNA

Endomembrane System

These structures work together to make, process and transport all macromolecules in a region separate from the cytosolOnly seen with TEM

Rough Endoplasmic ReticulumEndoplasmic (within the cytoplasm)Reticulum (little net)Makes, sequesters and folds proteins for export or transportPackages proteins in vesicles to send to the Golgi ApparatusAttaches carbohydrates to proteins

Smooth Endoplasmic ReticulumMakes and packages polysaccharides and lipids (with enzymes)Packages polysaccharides and lipids in vesiclesDetoxifies many poisons

Golgi Apparatus

Receives proteins from the RER and adds oligosaccharides to proteinsTags vesicles for proper delivery and sends them out for shipment

LysosomesSpecialized vesicles made from the golgi that break down old organelles, foreign materials, bacteria and viruses

Cytoskeleton (Broad Category)Creates internal structure and allows for movement internally and externally

MicrotubulesBig tubesMove chromosomes & vesiclesProvide internal support

Microfilaments

Small tubesMove vesiclesCreate muscle contractions (actin & myosin)

Centrioles

Barrel shapedAnchor spindle fibersMade of a collection of microtubules

Basal Bodies

Barrel shapedAnchor cilia and flagellaMade of a collection of microtubules

Cilia

Shorter versions of flagellaMove cells or beat to create currentsMade of a collection of microtubules

Flagella

Longer than ciliaUsed for the movement of one cellMade of a collection of microtubules