Chapter 3 The Cell

Chapter 3The Cell3.1Our understanding of the cell grew as microscope quality improved.Cell TheoryMainly Schleiden, Schwann, VirchowAll organisms are made of cellsAll existing cells are produced by other cellsThe cell is the most basic unit of life.General Cell CharacteristicsTend to be microscopicEnclosed in a membraneFilled with cytoplasmTypes of cellsProkaryoticNo nucleusNo membrane bound organellesLike bacteriaEukaryotic NucleusMembrane bound organellesLike not bacteria3.2Cells have an internal structureCytoskeleton Support and shapePosition and transport organellesStrength Assists in cell divisionCell movementNucleusStores genetic informationControl center of the cellEndoplasmic ReticulumTransportRough: has ribosomes for processing proteinsSmooth: no ribosomes, process lipids and carbohydratesRibosomesMade of rRNAForm proteinsGolgi apparatusGolgi bodiesPackaging and shippingVesiclesMembrane bound sacksStorageMitochondria Energy Vacuoles Like little warehousesStorage LysosomesWaste disposalDigest materialCentriolesTubes in centrosomesHelp in mitosisForm cilia and flagellaPlant cell partsChloroplasts: where photosynthesis occursHave a cell wall of cellulose for support3.3Cell membraneFunctions Enclose cell like a fence doesControls passage of stuff like a fence does

Structure Phospholipid bilayerProteins, carbohydrates, and lipids may be imbedded in the membraneThe fluid mosaic modelSelectively permeableLets some stuff in, keeps other stuff out. Kinda like a fence doesReceptors A substance can bind to its receptorCauses an action on the other side of the membrane3.4Stuff can move across cell membranesTransport Passive: just happensActive: requires energyPassive transportDiffusion: stuff diffuses from regions of high concentration to regions of low concentrationOsmosis: diffusion of water

Three types of solutionsHypotonic: Lower concentrationWater moves out of cellHypertonic Higher concentrationWater moves out of cellIsotonic Same concentrationNo net movement of waterExamples

Facilitated diffusionSome molecules can only diffuse through transport proteins.Facilitated diffusion is diffusion through transport proteins. Revolving door

3.5Some transport requires energyActive transportRequires energyGoes against a gradient

TypesPumpsEndocytosis: takes material into the cellPinocytosis: cell drinkingPhagocytosis: cell eatingExocytosis: expels material from the cell