2Cell Theory All living things are composed of cells Cells are basic units of lifeEarth billion years ago---life 3.5 billion years agoLife: 1996 meteorite w/amino acids landed near mexico---could have started lifesupernatural (no scientific explanation),organic chemical evolutionNew cells come from pre-existing cells
3There’s always exceptions to the rule: BUT….How did the very first cell get here????Viruses lack typical cell structure, use hostcells to reproduceMitochondria and chloroplasts have their owngenetic material/can reproduce independentof cell
4Then what do they have? Prokaryotic Cells Small Simple No Nucleus No membrane bound organellesThen what do they have?Cell membraneCytoplasmMoneraSame family as bacteria responsible for choleraPlaqueBacteria, algaeDNA:Circular, not in nucleusRibosomesBacteria
9OrganellesHW: give cell diagrams, label ---only checking in class
10Oh where, oh where do we find cell organelles? Cytoplasm (protoplasm):The fluid inside a cell, but outside the nucleus“Holds” organelles in placeSite of cellular chemical reactionsLink work at school?Define organelles: “specialized organ”Elodea, chloroplasts moving---transport material within cell, inc. rate of diffusionCyclosis:Streaming movement of cytoplasm
14Mitochondria Release energy from food to make useable energy (ATP) Outer and inner membranesInner membrane folded(Increased surface area)Found in:Animal cellsCellular respiration……..divide process similar to binary fission….asexual?!?!?!Art gallery example---surface area---paper/cardboard boxWhich cells likely to have lots of mitochondria?Plant cellsContain their own DNA!
16Chloroplasts Site of photosynthesis Convert light energy to chemical bond energyOnly in plant cellsExceptions to plants: euglena-- Protist kingdom, blue green algae –monera NOT fungi (have cell walls)Endosymbiotic theory: mitochondria/chloroplasts descendents of anaerobic prokaryotes---formed relationship w/aerobic eurkaryotes (+,+) Over time, nucleus took over more and more of the DNA from mito/chloroplastsContain their own DNA!
20Endoplasmic reticulum “ER”A system of membranous sacsAssembles components of cell membraneProtein modificationProtein foldingDefect here may be involved in alzheimers, diabetes, ALS
21Rough endoplasmic reticulum Protein synthesisRough:RibosomesRERSmooth endoplasmic reticulumProtein synthesis and transport----cell’s highwayContains enzymes needed for cellEx. enzymes for lipid synthesisSmooth:No ribosomesSER
22Review parts of nucleus…show attached, transport mat’ls from nucleus
24Golgi Who? apparatus, complex, bodies Marks proteins for use in cell orexport (adds address w/proteins)Produces digestive enzymesProtein sorting, post translational modificationAutolysis (break down of old cell parts)
31Vacuole Cell storage: Water Food Wastes Plants: Water—pressure in vacuoles from liquid allows them to support heavy structuresFood, water----maintain homeostasisPlants:One large central vacuoleAnimals:Few small vacuolesVacuoles are crucial in single-celled organisms tomaintain homeostasis
33Cell Wall Provides support Provides shape Made up mostly of cellulose Animal cells don’t have!Fungi kingdom—cell wall, some monera (algea)Masons/cement blocks arranged same as cell wallsIndigestible----egestion
41Lipid Bilayer Main component of cell membranes lipid bilayer fluid
42Cell (Plasma) Membrane Structure ☼ 2 layers of phospholipids(lipids with phosphate groups attached)☼ Proteins - embedded in lipid layers- fortransport or receptors☼ Carbohydrates - attached to surface proteinsor lipids – markers☼ Lipids & Proteins can move along membrane= “Fluid”FLUID MOSAIC MODEL of Cell Membrane