2 Cell 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
3 There’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
4 Then 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
9 OrganellesHW: give cell diagrams, label ---only checking in class
10 Oh 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
14 Mitochondria 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!
16 Chloroplasts 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!
24 Golgi 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)
31 Vacuole 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
33 Cell 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
41 Lipid Bilayer Main component of cell membranes lipid bilayer fluid
42 Cell (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