BIO 101 1st EditionLecture 9Outline of Last LectureI. Water Balance in Cellsa. Hypertonicb. Hypotonicc. IsotonicII. Facilitated DiffusionIII. Active Transporta. Ion Transportb. Co-TransportIV. Traffic of Large Moleculesa. Exocytosisb. Endocytosisi. Phagocytosisii. Pinocytosisiii. Receptor-mediated endocytosisOutline of Current LectureI. Main Kinds of Cellsa. Prokaryoticb. EukaryoticII. Cell SizeIII. Eukaryotic Cell ComponentsIV. Endomembrane SystemV. Other OrganellesCurrent LectureChapter 6- Tour of the CellRemember the cell theory: all living things are made of cells; all cells come from other cells.The cell is the basic unit of life2 main kinds of cells:Prokaryotic- smaller simpler cellsBacteria and blue green algaeNo true nucleusNo membrane- bound organellesEukaryotic- larger, more complexTrue nucleus (membrane bound)Membrane bound organelleFungi, plants and animalsBIO 101 1st EditionCell SizeMost are small- visible only under microscopeSmall size is because the surface area/volume rationNeeds to be large: transport reasons (getting things in and out)Nuclear control (close proximity to nucleus)Eukaryotic cells are approx.. 10x larger than prokaryotic cellsHow do they compensate? They have developed a system of membrane bound structures called organellesThese organelles are used to compartmentalize incompatible processes (keep them separate)The abundant complex internal membranes effectively increase surface area of eukaryotic cellsEukaryotic Cell ComponentsNucleus- source of genetic material (DNA) surrounded by double membrane with nuclear pores- big enough for large molecules and ribosomes to pass throughNucleolus- place inside nucleus where ribosomes are assembled (looks like a dark spot innucleus)Cytoplasm- everything between nucleus and plasma membrane, includes semi-fluid cytoplasm and organellesRibosomes- site of protein synthesis, made of RNA and proteinsEndomembrane system- complex system of interrelated membranes that are either DIRECTLY CONNECTED to one another or INDIRECTLY CONNECTED by vesicles= membrane sacs which are pinched off and move from one membrane site to anotherSummary of Endomembrane System Nuclear membrane is directly connected to the ROUGH ENDOPLASMIC RETICULUM (RER), which is directly connected to the SMOOTH ER (SER)ER is connected via vesicles to GOLGI APPARATUS, which is connected via vesicles to LYSOSOMES, VACUOLES, and PLASMA MEMBRANEFunctions1. RER- network of membranes with ribosomes attached, like tubes with inner space called cistemae, membranes are made on RER (phospholipids are made by enzymes in the RER membrane, membrane proteins are made by ribosomes on the RER and embedded in newly made phospholipid bilayer)2. SER- connected to RER but without ribosomes, synthesizes fat, steroids, sex hormones, DETOXIFIES drugs and poisons.3. Golgi Complex- stacked flattened membrane sacs modify, store and route products of ERBIO 101 1st Editiona. Forming face- vesicles from ER fuse hereb. Maturing face- gives rise to new vesicles. Often carbohydrates are added and modified to proteins; these direct the protein to correct destination4. Lysosomes- sac of hydrolytic enzymes (single membrane) clean up “garbage” in cell, digest food particles, destroy invading bacteria, role in cell “suicide”- part of development5. Vacuoles- like transport vesicles, but bigger storage space, “garbage dump”, plantcells have large central vacuole- very versatile: storage, toxic compoundsOther Organelles (NOT part of Endomembrane System)**membranes not made on ER- increase by dividing**microbodies- sacs that contain specialized teams of enzymes for a specific metabolic taskex: peroxisome- breakdown fats, detoxify alcohol process produces H2O2 (hydrogen peroxide), which is toxic, so also contain catalase- and enzyme that turns H2O2 (toxic) H2O + O2 (harmless)Energy TransducersMitochondria and chloroplasts- “captured prokaryotic cells”- Produce energy for the cell- Surrounded by double membrane - Not part of endomembrane system- not made by ER- Grow and divide- Have their own ribosomes- Code for some of their own proteins (contain own DNA)Mitochondria- site of cellular respiration, found in nearly ALL eukaryotic cellsChloroplasts- site of photosynthesis- PLANTS ONLY- make sugar using CO2 and
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