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LECTURE 1PlantsMulticellular organismsCellulose-rich cell wallChlorophyll, photosyntheticAdapted to life on landPlant structureShootUsually grows aboveStem, leaves, nodes, internodes, budsFlowersSpecialized shoot where reproduction occurs, fruit & seeds developLeavesSite of photosynthesisBlade, petioleNodePlace in stem where leaf is attachedStemHolds leaves, transports water & nutrients, provides support above groundRootUsually grows below groundAnchors to soil absorbs water & mineralsMay serve as storage in some speciesBranch roots, root hairs, root capShoot & root apical meristemsRegion of embryonic tissue capable of developing new parts of the plantVariations in structurePotatoes- stems that grow undergroundCelery- overgrown leaf petioleRadishes & yams- storage rootsSpines of cacti- modified leavesLECTURE 2Cell macromolecules- the molecules of life4 molecules of life: carbohydrates, lipids, proteins, nucleic acidsCarbohydratesSugars, starches, celluloseOrganic molecules composed of C, H, O (1:2:1 ratio)Most abundant of life’s molecules3 typesMonosaccharides (one)Simple sugars of 3-6 carbons, CnH2nOnGlucose- blood sugarFructose- fruitRibose- nucleic acidsDisaccharides (two)Sucrose- table sugarMaltose- 2 glucoseLactose- milkPolysaccharides (many)Starch- energy storageCellulose- plant cell walls, wood, paper, clothFunctionsEnergy storage- in the C-H bonds, glucose, starchFor structure in plants- cellulose for cell wallCarbon sources to make other molecules- nucleic acids, amino acidsLipidsDiverse group of organic compoundsUsually composed of C, O, H, sometimes P3 main typesFats, oils, waxesMade from 2 building blocks- glycerol molecule & fatty acidsFats & oils are water insolubleFats are solid lipids at room temperatureUsually animal derived- lard, butterOils are liquid lipids & do not dissolve in waterUsually plant derived- corn oil, peanut oil, olive oilPhospholipidsSimilar to fats & oils but contain phosphorous (a phosphate group)Phosphate group makes head hydrophilic (water loving)Fatty acid chain is hydrophobic (water hating)Membranes of cells are lipid bilayersSteroidsStructurally different from other lipidsComposed of 4 carbon rings & side groupsSex hormones, cortisol, cholesterol, & othersFunctionsHigh-energy foodPart of cell membraneWaxes, hormones, vitamins, pigmentsEnergy storage of lipidsMonoglycerides (glycerol + 1 fatty acid chain)Diglycerides (monoglyceride + 2nd fatty acid chain)Triglycerides (diglyceride + 3rd fatty acid chain)Triglycerides- highest neergyProteinsComposed of amino acidsThere are 20 amino acidsLarge complex moleculesComposed of C, H, O, S, NFunctionsBuilding blocks of cellsTransport- they help control what passes through the plasma membraneAnimal structure- hair, nails, tendons, musclesEnzymes- to speed up chemical reactionsNucleic acidsDNA, RNALarge organic moleculesComposed of C, H, O, P, NBasic unit is the nucleotideA sugar, phosphate, & nitrogenous baseNucleic acids are long chains of nucleotidesDNADeoxyribonucleic acidCarries information about the entire cellRNARibonucleic acidCopy of DNAATPNucleotide compoundEnergy transfer/exchangeFunctionsInformation storage- DNA & RNA are like a blueprint for the cellEnergy carrier- ATPCharacteristics of life’s moleculesCarbon-basedFormed from a few elements- C, H, O, P, NModular construction- like bricks, cheap & easy to build small building blocksTheir function depends on structure- structure/shape determines functionWe eat them every dayWe are composed of fats, carbohydrates, proteinsCellsBasic building blocks of living organismsForm tissues & organsEach cell is functionally independent- it can live on its own under the right conditionsUses sugars to get energy & stay aliveContains all necessary info to replicate- produce a multicellular organismCan make a whole plant from a single cellCell theoryCell is the basic unit of lifeOrganisms are composed of cellsCells arise from other cells2 types of cellsProkaryoticSimple cells, lack organelles10-100 times smaller than animal or plant cellsBacteriaOlder organisms- 3.5 billion years oldEukaryoticHave organellesCells of plants, animals, fungiSome unicellular organisms also- algae, amoebaMore recent- 1.5 billion years oldPlant cells vs. animal cellsPlant cells have 4 things animal cells do notCell wallsChloroplastsPlasmodesmataVacuolesCells from animals & other organisms have them but they are much smaller & not as significantOutside of the plant cellCell wallProtects & supports the cellMade mostly of celluloseAllows water & other molecules to pass through (like a cardboard box)Primary wallFormed earlyLocated on outermost layerSecondary wallDeposited on the inside between primary cell wall & plasma membraneMiddle lamellaWhat glues adjacent cells togetherPlasmodesmataCytoplasmic connections between adjacent cellsAllow for the movement of materials from cell to cellPlasma membrane/plasma membraneLipid bilayerHydrophilic heads (outer) & hydrophobic tails (inner)Differentially permeableLets water pass through, but not other moleculesFluid mosaic modelDouble layer of phospholipids with scattered proteins (looks like protein icebergs in a sea of lipids)Inside of the plant cellCytosolA matrix of water (90%), proteins, organic molecules, ionsCytoplasmCytosol & organelles only, except nucleusProtoplastAll of the plant cell enclosed by the cell wall (plasma membrane, cytosol, organelles)CytoskeletonMicrotubules & microfilamentsMake up the cytoskeletonA network of protein cables that provide structural support to the cellHelp in cell division & elongationImportant for mitosis & cell divisionOrganellesMembrane bound sub compartments within the cellSee below*Plant cell organellesNucleusContains all genetic information (DNA) in chromosomesChromosomes- DNA & proteinsNucleolus- bodies where ribosomes are madeMitochondriaProvides energy to the cell by converting sugars into chemical energy (respiration)Powerhouse of the cellChloroplastSite for photosynthesisProduces sugars from carbon dioxide, water, & sunlightContain chlorophyll (makes the plant green) & other pigmentsVacuoleStores a watery solution of sugars, salts, acids, proteinsMakes up to 90% of plant cell volumeMakes cells turgid- water pressure in cellTonoplast- vacuole’s own membraneOften acidic content- sap, what makes lemons & limes tartRibosomesSite for protein synthesisUse information contained in DNA to produce proteinsNot membrane boundEndoplasmic reticulumA network of folded membranes throughout the


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UMD BSCI 124 - Plants

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