Presentation on theme: "Chapter 6. The Cell: Mitochondria & Chloroplasts"— Presentation transcript:
1Chapter 6. The Cell: Mitochondria & Chloroplasts Modified from: Kim Folgia, Explore Biology
2OverviewMitochondria & chloroplasts are the organelles that convert energy to forms that cells can use for workmitochondria: from glucose to ATPchloroplasts: from sunlight to ATP & carbohydratesATP = active energycarbohydrates = stored energyATP+ATP
3Mitochondria & Chloroplasts Important to see the similaritiestransform energygenerate ATPdouble membranes = 2 membranessemi-autonomous organellesmove, change shape, divideinternal ribosomes, DNA & enzymes
4Mitochondria Function cellular respiration generate ATP from breakdown of sugars, fats & other fuelsin the presence of oxygenbreak down larger molecules into smaller to generate energy = catabolismgenerate energy in presence of O2 = aerobic respiration
5Mitochondria Structure 2 membranes smooth outer membranehighly folded inner membranethe cristaefluid-filled space between 2 membranesinternal fluid-filled spacemitochondrial matrixDNA, ribosomes & enzymesWhy 2 membranes?increase surface area for membrane-bound enzymes that synthesize ATP
8Dividing Mitochondria Who else divides like that?What does this tell us about the evolution of eukaryotes?
9Mitochondria Almost all eukaryotic cells have mitochondria there may be 1 very large mitochondrion or 100s to 1000s of individual mitochondrianumber of mitochondria is correlated with aerobic metabolic activitymore activity = more energy needed = more mitochondriaWhat cells would have a lot of mitochondria?active cells:• muscle cells• nerve cells
12Chloroplasts Chloroplasts are plant organelles class of plant structures = plastidsamyloplastsstore starch in roots & tuberschromoplastsstore pigments for fruits & flowerschloroplastsstore chlorophyll & function in photosynthesisin leaves, other green structures of plants & in eukaryotic algae
13Chloroplasts Structure 2 membranes outer membraneinner membraneinternal fluid-filled space = stromaDNA, ribosomes & enzymesthylakoids = membranous sacs where ATP is madegrana = stacks of thylakoidsWhy internal sac membranes?increase surface area for membrane-bound enzymes that synthesize ATP
15Who else divides like that? ChloroplastsFunctionphotosynthesisgenerate ATP & synthesize sugarstransform solar energy into chemical energyproduce sugars from CO2 & H2OSemi-autonomousmoving, changing shape & dividingcan reproduce by pinching in twoWho else divides like that?bacteria!
17Mitochondria & chloroplasts are different Organelles not part of endomembrane systemGrow & reproducesemi-autonomous organellesProteins primarily from free ribosomes in cytosol & a few from their own ribosomesOwn circular chromosomedirects synthesis of proteins produced by own internal ribosomesWho else has a circular chromosome no bound within a nucleus?bacteria
18Endosymbiosis theory 1981 | ?? Mitochondria & chloroplasts were once free living bacteriaengulfed by ancestral eukaryoteEndosymbiontcell that lives within another cell (host)as a partnershipevolutionary advantage for bothone supplies energythe other supplies raw materials & protectionLynn MargulisFrom hypothesis to theory!Paradigm shifting ideas in evolutionary biology.Lynn MargulisU of M, Amherst
19Evolution of eukaryotes Endosymbiosis theoryEvolution of eukaryotes