BIOL 1441 1st Edition Lecture 10 Outline of Last Lecture I Microscopy II Cell classification III Cell size IV Cell organelles Outline of current Lecture I Organelles II Cytoskeleton III Extracellular components Current Lecture I Organelles a Lysosomes i Membrane sac holds hydrolytic enzymes 1 Breakdown proteins fats carbs nucleic acids 2 DIGESTION 3 NOT detox ii very specialized Proteins in the inner surface of the membrane or enzymes themselvesiii Acidic environment iv Engulf smaller organisms or food particles amoebas 1 Phagocytosis cell eating 2 Breaks down into monomers simple sugars amino acids 3 Pass into cytosol as nutrients for the cell 4 Macrophage immune cell ingests mircoorganisms v Autophagy recycle organelles and macromolecules eating organelles 1 Membranes fuse 2 Enzymes break it down 3 Returns to cytosol for reuse These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute vi Liver cell recycles half its macromolecules each week vii Tay Sachs Disease 1 Genetic mutation autosomal recessive rare 2 Lack hydrolytic enzymes to break down lipids 3 Build up in lysosome interfere with other cellular activities 4 Brain becomes impaired by accumulation of lipids 5 Side effects a Paralysis b Blindness c Die by age of 2 usually d Born with it must have gene from mom AND dad b Vacuoles i Large vesicles membrane bound sacs ii Food vacuole formed by phagocytosis fuses with lysosome iii Contractile vacuole protists pump excess water out of a cell to maintain the salt concentration iv Central vacuole plants enclosed by tonosplast membrane 1 Organic molecules 2 Inorganic ions potassium chloride 3 Disposal sites metabolic by products 4 Pigments color flower petals 5 Store water v Plant Cell Central Vacuole 1 Plant growth cell enlarge as vacuole absorb water 2 Fills with water for turgor pressure 3 increase volume with water but not metabolism change so no limits on size c Mitochondria not part of the endomembrane system i Sites of cellular respiration ii Respiration metabolic process generates ATP by extracting energy from sugars fats using oxygen iii Membrane bound organelle membrane not made by rough ER 1 Made by free ribosomes in cytosol iv Have its own DNA and ribosomes v Cell can have hundreds thousands mitochondria 1 More active cells have more mitochondria vi Smooth outer membrane inner membrane folded into cristae each is a phospholipid bilayer 1 Folded membrane more surface area when volume increases vii Inner membrane creates two compartments 1 Intermembrane space 2 Mitochondrial matrix viii Mitochondrial matrix contains 1 Enzymes 2 Mitochondrial DNA 3 Ribosomes ix Metabolic steps of cellular respiration are catalyzed in the mitochondrial matrix x Cristae present a large surface area for enzymes that synthesize ATP increasing productivity of respiration d Chloroplasts i Make ATP too also has its own DNA and ribosomes ii Type of organelle called a plastid iii Only in plants and algae contain the green pigment chlorophyll enzymes that function in photosynthesis 1 In leaves and other green organs of plants and in algae iv Convert solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds like sugars from CO2 H2O v Thylakoids membranous sacs 1 Granum stack of thylakoids vi Stroma internal fluid 1 Contain ribosomes DNA vii Divided into 3 compartments 1 Intermembrane space 2 Stroma 3 Thylakoid space viii Replicate themselves ix Mobile and move within the cell e Peroxisomes DETOXIFICATION i Specialized metabolic compartments bounded by a single membrane ii Produce hydrogen peroxide H2O2 convert it to water 1 Enzymes that transfer hydrogen from substances to oxygen 2 Special enzymes peroxidase converts H2O2 to H2O iii Use oxygen to break down fatty acids fuel in mitochondria iv Liver detoxify alcohol drugs RH2 toxic substance O2 II R H2O2 hydrogen peroxide Cytoskeleton a Network of fibers extending throughout the cytoplasm b Composed of 3 types of molecular structures i Microtubules ii Microfilaments iii Intermediate filaments c Roles of the Cytoskeleton in general H2O i Support cell and maintain its shape 1 Animal cells lack cell walls ii Remarkable strength and resilience 1 Stabilized by balance of opposing forces iii Provides anchorage for organelles iv Dynamic quickly dismantled and reassembled v Motility cell movement parts within the cell vi Motor proteins bind tubules filaments 1 Slide them past one another 2 Similar to how your muscles contract vii Vesicles organelles travel along microtubules 1 Neurotransmitter molecules migrate to tips of axons 2 ER transport vesicles travel to Golgi viii Manipulate plasma membrane to form vesicles d Components of the Cytoskeleton based on width i Microtubules thickest ii Microfilaments actin filaments thinnest iii Intermediate filaments middle e Microtubules i PROTEIN TUBULIN ii Hollow rods 1 Tubulin dimer iii Grow in length add a dimer 1 Disassembled as well iv Plus side accumulates releases dimers higher rate v Functions 1 Cell motility 2 Separate chromosome division vi Centrosomes Centrioles on plus end 1 In animal cells microtubules grow out from a centrosome MTOC a Region near the nucleus microtubule organizing center 2 Centrioles within centrosome each with 9 triplets of microtubules arranged in a ring 27 total vii Cilia and Flagella 1 Microtubules control the beating of cilia flagella 2 Cilia and flagella differ in their beating patterns 3 A core of microtubules sheathed by the plasma membrane 4 Basal body anchors the cilium or flagellum Where it attaches to cell 5 9 2 pattern a 9 doublets in a ring b 2 single in the center f Microfilaments PROTEIN ACTIN III i Solid rods actin 1 Twisted double chain of actin subunits ii Linear filaments networks 1 Inside plasma membrane cortical microfilaments iii Cortex outer cytoplasmic layer gel iv Functions 1 Muscle contraction 2 Cell motility psuedopodia 3 Cell division cleavage furrow v Actin Filaments Muscle 1 Thousands of strands of actin parallel with thicker filamentsmyosin 2 Myosin walks along actin 3 Contraction actin and myosin sliding past each other g Intermediate Filaments PROTEIN KERATIN i Diverse class of cytoskeletal fibers many different things make it up ii Made out of keratin proteins iii Permanent fixture don t unassemble CANT BREAK DOWN REBUILD NO PLUS SIDE iv Function 1 Make up nuclear lamina Extracelluar Components a Cell walls