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CELL Endomembrane System, Mitochondria, Chloroplasts, Cytoskeleton, and Extracellular Components “Living things are compose...

CELL Endomembrane System, Mitochondria, Chloroplasts, Cytoskeleton, and Extracellular Components “Living things are composed of lifeless molecules” (Albert Lehninger) Cells Carry out all chemical activities needed to sustain life Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function  Basic Features of All Cells Eukaryotes & –Plasma membrane Prokaryotes –Cytosol –Chromosomes (DNA) –Ribosomes  Prokaryotic Cells – No nucleus – DNA (single & circular) in a region called the nucleoid – No membrane-bound organelles – Cytoplasm bound by the plasma membrane Figure 6.8a Eukaryotic Cells Flagellum ENDOPLASMIC RETICULUM (ER) Rough Smooth ER ER Nuclear envelope Nucleolus NUCLEUS Chromatin Centrosome Plasma membrane CYTOSKELETON: –Nucleus Microfilaments Intermediate filaments Microtubules –Membrane-bound organelles Ribosomes –Much larger than prokaryotic cells Microvilli Golgi apparatus Peroxisome Mitochondrion Lysosome  Figure 6.8b Figure 6.8c Nuclear Rough envelope endoplasmic NUCLEUS reticulum Smooth Nucleolus endoplasmic Chromatin reticulum Ribosomes Central vacuole Golgi apparatus Microfilaments Intermediate CYTOSKELETON filaments Microtubules Mitochondrion Peroxisome Plasma membrane Chloroplast Cell wall Plasmodesmata Wall of adjacent cell  The Nucleus Figure 6.9 1 µm Cell &Parts Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Functions Rough ER Pore complex Surface of nuclear envelope Ribosome Close-up 0.25 µm of nuclear Chromatin envelope 1 µm Pore complexes (TEM) Nuclear lamina (TEM) Figure 6.10 Ribosomes Endomembrane System 0.25 µm regulates protein traffic and performs metabolic functions Free ribosomes in cytosol Components Endoplasmic reticulum (ER) – Endoplasmic reticulum – Nuclear Envelope Ribosomes bound to ER – Endoplasmic Reticulum Large – Golgi apparatus subunit – Lysosomes – Vacuoles Small – Plasma membrane subunit TEM showing ER and Continuous or connected via transfer by vesicles ribosomes Diagram of a ribosome  Endoplasmic Reticulum Figure 6.11 Smooth ER SER Nuclear Smooth ER envelope Nuclear envelope Rough ER Rough ER The ER membrane is continuous with ER lumen – Synthesizes lipids ER lumen the nuclear envelope Cisternae Transitional ER Cisternae Ribosomes Transitional ER There are two distinct regions of ER Ribosomes Transport vesicle 200 nm – Metabolizes carbohydrates Transport vesicle Smooth ER Rough ER 200 nm Smooth ER Rough ER – Smooth ER, which lacks ribosomes – Detoxifies drugs and poisons – Rough ER, surface is studded with – Stores calcium ions ribosomes Smooth ER RER Figure 6.12 Golgi Apparatus Nuclear envelope Rough ER cis face (“receiving” side of 0.1 µm Golgi apparatus) – Modifies products of ER lumen – Bound ribosomes Cisternae the ER Cisternae Transitional ER Ribosomes Transport vesicle 200 nm – Distributes transport – Manufactures certain Smooth ER Rough ER vesicles macromolecules – Is a membrane factory for – Sorts and packages trans face the cell (“shipping” side of TEM of Golgi apparatus materials into Golgi apparatus) transport vesicles  Lysosomes Figure 6.13a Lysosomes-Phagocytosis Nucleus 1 µm Lysosomal enzymes can hydrolyze proteins, fats, Lysosome Some types of cell can engulf another cell polysaccharides, and nucleic Lysosome Digestive Generate epitopes enzymes acids Plasma membrane PhagolysosomeDigestion Food vacuole Phagosome (a) Phagocytosis Lysosomes-Autophagy Vacuoles Figure 6.13b Vesicle containing two damaged 1 µm organelles Food vacuoles - formed by phagocytosis Mitochondrion fragment Contractile vacuoles - found in many freshwater protists, Peroxisome pump excess water out of cells fragment Central vacuoles - found in many mature plant cells, hold Lysosome Autophago-lysosome organic compounds and water Peroxisome Mitochondrion Digestion Vesicle Autophagosome (b) Autophagy  Figure 6.14 Contractile Central vacuole Osmoregulation Cytosol Central Nucleus vacuole Cell wall Chloroplast 5 µm The Evolutionary Origins of Mitochondria and Chloroplasts Figure 6.17 Figure 6.18 Mitochondria Chloroplast 10 µm a type of plastid Intermembrane space Outer Mitochondria Ribosomes 50 µm membrane Stroma Inner and outer DNA membranes Granum Inner Free membrane Mitochondrial ribosomes DNA Cristae Chloroplasts in the (red) mitochondrial DNA Matrix Nuclear DNA matrix Thylakoid Intermembrane space 1 µm 0.1 µm (a) Diagram and TEM of chloroplast (b) Chloroplasts in an algal cell (a) Diagram and TEM of mitochondrion (b) Network of mitochondria in a protist cell (LM) Peroxisomes Figure 6.19 breaks down fatty acids starch produces hydrogen phenylpropanoids protein peroxide and converts it to water and oxygen H2O2 H2O + O2 carotenoids oils  Table 6.1a Cytoskeleton 10 m Column of tubulin dimers 25 nm   Tubulin dimer Figure 6.22 Centrosome Microtubule Centrioles 0.25 m Longitudinal section of one centriole Microtubules Cross section of the other centriole  Table 6.1b Figure 6.26 Microvillus 10 m Plasma membrane Microfilaments (actin filaments) Actin subunit Intermediate filaments 7 nm 0.25 m Figure 6.27a Table 6.1c 5 m Muscle cell 0.5 µm Actin filament Myosin filament Myosin head Keratin proteins (a) Myosin motors in muscle cell contraction Fibrous subunit (keratins coiled together) 8−12 nm  Plant Cell Wall Cell Junctions Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical protection contact shape Types – Plasmodesmata cell – cell – Tight junctions communication – Desmosomes – Gap junctions Figure 6.31 Figure 6.32 Plasmodesmata Tight junctions prevent fluid from moving Tight junction across a layer of cells Cell walls TEM 0.5 µm Interior Tight junction of cell Intermediate filaments Desmosome anchoring junctions Interior TEM 1 µm of cell Gap junction 0.5 µm Plasmodesmata Plasma membranes communicating junctions Ions or small molecules water and small solutes (and sometimes proteins Space between cells TEM Extracellular and RNA) can pass from cell to cell Plasma membranes of adjacent cells matrix 0.1 µm CELL WORKSHEET