(a) TEM of a plasma. Fimbriae. Nucleoid. Ribosomes. Plasma membrane. Cell wall Capsule. Bacterial chromosome

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1 0 m m 0. m cm mm 00 µm 0 µm 00 nm 0 nm Human height Length of some nerve and muscle cells Chicken egg Frog egg Most plant and animal cells Most bacteria Smallest bacteria Viruses Proteins Unaided eye Light microscope Electron microscope Bacterial chromosome (a) A typical rod-shaped bacterium Fimbriae Nucleoid Capsule Flagella (b) A thin section through the bacterium Bacillus coagulans (TEM) nm Lipids Small molecules 0. nm Atoms 2 Outside of cell (a) TEM of a plasma Surface area increases while total volume remains constant 5 Inside of cell 0. Carbohydrate side chain Hydrophilic Hydrophobic Hydrophilic Phospholipid Proteins (b) Structure of the plasma 3 Total surface area [Sum of the surface areas (height width) of all boxes sides number of boxes] Total volume [height width length number of boxes] Surface-to-volume (S-to-V) ratio [surface area volume] ENDOPLASMIC RETICULUM (ER) Flagellum Nuclear NUCLEUS NUCLEUS Nuclear Rough endoplasmic reticulum Smooth endoplasmic reticulum Centrosome CYTOSKELETON: Micro s Golgi apparatus Micro s CYTO- SKELETON Microvilli Golgi apparatus 5 Wall of adjacent cell Plasmodesmata 6

2 Endoplasmic reticulum (ER) Nuclear : Inner Outer Free ribosomes Nuclear pore Bound ribosomes Pore complex Surface of nuclear Ribosome Large subunit Close-up of nuclear Small subunit TEM showing ER and ribosomes Pore complexes (TEM) Diagram of a ribosome Nuclear lamina (TEM) 7 8 Nuclear cis face ( receiving side of Golgi apparatus) ER lumen Cisternae Transport vesicle 0. Cisternae Transitional ER 200 nm trans face ( shipping side of Golgi apparatus) TEM of Golgi apparatus 9 Vesicle containing two damaged organelles 0 fragment fragment Digestive enzymes Digestion Food vacuole Vesicle (a) Phagocytosis Central vacuole Digestion (b) Autophagy 5 µm 2

3 Inter space Outer Free ribosomes in the mitochondrial matrix cis Golgi Inner Cristae Matrix 0. trans Golgi 3 4 Stroma Inner and outer s Granum Thylakoid 5 6 Vesicle Receptor for motor protein (a) Motor protein ( powered) of cytoskeleton Vesicles Micro (b) 7 8

4 Centrosome Centrioles 0 µm 0 µm Column of tubulin dimers Keratin proteins Actin subunit Fibrous subunit (keratins coiled together) 25 nm β Longitudinal section s Cross section of one centriole of the other centriole 8 2 nm 7 nm α 0 µm Tubulin dimer 9 Direction of swimming Outer microtubule doublet 0. Dynein proteins 20 Central microtubule Radial spoke Protein crosslinking outer doublets s (a) Motion of flagella 5 µm (b) Cross section of cilium Basal body Direction of organism s movement 0. (a) Longitudinal section of cilium Power stroke Recovery stroke (b) Motion of cilia Triplet (c) Cross section of basal body 5 µm 2 doublets 22 Microvillus Dynein protein (a) Effect of unrestrained dynein movement Cross-linking proteins inside outer doublets Micro (actin ) Anchorage in cell (b) Effect of cross-linking proteins 3 2 (c) Wavelike motion 23 24

5 Muscle cell Actin filament Myosin filament Myosin arm (a) Myosin motors in muscle cell contraction Cortex (outer cytoplasm): gel with actin network Secondary cell wall Primary cell wall Middle lamella Inner cytoplasm: sol with actin subunits Extending pseudopodium (b) Amoeboid movement Nonmoving cortical cytoplasm (gel) Streaming cytoplasm (sol) Vacuole Parallel actin Plant cell walls (c) Cytoplasmic streaming in plant cells 25 Plasmodesmata 26 Collagen EXTRACELLULAR FLUID Proteoglycan complex Polysaccharide molecule Carbohydrates s Fibronectin Integrins Core protein Interior of cell Proteoglycan molecule Proteoglycan complex Interior of cell Plasmodesmata s Micro CYTOPLASM Cell Component Structure Function Tight junctions prevent fluid from moving across a layer of cells Tight junction Concept 6.3 The eukaryotic cell s genetic instructions are housed in the nucleus and carried out by the ribosomes (ER) Surrounded by nuclear (double ) perforated by nuclear pores. The nuclear is continuous with the endoplasmic reticulum (ER). Houses chromosomes, made of chromatin (DNA, the genetic material, and proteins); contains nucleoli, where ribosomal subunits are made. Pores regulate entry and exit of materials. Ribosome Two subunits made of ribo- Protein synthesis somal RNA and proteins; can be free in cytosol or bound to ER Concept 6.4 The endo system regulates protein traffic and performs metabolic functions in the cell Endoplasmic reticulum Extensive network of : synthesis of -bound tubules and lipids, metabolism of carbohy- (Nuclear sacs; separates drates, Ca ) 2+ storage, detoxification of drugs and poisons lumen from cytosol; continuous with the nuclear. : Aids in synthesis of secretory and other proteins from bound ribosomes; adds carbohydrates to glycoproteins; produces new Tight junction Golgi apparatus Stacks of flattened membranous sacs; has polarity (cis and trans faces) Modification of proteins, carbohydrates on proteins, and phospholipids; synthesis of many polysaccharides; sorting of Golgi products, which are then released in vesicles. Desmosome Membranous sac of hydrolytic Breakdown of ingested substances, enzymes (in animal cells) cell macromolecules, and damaged organelles for recycling Gap junctions Desmosome Vacuole Large -bounded vesicle in plants Digestion, storage, waste disposal, water balance, cell growth, and protection Concept 6.5 Mitochondria and chloroplasts change energy from one form to another Bounded by double ; inner has infoldings (cristae) Cellular respiration Space between cells s of adjacent cells Extracellular matrix Gap junction Typically two s Photosynthesis around fluid stroma, which contains membranous thylakoids stacked into grana (in plants) Specialized metabolic Contains enzymes that transfer compartment bounded by a hydrogen to water, producing single hydrogen peroxide (H 2 O 2 ) as a by-product, which is converted to water by other enzymes in the peroxisome 30