10 m 1 m 0.1 m 1 cm Human height Length of some nerve and muscle cells Chicken egg Unaided eye 1 mm Frog egg 100 µm 10 µm 1 µm 100 nm 10 nm Most plant and animal cells Nucleus Most bacteria Mitochondrion Smallest bacteria Viruses Ribosomes Proteins Light microscope Electron microscope 1 nm Lipids Small molecules 0.1 nm Atoms 1
Fimbriae Nucleoid Ribosomes Plasma membrane Bacterial chromosome (a) A typical rod-shaped bacterium Cell wall Capsule Flagella 0.5 µm (b) A thin section through the bacterium Bacillus coagulans (TEM) 2
Outside of cell (a) TEM of a plasma membrane Inside of cell 0.1 µm Carbohydrate side chain Hydrophilic region Hydrophobic region Hydrophilic region Phospholipid Proteins (b) Structure of the plasma membrane 3
Surface area increases while total volume remains constant 1 5 1 Total surface area [Sum of the surface areas (height width) of all boxes sides number of boxes] 6 150 750 Total volume [height width length number of boxes] 1 125 125 Surface-to-volume (S-to-V) ratio [surface area volume] 6 1.2 6 4
ENDOPLASMIC RETICULUM (ER) Rough ER Smooth ER Flagellum Nuclear envelope Nucleolus Chromatin NUCLEUS Centrosome Plasma membrane CYTOSKELETON: Microfilaments Intermediate filaments Microtubules Ribosomes Microvilli Peroxisome Golgi apparatus Mitochondrion Lysosome 5
NUCLEUS Nuclear envelope Nucleolus Chromatin Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Golgi apparatus Central vacuole Microfilaments Intermediate filaments Microtubules CYTO- SKELETON Mitochondrion Peroxisome Plasma membrane Chloroplast Cell wall Wall of adjacent cell Plasmodesmata 6
1 µm Nuclear envelope: Inner membrane Outer membrane Nucleolus Chromatin Nucleus Nuclear pore Pore complex Surface of nuclear envelope 0.25 µm Ribosome Rough ER 1 µm Close-up of nuclear envelope Pore complexes (TEM) Nuclear lamina (TEM) 7
Cytosol Endoplasmic reticulum (ER) Free ribosomes Bound ribosomes Large subunit 0.5 µm TEM showing ER and ribosomes Small subunit Diagram of a ribosome 8
Smooth ER Rough ER Nuclear envelope ER lumen Cisternae Ribosomes Transport vesicle Smooth ER Rough ER Transitional ER 200 nm 9
cis face ( receiving side of Golgi apparatus) Cisternae 0.1 µm trans face ( shipping side of Golgi apparatus) TEM of Golgi apparatus 10
Nucleus 1 µm Vesicle containing two damaged organelles 1 µm Mitochondrion fragment Lysosome Peroxisome fragment Lysosome Digestive enzymes Lysosome Plasma membrane Digestion Peroxisome Food vacuole Vesicle Mitochondrion Digestion (a) Phagocytosis (b) Autophagy 11
Central vacuole Cytosol Nucleus Central vacuole Cell wall Chloroplast 5 µm 12
Nucleus Rough ER Smooth ER cis Golgi trans Golgi Plasma membrane 13
Intermembrane space Outer membrane Free ribosomes in the mitochondrial matrix Inner membrane Cristae Matrix 0.1 µm 14
Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm 15
Chloroplast Peroxisome Mitochondrion 1 µm 16
Microtubule 0.25 µm Microfilaments 17
ATP Vesicle Receptor for motor protein (a) Motor protein (ATP powered) Microtubule of cytoskeleton Microtubule Vesicles 0.25 µm (b) 18
10 µm 10 µm 10 µm Column of tubulin dimers 25 nm Actin subunit Keratin proteins Fibrous subunit (keratins coiled together) α β Tubulin dimer 7 nm 8 12 nm 19
Centrosome Microtubule Centrioles 0.25 µm Longitudinal section of one centriole Microtubules Cross section of the other centriole 20
Direction of swimming (a) Motion of flagella 5 µm Direction of organism s movement Power stroke Recovery stroke (b) Motion of cilia 15 µm 21
Microtubules Plasma membrane Basal body 0.1 µm (b) Cross section of cilium Outer microtubule doublet Dynein proteins Central microtubule Radial spoke Protein crosslinking outer doublets Plasma membrane 0.5 µm (a) Longitudinal section of cilium 0.1 µm Triplet (c) Cross section of basal body 22
Microtubule doublets ATP Dynein protein (a) Effect of unrestrained dynein movement Cross-linking proteins inside outer doublets ATP Anchorage in cell (b) Effect of cross-linking proteins 1 3 2 (c) Wavelike motion 23
Microvillus Plasma membrane Microfilaments (actin filaments) Intermediate filaments 0.25 µm 24
Actin filament Muscle cell Myosin filament Myosin arm (a) Myosin motors in muscle cell contraction Cortex (outer cytoplasm): gel with actin network Inner cytoplasm: sol with actin subunits Extending pseudopodium (b) Amoeboid movement Nonmoving cortical cytoplasm (gel) Chloroplast Streaming cytoplasm (sol) Vacuole Parallel actin filaments Cell wall (c) Cytoplasmic streaming in plant cells 25
Secondary cell wall Primary cell wall Middle lamella 1 µm Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata 26
Collagen EXTRACELLULAR FLUID Proteoglycan complex Polysaccharide molecule Carbohydrates Fibronectin Core protein Integrins Plasma membrane Proteoglycan molecule Proteoglycan complex Microfilaments CYTOPLASM 27
Cell walls Interior of cell Interior of cell 0.5 µm Plasmodesmata Plasma membranes 28
Tight junctions prevent fluid from moving across a layer of cells Tight junction 0.5 µm Tight junction Intermediate filaments Desmosome Gap junctions Desmosome 1 µm Space between cells Plasma membranes of adjacent cells Extracellular matrix Gap junction 0.1 µm 29
Cell Component Structure Function Concept 6.3 The eukaryotic cell s genetic instructions are housed in the nucleus and carried out by the ribosomes Nucleus Surrounded by nuclear envelope (double membrane) perforated by nuclear pores. The nuclear envelope 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. (ER) Ribosome Two subunits made of ribosomal RNA and proteins; can be free in cytosol or bound to ER Protein synthesis Concept 6.4 The endomembrane system regulates protein traffic and performs metabolic functions in the cell Endoplasmic reticulum (Nuclear envelope) Extensive network of membrane-bound tubules and sacs; membrane separates lumen from cytosol; continuous with the nuclear envelope. Smooth ER: synthesis of lipids, metabolism of carbohydrates, Ca 2+ storage, detoxification of drugs and poisons Rough ER: Aids in synthesis of secretory and other proteins from bound ribosomes; adds carbohydrates to glycoproteins; produces new membrane 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. Lysosome Membranous sac of hydrolytic enzymes (in animal cells) Breakdown of ingested substances, cell macromolecules, and damaged organelles for recycling Vacuole Large membrane-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 Mitochondrion Bounded by double membrane; inner membrane has infoldings (cristae) Cellular respiration Chloroplast Typically two membranes around fluid stroma, which contains membranous thylakoids stacked into grana (in plants) Photosynthesis Peroxisome Specialized metabolic compartment bounded by a single membrane Contains enzymes that transfer hydrogen to water, producing hydrogen peroxide (H 2 O 2 ) as a by-product, which is converted to water by other enzymes in the peroxisome 30