Cytology = the study of cells Chapter 4 CELL STRUCTURE Cellular basis of life: Basic unit of life Lowest level with all attributes of life Organisms composed of one or more cells Cell structure correlated to function All cells are related
BIOLOGY Chapter 4 CELL STRUCTURE
Which cellular structure is common to all 3 domains of life? a) Nucleus b) Endoplasmic reticulum c) Mitochondria d) Phospholipid bilayer cell membrane e) Endocytotic vesicles
Figure 4.6 Prokaryotic Eukaryotic
50 m Figure 6.3 Light Microscopy (LM) Electron Microscopy (EM) Brightfield (unstained specimen) Confocal Longitudinal section of cilium Cross section of cilium Cilia Brightfield (stained specimen) 2 m 1 m 10 m 50 m Deconvolution Scanning electron microscopy (SEM) 2 m Transmission electron microscopy (TEM) Phase-contrast Cellular observations microscopy Differential-interferencecontrast (Nomarski) Super-resolution Fluorescence 10 m
Figure 6.4 TECHNIQUE Cellular fractionation To study organelle function Tissue cells Centrifuged at 1,000 g (1,000 times the force of gravity) for 10 min Supernatant poured into next tube 20,000 g 20 min Homogenization Centrifugation Differential centrifugation Homogenate Pellet rich in nuclei and cellular debris 80,000 g 60 min 150,000 g 3 hr Pellet rich in mitochondria (and chloroplasts if cells are from a plant) Pellet rich in microsomes (pieces of plasma membranes and cells internal membranes) Pellet rich in ribosomes
Figure 4.5 size 1 10 µm Nucleoid Circular DNA plasmid Cell wall Gram + Gram -
Prokaryotes DNA not membrane bound Lack membrane bound organelles No histone proteins Peptidoglycan Widespread Size (0.5 5 µm) Bacteria or Archaea
Fig. 27-2 Diplo- Staphylo- Strepto- 1 µm (a) Spherical (cocci) 2 µm (b) Rod-shaped (bacilli) (c) Spiral 5 µm
Prokaryotic Reproduction Binary Fission Genetic Diversity via Horizontal Gene Transfer Transformation Transduction Conjugation
Fig. 27-3 Cell Surface Structures Hans Christian Gram Gram Staining LPS component O polysacch antigens for ID (E. coli O157:H7) Lipid A endotoxin toxic (fever/shock) antibiotics Cell wall Peptidoglycan layer Plasma membrane Carbohydrate portion of lipopolysaccharide Cell wall Outer membrane Peptidoglycan layer Plasma membrane Protein Protein Grampositive bacteria (a) Gram-positive: peptidoglycan traps crystal violet. Gramnegative bacteria 20 µm (b) Gram-negative: crystal violet is easily rinsed away, revealing red dye.
Fig. 27-3c Grampositive bacteria Gramnegative bacteria 20 µm
Figure 6.6 Outside of cell TEM of a plasma membrane Phospholipid bilayer Cholesterol Proteins Carbohydrates Inside of cell 0.1 m Carbohydrate side chains Hydrophilic region Outside cell cholesterol Hydrophobic region Hydrophilic region Phospholipid Proteins Inside cell (b) Structure of the plasma membrane 8 m
Figure 4.7 Why are cells so small? Efficiency in: Acquisition of nutrients Disposal of wastes What makes this possible? High surface areas to volume ratio
Cell size & plasma membrane shape affect SA:V a) One large cell. b) Eight small cells. c) Cell with microvilli on one surface. Which cell has the larger SA? Larger Vol? Larger SA:V ratio?
Figure 4.8 Figure 4.8
5 m 10 m Cell structure reflects eukaryotic cell s function How are these cells similar? What makes these cells different? a) A portion of several muscle cells of the heart (X 1,500). b) Nerve cells of the central nervous system (X 830). c) Cells lining a tubule of a kidney (X 250). Animal Cells Cell Fungal Cells Parent cell Buds 1 m Cell wall Vacuole Figure 6.8b Human cells from lining of uterus (colorized TEM) Nucleus Nucleolus Yeast cells budding (colorized SEM) A single yeast cell (colorized TEM) Nucleus Mitochondrion
Endomembrane System
Nuclear Envelope Nucleus Genetic control ctr DNA synthesis RNA synthesis Nuclear pores Ribosome Nuclear envelope: Inner membrane Figure 6.9a Nucleolus Chromatin Outer membrane Nuclear pore Pore complex Nucleus Rough ER Close-up of nuclear envelope Chromatin
Figure 4.12 Chromatin a) DNA + histone proteins (8) nucleosome b) Replicated chromosome
Nucleolus Ribosome production Free or bound» Protein synthesis Nucleolus Nuclear membrane Nuclear pores Nuclear membrane A transmission electron micrograph (X 6,000) of Figure 3.15
Nucleolus/nucleoli Ribosome production Free or bound Protein synthesis 0.25 m Free ribosomes in cytosol Figure 6.10 Endoplasmic reticulum (ER) A transmission electron micrograph (X 6,000) of the nucleus of an animal cell Nucleolus Nuclear membrane TEM showing ER and ribosomes Ribosomes bound to ER Nuclear pores Nuclear membrane Figure 3.15 Large subunit Small subunit Diagram of a ribosome
Endoplasmic Reticulum Rough ER Smooth ER Rough ER Smooth ER Nuclear envelope ER lumen Cisternae Ribosomes Transitional ER Smooth ER Transport vesicle Rough ER 200 nm Figure 6.11
Endomembrane Organelles Rough Endoplasmic Reticulum (RER) Ribosomes Protein synthesis
Endomembrane Organelles Smooth Endoplasmic Reticulum No ribosomes Some functions: Carbo metabolism Ca ++ storage Detoxification Phospholipid synthesis
Endomembrane Organelles Golgi apparatus/body/complex warehouse Receives Modifies Stores Ships cis face ( receiving side of Golgi apparatus) Cisternae 0.1 m trans face ( shipping side of Golgi apparatus) TEM of Golgi apparatus
Figure 6.15-3 Endomembrane System Nucleus Rough ER Smooth ER cis Golgi trans Golgi Plasma membrane
Endomembrane Figure 6.13a Nucleus 1 m Lysomsome Organelles Contains hydrolytic enzymes Breaks down stuff Lysosome Intracellular digestion of nutrients Digestive enzymes Lysosome Plasma membrane Digestion Food vacuole (a) Phagocytosis
Endomembrane Organelles Lysomsome Contains hydrolytic enzymes Breaks down stuff Mitochondrion fragment Peroxisome fragment Intracellular digestion of nutrients Garbage man dead organelles Programmed cell destruction Tay Sachs Disease Peroxisome Lysosome Vesicle containing two damaged organelles 1 m Figure Vesicle Mitochondrion Digestion (b) Autophagy
Figure 6.14 Central vacuole Cytosol Nucleus Central vacuole Cell wall Chloroplast 5 m
Figure 6.15-1 Endomembrane System Nucleus Rough ER Smooth ER Plasma membrane
Figure 6.15-2 Endomembrane System Nucleus Rough ER Smooth ER cis Golgi trans Golgi Plasma membrane
Figure 6.15-3 Endomembrane System Nucleus Rough ER Smooth ER cis Golgi trans Golgi Plasma membrane
Enzymes responsible for biosynthesis of membrane lipids would be located in what part of the cell? a) endoplasmic reticulum. b) nucleus. c) lysosomes. d) Golgi. e) plasma membrane
Endomembrane Organelles Lysomsome Contains hydrolytic enzymes Breaks down stuff Intracellular digestion of nutrients Garbage man dead organelles Programmed cell destruction Tay Sachs Disease
Endomembrane Organelles Vacuoles Food Temp. storage of food Contractile Expels waste
Types of Vesicles Storage & shipping vesicles Secretory vesicles Endocytic vesicles Vacuoles Food Contractile Expels waste Peroxisomes Contain enzymes that detoxify Lysosomes Peroxisome Golgi apparatu s Contain digestive enzymes Bacterium Harmless waste Alcohol Cell toxic waste Lysosome Residual body Plasma membrane
Endomembrane System A membrane protein synthesized in the rough ER may be directed to: a) peroxisomes. b) lysosomes. c) mitochondria. d) all of the above
Golgi Brefeldin A is a drug that disrupts transport from the ER to the Golgi apparatus. What other organelles and membranes are affected? A. lysosomes, vacuoles, plasma membrane B. lysosomes, peroxisomes, plasma membrane C. vacuoles, mitochondria, plasma membrane D. lysosomes, vacuoles, nuclear membrane E. all intracellular organelles and membranes
Endosymbiotic Eukaryotic Origins Engulfing of oxygenusing nonphotosynthetic prokaryote, which becomes a mitochondrion Mitochondrion Endoplasmic reticulum Nuclear envelope Nucleus Ancestor of eukaryotic cells (host cell) Nonphotosynthetic eukaryote At least one cell Engulfing of photosynthetic prokaryote Chloroplast Mitochondrion Figure 6.16 Photosynthetic eukaryote
Mitochondrion/mitochondria Double membrane Inner membrane Cristae energy production Matrix energy production DNA 1 chromosome Binary fission All aerobic eukaryotes Intermembrane space Outer membrane 10 m Mitochondria Free ribosomes in the mitochondrial matrix DNA Inner membrane Cristae Matrix (a) Diagram and TEM of mitochondrion 0.1 m Mitochondrial DNA Nuclear DNA (b) Network of mitochondria in a protist cell (LM)
Figure 6.17a Mitochondrion/mitochondria Intermembrane space Outer membrane DNA Free ribosomes in the mitochondrial matrix Inner membrane Cristae Matrix (a) Diagram and TEM of mitochondrion 0.1 m
Chloroplasts Double membrane Thylakoid (granum/grana) Sunlight NRG chemical NRG Photosynthetic pigments Stroma Uses chemical NRG Sugar production Own DNA Ribosomes Stroma Inner and outer membranes Granum DNA Thylakoid Intermembrane space (a) Diagram and TEM of chloroplast 1 m
According to the endosymbiont theory, which of the following organelles were once endosymbiotic prokaryotic organisms? a) Mitochondria and lysosomes b) Mitochondria and chloroplasts c) Chloroplasts and Golgi apparatus d) Golgi apparatus and ribosomes e) Ribosomes and lysosomes
Peroxisome Single membrane Plants & animals Detoxifies cells H 2 O 2 1 m Figure 6.19 Chloroplast Peroxisome Mitochondrion
Figure 6.21 ATP Vesicle Receptor for motor protein (a) Motor protein (ATP powered) Microtubule of cytoskeleton Microtubule Vesicles 0.25 m (b)
Table 6.1 10 m 10 m 5 m Column of tubulin dimers 25 nm Actin subunit Keratin proteins Fibrous subunit (keratins coiled together) Tubulin dimer 7 nm 8 12 nm
Microtubule Function Taxol, a drug approved for treatment of breast cancer, prevents depolymerization of microtubules. What cellular function that affects cancer cells more than normal cells might taxol interfere with? a) maintaining cell shape b) cilia or flagella c) chromosome movements in cell division d) cell division (cleavage furrow formation) e) cytoplasmic streaming
Figure 6.22 Centrosome Microtubule Centrioles 0.25 m Longitudinal section of one centriole Microtubules Cross section of the other centriole
Direction of swimming (a) Motion of flagella 5 m Direction of organism s movement Power stroke Recovery stroke (b) Motion of cilia Figure 6.23 15 m
Figure 6.24 0.1 m Outer microtubule doublet Dynein proteins Plasma membrane Central microtubule Radial spoke Microtubules Plasma membrane Basal body (b) Cross section of motile cilium Cross-linking proteins between outer doublets 0.5 m 0.1 m (a) Longitudinal section of motile cilium Triplet (c) Cross section of basal body
Figure 6.25 Microtubule doublets ATP Dynein protein (a) Effect of unrestrained dynein movement Cross-linking proteins between outer doublets ATP Anchorage in cell (b) Effect of cross-linking proteins 1 2 3 (c) Wavelike motion
Figure 6.27 Muscle cell Actin filament Myosin filament Myosin head (a) Myosin motors in muscle cell contraction 0.5 m Cortex (outer cytoplasm): gel with actin network Inner cytoplasm: sol with actin subunits 100 m Extending pseudopodium (b) Amoeboid movement Chloroplast (c) Cytoplasmic streaming in plant cells 30 m
Figure 6.27a Locomotion Muscle cell Actin filament Myosin filament Myosin head (a) Myosin motors in muscle cell contraction 0.5 m
Figure 6.27b Cytoplasmic streaming Cortex (outer cytoplasm): gel with actin network Inner cytoplasm: sol with actin subunits 100 m Extending pseudopodium (b) Amoeboid movement
Figure 6.27c Cyclosis/Cytoplasmic streaming Chloroplast (c) Cytoplasmic streaming in plant cells 30 m
Cytoskeleton & extracellular matrix Collagen EXTRACELLULAR FLUID Polysaccharide molecule Proteoglycan complex Microfilaments Carbohydrates Fibronectin Core protein Integrins Plasma membrane Proteoglycan molecule Proteoglycan complex CYTOPLASM
Figure 6.32 TEM Cellular Junctions Tight Anchoring Gap Tight junctions prevent fluid from moving across a layer of cells Tight junction TEM 0.5 m Tight junction Intermediate filaments Desmosome Gap junction TEM 1 m Ions or small molecules Plasma membranes of adjacent cells Space between cells Extracellular matrix 0.1 m
Figure 6.28 Plasmodesmata Secondary cell wall Primary cell wall Middle lamella 1 m Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata
Figure 6.UN01 Nucleus (ER) (Nuclear envelope)
Semen & Ovum