CELLS THE CELL THEORY
CELLS
THE CELL THEORY
THE TENETS OF THE CELL THEORY
• ALL ORGANISMS ARE COMPOSED OF ONE OR MORE CELLS
• THE CELL IS THE STRUCTURAL UNIT OF LIFE
• CELLS CAN ARISE ONLY BY DIVISION FROM A PREEXISTING CELL.
CELLS
EUKARYOTIC VS PROKARYOTIC
CHARACTERISTICS
• SIMILAR CHARACTERISTICS DUE TO COMMON ANCESTORS
• DIFFERING CHARACTERISTICS DUE TO EVOLUTION
SIMILARITIES
• CELL MEMBRANES
• GENETIC INFORMATION
• TRANSCRIPTION AND TRANSLATION
• METABOLIC PATHWAYS
• ENERGY CONSERVATION
• PHOTOSYNTHESIS
• SIMILAR ENZYMES
DIFFERENCES
• COMPLEXITY OF CHROMOSOMES
• DIVISION OF CELLS– MEIOSIS/MITOSIS
• LIPID MEMBRANE BOUND ORGANELLES
• MITOCHONDRIA/CHLOROPLASTS
• CYTOSKELETON
• CILIA• ENDOCYTOSIS &
EXOCYTOSIS• CELLULOSE/CHITIN IN
CELL WALLS• DIPLOIDY• RNA POLYMERASES• SEXUAL
REPRODUCTION
KARYON = NUCLEUS
• PRO = BEFORE • EU = TRUE
CYTOPLASM
PROKARYOTIC ORGANELLES
• NON MEMBRANE BOUND ORGANELLES
• NUCLEOID• PLASMIDS• RIBOSOMES• INCLUSION BODIES
– SOME
• MEMBRANE BOUND ORGANELLES
• PLASMA MEMBRANE– LIPID
– MESOSOMES
• INCLUSION BODIES– SOME
EUKARYOTIC ORGANELLES• BOUND BY LIPID
MEMBRANES• MITOCHONDRIA• CHLOROPLASTS• LYSOSOMES• ENDOPLASMIC
RETICULUM• GOLGI APPARATUS• PLASMA MEMBRANE• NUCLEUS• MICROBODIES• VACUOLES/VESSICLES
• NOT BOUND BY LIPID MEMBRANES
• RIBOSOMES• CENTRIOLES• BASAL BODIES• CYTOSKELETON
CELL DIVISION
• EUKARYOTE• DIVISION OF THE
NUCLEUS– MITOSIS– MEIOSIS
• DIVISION OF THE CYTOPLASM– CYTOKINESIS– BINARY FISSION– BUDDING
• PROKARYOTE• NO NUCLEUS• BINARY FISSION• BUDDING
MITOSIS/BINARY FISSION
MITOSIS/BUDDING
MITOSIS/CYTOKINESIS
PROKARYOTIC BINARY FISSION
• http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookDiversity_2.html
PROKARYOTIC BUDDING
SEXUAL RECOMBINATION
• EUKARYOTES– MEIOSIS
• PROKARYOTES– TRANSDUCTION
– TRANSFORMATION
– CONJUGATION
CELL STRUCTURE AND FUNCTION
EUKARYOTIC VS PROKARYOTIC
THE PROKARYOTES
KINGDOM MONERA
GENERALIZED STRUCTURE
CELLULAR APPENDAGES
• COMMON BUT NOT FOUND ON ALL SPECIES
• FLAGELLA AND AXIAL FILAMENTS
• FIMBRIAE AND PILI
ATTACHMENTS FOR MOTILITY
FLAGELLA
• EXTREMELY THIN• PROVIDES
MOTILITY• FILAMENT• HOOK• BASAL BODY• ROTATES 360
DEGREES
FLAGELLAR ARRANGEMENTS
MONOTRICHOUS,
LOPHOTICHOUS,
AMPHITRICHOUS,
PERITRICHOUS
MONOTRICHOUS
LOPHOTRICHOUS
AMPHITRICHOUS
PERITRICHOUS
SWIMMING SPEED OF BACTERIA
• POLAR FLAGELLATED--THIOSPIRILLUM, PSEUDOMONAS AERUGINOSA
• PERITRICHOUS--ESCHERICIA COLI
BACTERIAL FLAGELLA AND TAXONOMY
• NUMBER AND PLACEMENT CAN HELP IDENTIFY SPECIES
• SPECIAL STAINS OR ELECTRON MICROSCOPE
• MOTILITY MEDIUM
• HANGING DROP SLIDE
CHEMOTAXIS
• RESPOND TO CHEMICAL SIGNALS
• POSITIVE TOWARD
• NEGATIVE AWAY
• DETECTION OF CHEMICALS IS LINKED TO FLAGELLA
• CELL IS DRIVEN CLOCKWISE IN RUNS AND TUMBLES
CHEMOTAXIS
INTERNAL FLAGELLA
• SPIROCHETES
• AXIAL FILAMENTS
• MODIFIED FLAGELLUM
• ENCLOSED IN PERIPLASMIC SPACE
• ENDOFLAGELLUM
• GIVE TWISTING OR FLEXING MOTION
APPENDAGES FOR ATTACHMENT AND MATING
FIMBRIAE
• SMALL BRISTLE FIBERS
• COMPOSITION VARIES
• STICKY
• ALLOW ADHESION OF PATHOGENS
• ESCHERICIA COLI, & NEISSERIA GONORRHEAE
PILI
• SEX PILUS
• ELONGATED, RIGID, TUBULAR
• PILIN
• GRAM NEGATIVE BACTERIA
• CONJUGATION
• PRODUCTION IS CONTROLLED GENETICALLY
THE CELL ENVELOPE
EVERYTHING OUTSIDE PROTOPLASM
THE GLYCOCALYX
• PROTECTS CELL FROM SEVERE ENVIRONMENTS
• DIFFERS GREATLY IN COMPOSITION, THICKNESS, AND ORGANIZATION
• SLIME LAYER• CAPSULE• NOT ABSOLUTELY ESSENTIAL TO
SURVIVAL
CAPSULES
• STREPTOCOCCUS PNEUMONIAE
• HAEMOPHILUS INFLUENZAE
• BACILLUS ANTHRACIS
• USUALLY MORE PATHOGENIC
• AVOID PHAGOCYTES
VARIATION IN THE GLYCOCALYX
• PLAQUE ON TEETH• COLONIZERS OF
PLASTIC, METAL
CELL WALL• IMMEDIATELY BELOW
GLYCOCALYX• DETERMINES SHAPE OF
CELL• PREVENTS BURSTING AND
COLLAPSE• MOST HAVE
PEPTIDOGLYCAN• PENICILLIN,
CEPHALOSPORIN, LYSOZYME, ALCOHOL AND DETERGENTS TARGET
GRAM STAINING
• DIVIDES INTO TWO MAJOR GROUPS
• GRAM NEGATIVE • GRAM POSITIVE
GRAM POSITIVE STAIN
IMPORTANCE OF DIFFERENCES
• GRAM NEGATIVE MORE IMPERVIOUS TO SOME ANTIMICROBIAL CHEMICALS
• GRAM NEGATIVE HARDER TO KILL• ALCOHOL IS EXCEPTION• REQUIRES DIFFERENT TREATMENT
OF GRAM NEGATIVE AND GRAM POSITIVE DISEASES
CELL MEMBRANE
• BELOW CELL WALL
• LIPID BILAYER • PROTEINS
EMBEDDED• 30-40%
PHOSPHOLIPIDS• 60-70% PROTEINS
MESOSOMES
• MESOSOMES-EXTENSIONS INTO CYTOPLASM
• PROMINENT IN GRAM +
• INCREASE SURFACE AREA
• MAY BE ARTIFACTS
• MAY HAVE ROLE IN DIVISION AND WALL SYNTHESIS
MESOSOME FUNCTION
• ENERGY REACTIONS
• NUTRIENT PROCESSING & SYNTHESIS
• REGULATE TRANSPORT
• SECRETION
INTERNAL STRUCTURES
CHROMATIN BODIES
• SINGLE STRAND OF DNA
• NUCLEOID REGION• NO HISTONES• HAPLOID
PLASMIDS
• NOT ESSENTIAL
• EXTRACHROMOSOMAL
• CAN BE FREE OR INCORPORATED INTO CHROMOSOME
• CONFER PROTECTIVE TRAITS
• DRUG RESISTANCE
• TOXIN & ENZYME PRODUCTION
RIBOSOMES
• IN CYTOPLASM• POLYSOMES • ATTACHED TO
MESOSOMES AND MEMBRANE
• 60% rRNA & 40% PROTEIN
RIBOSOMES
• 30s & 50 s SUBUNITS
• CLASSIFIED BY SVEDBERG UNITS
INCLUSION BODIES
• VARY IN SIZE, NUMBER & CONTENT
• PROTEIN LAYER MEMBRANE
• GLYCOGEN
• POLYBETAHYDROXYBUTRYRATE
• GAS VACUOLES
POLYHYDROXYBUTYRATE
GRANULES
• SULFUR GRANULES
• POLYHYDROXYBUTRATE GRANULES
• PHOSPHATE GRANULES
• METACHROMATIC GRANULES
SULFUR GRANULES
POLYPHOSPHATE GRANULES
GAS VACUOLES
ENDOSPORES
• BACILLUS, CLOSTRIDIUM & SPOROSARCINA
• VEGETATIVE CELL & ENDOSPORE
• VALUABLE IN CLASSIFYING BACTERIA
ENDOSPORE GERMINATION
• REVITALIZE WHEN FAVORABLE CONDITIONS REAPPEAR
• BREAK DORMANCY• NEEDS WATER, SPECIFIC CHEMICAL,
ENVIRONMENTAL STIMULUS• OCCURS RAPIDLY• ENZYMES FROM SPORE DIGEST CORTEX • REVERTS TO VEGETATIVE CELL
BACTERIAL SHAPES
• ROUND--COCCUS
• ROD--BACILLUS• SPIRAL--
SPIRILLUM
PLEOMORPHISM
• VARIATIONS IN SHAPE
• INDIVIDUAL VARIATIONS IN CELL WALLS
• CAUSED BY NUTRITIONAL OR GENETIC DIFFERENCES
EUKARYOTES CELLS
EUKARYOTIC CELLS
• ABOUT 2 BILLION YEARS AGO
• EVOLVED FROM PROKARYOTIC SYMBIONTS
• SINGLE CELLED
• INDEPENDENT
• SOME FORMED COLONIES AND FILAMENTS
FORM AND STRUCTURE
CYTOPLASM
• EVERYTHING BETWEEN CELL MEMBRANE AND NUCLEAR MEMBRANE
• ORGANELLES
• CYTOSOL
NUCLEOPLASM
• MATERIAL IN NUCLEUS
ENDOPLASMIC RETICULUM
• PARALLEL • FLAT • THIN POUCHES• ROUGH E.R.• SMOOTH E.R.
SMOOTH ER
• RESPONSIBLE FOR LIPID METABOLISM
• SITE OF COMPLEX CARBOHYDRATE ANABOLISM
• DETOXIFICATION
ROUGH E.R.• ORIGINATES FROM OUTER
PART OF NUCLEAR ENVELOPE
• CONTINUOUS LABYRINTH
• MAY REACH CELL MEMBRANE
• STUDDED WITH RIBOSOMES
• MAKES PROTEINS FOR EXPORT
RIBOSOMES
• FREE • BOUND• POLYRIBOSOMES
POLYRIBOSOMES
RIBOSOMAL STRUCTURE
• 60s RIBOSOME• 40s RIBOSOME• PRODUCED IN
NUCLEOLUS
80 s RIBOSOME SUBUNIT
40 s RIBOSOME SUBUNIT
GOLGI COMPLEX
• SAC LIKE • TO ONE SIDE OF
NUCLEUS • CISTERNAE• SIMILAR TO E.R.• MODIFIES,
PACKAGES, SHIPS
LYSOSOMES
• SAC OF HYDROLYTIC ENZYMES
• INTRACELLULAR DIGESTION OF FOOD PARTICLES
• PROTECTION AGAINST INVADERS
• REMOVAL OF DEBRIS
MICROBODIES
• CONTAIN OXIDATIVE ENZYMES
• PROMOTE MANY METABOLIC REACTIONS
• PEROXISOMES ONE EXAMPLE
MITOCHONDRIA
• ENERGY SUPPLIER• VARIOUS SHAPES• SMOOTH
CONTINUOUS OUTER MEMBRANE
• INNER FOLDED MEMBRANE
• CRISTAE
CRISTAE
• SITE OF ELECTRON TRANSPORT SYSTEM
MATRIX
• SITE OF ENZYMES OF TCA CYCLE
INTERMEMBRANOUS SPACE
• SITE OF PREPRATORY REACTION– FORMATION OF
ACETYL CoA FROM PYRUVATE
• SITE OF BETA OXIDATION– CONVERSION OF
FATTY ACIDS TO ACETYL CoA
OUTER MITOCHONDRIAL MEMBRANE
• PERMEABLE TO PYRUVATE
• NOT TO NADH
MITOCHONDRIAL GENETICS
• OWN DNA• OWN RIBOSOMES
(70s)• POOL OF ENZYMES • INDEPENDENT
DIVISION
PLASTIDS
CHLOROPLASTS, LEUKOPLASTS, AND
CHROMOPLASTS
CHLOROPLASTS
• ALGAE • PLANTS• CONVERT
SUNLIGHT TO CHEMICAL ENERGY
• PRODUCE OXYGEN
• CHLORPHYLL• CAROTENOIDS
• CHLAMYDOMONAS • PLANT CELL
LEUKOPLASTS
• STORAGE OF STARCH OR OTHER MATERIALS
CHROMOPLASTS
• CONTAIN PIGMENTS
CYTOSKELETON
• ANCHORING ORGANELLES
• PROVIDING SUPPORT
• PERMITS SHAPE CHANGES
MICROTUBULES• LONG HOLLOW
TUBULES
• MAINTAIN SHAPE OF CELLS WITHOUT WALLS
• TRANSPORT SUBSTANCES IN CELL
• SPINDLE FIBERS
• FLAGELLA & CILIA
MICROFILAMENTS
• THIN PROTEIN STRANDS
• FORM NETWORK• MOVEMENT OF
CYTPOLASM• AMEBOID
MOVEMENT
INTERMEDIATE FILAMENTS
CENTRIOLES, CILIA AND FLAGELLA
CENTRIOLES
• ASSOCIATED WITH NUCLEAR DIVISION
• FOUND IN CENTROSOME
• HOLLOW ROD OF NINE SETS OF MICTOTUBULES
CILIA & FLAGELLA
• MOTILITY• PROTOZOA• MANY ALGAE• SOME FUNGAL
PROTISTS• SOME ANIMAL
CELLS
FLAGELLA • THICKER• LONG SHEATHED
CYLINDER• MICROTUBULES• 9 +2 ARRANGEMENT• SLIDE OVER ONE
ANOTHER• WHIPLIKE MOVEMENT• REQUIRES ENERGY• CELL MEMBRANE
COORDINATES
BASAL BODIES
• FOUND AT BASE OF CILIA AND FLAGELLA
• SIMILAR STRUCTURE TO CENTRIOLE
CILIA
• SHORTER• MORE NUMEROUS• CILATES &
ANIMAL CELLS• MOTILITY,
FEEDING & FILTERING
• 2, 500 MICRONS PER SECOND
VESICLES &VACUOLES
• STORAGE• FATS• GLYCOGEN• CONTRACTILE
VACUOLES CONTROL OSMOTIC PRESSURE
NUCLEUS
• LARGEST ORGANELLE
• SURROUNDED BY NUCLEAR ENVELOPE
• PORES• NULEOPLASM• CHROMATIN• NUCLEOLUS
NUCLEOLUS
• DEVELOPS AROUND THE NUCLEAR ORGANIZER
• SYNTHESIS OF RIBOSOMAL RNA
• USUALLY DISAPPEARS DURING CELL DIVISION
• MAY BE MORE THAN ONE IN NUCLEUS
GENETIC MATERIAL
• CHROMATIN• CHROMATID• CHROMOSOMES
CHROMATIN
• IRREGULAR NETWORK OF STRANDS
• HISTONE PROTEIN AND UNCOILED DNA
• TRANSCRIPTION OR DUPLICATION MAY BE OCCURRING
EUCHROMATIN VS HETEROCHROMATIN
CHROMATIDS
CHROMOSOMES
CHROMOSOMAL NUMBER
• SPECIFC # OF CHROMOSOMES
• 2 SETS OF EACH--DIPLOID
• 1 SET OF EACH --HAPLOID
• MITOSIS• MEIOSIS
IMPORTANCE OF THE NUCLEUS
• NUCLEUS GOVERNS CELL ACTIVITIES
• DOES THROUGH RIBOSOMES, ROUGH ENDOPLASMIC RETICULUM
GLYCOCALYX• OUTER MOST BOUNDARY
• POLYSACCHARIDES
• NETWORK OF FIBERS
• SLIME LAYER
• CAPSULE
• PROTECTION
• ADHERANCE
• SIGNALRECEPTION
• VARY GREATLY
CELL WALL
• RIGID
• STRUCTURAL SUPPORT
• THICK INNER LAYER OF POLYSACCHARIDE FIBERS
• CHITIN OR CELLULOSE
• THIN OUTER LAYER OF GLYCANS
• PECTINS, MANNANS, MINERALS
PLASMODESMATA
COMPONENTS OF THE CELL WALL
• CHITIN OR CELLULOSE
• PECTINS, MANNANS AND MINERALS
CELLULOSE
• LONG POLYSACCHARIDE CHAIN
• ACTS LIKE REBAR IN CONCRETE
• LIGNIN MAY BE PRESENT TO HELP REINFORCE
CHITIN
• POLYSACCHARIDE• FOUND IN FUNGAL
CELL WALLS• FOUND IN
EXOSKELETON OF INSECTS
CHITIN
PROTISTS
• SOME FUNGAL PROTISTS HAVE A MIXTURE OF CHITIN AND CELLULOSE
• SOME PROTISTS HAVE A PELLICLE– CELL WALL LIKE
STRUCTURE
PELLICLE
ANIMALS DO NOT HAVE CELL WALLS
• TUNICATES DO HAVE A CELLULOSE SKELETON BUT IT IS NOT A CELL WALL
CYTOPLASMIC MEMBRANE
• TYPICAL BILAYER• STEROLS• CONFER
STABILITY• SELECTIVELY
PERMEABLE• 60 - 80 % OF CELL
VOLUME IS ORGANELLES
JUNCTIONAL COMPLEXES
• TIGHT JUNCTIONS
• DESMOSOMES
• HEMIDESMOSOMES
• GAP JUNCTIONS
• PLASMODESMATA
TIGHT JUNCTIONS
• FUSION OF OUTERMOST PORTION OF MEMBRANE
• BRAIN• DIGESTIVE TRACT• TESTES
DESMOSOMES
• MEMBRANE CLOSE TOGETHER
• PLAQUES IN BOTH CELLS
HEMIDESMOSOMES
• CELLS CLOSE TOGETHER
• PLAQUE ONLY IN ONE CELL
PLASMODESMATA
GAP JUNCTIONS
• SEPARATE CELLS BUT CLOSE TOGETHER
• CHANNELS BETWEEN CELLS
COMPARISON OF EUKARYOTIC CELLS
PLANT, ANIMAL, AND FUNGAL CELLS
PLANT CELL ANIMAL CELL
• CELL WALL• PLASTIDS• VACUOLES• NO CENTRIOLES
• NO CELL WALL• NO PLASTIDS• VESSICLES• CENTRIOLES