Class 3 Microbiology

Seite 1

Comparing Prokaryotic and Eukaryotic Cells

•Prokaryote comes from the Greek words for prenucleus.

•Eukaryote comes from the Greek words for true nucleus.

Prokaryote

•No nucleus; one circular chromosome not in a membrane, can also have plasmids

•No Histones

•No Organelles

•Bacteria: Peptidoglycan cell walls

•Archaea: Psuedomurein cell walls

•Divides by binary fission

Eukaryote

•Nucleus; Paired chromosomes in nuclear membrane

•Histones

•Organelles

•Polysaccharides cell walls, when present (plants)

•Divides by mitosis

Size and Shape of Bacterial Cells

•Average size: 0.2 -> 2.0 um diameter ´ 2->8 um length

•Most bacteria are monomorphic (single shape)

•A few are polymorhpic (many shapes)

•Bacillus (rod-shaped)

•Coccus (spherical)

•Spiral

•Vibrio (elbow noodle)

•Spirillum (Straganoff)

•Spirochete (ramen)

•Star-shaped

•Rectangular

Arrangement of Bacterial Cells

•Determined by

•number of planes in which division occurs

•whether cells separate after division

•Coccus (plural – cocci)

•Pairs: diplococci

•

•Chains: straptococci

•

•Groups of four: tetrads

•

•Cube-like groups of eight OR more: sarcinae

•

•Clusters: staphylococci

•Bacillus (plural – bacilli)

•Pairs: _____________

•

•Chains: _______________

•

•Some are oval and look like cocci:

______________

•“Bacillus” – two meanings

•______________ – shape

•_________ - Scientific name

Structures External to the Cell Wall

•Glycocalyx

•Flagella

•Axial Filaments

•Fimbriae and Pili

Glycocalyx

•Glycocalyx - Means __________

•External to the cell wall

•Viscous and gelatinous

•Made of _______________________

•Two types

•________: neatly organized and firmly attached

•__________: unorganized and loose

•Capsules

•Contribute to __________

•Prevent ______________

•Extracellular polymeric substance (EPS) helps form ________

Flagella (singular Flagellum)

•___________ appendages on the outside of the cell

•Propel bacteria (__________)

•Three parts:

•________: outermost region - made of protein __________

•_____: attaches to the filament

•__________: consists of a ___ and pairs of ____; ______ flagellum to the cell wall and membrane

•Gram negative – two pairs of rings

•Gram positive – ____________

Arrangements of Bacterial Flagella

•___________ – No flagella

•_____________ – flagella dispersed randomly all over the surface

•_____ - at one or both ends of the cell

•___________ – _____ flagellum at one pole

•_____________ – ________________________ at one pole

•_____________ – flagella at ________

Motility using Flagella

•Flagella allow bacteria to move (____) toward or away from stimuli

•Chemicals – ____________

•Light - ____________

•Flagella _____ to “___" or “_____“

•Run or swim – movement in ___________ for a length of time

•Tumbles – ________________ due to _______ of rotation

•Flagella proteins are _________ and distinguish among __________ (e.g., Escherichia coli O157:H7)

Axial Filaments

•Also called ______________

•Found in ____________

•Treponema pallidum (Syphilis)

•Borrelia burgdorferi (Lyme disease)

•_______________

•Arise at ____ of cells beneath on _________

•________ wrap around the cell

•__________ causes cell to move like a ___________

Fimbriae and Pili

•Fimbriae (singular: fimbria)

•_______ appendages

•Can be at ends/poles or evenly distributed

•Vary from few to several hundred

•Assist in ________ – to each other and to surfaces

•Involved in formation of __________

•Also attachment to ______________

•Pili (singular: pilus)

•_______ than fimbriae; only ______ per cell

•Involved in _______ (_______ and ________ motility)

•_____________ pili involved in ___________ from one cell to another

The Cell Wall

•Prevents __________ and _______ the cell membrane

•Also provides _____ to the cell

•Made of ____________ (in bacteria)

•Contributes to ____________

•Site of action of some __________

•Used to differentiate ___________ and ___________ bacteria

Peptidoglycan (murein) *PG

•______ portion

•Polymer of a _______________ in rows:

•N-acetylglucosamine (____)

•N-acetylmuramic acid (____)

•Linked in rows of _____ sugars to form a “________”

•_______ portion

•_____ amino acids attached to the NAMs (_____________ side chain)

•May be ____________ to each other

OR

•Linked by a ________________

•Target of ___________

Gram Positive and Gram Negative Cells

Gram-Positive Cell Walls Gram-Negative Cell Walls

_____ peptidoglycan _____ peptidoglycan

__________ _______________

Gram-Positive Cell Walls

•___________ layers of peptidoglycan (up to __%)

•__________ – polymers of glycerol or ribitol phosphates

•_____ teichoic acid - Connected to the ______________

•_____________ acid – Linked to _____ in the _________________

•Carry a negative charge

•Regulate movement of cations

•Polysaccharides and teichoic acids provide _______________

Gram-Negative Cell Walls

•_________________ layers of peptidoglycan (~ __ %)

•________________

•_________ – region between the _____ membrane and the _______ membrane

•Peptidoglycan is within the periplasm (contained in the periplasm)

Membrane of Gram-Negative Cell Walls

•Protect cells from phagocytosis, complement mediated killing, and antibiotics

•Consists of

•______________________

•_______________

•____________ – link outer membrane with the PG

•_______ (proteins) form channels through the outer membrane

Lipopolysaccharide (LPS)

•_______ - is an ________ embedded in the top layer

•Released only when the cell ___ (or is ______) – endotoxin

•Symptoms – fever, dilation of blood vessels, shock etc

•____ polysaccharide – contains unusual sugars (provides _______)

•__ polysaccharide functions as ______

•Useful for distinguishing species of Gram negative bacteria (e.g., E. coli O157:H7)

Cell Walls and the Gram Stain Mechanism

•__________________ crystals form inside cell

•Gram-positive

•Alcohol __________ peptidoglycan

•CV-I crystals ______________ - Appear ____________

•Gram-negative

•Alcohol ____________________ and leaves ____ in peptidoglycan

•CV-I ___________; cells are _________

•Counterstained with Safranin

•Appear _________

Gram-Positive Cell Walls

•___ (multilayered) PG

•Teichoic acids ____

•Granular plasmic space

•Outer membrane _____

•__ LPS

•_____ in basal body of flagella

•Produce _______

•____ susceptibility to penicilli

Gram-Negative Cell Walls

•____ (single layered) PG

•Teichoic acids _____

•_____________

•Outer membrane _______

•____________ of LPS

•______ in basal body of flagella

•Produce _________ and _________

•___ susceptibility to penicillin

Atypical Cell Walls

•__________ cell walls

•Like gram-positive cell walls

•__________________ bound to PG

•Mycobacterium, Nocardia

•Stain with carbolfuchsin

•Mycoplasmas

•______ cell walls

•_____ in plasma membrane – ___________ the membrane

•Archaea

•________, OR

•Walls of _____________

•Very similar to peptidoglycan

•N-acetyl-talosaminuronic acid (_____) instead of _____

Damage to the Cell Wall

•________ (enzyme in tears, saliva etc) ________ (_____ _____) bonds between the _____ in peptidoglycan

•More effect on Gram positive than Gram negative cells

•__________ is a __________ gram-positive cell

•____________ is a ________ gram-negative cell

•Protoplasts and spheroplasts are susceptible to osmotic lysis

•_______ are wall-less cells that swell into ____________

•

•Penicillin (antibiotic) inhibits formation of ___________ _______ in peptidoglycan

•Usually more effect on Gram positive than Gram negative cells

Structures Internal to the Cell Wall

•Plasma (Cytoplasmic) Membrane

•Cytoplasm

•Nucleoid

•Ribosomes

•Inclusions

•Endospores

The Plasma (Cytoplasmic) Membrane

•Thin structure lying inside the cell wall

•Encloses the ____________

•Made up mainly of

•_____________________________

•___________

•Eukaryotes – also contain ______________ and _______

•Prokaryotes – _____ sterols (exception ____________)

•less rigid

Structure of the Plasma (Cytoplasmic) Membrane

•Phospholipid molecules arranged in two parallel rows

•___________

•Individual phospholipids

•____ head (made of __________ and _______)

•___________ (water loving); ______ in water

•__________ tails (made of ________)

•___________ (water fearing); _______ in water

Structure of the Plasma (Cytoplasmic) Membrane

•Proteins

•________________ on the membrane surface (inner or outer)

•Easily removable

•______________

•Difficult to remove (only by disrupting the lipid bilayer)

•Most are _______________ proteins

•penetrate the membrane completely

•______________ – proteins with ____________ attached

•____________ – lipids with _________________ attached

•__________________

•Proteins move freely for various functions

•Phospholipids rotate and move laterally

•Self-sealing

•Membrane is as viscous as olive oil

•The plasma membrane's __________________ allows the passage of some molecules, but not others

•_____________ for ATP production

•Some membranes have photosynthetic pigments

on foldings called ________________

•__________ to the membrane by alcohols, quaternary ammonium compounds (detergents), and polymyxin antibiotics causes ______________________

The Movement of Materials across Membranes

•________ processes: substances move from high concentration to low concentration; _________ expended

•Simple diffusion

•Facilitated diffusion

•Osmosis

•______ processes: substances move from low concentration to high concentration; ______ expended

•Active transport

•Group Translocation

•______________: movement of a solute from an area of high concentration to an area of low concentration

•Continues until molecules reach __________

•

•_______________: _______ proteins act as ______

•Solute combines with the protein (__________or __________)

•Transports ions and larger molecules across a membrane with the concentration gradient

•___ energy expenditure

•Prokaryotes - _________; Eukaryotes - _______

•Role of Extracellular enzymes

•________: the movement of _____ across a selectively permeable membrane from an area of high water to an area of lower water concentration

•Through lipid layer

•___________ (water channels)

•____________: the pressure needed to stop the movement of water across the membrane

•______ solution: solute concentrations equal inside and outside of cell; water is ____________

•__________ solution: solute concentration is lower outside than inside the cell; water moves _______ cell

•____________ solution: solute concentration is higher outside of cell than inside; water moves _____ cell

•In situations where nutrients are in _____________

•Goes ______ concentration gradient

•________________

•Uses energy in the form of ______

•Requires a _________________

•Transported substance is ______________ (no change of structure)

•____________________

•Special type of active transport (only in prokaryotes)

•Energy from the high energy compound _______________________

•Requires ____________ transporter proteins

•Substance __________ as it crosses the membrane

•Eg: Glucose converted to Glucose-6-phosphate

Cytoplasm

•All the substances inside the plasma membrane

•______________ plus proteins, carbohydrates, lipids, and ions

•Thick, aqueous, semitransparent and elastic

•Structures inside – ________ (DNA material), __________ and __________

•____________ – collective term for series of rods and fibers

•Recently discovered that prokaryotes also have a cytoskeleton

•_____________________________

•Roles in _________, __________________, ______, ______________ etc

Nucleoid

•___________________ : ______ thread of DNA that contains the cell's genetic information

•Not surrounded by ____________

•No _________

•__________ chromosome usually

•_________ only

•____________: ___________________ genetic elements

•________ than chromosome

•Replicate ______________ of the chromosome

•Carry _________ genes (e.g., antibiotic resistance, production of toxins)

•Can be __________ from one bacterium to another (____________)

Ribosomes

•Sites of _______ synthesis

•Made of ______ and ___________ (____)

•Contain ___ subunits

•Prokaryotes have ____ ribosomes (___ + ____ subunits)

•Small subunit (30S) – one molecule of rRNA (16S rRNA)

•Large subunit (50S) – two molecules of rRNA (5S and 23S rRNAs)

**S = _______________; sedimentation coefficients when subjected to centrifugal force**

•Eukaryotes have ____ ribosomes (____ + ____subunits)

•Many antibiotics inhibit protein synthesis

•Some attach to the 30S unit and some attach to the 50S unit

Inclusions

•Mainly __________

•Metachromatic granules (volutin) - _______ reserves

•Polysaccharide granules - ______ reserves

•Lipid inclusions - ______ reserves

•Sulfur granules - ______ reserves

•Carboxysomes - RuBisCO enzyme for ___________ during photosynthesis

•Gas vacuoles- protein-covered cylinders that maintain __________

•Magnetosomes - ________ inclusions; destroy ____

Endospores

•_______________ cells; produced when nutrients are depleted

•Resistant to ________, _____, _______, and _______

•Can survive for thousands or millions of years, but can germinate under appropriate conditions

•Produced commonly by ______________ bacteria

•Eg: Bacillus and Clostridium

•Coxiella burnetti (Gram negative – forms “__________” structures)

•______________: endospore formation

•_________ cell (actively dividing cell) changes to endospore

•____________: endospore returns to vegetative state

•Sporulation: stimulus is usually _______ of nutrients

•_____________

•___________ – double layered membrane

•Formation of _____________ layer

•____________ around the outside membrane

•Original cell degraded – endospore is released

•

•___________ (made of protein _____) is responsible for resistance of spores

•Location : __________, ____________ or ________

•Spores - more ________ (only ____ water) than vegetative cells

•Metabolically _______

•Contains _________________ and large amounts of _______

•DPA – _____ to spores; protects the DNA from damage

•Germination: endospore returns to vegetative state

•Triggered by

•_______

•_______________ (small molecules like alanine and inosine)

•Enzymes break down external layers, water enters, metabolism resumes

•__________ in number (_____ a means of reproduction)

•Relevant in the food industry and in clinical settings

•Difficult to get rid off

Flagella and Cilia

•Projections used for locomotion or moving substances along the cell surface

•Flagella—____ projections; ___ in number

•Cilia—____ projections; ________

•Both consist of ____________ made of the protein ________

•Microtubules are organized as nine pairs in a ring, plus two microtubules in the center (__________)

•Allow flagella to move in a __________ manner

(___ rotation)

Plasma/Cytoplasmic Membrane

•Similar in structure to prokaryotic cell membranes

•Phospholipid bilayer

•Integral and peripheral proteins

•Differences in structure

•_____ —complex lipids

•____________ —for attachment and cell-to-cell recognition

•Similar in function to prokaryotic cell membranes

•Selective permeability

•Simple diffusion, facilitated diffusion, osmosis, active transport

•Differences in function

•___________—phagocytosis, pinocytosis and receptor mediated endocytosis

•Phagocytosis: pseudopods extend and engulf particles

•Pinocytosis: membrane folds inward, bringing in fluid and dissolved substances

•Receptor mediated endocytosis: substances (ligands) bind to receptors in the membrane, the membrane then folds inward

Ribosomes

•Sites of protein synthesis

•80S - Consists of the large 60S subunit and the small 40S subunit

•70S - In ___________ and ____________

•____ ribosomes: in cytoplasm

•Make proteins used inside the cell

•________________ ribosomes: attached to endoplasmic reticulum

•Make proteins destined for insertion in the plasma membrane or export from the cell

•_____________ – 10-20 ribosomes joined together in a string like arrangement

Organelles

•Characteristic of ___________ cells

•Structures with specific _____ and _______

•Include

•Nucleus

•Spherical or oval; Largest structure in the cell

•Contains all of the cell’s ___________________

•_______________ - Double membrane structure that surrounds the nucleus

•__________ – tiny channels in the nuclear membrane

•__________ (plural _______) – condensed regions of chromosomes

•DNA is complexed with _____ proteins to form _____________

•During mitosis and meiosis, chromatin condenses into chromosomes

•Endoplasmic reticulum

•Folded transport network

•_______ – membranous sacs or tubules

•_______ ER: studded ____________; sites of _____ synthesis

•______ ER: __________; synthesizes cell membranes, fats, and hormones

•Golgi complex

•Transport organelle

•3 to 20 __________

•Modifies proteins from the ER

•Transports modified proteins via _____________ to the plasma membrane

•Mitochondria

•Number varies (Giardia – no MC; liver cells – 1000-2000/cell)

•Double membrane

•Outer membrane - _______

•Inner membrane – series of ____ (______)

•Center – semifluid (_____)

•Involved in _____________________

•Contain _____ ribosomes

•Can reproduce on their own

•Lysosomes

•Vacuoles

•______________

•Vesicles formed in the Golgi complex

•Single membrane

•Contain various ______________

•Break down complex molecules

•Kill bacteria

•__________

•Cavities in the cell formed from the Golgi complex

•Bring food into cells; provide shape and storage

•Chloroplasts

•Present in _________________

•Locations of _______________

•Contain flattened membranes (__________) that contain _______________

•Stacks of thylakoids – grana (granum)

•____ ribosomes

•Multiply on their own

•Peroxisomes, and centrosomes

•________________

•Similar in structure to lysosomes, but smaller

•Contain enzymes that can oxidize amino acids and fatty acids

•Byproduct – ___________________ – toxic

•Another enzyme, __________ destroys H2O2

•_______________

•___________________ - networks of protein fibers

•Form the mitotic spindle; critical role in ___________

•For _______________ in non dividing cells

•____________ - pair

•Each composed of 9 clusters of 3 microtubules

The Evolution of Eukaryotes

•Life arose as simple organisms _________ billion years ago

•First eukaryotes evolved _____ billion years ago

•_________________

•Larger bacterial cells engulfed smaller bacterial cells, developing the first eukaryotes

•_____________ relationship

•Host supplying _________ and the symbiotic bacterium producing ____

•Plasma membrane folded around the chromosome – __________ _______

•______ bacteria ingested - _______________

•_______________ bacteria ingested - ____________

•Evidences for endosymbiotic theory

•Mitochondria and chloroplasts __________ bacteria in size and shape

•Contain __________

•Can _________________

•_______________ to those of prokaryotes; _________________ also

•Antibiotics inhibit _____________________

Seite 2

Comparing Prokaryotic and Eukaryotic Cells

•Prokaryote comes from the Greek words for prenucleus.

•Eukaryote comes from the Greek words for true nucleus.

Prokaryote

•No nucleus; one circular chromosome not in a membrane, can also have plasmids

•No Histones

•No Organelles

•Bacteria: Peptidoglycan cell walls

•Archaea: Psuedomurein cell walls

•Divides by binary fission

Eukaryote

•Nucleus; Paired chromosomes in nuclear membrane

•Histones

•Organelles

•Polysaccharides cell walls, when present (plants)

•Divides by mitosis

Size and Shape of Bacterial Cells

•Average size: 0.2 -> 2.0 um diameter ´ 2->8 um length

•Most bacteria are monomorphic (single shape)

•A few are polymorhpic (many shapes)

•Bacillus (rod-shaped)

•Coccus (spherical)

•Spiral

•Vibrio (elbow noodle)

•Spirillum (Straganoff)

•Spirochete (ramen)

•Star-shaped

•Rectangular

Arrangement of Bacterial Cells

•Determined by

•number of planes in which division occurs

•whether cells separate after division

•Coccus (plural – cocci)

•Pairs: diplococci

•

•Chains: straptococci

•

•Groups of four: tetrads

•

•Cube-like groups of eight OR more: sarcinae

•Clusters: staphylococci

•Bacillus (plural – bacilli)

•Pairs: diplobacilli

•Chains: streptobacilli

•Some are oval and look like cocci:

coccibacilli

•“Bacillus” – two meanings

•Bacillus – shape

•Bacillus - Scientific name

Structures External to the Cell Wall

•Glycocalyx

•Flagella

•Axial Filaments

•Fimbriae and Pili

Glycocalyx

•Glycocalyx - Means sugar coat

•External to the cell wall

•Viscous and gelatinous

•Made of polysaccharides and/or polypeptides

•Two types

•capsule: neatly organized and firmly attached

•slime layer: unorganized and loose

•Capsules

•Contribute to virulence

•Prevent phagocytosis*

•Extracellular polymeric substance (EPS) (*the capsule and/or Glycocalyx?) helps form biofilms

Flagella (singular Flagellum)

•Filamentous appendages on the outside of the cell

•Propel bacteria (movement)

•Three parts:

•Filament: outermost region - made of protein flagellin

•Hook: attaches to the filament

•Basal Body: consists of a rod and pairs of rings; anchors flagellum to the cell wall and membrane

•Gram negative – two pairs of rings

•Gram positive – only one pair of rings

Arrangements of Bacterial Flagella

•___________ – No flagella

•_____________ – flagella dispersed randomly all over the surface

•_____ - at one or both ends of the cell

•___________ – _____ flagellum at one pole

•_____________ – ________________________ at one pole

•_____________ – flagella at ________

Motility using Flagella

•Flagella allow bacteria to move (taxis) toward or away from stimuli

•Chemicals – chemotaxis

•Light - phototaxis

•Flagella rotate to “run" or “tumble“

•Run or swim – movement in one direction for a length of time

•Tumbles – change in direction due to reversal of rotation

•Flagella proteins are H.antigens and distinguish among serovars (e.g., Escherichia coli O157:H7)

Axial Filaments***

•Also called endoflagella

•Found in spirochetes

•Treponema pallidum (Syphilis)

•Borrelia burgdorferi (Lyme disease)

•Bundles of fibris

•Arise at ends of cells beneath an outer sheath

•Spirally wrap around the cell

•Rotation causes cell to move like a corkscrew

Fimbriae and Pili

•Fimbriae (singular: fimbria)

•Hairlike appendages

•Can be at ends/poles or evenly distributed

•Vary from few to several hundred

•Assist in attachment – to each other and to surfaces

•Involved in formation of biofilms

•Also attachment to epithelial surfaces

•Pili (singular: pilus)

•Longer than fimbriae; only 1 or 2 per cell

•Involved in motility (gliding and twitching motility)

•Conjugation (sex) pili involved in DNA transfer from one cell to another

The Cell Wall

•Prevents osmotic lysis and protects the cell membrane

•Also provides shape to the cell

•Made of peptidoglycan (in bacteria)

•Contributes to pathogenicity

•Site of action of some antibiotics

•Used to differentiate gram + and gram - bacteria

Peptidoglycan (murein) *PG

•Glycan portion

•Polymer of repeating disaccharide in rows:

•N-acetylglucosamine (NAG)

•N-acetylmuramic acid (NAM)

•Linked in rows of 10-65 sugars to form a “backbone”

•Peptide portion

•Four amino acids attached to the NAMs (tetra peptide side chain)

•May be directly bonded to each other

OR

•Linked by a peptide cross bridge

•Target of penicillins

Gram Positive and Gram Negative Cells

Gram-Positive Cell Walls Gram-Negative Cell Walls

thick peptidoglycan thin peptidoglycan

Teichoic Acids Periplasmic space

Gram-Positive Cell Walls********

•Many (thick) layers of peptidoglycan (up to 90%)

•Teichoic Acids– polymers of glycerol or ribitol phosphates

•Wall teichoic acid - Connected to the peptidoglycan

•Lipoteichoic acid – Linked to lipids in the cytoplasmic membrane

•Carry a negative charge

•Regulate movement of cations

•Polysaccharides and teichoic acids provide antigenic specifity

Gram-Negative Cell Walls

•One or very few thing layers of peptidoglycan (~ 10 %)

•Outer membrane

•Periplasm – region between the outer membrane and the plasma membrane

•Peptidoglycan is within the periplasm (contained in the periplasm)

Membrane of Gram-Negative Cell Walls

•Protect cells from phagocytosis, complement mediated killing, and antibiotics

•Consists of

•Lipopolysaccharides (LPS)

•Phospholipids

•Lipoproteins– link outer membrane with the PG

•Porins (proteins) form channels through the outer membrane

Lipopolysaccharide (LPS)

•Lipid A - is an endotoxin embedded in the top layer

•Released only when the cell dies (or is dividing) – endotoxin

•Symptoms – fever, dilation of blood vessels, shock etc

•Core polysaccharide – contains unusual sugars (provides structure)

•O polysaccharide functions as an antigen

•Useful for distinguishing species of Gram negative bacteria (e.g., E. coli O157:H7)

Cell Walls and the Gram Stain Mechanism

•__________________ crystals form inside cell

•Gram-positive

•Alcohol __________ peptidoglycan

•CV-I crystals ______________ - Appear ____________

•Gram-negative

•Alcohol ____________________ and leaves ____ in peptidoglycan

•CV-I ___________; cells are _________

•Counterstained with Safranin

•Appear _________

Gram-Positive Cell Walls

•___ (multilayered) PG

•Teichoic acids ____

•Granular plasmic space

•Outer membrane _____

•__ LPS

•_____ in basal body of flagella

•Produce _______

•____ susceptibility to penicilli

Gram-Negative Cell Walls

•____ (single layered) PG

•Teichoic acids _____

•_____________

•Outer membrane _______

•____________ of LPS

•______ in basal body of flagella

•Produce _________ and _________

•___ susceptibility to penicillin

Atypical Cell Walls

•__________ cell walls

•Like gram-positive cell walls

•__________________ bound to PG

•Mycobacterium, Nocardia

•Stain with carbolfuchsin

•Mycoplasmas

•______ cell walls

•_____ in plasma membrane – ___________ the membrane

•Archaea

•________, OR

•Walls of _____________

•Very similar to peptidoglycan

•N-acetyl-talosaminuronic acid (_____) instead of _____

Damage to the Cell Wall

•________ (enzyme in tears, saliva etc) ________ (_____ _____) bonds between the _____ in peptidoglycan

•More effect on Gram positive than Gram negative cells

•__________ is a __________ gram-positive cell

•____________ is a ________ gram-negative cell

•Protoplasts and spheroplasts are susceptible to osmotic lysis

•_______ are wall-less cells that swell into ____________

•

•Penicillin (antibiotic) inhibits formation of ___________ _______ in peptidoglycan

•Usually more effect on Gram positive than Gram negative cells

Structures Internal to the Cell Wall

•Plasma (Cytoplasmic) Membrane

•Cytoplasm

•Nucleoid

•Ribosomes

•Inclusions

•Endospores

The Plasma (Cytoplasmic) Membrane

•Thin structure lying inside the cell wall

•Encloses the ____________

•Made up mainly of

•_____________________________

•___________

•Eukaryotes – also contain ______________ and _______

•Prokaryotes – _____ sterols (exception ____________)

•less rigid

Structure of the Plasma (Cytoplasmic) Membrane

•Phospholipid molecules arranged in two parallel rows

•___________

•Individual phospholipids

•____ head (made of __________ and _______)

•___________ (water loving); ______ in water

•__________ tails (made of ________)

•___________ (water fearing); _______ in water

Structure of the Plasma (Cytoplasmic) Membrane

•Proteins

•________________ on the membrane surface (inner or outer)

•Easily removable

•______________

•Difficult to remove (only by disrupting the lipid bilayer)

•Most are _______________ proteins

•penetrate the membrane completely

•______________ – proteins with ____________ attached

•____________ – lipids with _________________ attached

•__________________

•Proteins move freely for various functions

•Phospholipids rotate and move laterally

•Self-sealing

•Membrane is as viscous as olive oil

•The plasma membrane's __________________ allows the passage of some molecules, but not others

•_____________ for ATP production

•Some membranes have photosynthetic pigments

on foldings called ________________

•__________ to the membrane by alcohols, quaternary ammonium compounds (detergents), and polymyxin antibiotics causes ______________________

The Movement of Materials across Membranes

•________ processes: substances move from high concentration to low concentration; _________ expended

•Simple diffusion

•Facilitated diffusion

•Osmosis

•______ processes: substances move from low concentration to high concentration; ______ expended

•Active transport

•Group Translocation

•______________: movement of a solute from an area of high concentration to an area of low concentration

•Continues until molecules reach __________

•

•_______________: _______ proteins act as ______

•Solute combines with the protein (__________or __________)

•Transports ions and larger molecules across a membrane with the concentration gradient

•___ energy expenditure

•Prokaryotes - _________; Eukaryotes - _______

•Role of Extracellular enzymes

•________: the movement of _____ across a selectively permeable membrane from an area of high water to an area of lower water concentration

•Through lipid layer

•___________ (water channels)

•____________: the pressure needed to stop the movement of water across the membrane

•______ solution: solute concentrations equal inside and outside of cell; water is ____________

•__________ solution: solute concentration is lower outside than inside the cell; water moves _______ cell

•____________ solution: solute concentration is higher outside of cell than inside; water moves _____ cell

•In situations where nutrients are in _____________

•Goes ______ concentration gradient

•________________

•Uses energy in the form of ______

•Requires a _________________

•Transported substance is ______________ (no change of structure)

•____________________

•Special type of active transport (only in prokaryotes)

•Energy from the high energy compound _______________________

•Requires ____________ transporter proteins

•Substance __________ as it crosses the membrane

•Eg: Glucose converted to Glucose-6-phosphate

Cytoplasm

•All the substances inside the plasma membrane

•______________ plus proteins, carbohydrates, lipids, and ions

•Thick, aqueous, semitransparent and elastic

•Structures inside – ________ (DNA material), __________ and __________

•____________ – collective term for series of rods and fibers

•Recently discovered that prokaryotes also have a cytoskeleton

•_____________________________

•Roles in _________, __________________, ______, ______________ etc

Nucleoid

•___________________ : ______ thread of DNA that contains the cell's genetic information

•Not surrounded by ____________

•No _________

•__________ chromosome usually

•_________ only

•____________: ___________________ genetic elements

•________ than chromosome

•Replicate ______________ of the chromosome

•Carry _________ genes (e.g., antibiotic resistance, production of toxins)

•Can be __________ from one bacterium to another (____________)

Ribosomes

•Sites of _______ synthesis

•Made of ______ and ___________ (____)

•Contain ___ subunits

•Prokaryotes have ____ ribosomes (___ + ____ subunits)

•Small subunit (30S) – one molecule of rRNA (16S rRNA)

•Large subunit (50S) – two molecules of rRNA (5S and 23S rRNAs)

**S = _______________; sedimentation coefficients when subjected to centrifugal force**

•Eukaryotes have ____ ribosomes (____ + ____subunits)

•Many antibiotics inhibit protein synthesis

•Some attach to the 30S unit and some attach to the 50S unit

Inclusions

•Mainly __________

•Metachromatic granules (volutin) - _______ reserves

•Polysaccharide granules - ______ reserves

•Lipid inclusions - ______ reserves

•Sulfur granules - ______ reserves

•Carboxysomes - RuBisCO enzyme for ___________ during photosynthesis

•Gas vacuoles- protein-covered cylinders that maintain __________

•Magnetosomes - ________ inclusions; destroy ____

Endospores

•_______________ cells; produced when nutrients are depleted

•Resistant to ________, _____, _______, and _______

•Can survive for thousands or millions of years, but can germinate under appropriate conditions

•Produced commonly by ______________ bacteria

•Eg: Bacillus and Clostridium

•Coxiella burnetti (Gram negative – forms “__________” structures)

•______________: endospore formation

•_________ cell (actively dividing cell) changes to endospore

•____________: endospore returns to vegetative state

•Sporulation: stimulus is usually _______ of nutrients

•_____________

•___________ – double layered membrane

•Formation of _____________ layer

•____________ around the outside membrane

•Original cell degraded – endospore is released

•

•___________ (made of protein _____) is responsible for resistance of spores

•Location : __________, ____________ or ________

•Spores - more ________ (only ____ water) than vegetative cells

•Metabolically _______

•Contains _________________ and large amounts of _______

•DPA – _____ to spores; protects the DNA from damage

•Germination: endospore returns to vegetative state

•Triggered by

•_______

•_______________ (small molecules like alanine and inosine)

•Enzymes break down external layers, water enters, metabolism resumes

•__________ in number (_____ a means of reproduction)

•Relevant in the food industry and in clinical settings

•Difficult to get rid off

Flagella and Cilia

•Projections used for locomotion or moving substances along the cell surface

•Flagella—____ projections; ___ in number

•Cilia—____ projections; ________

•Both consist of ____________ made of the protein ________

•Microtubules are organized as nine pairs in a ring, plus two microtubules in the center (__________)

•Allow flagella to move in a __________ manner

(___ rotation)

•Cell wall- found in most eukaryotic cells (plants, algae, and fungi)

•Much simpler than those of prokaryotes- made of carbohydrates

•Plants and algae- cellulose

•Fungi- mainly chitin (polymer of NAG units)

•Yeasts- glucan and mannan (sugars?

•Glycocalyx- found mainly in animals cells

•Made of sticky carbohydrates

•Bonded to proteins and lipids in the plasma membrane

•NO PEPTIDOGLYCAN IN EUKARYOTIC CELLS

Plasma/Cytoplasmic Membrane

•Similar in structure to prokaryotic cell membranes

•Phospholipid bilayer

•Integral and peripheral proteins

•Differences in structure

•Sterols —complex lipids

•Carbohydrates —for attachment and cell-to-cell recognition

•Similar in function to prokaryotic cell membranes***

•Selective permeability

•Simple diffusion, facilitated diffusion, osmosis, active transport

•Differences in function

•Endocytosis—phagocytosis, pinocytosis and receptor mediated endocytosis

•Phagocytosis: pseudopods extend and engulf particles

•Pinocytosis: membrane folds inward, bringing in fluid and dissolved substances

•Receptor mediated endocytosis: substances (ligands) bind to receptors in the membrane, the membrane then folds inward***

Ribosomes

•Sites of protein synthesis

•80S - Consists of the large 60S subunit and the small 40S subunit

•70S - In chloroplasts and mitochondria

•70S ribosomes: in cytoplasm

Free ribosomes in cytoplasm

•Make proteins used inside the cell

•Membrane boudn ribosomes: attached to endoplasmic reticulum

•Make proteins destined for insertion in the plasma membrane or export from the cell

•Polyribosome – 10-20 ribosomes joined together in a string like arrangement

Organelles

•Characteristic of eukaryotic cells

•Structures with specific shape and size

•Include

•Nucleus

•Spherical or oval; Largest structure in the cell

•Contains all of the cell’s hereditary info. DNA

•Nuclear envelope - Double membrane structure that surrounds the nucleus

•Nuclear pores – tiny channels in the nuclear membrane

•Nucleolus (plural Nucleoli) – condensed regions of chromosomes

•DNA is complexed with histone proteins to form chromosomes

•During mitosis and meiosis, chromatin condenses into chromosomes

•Endoplasmic reticulum

•Folded transport network

•cisternae – membranous sacs or tubules

•Rough ER: studded with ribosomes; sites of protein synthesis

•Smooth ER: no ribosomes; synthesizes cell membranes, fats, and hormones

•Golgi complex

•Transport organelle

•3 to 20 cisternae

•Modifies proteins from the ER

•Transports modified proteins via secretory vesicles to the plasma membrane

•Mitochondria

•Number varies (Giardia – no MC; liver cells – 1000-2000/cell)

•Double membrane

•Outer membrane - smooth

•Inner membrane – series of folds (cristae)

•Center – semifluid (matrix)

•Involved in cellular respiration (ATP production)

•Contain 70S ribosomes

•Can reproduce on their own

•Lysosomes***

•Vacuoles***

•Lysosomes

•Vesicles formed in the Golgi complex

•Single membrane

•Contain various digestive enzymes

•Break down complex molecules

•Kill bacteria

•Vacuoles

•Cavities in the cell formed from the Golgi complex

•Bring food into cells; provide shape and storage

•Chloroplasts

•Present in green algae and plants

•Locations of Photosynthesis

•Contain flattened membranes (thlyakoids) that contain chlorophyll

•Stacks of thylakoids – grana (granum)

•70S ribosomes

•Multiply on their own

•Peroxisomes, and centrosomes

Peroxisomes

•Similar in structure to lysosomes, but smaller

•Contain enzymes that can oxidize amino acids and fatty acids

•Byproduct – hydogen peroxide (H2O2) – toxic

•Another enzyme, catalase destroys H2O2

•Centrosomes

•___________________ - networks of protein fibers

•Form the mitotic spindle; critical role in ___________

•For _______________ in non dividing cells

•____________ - pair

•Each composed of 9 clusters of 3 microtubules

The Evolution of Eukaryotes

•Life arose as simple organisms 3.5-4 billion years ago

•First eukaryotes evolved 2.5 billion years ago

•Endosymbiotic Theory

•Larger bacterial cells engulfed smaller bacterial cells, developing the first eukaryotes

•Symbiotic relationship

•Host supplying nutrients and the symbiotic bacterium producing energy

•**Plasma membrane folded around the chromosome – rudimentary nucleus

•Aerobic bacteria ingested - mitochondria

•Photosynthetic bacteria ingested - chloroplast

•Evidences for endosymbiotic theory

•Mitochondria and chloroplasts resemble bacteria in size and shape

•Contain circular DNA

•Can reproduce independently

•Ribosomes similar to those of prokaryotes; protein synthesis also

•Antibiotics inhibit protein synthesis similarly