Microbial Cell Structure

A Features common to all cell typesB Prokaryotic cells

1 General features2 Prokaryotic Cell Structures

C Eukaryotic cells1 General Features2 Eukaryotic Cell Structures

D Viruses

Updated Jan 23 2007

A Features Common to All Cell TypesB Prokaryotic CellsC Eukaryotic CellsD Viruses

A Features common to all cell types

1 Bounded by a plasma membrane

2 Contain cytoplasm

3 Utilize energy and raw materials through metabolism

4 Have both DNA and RNA

5 Reproduce by cell division processes

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic CellsD Viruses

A Features common to all cell types

1 Bounded by a plasma membrane

2 Contain cytoplasm

3 Utilize energy and raw materials through metabolism

4 Have both DNA and RNA

5 Reproduce by cell division processes

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic CellsD Viruses

B Prokaryotic Cells

1 General Featuresa) Have no (or few) internal membranes

b) Many processes that are associated with organelles in eukaryotes (eg Respiration photosynthesis) are mediated by specialized regions of the plasma membrane in prokaryotes

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B Prokaryotic Cells

1 General Features (cont)c) There is no membrane-bound nucleus in

prokaryotes Instead the DNA is located within a specialized region of the cytoplasm of the cell called the nucleoid region There is no nuclear membrane surrounding the nucleoid

d) Includes the bacteria amp archaeathe terms ldquoprokaryotic cellrdquo and ldquobacterial cellrdquo often are used interchangeably

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B Prokaryotic Cells

1 General Features (cont)e) Shapes amp Arrangements See shapes handout

f) Sizesbull Typically ~ 01 - 20 m (with some exceptions)

bull Typical coccus ~ 1 m (eg Staphylococcus)

bull Typical short rod ~ 1 x 5 m (eg E coli)

bull Barely within the best resolution of a good compound light microscope

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B Prokaryotic Cells

B 2 Prokaryotic Cell Structuresa) Plasma membrane

bull Structurendash Phospholipid Bilayer with Associated Proteins

ndash Cholesterol is absent (except in the mycoplasma group)

ndash Hopanoids are often present

ndash Some archaea have plasma membranes with unusual lipids and monolayer structures

bull Functions ndash Maintain Cell Integrity

ndash Regulate Transport

ndash Specialized Functions in Bacteria

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structuresa) Plasma membrane

bull Structurendash Phospholipid Bilayer with Associated Proteins

ndash Cholesterol is absent (except in the mycoplasma group)

ndash Hopanoids are often present

ndash Some archaea have plasma membranes with unusual lipids and monolayer structures

bull Functions ndash Maintain Cell Integrity

ndash Regulate Transport

ndash Specialized Functions in Bacteria

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

a) Plasma membrane (cont)bull Internal membranes

ndash ldquoMesosomesrdquo

ndash Respiratory and Photosynthetic folds

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

b) The cytoplasmic matrixbull Composition

ndash Viscous aqueous suspension of proteins nucleic acid dissolved organic compounds mineral salts

ndash Network of protein fibers similar to the eukaryotic cytoskeleton

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

c) Ribosomesbull Sites of protein synthesisbull Typically several thousand ribosomes per bacterial

cell depending on the state of its metabolic activitybull Smaller than eukaryotic ribosomes

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

d) Cytoplasmic inclusionsbull Glycogen Granulesbull Poly--hydroxyutyrate granulesbull Lipid dropletsbull Gas vacuolesbull Metachromatic granules

(Phosphate crystals or volutin granules)bull Sulfur Granules

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

e) Nucleoidbull Chromosomal DNA

ndash Typically one chromosome per bacterial cell

ndash Consists of double-stranded circular DNA

ndash A few recently discovered groups have gt1 chromosome per cell and linear chromosomes

bull Plasmid DNA ndash R-Plasmids

ndash F-Plasmids

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls bull Gram Staining

ndash Method developed by Gram in 1888ndash Gram-positive cells stain purple

Gram-negative cells stain pinkndash Later it was discovered that the major factor determining

Gram reactions is the bacterial cell wall structurendash ldquoGram-positiverdquo amp ldquoGram-negativerdquo

These terms can mean eitherStaining results or Types of cell wall structure

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Peptidoglycan Structure

ndash Composition raquo A Polysaccharide raquo Composed of alternating units of

N-acetylglucosamine (NAG) andN-acetylmuramic acid (NAM)

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Peptidoglycan Structure (cont)

ndash Peptide crosslinking between NAM unitsraquo Tetrapeptide or pentapeptide chains attached to NAM

may ldquocrosslinkrdquo adjacent PG strandsraquo This gives PG a net-like or mesh-like structure

ndash Indirect crosslinkingraquo Found in Gram-positive bacteriaraquo TP chains of adjacent PG strands are linked by

pentapeptide chainsndash Direct crosslinking

raquo Found in both Gm + and Gm - bacteriaraquo TP chains are directly attached to each other

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Gram-positive Cell Wall

ndash Thick layer of Peptidoglycanraquo 20-80 nm in thicknessraquo Extensively crosslinked both with indirect amp direct links

ndash Teichoic Acidsraquo Polymers of glycerol or ribitolraquo Inserted into the PG layerraquo Sometimes attached to plasma membrane lipids

ndash Periplasmic Spaceraquo Space between the PG layer and the plasma membraneraquo Much smaller than in gram negative bacteria --

significance questioned

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structuresf) Prokaryotic cell walls

bull Gram-negative Cell Wallsndash Outer Membrane

raquo 7 - 8 nm in thicknessraquo Bilayer of lipopolysaccharide and phospholipid with outer

membrane proteinsraquo Lipopolysaccharide contains

Lipid A A dimer of glucosamine with 6 fatty chains Core Polysaccharide About 10 monosaccharide units O-side chain (O antigen)

raquo Lipid A is the bacterial endotoxin triggers inflammatory effects and hemorrhaging

raquo Outer Membrane ProteinsPorin Protein 3 porin molecules form a channel for transportdiffusion

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structuresf) Prokaryotic cell walls (cont)

bull Gram-negative Cell Walls (cont)ndash Peptidoglycan Layer

raquo Thinner than gm positiveraquo 1 - 3 nm thickraquo Less extensively crosslinkedraquo Anchored to outer membrane via Brauns lipoprotein

ndash Periplasmic Spaceraquo Fluid or gel-filled spaceraquo Much larger in Gm negative cells possibly 20 - 40 of cell

volumeraquo Periplasmic proteins

Hydrolytic enzymes amp Transport proteins

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Variations on Cell Wall Architecture

ndash Acid-fast Cell Wallsraquo Many genera in the ldquoHigh GC gram-positiverdquo bacterial

group contain mycolic acids embedded in the peptidoglycan

raquo Mycolic acids are a class of waxy extremely hydrophobic lipids

raquo Certain genera contain very large amounts of this lipid and are difficult to gram stain

raquo These genera may be identified by the ldquoacid-fastrdquo staining technique

raquo Includes Mycobacterium and Nocardia

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Variations on Cell Wall Architecture

ndash Acid-fast Cell Wallsraquo Many genera in the ldquoHigh GC gram-positiverdquo bacterial

group contain mycolic acids embedded in the peptidoglycan

raquo Mycolic acids are a class of waxy extremely hydrophobic lipids

raquo Certain genera contain very large amounts of this lipid and are difficult to gram stain

raquo These genera may be identified by the ldquoacid-fastrdquo staining technique

raquo Includes Mycobacterium and Nocardia

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

f) Prokaryotic cell walls (cont)bull Variations on Cell Wall Architecture (cont)

ndash Mycoplasmasraquo Bacteria that are naturally have no cell wallsraquo Includes Mycoplasma and Ureaplasma

ndash Archaea raquo Have archaea cell walls with no peptidoglycanraquo Many have cell walls containing pseudomurein a

polysaccharide similar to peptidoglycan but containing N-acetylglucosamine and N-acetyltalosaminuronic acid

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

g) Capsules slime layers and S-layersbull Species and strain specific bull Structure of capsules amp slime layers

ndash Polysaccharide or polypeptide layer outside cell wall ndash May be tightly or loosely bound ndash Detected by negative staining techniques

bull Structure of S-layersndash Found on surfaces of some bacteria and archaeandash Protein layer on exterior of cellndash Regular ldquofloor tilerdquo patternndash Function not clear -- Stability

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

g) Capsules slime layers and S-layers (cont)bull Functions of capsules amp slime layers

ndash Attachment

ndash Resistance to desiccation

ndash Nutrient Storage

ndash Evasion of phagocytosis

eg in Streptococcus pneumoniae

S strain is encapsulated amp virulent

R strain is non-encapsulated amp non-virulent

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

h) Fimbriae and Pilibull Short hair-like filaments of protein on certain

bacterial cellsbull Believed to function in attachmentbull In a few species specialized pili (sex pili encoded

by genes on the F plasmid) enable the transfer of DNA from one cell to another (conjugation)

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

i) Bacterial flagella and motilitybull Function

ndash MotilityAlmost all motile bacteria are motile by means of flagella

ndash Motile vs nonmotile bacteriandash Detected by flagella staining or by motility agarndash Different species have different flagella arrangements

bull Structurendash Filament

Composed of the protein flagellinndash Hook amp Rotor Assembly

Permits rotational spinning movement

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

i) Bacterial flagella and motility (cont)bull Mechanism of Motility

ndash ldquoRun and Tumblerdquo Movementcontrolled by the direction of the flagellar spin

ndash Counterclockwise spin = Straight RunClockwise spin = Random Tumble

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

i) Bacterial flagella and motility (cont)bull Chemotaxis

ndash Response to the concentration of chemical attractants and repellants

ndash As a bacterium approaches an attractantthe lengths of the straight runs increase

ndash As a bacterium approaches a repellantthe lengths of the straight runs decrease

ndash Mechanism of chemotaxisStimulation of chemotactic receptors in the PM this triggers a ldquocascaderdquo of enzymatic activity that alters the timer setting of the flagella rotors

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

j) Bacterial sporesbull Function

ndash To permit the organism to survive during conditions of desiccation nutrient depletion and waste buildup

ndash Bacterial spores are NOT a reproductive structure like plant or fungal spores

bull Occurrence ndash Produced by very few genera of bacteria ndash Major examples

Bacillus Clostridium

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

j) Bacterial spores (cont)bull Significance in Medicine amp Industry

ndash Spores are resistant to killing ndash Cannot be killed by moist heat at 100degC (boiling) ndash Killing spores by moist heat requires heating to 120degC for

15-20 min (autoclaving or pressure cooking)

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

j) Bacterial spores (cont)bull Sporulation

ndash The process of spore formation ndash Governed by genetic mechanism ndash A copy of the bacterial chromosome is surrounded by a

thick durable spore coat ndash This forms an endospore within a vegetative cell ndash When the vegetative cell dies and ruptures the free spore

is released

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

B 2 Prokaryotic Cell Structures

j) Bacterial spores (cont)bull Spore Germination

ndash When a spore encounters favorable growth conditions ndash The spore coat ruptures and a new vegetative cell is

formed

A Features Common to All Cell TypesB Prokaryotic Cells

1 General Features2 Prokaryotic Cell Structures

a Plasma membraneb The cytoplasmic matrixc Ribosomesd Cytoplasmic inclusionse The nucleoidf Prokaryotic cell wallsg Capsules slime layers and S-layersh Fimbriae and pilii Bacterial flagella and motilityj Bacterial spores

C Eukaryotic CellsD Viruses

C Eukaryotic Cells

1 General Featuresa) Have complex internal membrane system

compartmentalization membrane-enclosed organelles

b) DNA is enclosed in a membrane-bound nucleus

c) Includes animal amp plant cells fungi amp protists (protozoa amp algae)

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

2 Eukaryotic Cell Structuresa) Nucleus

bull Location of the cellrsquos DNAbull Major processes

ndash DNA replicationndash DNA expression (transcription)

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

b) Ribosomesbull Thousands are located suspended in the cytoplasm

and attached to the rough endoplasmic reticulumbull Major process

ndash Protein synthesis (translation)

bull Ribosomes in the eukaryotic cytoplasm are larger than prokaryotic ribosomes

bull Ribosomes are also found within mitochondria and chloroplasts the ribosomes of these organelles are very similar in structure amp size to prokaryotic ribosomes

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

c) Cytomembrane systembull Folded sacks of membranes within the cytoplasm

bull Carry out processing and export of the cellrsquos proteins

bull Major components ndash Endoplasmic reticulum (rough and smooth)

ndash Golgi apparatus

ndash Transport vesicles

ndash Lysosomes

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

d) Mitochondriabull Located in the cellrsquos cytoplasm

bull Major process cellular respirationndash The mitochondria oxidize nutrient molecules with the help

of oxygen

ndash Some of the energy is conserved in the form of chemical energy (energy-containing chemical compounds) that can be used for biological processes

bull Evolved from bacteria by a process called endosymbiosis

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

e) Chloroplastsbull Located in the cytoplasm of plant cells algae cells

and certain protozoan cells

bull Major process photosynthesisndash Using the energy from light CO2 is converted into

carbohydrates such as glucose

bull Evolved from bacteria by endosymbiosis

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

C 2 Eukaryotic Cell Structures

f) Cytoskeletonbull Microfilaments

bull Microtubules

bull Intermediate filaments

g) Vacuoles

h) Peroxisomes

A Features Common to All Cell Types B Prokaryotic CellsC Eukaryotic Cells

1 General Features2 Eukaryotic cell structures

a Nucleusb Ribosomesc Cytomembrane systemd Mitochondriae Chloroplastsf Cytoskeletong Vacuolesh Peroxisomes

D Viruses

D Viruses

1 Structure of a ldquoVirus Particlerdquoa) Noncellular Biological Entity

b) Contains either DNA or RNA (not both)

c) Nucleic Acid is surrounded or coated by a protein shell (capsid)

d) Some viruses possess a membrane-like envelope surrounding the particle

A Features Common to All Cell TypesB Prokaryotic CellsC Eukaryotic CellsD Viruses

D Viruses

2 Viral Replicationa) No independent metabolism or replication

b) Replicate only inside an infected host cell

c) Do not replicate via a process of cell division

d) Replicate via a process ofbull Attachment and Penetrationbull Disassembly (uncoating)bull Synthesis of Viral Protein and Nucleic Acidbull Reassembly of new viral particlesbull Release of new viral particles

A Features Common to All Cell TypesB Prokaryotic CellsC Eukaryotic CellsD Viruses