01 BIO+210+FQ+2014+Ch+3+Cell+structure
Transcript of 01 BIO+210+FQ+2014+Ch+3+Cell+structure
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Welcome
BIO 210 Microbiology
FQ 2014
Dr. Joanna S. Brooke
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Lectures:- Mon., Wed. at 11:20-12:50 Room SAC 161
Lab sections all in Room 234 McGowan North Section 1L1: Mon. 2:40 p.m. - 5:40 p.m. Section 1L2: Tues. 9:40 a.m. - 12:40 p.m.
Section 1L3: Tues. 2:40 p.m. - 5:40 p.m. Section 1L4: Wed. 8:00 a.m. 11:00 a.m.
Labs will start next week: Mon. Sept. 15
Laboratorian: Dr. Megan Schrementi
Graduate Teaching Assistants2
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The BIO 210 Course Syllabus
Note: a select part or parts of the following
chapters will be covered in this course:Chapters 8-11, 13-16, 22, 23, and 25
Introduction to Microbiology
https://www.youtube.com/watch?v=Prhn_U5HEio
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Introduction to Microbiology
https://www.youtube.com/watch?v=Prhn_U5HEio
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All living things can be classified in one of three
Domains:
Bacteria Archaea Eucarya
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Domains Bacteria and Archaea
Prokaryotes
Single-celled organisms, ~ 1.0 m in diameter
Contain no membrane bound nucleus, insteadcontain a nucleoid
No organelles
Have rigid cell wall 7
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Typical prokaryotic cell
Ribosome
CytoplasmNucleoid
GlycocalyxCell wall
Cytoplasmic membrane
Inclusions
Flagellum
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Domain Eucarya
Larger than prokaryotes, ~ 10-100 m diameter
Eukaryotes contain a membrane bound nucleus
Eukaryotes contain internal organelles
Algae, fungi, protozoa, plants, and animals
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Typical eukaryotic cell
Nucleolus
Cilium
Ribosomes
Nuclear envelope
Nuclear pore
LysosomeMitochondrion
CentrioleSecretoryvesicle
Golgi bodyTransportvesicles
Rough endoplasmicreticulum
Smooth endoplasmicreticulumCytoplasmic
membraneCytoskeleton
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Capsules and Slime layers
- made of polysaccharide
Referred to as glycocalyx Glyco = sugar calyx = shell
- enable bacteria to adhere tohost cells
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Bacterial Flagella:
- protein appendages thatprovide motility and allowbacteria to move through theirenvironment
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Flagella
Function Rotation propels bacterium through environment
Rotation reversible, can be clockwise or
counterclockwise
Bacteria move in response to stimuli (taxis)
Runs Tumbles
https://www.youtube.com/watch?v=4hexn-
DtSt4&list=TL5MNSeDvXTUw 13
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Chemotaxis movement of a cell towards a favorablechemical stimulus (e.g. nutrient) or away from a repellent.
Bacteria use flagella for motility Motile through sensing chemicals
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Fimbriae and Pili
Rod-like proteinaceous appendages thatextend out from the cell
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Fimbriae
Shorter than flagella
Used by bacteria to adhere to one another,to hosts, and to substances in environment
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Flagellum Fimbria
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Conjugation pili
Longer than fimbriae but shorter than flagella
control the transfer of DNA from one cell toanother during the process of conjugation
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Conjugation pilus
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Cell Wall: determines shape &provides structural support
- made of peptidoglycan (PG)
- unique chemical structure
distinguishes Gram-positive fromGram-negative bacteria
Bacil lus subtil is 20
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Basic structure of peptidoglycan Alternating series of two subunits: N-acetylglucosamine(NAG)
and N-acetylmuramic acid (NAM)
Joined subunits form glycan chain Glycan chains held together by string of four amino acids
Tetrapeptide chain
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- Thin layer of peptidoglycan
- Outer membrane outside the peptidoglycan containsphospholipids, proteins, and lipopolysaccharide (LPS)
Gram-negative cell wall
Peptidoglycan
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PG as a target Many antimicrobials interfere with the synthesis of PG
Penicillin Binds to bacterial proteins used for PG synthesis
Prevents cross-linking of glycan chains bytetrapeptides
Lysozyme Produced in tears and saliva Breaks bond linking NAG and NAM
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Cytoplasmic membrane is selectively permeable Determines which molecules pass into or out of cell
Few molecules pass through freely
Molecules pass through membrane via simple diffusionor transport mechanisms that may require carrier
proteins and energy
Cytoplasmic Membrane
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Phosphate head
Tail
Phospholipid
bilayerIntegral protein
Peripheral protein
Integralprotein
Cytoplasm
Integralproteins
Phospholipid
Cytoplasmic Membrane
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Cytoplasmic Membrane (CM)
site of energy production
energy produced through electron transport chain and in proton motive force
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- has 70-80 % water
- sugars, amino acids, salts
- ribosomes
- granules (inclusion bodies for energy-richsubstances e.g. glycogen)
Cell Cytoplasm (cytosol)
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Internal Structures
Bacterial cells have variety of internal structures
Some structures are essential for life Chromosome
Ribosome
Others are optional and can confer selective advantage Plasmid
Storage granules Endospores
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Bacterial Endospores
- produced through sporulation
- theoretically remain dormant for years
- resistant to heat, desiccation, chemicals and UVlight
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