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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01 BIO+210+FQ+2014+Ch+3+Cell+structure

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