Lecture: Unit 3 exam – Flashcards

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A component which project from the body.

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Questions to ask...

How many appendages does M/O have?

How will this affect me?

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Mainly present in bacilli ; spirilla

;~ motility

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~ chemotaxis (to detect a specific chemical)

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~ phototaxis (ability to detect light)

Note: psychrophiles are negatively phototactic and only like cold and absence of light.

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A flagellum is comprised of:

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BODY (anchors)

HOOK (moves, spins)

FILAMENT (can regenerate if cut)

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The body is attached to the M/O.

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~ Monotrichous

(one flagellum)

~ Lophotrichous

(2 flagella, usually opposite sides of M/O)

~ Amphitrichous

(flagella fanned out in 2 groups opposite sides of M/O)

~ Peritrichous

(flagella all around M/O)

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SEMISOLID STAB

(colony visible distinctly separate from stab line)

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HANGING DROP SLIDE

(technically possible BUT not a good method since M/O dies from heat quickly and isn't stained)

Determined by trial and error, reading can be +/-

Chemical/different types of light placed on opposite end of slide, watch for movement,

done one chemical at a time.

No, it is not an appendage.

It is never used for chemotaxis or phototaxis.

Internal/Periplasmic flagella

found mostly in spirochetes.

Located within cell envelope between cell wall and cell membrane.

Purpose: varied & precise movement

(↑ risk of infection to host)

Present only in Grm-

but not in ALL Grm-

Questions to ask...

Is M/O Gm+ or Gm-? Does M/O have pilus?

Long, tube-like structure,

originates from one bacterium and attaches to another.

Both ends of tube are open.

Conjugation is called Transformation in lab.

Pili are used in this process, which isn't the same as Reproduction, and is more of an Association between M/Os.

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An excised or copied piece of DNA which is transferred from a donor bacterium to a recipient bacterium through the pilus.

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during shift from favorable to unfavorable environment...

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Donor bacterium knows the other cannot tolerate; - environment, builds pilus, copies its strong genes (plasmids), sends plasmids to recipient bacterium via pilus, both bacteria survive.

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Donor bacterium knows the other cannot tolerate; - environment, builds pilus, EXCISES its strong genes (plasmids), sends plasmids to recipient bacterium via pilus, DONOR DIES.

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example: MRSA is highly transformed

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~ have bristle-like proteins, stick out all over surface;

;;; of M/O

~ adhesive

~ linked to process of infection

;;; (due to length of association with host's system

     through adhesion)

~ outermost layer of cell envelope

~ composition varies (usually polysaccharides)

~ thickness varies

1. SLIME LAYER: loosely bound, prevents water & nutrient loss, making M/O stronger, less leaky. (This is less threatening than M/O with capsule.)
2. CAPSULE: tightly bound & sticky (can't be removed by meds), protects against WBCs due to adherence
   

Streptococcus pneumoniae

(eats holes in simple squamous epithelium of alveoli and capillaries, then blood pools into alveolar regions. This is "fluid in the lungs".)

Haemophilus influenzae

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Bacillus anthracis

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Peptidoglycan is the most important component of the cell wall, as it's very rigid and prevents collapse/bursting, helps maintain shape.

5 cell membranes are common because of selective permeability (into/out of cell body).

Composition varies - some resemble human cell membranes.

1. Glycocalyx
2. Cell wall
3. Cell membrane
4. Cytoplasm (chromosome, plasmids, ribosomes, storage bodies, endospores)

1. one double helix, loose, no nucleus
2. looped or linear shape
3. DNA is coiled
4. contains ;250,000 genes
5. genes used for many purposes, mainly protein synthesis (ie, enzymes)

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DNA

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COPY of a small segment of DNA

~or~

EXCISED SEGMENT of DNA

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They are intended for donation

or have just been received.

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Only Gram - bacteria use plasmids*

*but not all Gram- M/Os do it*

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To impart Resistance, survival.

;;; (accomplished by plasmid type "P_r")

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;; An environment has become unfavorable.

;; M/O#1 is OK (resistant) and M/O#2 isn't OK 

    (susceptible).

>  Here the plasmid is usually a copy (not excised).

    This plasmid's purpose: resistance "P_r"

;; Plasmid sent via Pilus (singular) from M/O#1 to

;;;; the other.

;; M/O#2 is now resistant, no longer susceptible.

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To improve Abilities (not linked to resistance)**

**accomplished by "P_a" plasmids

;; An environment is favorable.

;; Both M/Os are OK (resistant).

;; Here the Abilities plasmid (P_a) contains genes

;;; that M/O#2 doesn't have.

    ***Plasmid's purpose: PLANNING ONLY (not survival)

;; Plasmid sent via Pilus (singular) from M/O#1 to

;;;; the other.

;; M/O#2 now has NEW ABILITIES.

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Target the Ribosomes with medication.

why?

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Because it's where Proteins are synthesized.

Prokaryotic ribosomes float in the cytoplasm and are

smaller/less dense (70S) than

eucaryotic ribosomes (80S).

S= Svedberg Unit (a unit of mass)

MAJORITY OF MEDS work by killing 70S ribosomes because of ↓ risk of damage to humans (80S eucaryotic).

INCLUSIONS used for basic nutrients

Dedicated inclusions - 1 type of nutrient (ie, carbs).

General inclusions store variety of nutrients.

GRANULES have variety of purposes.

Pigment Granules (S. marcescens) purpose unknown

Gas Granules - one purpose: float for survival

ENDOSPORES

a/k/a

"SPORES"

BACILLI are the only type

capable of sporulation.

(example: B. anthracis)

When it is near death.

1) chromosomes are replicated

    (some M/Os make 10, some make 1,000)

2) envelope of nearly dead M/O is used to envelope

    new chromosomes

3) spores are released

4) spores eat & grow to match size of original

Spore = a copied chromosome

a/k/a "clone" that is wrapped in pieces of the M/O's old envelope

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VEGETATIVE FORM

not not not

"parent cell"

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Flagella, Pili, Fimbrae

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Glycocalyx (1 layer), Cell Wall (1 layer)

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Cell Membranes (5 or more layers)

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(remember bacteria have ; 7 layers/covers)

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Chromosomes

Plasmids

Ribosomes

Storage Bodies

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0.2 microns (;m) - Bacilli

to

250 microns (;m)- Spirochetes

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Bacteria can hide from the immune system.

Bacteria can fit everywhere/harm everywhere.

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SURVIVAL

Coccus - roundish (not perfect sphere);;

;;; Bacillus - rod, elongated (found where nutrients

;;; are dispersed, long shape ; ability to eat)

Coccobacillus - elongated but still round

;;; Vibrio - crescent moon shape (always in

;;; windy environment, hanging)

Spirillum - spiral shaped

;;; Spirochete - spiral, highly coiled

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definition: Changing shape/morphing.

**MOST microbes are created with

1 shape and remain so.

**A few, Pleimorphic, species

can have more than one shape.

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access to NUTRITION

(if nutrients in Env. disperse, M/O has to elongate to increase reach)

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HEREDITY

just because this M/O

can change shape

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Rhizobium

Corynebacterium

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Some bacteria live as Independents (E. coli)

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Others live in Association,

but not necessarily for protection or sharing.

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;Diplococci: 2 paired cocci

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Tetrads: always cocci, 4 together

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Sarcinae: cocci clustered in multiples of 8

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Streptococci: cocci living in a straight chain (a/k/a serial arrangement)

**causes a wound that is wide but superficial

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Staphylococci: cluster of cocci,

NOT in multiples of 8

**wound deep

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Diplobacilli: side by side contact of bacilli

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Streptobacilli: straight chain of bacilli

example: B. megaterium (a large, rare strep)

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1); morphology (shape, size, arrangement)
2); Gram status
3); presence of specific structures;;

;;;;; (internal/external appendages, storage bodies)
4);; colony characteristics (streak plate)

5); biochemical reactions

6); nucleic acid composition (DNA analysis)

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Obligate intracellular parasites must live inside a cell, eats it from inside out.

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Immune system can't see since it's hidden in cell. Best defense is vaccination.

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Mammal host;Arthropod (lice, ticks);Human

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Rocky mountain spotted fever

(destroys connective tissue)

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Typhus will go into all human cells

(not fastidious)

Eye infection from environment.

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STD (human transmission)

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Ornithosis (infection from pet bird)

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Mycoplasma:

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With no cell wall, M/O releases sterols (alcohol) when it's threatened.

(ie, Atypical Pneumonia eats alveoli while releasing sterols. LETHAL)

Photosynthetics:

• Cyanobacteria
• Green & Purple Sulfur bacteria
• Myxobacteria fruiting bodies

Bergey's Manual of

Systemic Bacteriology

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Evolutionary: scientists want the M/O name to include ALL characteristics (too complex)

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Phenetic: scientists want to name according to morphology (size, shape, etc.) ONLY (too simplistic)