Lecture: Unit 3 exam – Flashcards
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Compared to eucaryotic cells (human cells) prokaryotic cells are... |
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(continued) Compared to eucaryotic cells (human cells) prokaryotic cells are... |
have no nucleus (DNA unprotected in cytoplasm~BUT~we can't attack w/abx all the time since human DNA also targeted) (Activities hard to target since all happens within cytoplasm) (vs- human's 46 chromosomes) |
(continued) Compared to eucaryotic cells (human cells) prokaryotic cells are... |
Much more sophisticated in terms of:
~ adaptation capabilities ~ cell envelope structure (≥ 7 layers VS humans' 1 layer) ~ mechanisms for motility ~ mechanisms for adhesion |
; ; ; State the definition of a bacterium: |
; ; A microorganism whose body is procaryotic (unicellular). ; ; The term "bacteria" is plural. |
; ; ; Define appendage: |
; A component which project from the body. ; Questions to ask... How many appendages does M/O have? How will this affect me? |
; FLAGELLA - EXTERNAL ; Flagella are mainly present in M/Os of which shapes? ; ; |
; ; ; Mainly present in bacilli ; spirilla |
; ; FLAGELLA - EXTERNAL ; What are the 3 purposes of flagella? |
;~ motility or ~ chemotaxis (to detect a specific chemical) or ~ phototaxis (ability to detect light) Note: psychrophiles are negatively phototactic and only like cold and absence of light. |
; ; FLAGELLA - EXTERNAL ; What is the composition of a flagellum? ; |
; A flagellum is comprised of: ; BODY (anchors) HOOK (moves, spins) FILAMENT (can regenerate if cut) |
; ; FLAGELLA - EXTERNAL ; Is the body attached to the microorganism, or IS IT the M/O? |
; ; ; The body is attached to the M/O. ; |
; ; FLAGELLA - EXTERNAL ; Each bacterial species has specific # and arrangement of flagella... |
~ 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) |
; ; What are 2 methods to determine if a microorganism is motile? ; |
; SEMISOLID STAB (colony visible distinctly separate from stab line) ; HANGING DROP SLIDE (technically possible BUT not a good method since M/O dies from heat quickly and isn't stained) |
Chemotaxis and Phototaxis |
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.
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FLAGELLA: INTERNAL
Is an internall flagellum an appendage? |
No, it is not an appendage.
It is never used for chemotaxis or phototaxis. |
FLAGELLA: INTERNAL
a/k/a "periplasmic" are found in: |
Internal/Periplasmic flagella found mostly in spirochetes.
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FLAGELLA - INTERNAL
Location and purpose |
Located within cell envelope between cell wall and cell membrane.
Purpose: varied & precise movement (↑ risk of infection to host) |
PILI singular: "pilus" |
Present only in Grm- but not in ALL Grm-
Questions to ask... Is M/O Gm+ or Gm-? Does M/O have pilus? |
PILUS |
Long, tube-like structure, originates from one bacterium and attaches to another.
Both ends of tube are open. |
Pili are used during Conjugation. Explain... |
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. ; ; |
; ; During conjugation/transformation, a PLASMID comes into play. What is a plasmid? |
; ; An excised or copied piece of DNA which is transferred from a donor bacterium to a recipient bacterium through the pilus. |
; ; 1st TYPE OF CONJUGATION of Prokaryotic Cells ; ; |
; during shift from favorable to unfavorable environment... ; 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. ; ; |
; ; ; 2nd TYPE OF CONJUGATION of Prokaryotic Cells ; ; |
; ; Donor bacterium knows the other cannot tolerate; - environment, builds pilus, EXCISES its strong genes (plasmids), sends plasmids to recipient bacterium via pilus, DONOR DIES. ; ; example: MRSA is highly transformed |
; ; ; APPENDAGES: Fimbrae |
; ~ 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) |
CELL ENVELOPE COMPOSITION
Glycocalyx
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~ outermost layer of cell envelope
~ composition varies (usually polysaccharides)
~ thickness varies |
CELL ENVELOPE COMPOSITION
2 most common types of Glycocalyces |
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; ; ; ; examples of ENCAPSULATED microorganisms... ; |
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 ; Bacillus anthracis |
; ; ; CELL WALL ; PEPTIDOGLYCAN in Gram + M/Os because... |
; Peptidoglycan is the most important component of the cell wall, as it's very rigid and prevents collapse/bursting, helps maintain shape. |
How many PROKARYOTIC CELL MEMBRANES is common and why? |
5 cell membranes are common because of selective permeability (into/out of cell body).
Composition varies - some resemble human cell membranes. |
CELL ENVELOPE COMPOSITION
List main components... |
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CHROMOSOME within prokaryotic cell's cytoplasm |
; ; |
; ; What to Sulfa medications target? |
; ; ; DNA |
; ; ; Define PLASMID |
; ; COPY of a small segment of DNA ~or~ EXCISED SEGMENT of DNA |
; ; ; Unique features of Plasmids |
; They are intended for donation or have just been received. ; Only Gram - bacteria use plasmids* *but not all Gram- M/Os do it* |
; ; ; 1st of 2 Purposes of PLASMIDS |
; ; To impart Resistance, survival. ;;; (accomplished by plasmid type "Pr") ; |
; ; Describe how Plasmids impart resistance from one M/O to another. |
;; 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 "Pr" ;; Plasmid sent via Pilus (singular) from M/O#1 to ;;;; the other. ;; M/O#2 is now resistant, no longer susceptible. ; |
; ; ; 2nd of 2 Purposes of PLASMIDS |
; ; To improve Abilities (not linked to resistance)** **accomplished by "Pa" plasmids |
; ; Describe how one M/O improves abilities of another M/O by donating a plasmid. |
;; An environment is favorable. ;; Both M/Os are OK (resistant). ;; Here the Abilities plasmid (Pa) 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. ; |
; ; ; Most effective way of killing M/Os? |
; Target the Ribosomes with medication. why? ; Because it's where Proteins are synthesized. |
Prokaryotic Ribosomes >>where located? size? |
Prokaryotic ribosomes float in the cytoplasm and are smaller/less dense (70S) than eucaryotic ribosomes (80S). S= Svedberg Unit (a unit of mass)
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Why does medication target prokaryotic ribosomes successfully? |
MAJORITY OF MEDS work by killing 70S ribosomes because of ↓ risk of damage to humans (80S eucaryotic). |
STORAGE BODIES of prokaryotes 2 types |
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 |
The process of SPORULATION produces what? |
ENDOSPORES a/k/a "SPORES" |
The ONLY type of prokaryote capable of sporulation is: |
BACILLI are the only type capable of sporulation.
(example: B. anthracis) |
When does a bacillus undergo the process of sporulation? |
When it is near death. |
Describe 4 Stages of Sporulation |
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
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Define SPORE |
Spore = a copied chromosome a/k/a "clone" that is wrapped in pieces of the M/O's old envelope |
; ; In sporulation the ORIGINAL MICROORGANISM is referred to as... |
; ; VEGETATIVE FORM not not not "parent cell" |
; ; ; Name the 3 types of Appendages for prokaryotic cells |
; ; ; Flagella, Pili, Fimbrae |
; ; Prokaryotic Cell Envelope is composed of what? |
; Glycocalyx (1 layer), Cell Wall (1 layer) ; Cell Membranes (5 or more layers) ; (remember bacteria have ; 7 layers/covers) |
; ; Name the 4 structures found in Cytoplasm of prokaryotic cells. |
; Chromosomes Plasmids Ribosomes Storage Bodies |
; ; ; Range of size of Bacteria |
; ; 0.2 microns (;m) - Bacilli to 250 microns (;m)- Spirochetes |
; ; ; Implications of small size of bacteria... |
; ; Bacteria can hide from the immune system. Bacteria can fit everywhere/harm everywhere. |
; ; ; What gain is there in bacteria having certain shapes? |
; ; ; SURVIVAL |
; ; ; COMMON SHAPES (types) of Bacteria |
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 ; |
; ; define PLEIMORPHISM ; |
; ; definition: Changing shape/morphing. **MOST microbes are created with 1 shape and remain so. **A few, Pleimorphic, species can have more than one shape. |
; ; Most Pleimorphs have changed shape because of what? |
; ; access to NUTRITION (if nutrients in Env. disperse, M/O has to elongate to increase reach) |
; ; A 2nd type of Pleimorph has changed shape because: |
; ; HEREDITY just because this M/O can change shape |
; ; Name 2 Pleimorphic bacteria |
; ; Rhizobium Corynebacterium |
; ; Arrangements of Bacterial cells ~a LIFESTYLE~ |
; ; Some bacteria live as Independents (E. coli) ; Others live in Association, but not necessarily for protection or sharing. ; |
; ; 7 types of Bacterial cell Arrangements ; ; |
; ;Diplococci: 2 paired cocci ; Tetrads: always cocci, 4 together ; Sarcinae: cocci clustered in multiples of 8 ; ; ; ; ; |
; ; 7 types of Bacterial cell Arrangements ; (continued) |
; ; Streptococci: cocci living in a straight chain (a/k/a serial arrangement) **causes a wound that is wide but superficial ; Staphylococci: cluster of cocci, NOT in multiples of 8 **wound deep ; ; |
; ; ; 7 types of ; Bacterial cell Arrangements ; ; ; (continued) |
; ; Diplobacilli: side by side contact of bacilli ; Streptobacilli: straight chain of bacilli example: B. megaterium (a large, rare strep) ; ; |
; ; ID of Bacteria is based on 6 criteria. Name them... |
; ; 1); morphology (shape, size, arrangement) ;;;;; (internal/external appendages, storage bodies) 5); biochemical reactions 6); nucleic acid composition (DNA analysis) ; ; ; |
; Bacteria with unusual traits ; #1 - Obligate Intracellular Parasite |
; Obligate intracellular parasites must live inside a cell, eats it from inside out. ; Immune system can't see since it's hidden in cell. Best defense is vaccination. ; ; ; |
; Bacteria with unusual traits ; #1 - Obligate Intracellular Parasite Rickettsias - 3 examples |
; ; Mammal host;Arthropod (lice, ticks);Human ; Rocky mountain spotted fever (destroys connective tissue) ; Typhus will go into all human cells (not fastidious) |
; Bacteria with unusual traits ; #1 - Obligate Intracellular Parasite Chlamydias - 3 examples |
Eye infection from environment. ; STD (human transmission) ; Ornithosis (infection from pet bird) |
; Bacteria with unusual traits ; #2 - Cell Wall deficient bacteria Mycoplasmas |
; Mycoplasma: ; With no cell wall, M/O releases sterols (alcohol) when it's threatened. (ie, Atypical Pneumonia eats alveoli while releasing sterols. LETHAL)
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Bacteria with unusual traits
#3 - Photosynthetic bacteria
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Photosynthetics:
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What contains every known fact about every known bacteria? |
Bergey's Manual of Systemic Bacteriology |
; ; explain Evolutionary-VS-Phenetic Relationships in Classification |
; Evolutionary: scientists want the M/O name to include ALL characteristics (too complex) ; Phenetic: scientists want to name according to morphology (size, shape, etc.) ONLY (too simplistic) |