MMG Exam 1

first description of microorganisms (molds)

first description of microorganisms (molds)

Contribution to science by: Hooke

living organisms could discriminate between optical isomers, suspected microbes catalyze reactions

Contribution to science by: Pasteur

first to see bacteria

Contribution to science by: Van

proving cause and effect in infectious disease

Contribution to science by: Koch

Binomial system

Contribution to science by: Linnaeus

Classified microorganisms through rRNA, discovered archaea

Contribution to science by: Woese

• Pathogen must be present in all cases of disease, and should not be found in healthy organisms

• Pathogen must grow in pure culture

• cells from culture of pathogen must cause disease

• Pathogen must be reisolated and shown to be same as before

List Koch’s postulates

Kingdom, Phylum, Class, Order Family, Genus, Species

Keeping Precious Creatures Organized For Grumpy Scientists

Summarize taxonomic hierarchy

light uses photons, CSLM uses laser, EM uses electrons

Light VS CSLM VS EM

uses polarizer, nucleus appears 3D

Differential Interference contrast microscopy

TEM must use thin sections, can see inside cell

SEM cells are coated with metal, only see outside

TEM Vs SEM

Prok: Bacteria and Archaea

Euk: Animal, plants, fungi, protists

Prokaryotic vs Eukaryotic microbes sorted:

NAG and NAM joined by beta 1-4 linkages

describe structure of peptidoglycan

O antigen, core polysaccharide, Lipid A

LPS is outer membrane of bacteria:
surface recognition, virulence factors, strength

Structure + Func of LPS

Neg: thin peptidoglycan, outer membrane, LPS, susceptible to drying

Pos: thick peptidoglycan, no outer membrane, no LPS, resistant to drying

Compare + Contrast gram neg and pos

heat, CV, iodine, decolorizer, safranin

gram stain steps

made up of carbs, for adherance

composition of bact cell wall: capsule

made up of protein, propellor, tumble, run

composition of bact cell wall: flagella

made up of protein, for adherence

composition of bact cell wall: fimbriae

made up of protein, for adherence, twitching, sex exchange

composition of bact cell wall: pili

mono- one

amphi- both

lopho- tuft

per- all over

differentiate between monotrichous, amphitrichous, lophotrichous, pertrichous

swimming: flagella, fastest

twitching: pulled by type IV pili, slow

gliding: requires proteins, slow

Differentiate between swimming, twitching, gliding

vegetative: endo

nonrefractile refractile

low high

absent present

high water low water

differentiate between vegetative cells and endospores with respect to :

appearance

calcium content

dipicolinic acid

water content

archaea: plasma mem and S layer, rarely capsule glycocalyx and slime

bacteria: plasma mem and cell wall, may include others

Compare archaea and bacteria cell envelopes:

similar: both function for motility, embedded in cell mem

archaea: thinner, filament, growth occurs at base, slower swimmer

bacteria: thicker, hollow, growth occurs at end, faster swimmer

compare archaea and bacteria flagella:

pseudomurein: archaea cell wall. NAG and N aminuronic acid, Beta 1-3 Linkges

peptidoglycan: bacteria cell wall, NAG and NAM, beta 1,4 linkages

pseudomurein vs peptidoglycan

cannulae: hollow tube like, allows daughter cells to stay connected

hami: grappling hook, help being washed away

describe structure and func of cannulae and hami

nucleus: bact and archaea no, euk yes

chromosome: bact and arch singular circular, euk multiple linear

photosynthesis: archaea no

ribosome: 70S for bact and arch, 80S for euk

bact and arch can grow above 80

only arch can grow above 100

archaea not pathogen

bacteria and euk have unbranched ESTER link, archaea has branched, ether link

Discuss key differences between bact, archaea, euk:

nucleus

chromosome

photosynthesis

ribosome size

growth above 80

growth above 100

pathogens

fatty acids and linkages

euk, multi or unicellular, heterotrophs, cell wall and chitin

4 features of fungi

sex spore, how fungi are classified

define conidia

flagellated sex spore for chytridiomycota

define zoospore

yeast: unicellular, stain purple with gram, smooth

mold: multicellular, special stain, fluffy (aerial hyphae),

compare yeasts vs molds

spore: reproductive unit of fungus

hyphae: multicellualr structure by which fungi grow

explain how hyphae and spore are related to fungal growth

euk, multicellular, parasitic worm, animalia

4 features of helminths

head, hooker, and sucker

define scolex

entire body

define stobila

one proglottid= reproductive unit

define proglottid

helminth

• helminth

  • nematode (round, non segment)

  • platyhelminth (flat, segment)

    • cestode (many segment)

    • trematode (one segment)

describe helminth tree

cannot be cultured

identify adult worms or eggs in patient samples

how are helminths identified in the lab

any euk that isnt a plant animal or fungus

define protist

excavates

alveolata- alveoli

stramenophiles- short hair extensions

rhizaria-threadlike pseudopod

haptophytes- haptonema

amoebozoa- use pseudopods

give the 6 categories of protists and defining characteristics

diplomonads, parabasalids, kinetoplasts

examples of excavates

ciliates, dinoflagellates, apicomplexans

examples of alveolata

apicomplexans are animal protists

have apicoplasts, sporozoite is the form that transmits parasite to host, oocyst is thick wall stage

what are apicomplexans and three things they have

diatom- pretty shape, cell wall made of silica

oomycetes- water protist cell wall made of cellulose

examples of stramenophile

active stage of protozoa

define trophozoite

growth, infectious stage of protozoa

define cyst

archaeplastida containing plants and algae

supergroup as a result of primary endosymbiosis of chloroplasts

Archaeplastida, SAR clade, Excavates, Amoebazoa, Opisthokonta

five supergroups within eukarya

fungi

microbial ekaryotes most closely related to animals

Amoeba, flagellates, ciliates, apicomplexa (no obvious motility)

Four groups of protozoa:

acellular, need host to replicate

two reasons viruses are nonliving

capsid -protein coat for shape and protection

genome- either RNA or DNA

All viruses have

envelope- surrounds capsid

spikes/glycoprotein- help with attachment and specificity

some viruses have

Lytic-destroys host APSAC

1. attachment of phage

2. penetration of viral nucleic acid

3. synthesis of nucleic acid and protein

4. assembly of new virus

5. cell lysis and release virions

5 steps for LYTIC bacteriophage replication

after viral nucleic acid is in cell, it is integrated into host DNA (prophase) and replicated during cell division

what happens in lysogenic vs lytic bacteriophage repliction

1. attachment : spike/envelope in enveloped or capsomeres in naked attach to host

2. penetration : enveloped targets lipids and membranes fuse. Naked is engulfed in endocytosis.

3. uncoating : capsid digested

4. replication

5. assembly : new virions

6. release : enveloped bud at low levels. naked go through lysis/exocytosis

animals go roar : APURAR

6 steps in animal viral replication

1. transformation from normal cell to tumor

2. virulent infections lyse host (naked)

3. persistent infection (budding)

4. latent- virus present but not replicating unless triggered

4 outcomes of animal virus

in + genome and mRNA are the same. in - genome is complementary to mRNA

difference between + and - RNA viruses

hepadnavirus, retrovirus

2 viral families that use RT

polyomavirus S-V40, herpesvirus

2 viral families that cause tumors

plaque assay- region of cell destruction from virus is seen as plaque

Describe lab method for identifying virus

viruses are not cells

viruses are not alive

viruses have capsid coat and inner DNA, prok have no nuclei or membrane bound, euk have

viruses use host energy, prok use asexual (binary fission), euk use mitosis or meiosis

viruses dont exhibit metabolism

Compare viruses, prokaryotes and eukaryotes by:

cells or not?

considered alive?

structure

replication

metabolism?

psychro -below 15ºC

thermophile 45-80ºC

define psychrophile, mesophile, thermophile

halophile is salt tolerant, and halotolerant can tolerate salt but prefers none

define halophile and halotolerant

sterilization removes ALL microbes

decontamination makes it safe, not all microbes gone

disinfection removes pathogens, not all microbes gone

pasteurization, uses heat to reduce microbial load

Difference between sterilization, decontamination, disinfection, pasteurization

microscopic cell counting, turbidity (spectrophotometer, OD540)

Total cell count methods:

plates and serial dilutions. CFU/mL

=

Viable cell count methods

binary- genetically and size identical

budding- different daughter cells

hyphae- cells elongate and replicate DNA at tip

compare growth patterns for binary, budding and hyphal growth

specific to bacteria, free floating or swimming

define planktonic

attached to surface can develop biofilms

define sessile

biofilm; population of cells enmeshed in a polysaccharide matrix that is attached to a surface

1. adhere to surface

2. secrete EPS

3. complex 3D structure

4. release planktonic cells

4 stages of biofilm formation + define it

facultative can live with or without O2, microaerophile can use O2 in small amounts

difference between facultative anaeobe and microaerophile