Microbiology

Adolf Mayer

Adolf Mayer

put sick tobacco sap into healthy tobacco plants, made them sick too, after assuming it was bacteria behind it, he tested it and found something smaller was behind the disease

Wendell Stanley

isolated the tobacco mosaic virus and determined that a virus caused the disease, NOT poison or bacteria

Virus

A nonliving particle made up mostly of a protein coat and nucleic acid (DNA or RNA, NEVER BOTH)

3 Main traits of Viruses

Extremely Small (need Electron microscope to observe)

Very Simple shape/structure

Very Specific

Why can't a light microscope be used to observe viruses?

They are too small and viruses cannot be caught in filters that isolate bacteria

Capsid

Protein coat that surrounds and protects the DNA/RNA in a Virus

Envelope

- An additional nucleic acid protection found in many animal-infecting viruses.

- made of lipids, proteins, and carbs found on the host cell's membrane.

- Has "spikes" to help identify and infect its host cell

- Blue spikey circle in the image

What does a Virus' shape indicate?

The type of cells they infect

ex. Rod, polyhedral, space craft, or round

Rod shaped virus

polyhedral shaped virus

Space craft shaped virus

Round virus shape

Host Range

The amount or extent of organisms/cells that a virus can infect

ex. Rabies effects mammals and humans - large host range

Human influenza - only affects upper respiratory tract in humans - small/limited host range

Why do Virus's need to infect host cells?

The can only way they can "reproduce" is by infecting a host cell to make more viruses

Virus Reproduction

known as VIRAL REPLICATION because:

- they asexually reproduce (clone themselves)

- They don't reproduce by themselves, they have the host cell do it for them

How does an envelope help viruses?

Specific proteins in the virus envelope and cell membrane bond, lock, and key fit

The envelope is made of the same stuff as the cell membrane, so cell does not defend itself

Animal Viral replication

A virus merges with the host cell membrane like endocytosis, and viral DNA takes over the cell and makes it make more viruses, released through a process like endocytosis

What happens when a virus injects DNA into the host cell?

It takes over the functions of the cell by making the cell make more viruses like it makes protein (protein synthesis)

What 2 things happen when a virus injects RNA into the host cell?

RNA used as template for replication and mRNA is used by ribosomes to make Viral Proteins

or

Makes a retrovirus

Retrovirus

- RNA used as template for replication

- Newly made Viral DNA incorporated into Cell genome (Dna made from enzyme from the virus called reverse transcriptase)

Bacteriophage

A virus that infects bacteria

- only a capsid usually

- 2 ways it replicates, Lytic cycle and lysogenic cycle

Lytic Cycle

Immediately takes over host cell, replicates viruses, lyses and makes the viruses go flying

Lysogenic Cycle

Slow takeover of the host cell, hyjacks the DNA and makes it behave normally, Viral DNA replicated along with the cell

ex. RNA Viruses like HIV

What happens when an enzymatic stimulus occurs?

The Viral DNA detaches from host cell DNA and lytic cycle is then activated (Lysogenic -> Lytic)

How are viruses fought off?

No medicine or cure, body has to kill all the infected cells

How are Viruses prevented?

Once your body fights off the virus once, it makes antibodies against that virus for the future so you can fight it off easily

*Vaccines are weak strains of virus that help body make antibodies for the virus

Viroids

virus-like particles that infect plants (infectious RNA molecules)

- NO CURE OR VACCINE

Prions

bits of virus particles that infect animals

ex. Mad cow disease and other degenerative brain diseases

- NO CURE OR VACCINE

- No Nucleic acid

Eubacteria and Archaebacteria are ____________.

Prokaryotes

- no nucleus

Basic Bacteria traits

- No nucleus (prokaryote)

- cell membrane (no membrane bound organelles)

- ribosomes for making proteins

- has cili/pili (little hairs)

Strains/Types

how the bacteria uses energy

5 strains of Bacteria

Heterotrophs

Photoheterotrophs

Photoautotrophs

Chemoautorophs

Decomposers

Heterotrophs

have to consume other organisms for energy

Photoheterotrophs

can perform Photosynthesis but must also eat others for energy

Photoautotrophs

make their own food from sunlight (photosynthesis)

Chemoautotrophs

make their own food from chemicals

ex. Hydrogen sulfide

Decomposers

digest dead organisms and recycle nutrients for others

3 Ways bacteria breaks down their energy?

Obligate Aerobes

Obligate Anaerobes

Facultative Anaerobes

Obligate Aerobes

NEED to use oxygen to digest food

Obligate Anaerobes

NEED to live without oxygen (killed by oxygen)

Facultative Anaerobes

can live with or without oxygen

2 kingdoms of bacteria

Eukarya (Eubacteria) and Archaea (Archaebacteria)

Archaebacteria

bacteria that lives in very HARSH environments

cell wall doesn't have Carbohydrate Peptidoglycan

Eubacteria

bacteria found everywhere

cell wall DOES have Carbohydrate Peptidoglycan

Carbohydrate Peptidoglycan

protein + sugar (carb - sugar, Peptidoglycan - protein)

4 subgroups of Archaebacteria

Methanogens

Thermoacidophiles

Chemosynthesizers

Extreme Halophiles

Methanogens

produce methane gas "swamp gas" (found in digestive system)

found:

Human intestines, swamps, sewage treatment plants

Thermoacidophiles

live in hot(thermo - heat), acidic(acido - acid) waters

ex. hot springs of Supervolcanoes (Yellowstone)

Chemosynthesizers

use inorganic compounds for energy (ex. hydrogen sulfide)

found around hot springs near volcanic vents in the ocean

Extreme Halophiles

live in extremely salty(hal - salt) conditions

Subgroups of Eubacteria

gram-positive and gram-negative

Gram-positive

have thick Peptidoglycan cell walls that stain purple

found and used everywhere in humans and environment

ex. yogurt, antibiotics, tetanus, botulism

Gram-negative

Lipid layer surrounding think peptidoglycan wall cell wall and stains pink

found everywhere in environment, base of aquatic food chains, first to colonize devastated areas

ex. Cyanobacteria

Gram staining

a type of dye that reacts with the peptidoglycan cell walls of bacteria

purple in gram-positive because it reacts with protein and sugar (peptidoglycan)

pink in gram-negative because it reacts with fat and sugar

What organelles do bacteria lack besides Nucleus?

Mitochondria, Chloroplasts, ER, and Golgi

*Mitochondria and Chloroplasts might be embedded to plasma membrane but not inside of it

3 Shapes of bacteria

coccus/cocci, bacillus/bacilli, spirillum/spirilli

Cocci/Coccus

Sphere-shaped, sometimes in clumps or chains

ex. Streptococcus and Staphylococci

Bacilli/Bacillium

rod-shaped, usually forms chains, may have flagella to move

ex. E. coli and Salmonella typhi (typhoid fever/food poisoning)

Spirilli/Spirillum

spiral-shaped

moves by twisting themselves like corkscrews and some have flagella

ex. Treponema Pallidumcholera (syphilis) and Borrelia Burgdoferi (Lyme disease)

How does bacteria reproduce?

Binary Fission

asexual (mitosis)

identical children

What do bacteria do in harsh conditions?

They form endospores with thick falls and some cytosol and dna

How can bacteria exchange genetic material (DNA)

Conjugation

Transformation

Transduction

Conjugation

Bacteria forms cytoplasm bridge between 2 cells and DNA can transfer

- Bacteria sex

Transformation

Bacteria collects free floating DNA from dead bacteria cells

Transduction

Virus takes some bacteria dna with it, and it comes with it into the new bacteria that the virus infects

2 ways bacteria can create infection in humans

- Uses human cells and tissues as food (ex. Mycobacterium tuberculosis)

- releasing toxins that interfere with normal cell activities (ex. Streptococcus)

What can be taken to fight bacteria?

Antibiotics

they block the growth of bacteria or disrupts their reproduction

3 ways to control bacterial growth

Sterilization by heat, most bacteria dies in high temperatures after a while

Disinfectants: soaps, cleaners, ammonia, and bleach

Food storage and processing - keep food in fridge with low temps, food should be fully cooked

Louis Pasteur

composed the Germ Theory of Infectious Disease -

diseases are caused by microorganisms called pathogens

Koch (Koch's postulates)

Several rules for bacteria

- pathogens should only be found in dead organisms, not healthy ones

- pathogens should be isolated and grown in a pure culture in a lab

- when cultured pathogens are placed in a new host, they should cause the same disease as the one that infected the original host

- injected pathogens should be isolated from 2nd host to be identical to the original pathogen

Protists

Kingdom - Protista

Eukaryotes

3 Categories:

Protozoans, Algae, and Fungi-like

Protozoans

animal-like protists

eukaryotes with animal-like traits (heterotrophs - eat others for energy)

ex. Amoeba and Paramecium

Algae

plant-like protists

eukaryotes with plant-like traits

- have chloroplasts and perform photosynthesis

ex. diatoms and seaweed

- 2 main types:

Unicellular

Multicellular

Fungi-like

some Molds

eukaryotes that act like fungi

- heterotrophs and decomposers (get energy from dead or dying stuff)

not regular fungi b/c no chitin cell well

ex. slime and water molds

2 Fungi-like categories

Slime mold

Water mold

Slime mold

alternates between two stages

- ability to move and ooze like blobs, move as single or merge and form a blob, feed on matter from nutrient-rich soil

or

- fruiting body that emerges when harsh conditions or food is depleted, all the single cells merge and create a fruit with spores, slime molds come out of their spores when things are good again

Water mold

thrive on dead and dying stuff in water (some are plant parasites)

grow in wet and cool conditions

ex. Potato famine in Ireland

4 Categories of Protozoans

based on how they move

- Sarcodinas (Sarcodines )

- Zooflagellates

- Ciliates

- Sporozoans

Sarcodines (Sarcodinas)

- move by extending loves of cytoplasm called pseudopods

- use the cell membrane to ingest food through phagocytosis

ex. amoeba, foraminiferans (protective shell), and radiolarians

Zooflagellates

- move by using their flagella

- some free living but most live in host organisms

EX.

Trichonympha - lives in termite guts (mutalistic relation)

Trypanosoma (african sleeping disease) - parasite that attacks RBC and you get it by a Tsete fly bite

Ciliates

- move and eat using Cilia

- sweep food articles into the oral groove(mouth) of the ciliophoran(ciliate) and a food vacuole is created (basically a to-go pack)

- have a contractile vacuole that squeezes out extra water so it doesn't lyse (burst)

ex. Paramecium and Stenator

Sporozoans

spore-forming parasites

have thick spore like walls and transmitted through fluids

CANT MOVE

ex. Plasmodium - causes Malaria

Unicellular Algae

one cell

3 types -

Dinoflagellates

Diatoms

Euglena

*can tell by number of flagella

dino has 2, euglena has 1, diatom has 0

Dinoflagellates

has 2 flagella that spin the cell thru salt water

covered with cellulose plates

contains chloroplasts and performs photosynthesis

ex. Gonyaulux and Ceratium

Diatom

has a glass like cell wall made of silica

They die and their cell wall sinks to bottom of ocean and are minded for cleaners, abrasive, and toothpaste

Euglena

has flagella but no cell well

photoheterotroph (photosynthesis or eat others if no sunlight)

Multicellular Algae

more than 1 cell

can tell by color

Chlorophyta - green

Rhodophyta - red

Phaeophyta - brown

Chlorophyta

green algae

ex. fish tank algae, Chlamydomonas, Volvox, Ulva

*can be uni or multi (why is it under multi? ihnc)

Rhodophyta

red algae

ex. sea fans in reefs

warm saltwater

Phaeophyta

brown algae

ex. kelp and seaweed

found in cool saltwater

Protozoans vs Animals

protozoans are unicellular

Taxon

group or level of organization into which organisms are classified

ex. Protozoans and Algae taxons in Protist kingdom

or Chlorophyta taxon in multicellular algae