Chapter 2: Microbiology

What is spontaneous generation?

• Lifeless substances can give rise to living organisms

What was John Needham’s experiment?

• Uncorked and corked bottle

• Broth

• Microorganisms formed in both bottles over several days

What was Needham’s hypothesis?

• Microorganisms come into existence “spontaneously” (from thin air)

How did Pasteur disprove Needham using the heated air experiment?

• Heated the air that came in through the neck of a flask

• The heat killed all microorganisms

What was Pasteur’s Swan-Neck flask experiment?

• Extended neck to look like a swan

• First heated the air

  • No microorganisms appeared

• Then broke the neck, exposing flask to air

  • Microorganisms appeared

  • Realized that air contaminated the flask

What is the Germ Theory of disease?

• Microorganisms are capable of living in the body and can cause illness

What was Pasteur’s Yeast experiment?

• Had grape juice + yeast in a flask

• Heated the juice killed the yeast

• Added yeast back after realizing there was no fermentation

• Wine was produced due to fermentation

• Concluded that yeast was necessary for fermentation

What are the steps to the yeast experiment?

• Had grape juice + yeast in a flask

• Heated the juice killed the yeast

• Added yeast back after realizing there was no fermentation

• Wine was produced due to fermentation

• Concluded that yeast was necessary for fermentation

What was Pasteur’s conclusion from the yeast experiment?

• Yeast was responsible for fermentation

What was the thought behind the bacteria experiment?

• Could microbes cause disease?

What are the steps to Pasteur’s bacteria experiment?

• Grape juice w/ yeast + bacteria

  • Tasted sour

• Heated it

  • Killed all microorganisms

• Added yeast only

• Wine produced

  • No sourness (no bacteria)

What was Pasteur’s conclusion from the bacteria experiment?

• Bacteria could spoil wine

• Similarly, it could harm the human body

What are Koch’s postulates?

• Find the suspect

• Isolate it

• Recreate the disease

• Recover it again

What disease was killing the cows that Koch observed?

• Anthrax

What was the first step in Koch’s experiment?

• Drew blood from dead cow

• Examined under a microscope

• Saw rod-shaped microorganisms (bacteria)

What was the second step in Koch’s experiment?

• Placed drop of blood onto solid nutrient jelly

• Distinct colonies appear

  • Each colony a clone of the bacteria in the blood

What was the third + fourth step in Koch’s experiment?

• Injected bacteria into healthy mouse

• Mouse dies of anthrax

How did Koch confirm his observations?

• Microscopic examination of bacterial growth from the mouse

• Made sure bacteria matched the same in the cow’s blood

What is the metric system?

• Universal language of science

• Meters or fractions of meters

Why is measurement important in biology?

• One inaccurate measurement can mess up big experiments

How long is a centimeter?

• 1 in = 2.5 cm

• 1 cm = 1000 mm

How long is a millimeter?

• 1 mm = 1/1000 cm

• 1 mm = 1000 micrometers

How long is a micrometer?

• 1 micrometer = 1/1000 mm

• 1 micrometer = 1000 nm

How long is a nanometer?

• 1/1000 micrometer

How are measurements used in biotechnology?

• Microscopes

• Spectrophotometers

• PCR machines

What are eukaryotic cells used for in biotech?

• Stem cell research

• Gene therapy

• Complex vaccine production

• Cancer treatment

What is a nucleus?

• Obvious

What is the mitochondria?

• Obvious

What are ribosomes?

• Obvious

What is the ER?

• Obvious

What is the golgi apparatus?

• Obvious

What are lysosomes?

• Obvious

What are the key features of prokaryotic cells?

• No nucleus

• Circular DNA

• No membrane bound organelles

• Smaller + simpler ribosomes

How are prokaryotic cells used in biotech?

• Genetic engineering

• Insulin production

• HGH

• Enzymes

• Antibiotic design

  • Targets prokaryotic features

What are viruses?

• Made of nucleic acid

• Cannot live/grow w/out infecting

• Diseases

  • Influenza

  • Chicken pox

  • HIV/AIDS

How are viruses used in biotech?

• Gene therapy to deliver genes

• Phage therapy

  • Using viruses to kill bacteria

What are algae?

• Similar to cyanobacteria

• Photosynthesis

• Source of omega 3 fatty acids

How are algae used in biotech?

• Renewable energy sources

What are protozoa?

• Single celled, but more complex

• Some cause disease

  • Malaria

  • Sleeping sickness

How are protozoa used in biotech?

• Studying cell motility

• Model for drug testing

What are cyanobacteria?

• AKA blue-green algae

• Photosynthesis

How are cyanobacteria used in biotechnology?

• Biofuel production

• Engineering for nitrogen fixing for sustainable farming

What are fungi?

• Mushroom

• Mold

• Yeast

How are fungi used in biotech?

• Antibiotics (mold)

• Fermentation of beer, wine, + bread (yeast)

What is bacillus?

• Rod-Shaped

  • Anthrax

  • Diphtheria

  • Tetanus

  • Rat Bile Fever

What is coccus?

• Spherical shaped

  • Pneumonia

  • Gonorrhea

  • Streptococcus

  • Staphylococcus

  • Sarcina

What is staphylococcus?

• Forms clusters (grapes)

• Causes

  • Food poisoning

  • Skin infections

What is spiral bacteria?

• Spiral-shaped

  • Vibrio

  • Rat Bile Fever

  • Spirochete

How do spirochete move?

• Like a corkscrew

Why does bacterial shape matter?

• ID

  • Identification of infections

• Pathogenicity

  • How bacteria causes diseases

• Industry

  • Some bacteria are more ideal for gen. eng.

Why does biotechnology care about the shape of bacteria?

• Biotech tools rely heavily on bacteria

• Some bacteria shapes are more ideal for biotech/engineering

What is the flagella?

• Tail

• Spins to push bacteria through fluids

• Used as markers in genetic engineering

What is the cell wall?

• Made of complex carbs (peptidoglycan)

• Shape + protection

What is the cytoplasm?

• Cmon bro u dont know this, you’re cooked

What is the plasma membrane?

• Ur even more cooked if u dont know this gang

What are plasmids?

• Small circular DNA, independent of nucleoid

• Non-essential, beneficial genes

What is the nucleoid?

• Singular circular DNA

• Command center

• Floats in cytoplasm

What are pili?

• Hairlike structures

• Attachment to surfaces

• Genetic exchange (conjugation)

How are bacterial structures targeted in biotechnology?

• Cell Wall

  • Enzymes like lysozyme target the wall (breaking cell)

• Nucleoid

  • Focus on bacterial cloning

  • CrispR

  • Plasmid insertion

• Plasma Membrane

  • Antibiotic targets membrane function

• Flagella

  • Used as markers in genetic trackin

• Pili

  • Horizontal gene transfer - basis for genetic engineering

What is a cell envelope?

• Includes everything from the outside move inward

  • Capsule

  • Cell Wall

  • Cell Membrane

What is the capsule?

• In some bacteria

• Made of sugars

• Surrounds the cell (outer coating)

What are the capsule’s functions?

• Bacteria adhering to surfaces

• Shield against immune cells

• Masks bacteria from detection

What is the cell wall made up of?

• Peptidoglycan

What is peptidoglycan?

• Sugar-protien meshwork that gives wall strength

Peptidoglycan layer on gram-negative bacteria?

• Thin peptidoglycan

Peptidoglycan layer on gram-positive bacteria?

• Thick

What is the cell membrane made up of?

• Phospholipid

What do proteins on the cell membrane do?

• Transport

Why does bacteria need to be stained?

• ID pathogen

• Antibiotic sensitivity

  • Gram positive sensitive to penicillin

  • Gram negative resistant to penicillin

• Affects how we manipulate or transform bacteria

Simple Stain Technique

• Painting bacteria a single color to make them stand out

• Crystal violet dye (basic)

• Dye has positive charge, bacterial negative

• Background remains colorless

Negative Stain Technique

• Only stain background

• Bacteria repel dye

• Use acid dye like nigrosin

• Observe shape and size with minimal distortion

What are the steps for gram-staining?

• Apply crystal violet

• Add iodine (locks color inside cell)

• Decolorize with ethanol (95%)

  • Gram positive retains dye

  • Gram-negative loses dye

• Counterstain with safranin

  • Gram-negative take up red dye and appear pink/red

How is gram-staining used in biotech?

• Differentiate between different types of bacteria (gram positive and gram negative)

Two ways life propagates itself

• Sexually

• Asexually

Binary fission

• Bacterial reproduction

Growth phase

• Cell elongates slightly

• Metabolism active

• Cell builds energy

DNA replication

• DNA replication begins

• Circular DNA copied

• 2 identical DNA loops

Organelle reproduction + Cytoplasmic division

• Exactly what it looks like

What happens during membrane pinching?

• Membrane constricts inwards

Cell division

• Division

Generation Time

• Time between one division and the next

• Depends on species and conditions

Why bacteria form spores

• Spores lock away most crucial belongings (DNA + Enzymes)

What triggers spore formation?

• Harsh environment

DNA Prep Stage

• DNA copied

• One copy w/ parent, other genes to spore formation

Spore Septum Formation

• Membrane pinches inward

• Encloses DNA + cytoplasm

What happens when the core wall forms?

• Inner membrane becomes the core wall

What happens when the cortex develops?

• Thick layer of special peptidoglycan forms around the core

• Gives spore resistance

Exosporium

• Outermost layer

• Made of glyco and lipoproteins

Why are bacterial spores important in biotech?

• Spores resist extremes

  • Heat

  • Chemicals

  • Pressure

• Sterilization must destroy spores in food biotech

• Pharmaceuticals: spores must be eliminated

• Industrial microbiology: dormant starter cultures

2 Ways Bacteria Get Nutrients

• Heterotrophy

• Autotrophy

What is autotrophy?

• U know this

What is heterotrophy?

• U know this as well

How are autotrophic bacteria used in biotech?

• Carbon capture

• Wastewater treatment

How do autotrophs create their own food?

• Inorganic molecules

• Sunlight

What are saprobes?

• Eat dead matter

What are parasites?

• Live off hosts

What do heterotrophs eat?

• Organic matter made by other organisms

How are heterotrophs used in biotech?

• E.coli for gene cloning feeds on glucose

• Turn sugars into proteins, drugs, vaccines

What are obligate aerobes?

• Bacteria that require O₂

• Sit at the top of the test tube

What are microphiles?

• Need little oxygen

• Below the surface