Chapter 2 Microbiology

What is spontaneous generation?

The belief that lifeless substances can give rise to other living organisms

What was John Needham’s experiment?

used sterile broth leaving one open and the other corked, waited a few days and observed the microbial growth

What was Needham’s hypothesis?

Microorganisms come into existence spontaneously from clear air.

How did Pasteur disprove Needham using the heated air experiment?

He used heat to prove that no microorganisms would appear if heat was applied to the flask

What was Pasteur’s Swan-Neck Flask Experiment?

It showed that the room air is what contaminated the broth by only seeing the growth of microorganisms after allowing room air in

What is the Germ Theory of Disease?

microorganisms (germs) are capable of living in the body and can cause illness

What was Pasteur’s Yeast Experiment?

took grape juice with yeast cells then heated which killed yeast, he then added yeast back in and after a few days wine was formed

What are the steps to the Yeast Experiment?

1: pour grape juice into flask that already has yeast cells

2: heated the juice to kill yeast

3: plugged the flask so fermentation appeared then let it sit

4: added yeast back into the same grape juice

5: wine was made

What was Pasteur’s conclusion from the Yeast Experiment?

Yeast wasn’t just present - it was necessary for fermentation. Something alive was making the change.

What was the thought behind the Bacteria Experiment?

Could microbes cause disease too?

What are the steps to Pasteur’s Bacteria Experiment?

1: pour grape juice into flask that already has yeast cells and bacteria

2: heated the juice to kill yeast and bacteria

3: added ONLY yeast back into the same grape juice

5: wine was made but no sourness

What was Pasteur’s conclusion from the Bacteria Experiment?

It wasn’t just yeast that could change liquids, Bacteria could spoil wine. Something similar might happen in the body

What are Koch’s postulates?

1: find the suspect

2: isolate it

3: recreate disease

4: recover it again

What disease was killing the cows that Koch observed?

Anthrax

What was the first step in Koch’s experiment?

draw blood from a dead cow and examine it under a microscope

What was the second step in Koch’s experiment?

grow the Bacteria from the blood on a solid nutrient jelly and observe the colonies that appeared after a couple days

What was the fourth step in Koch’s experiment?

inject mouse with bacteria grown from colonies

How did Koch observed his observations?

Saw bacteria that killed the mouse is the same under a microscope as from the original cow

What is the metric system?

universal language of science

Why is measurement important in biology?

microorganisms are too small for our eyes

How long is a centimeter?

1 in = 2.5 cm

How long is a millimeter?

10mm = length of knuckle

How long is a micrometer?

10 micrometers = 1 epithelial cell

How long is a nanometer

10nm = width of cell membrane

How are measurements used in biotechnology?

to measure microorganisms

What are eukaryotic cells used for in biotechnology?

• stem cell research

• gene therapy

• producing complex biological vaccines

• developing cancer treatments

What is a nucleus?

location where DNA is stored

What is the mitochondria?

where ATP is made

What are ribosomes?

proteins are here

What is the endoplasmic reticulum?

moves proteins around

What is the golgi apparatus?

packages proteins

What are lysosomes?

digest unwanted stuff

What are the key features of prokaryotic cells?

• no nucleus

• circular DNA

• no membrane bound organelles

• have smaller and simpler ribosomes

How are prokaryotic cells used in biotechnology?

• genetic engineering

• making insulin

• Human Growth Hormone, enzymes

• designing antibiotics targeting prokaryotic features

What are viruses?

made of nucleic acids or inside a protein shell

How are viruses used in biotechnology?

to deliver collected genes

What are algae?

like cyanobacteria but eukaryotic

How are algae used in biotechnology?

for renewable energy sources

What are protozoa?

single celled organisms but more complex

How are protozoa used in biotechnology?

used to study cell motility and models for drug testing

What are cyanobacteria?

blue-green algae

How are cyanobacteria used in biotechnology?

biofuel production and can be engineered to fix nitrogen for sustainable energy

What are fungi?

molds, mushrooms, and yeast

How are fungi used in biotechnology?

gives us antibiotics and ferments bread, wine, and beer

What is bacillus?

rod shaped bacteria

What is coccus?

spherical shaped bacteria

What is staphylococcus?

clusters of spherical shaped bacteria

What is spiral?

curved or twisted bacteria

How do spirochete move?

moves like a corkscrew

Why does bacterial shape matter?

• helps diagnose infections

• how Bacteria cause disease

• some bacteria is better for genetic engineering

Why does biotechnology care about the shape of bacteria?

genetic engineering ease

What is the flagella?

long whip like tail used for movement

What is the cell wall?

helps with shape and protection of bacteria cell

What Is cytoplasm?

gel like interior of cell

What is the nucleoid?

command center of a cell containing a singular circular DNA

What is the plasma membrane?

phospholipid bilayer

What are plasmids?

small circular DNA independent of nucleoid

What are pili?

hair like structures used for attachment to surfaces

How are bacterial structures targeted in biotechnology?

cytoplasm: all antibiotic reactions occur here

nucleoid: focus of bacterial cloning, CRISPR, and plasmid injection

plasma membrane: antibiotics target function of membrane

plasmid: recombinant DNA work

What is a cell envelope?

where capsule, cell wall, cell membrane, are located

What is the capsule?

made of polysaccharides and sometimes protein fibers

What are the functions of the cell envelope?

masks bacteria from detection, helps adhere to sticky surfaces

What is the cell wall made up of?

peptidoglycan

What is peptidoglycan?

dugar protein meshwork that gives wall it’s strength

Describe the peptidoglycan layer on gram-negative bacteria?

thin

Describe the peptidoglycan layer on gram-positive bacteria?

thick

What is the cell membrane made up of?

phospholipid bilayer

What do proteins on the cell membrane do?

channels and pores for transport

Why does bacteria need to be stained?

• observation

• identification

• differentiation

Describe the simple stain technique.

painting bacteria to stand out against colorless background using a positive charged dye such as crystal violet

Describe the negative stain technique.

staining background

What are the steps for gram-staining?

1: apply crystal violet

2: add iodine

3: decolorize with ethanol (95%)

4: counter stain with uv safranin

How is gram-staining used in biotechnology?

see if gram negative or gram positive

What are the two ways life propagates itself?

• sexual reproduction

• asexual reproduction

What is binary fission?

how bacteria reproduce

What happens during the growth phase?

• elongates slightly

• metabolism active, cell builds up energy

What happens during DNA replication?

• begins replicating DNA

• circular DNA

• now bacteria has two identical DNA copies

What happens during organelle reproduction and cytoplasmic division?

organelles replicate and cytoplasm separates

What happens during membrane pinching?

cell membrane starts to constrict inwards 

What happens during cell division?

• cell splits into 2 identical daughter cells

• each cell alive and ready to divide again

What does generation time mean?

time between one division and next

Why do bacteria form spores?

to store most important info - DNA and enzymes

What triggers spore formation?

When bacteria is in extreme environment

What happens during the DNA preparation stage of spore formation?

DNA is copied

What happens when spore septum is formed?

a membrane pinches inward and closes DNA as well as cytoplasm off

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 core

• gives spore resistance

What is the exosporium?

outer shell it sits in

Why are bacterial spores important in biotechnology?

• pharmaceutical production

• food

• industrial microbiology

What are the two ways bacteria get nutrients?

• autotrophy

• heterotrophy

What is autotrophy?

creating food for oneself

What is heterotrophy?

relying on organic matter made by other organisms

How are autotrophic bacteria used in biotechnology?

• carbon capture

• wastewater treatment

How do autotrophs create their own food?

inorganic molecules and energy from sunlight

What are saprobes?

heterotrophic organisms that eat dead matter

What are parasites?

heterotrophic organisms that live off of a host

What do heterotrophs eat?

organic matter made by other organisms

How are heterotrophs used in biotechnology?

gene cloning

What are obligate anaerobes?

they require O2 and found near top of test tube

What are microphiles?

they need a little O2 and sit below the surface