Microbiology - EXAM 1

The study of organisms that are to small to be seen with the naked eye, including bacteria, fungi, archea, and protists

What is the definition of microbiology?

Microbes cause/lead to disease

What does the Germ Theory of Disease state?

The causation and transmission of disease

What dose the sub-field of microbiology, Epidemology, study?

Resistance to disease

What does the sub-field of microbiology, Immunology, study?

Study of disease caused by microbes

What does the sub-field of microbiology, Pathology, study?

Study of bacteria

What does the sub-field of microbiology, Bacteriology, study?

Study of viruses

What does the sub-field of microbiology, Virology, study?

Study of fungi

What does the sub-field of microbiology, Mycology, study?

Study of algae

What does the sub-field of microbiology, Phycology, study?

Study of protozones

What does the sub-field of microbiology, Protozoology, study?

Known as the father of epidemiology

What is John Snow known as/for?

Popularizing the use of disinfectants and antiseptics to prevent disinfection

What is Joe Lister known for?

Conducting the bell jar experiment

What is Redi known for?

1) All life is composed of cells
2) Cells are fundamental units of life
3) All cells come from cells

What are the three main concepts of Cell Theory?

Disproving spontaneous generation

What is Louis Pasteur known for?

Life comes from life

What is the Law of Biogenesis?

Inventing the agar plate and microbial isolation

What is Robert Koch known for?

Discovering penicillin

What is Alex Flemming known for?

Creating the first vaccine

What is Jenner known for?

Creating the first microscope

What is Leeuwenhoek known for?

0.2mm or larger

What is the range that the human eye can see?

Creating the Oil Immersion method

What is Ernst Abbe known for?

Specimen are dark and the background is light

How does a bright field microscope work?

Specimen are light and the background is dark

How does a dark field microscope work?

Uses slits to focus the light in a way that causes interference patterns that increase the contrast of the specimen

How does a phase contrast microscope work?

Similar to a phase contrast microscope except it uses prisms to increase the contrast of the specimen

How does a Nomarski Optics Microscope work?

Uses a series of dyes where light energy is absorbed and emitted by the cells via the excitation and emission wavelengths

How does Fluorescence Microscopy work?

Use fluorescent microscopes that use lasers to focus the light on the z-plane of a specimen that creates a 3D image

How does Confocal Microscopy work?

Focuses a beam of electrons using magnets to illuminate the species and is able to resolve small objects

How does an Electron Microscope (EM) work?

Similar to a bright field microscope in that the beam of electrons make the specimen dark and the background light

How does a Transmission EM (TEM) work?

The specimen are coated in a thin layer of metal that the electron beam bounces off of and is detected by sensors that construct an image

How does a Scanning EM (SEM) work?

Oil immersion increases the light reaching your eye for better resolution

Why is oil immersion the preferred method when preparing samples for light microscopy?

Motility assays

What can hanging droplets be used for when viewing specimen using light microscopy?

A process in which you kill cells, attach them to a slide, and stop them from moving

What is fixation?

Heat fixation

What fixation is commonly used for light microscopy?

Formaldehyde and glutaraldehyde

What chemical fixatives are commonly used?

Uranyl acetate

What fixatives are commonly used in electron microscopy?

Positively charged and binds/stains cells

What are basic dyes?

Negatively charged and stain the background

What are acidic dyes?

Bind to mycolic acids in cell walls of certian gram-positive bacteria

What does an acid-fast stain react with?

Measures cell wall structure

What does a gram stain do?

Eukaryotic cells have a membrane-bound nucleus and prokaryotes don’t

What distinguishes a prokaryotic cell from a eukaryotic cell?

The genome in prokaryotes is circular and is held in the nucleoid

What shape a prokaryotes genome and where is it stored?

Spheres

What bacterial shape is cocci?

Rods

What bacterial shape is bacilli?

Chains

What does strepto- mean when talking about bacterial shapes?

Grape-like clusters

What does staphylo- mean when talking about bacterial shapes?

Glycocalyx is located outside of the cell wall and is described as a capsule

What is glycocalyx and what is its role?
(hint: glycocalyx is also referred to as the extracellular polysaccharide (EPS) or the extracellular matrix (ECM))

Gram-positive cell walls in bacteria have thick layers of peptidoglycan that retain the stain

Describe gram-positive cell walls

Gram-negative cell walls in bacteria have a thin layer of peptidoglycan and have a second lipid bilayer

Describe gram-negative cell walls

The main component of bacteria cell walls and consists of long sugar chains held together with short peptide linkages

What is a peptidoglycan and what is its function ?

Lipids

What is the outer membrane composed of?
(hint: similar to cell membrane, usually has a lot of lipopolysaccharides)

Storage bodies

What are cytoplasmic inclusions in prokaryotes?

Lipid droplets, polyphosphate bodies, and glycogen granules

List 3 types of cytoplasmic inclusions

Stiff protein rods that rotate and are used for locomotion

What are flagella?

Protein cables that act to hold things together and play a part in bacterial sex

What are fimbrae and/or pili?

Strings of phosphate that store energy

What are metachromatic granules?
(also called phosphate bodies or volutin)

One cell shape

What does the term “monomorphic” mean?

Many cell shapes

What does the term “pleomorphic” mean?

Circular DNA molecules

What is the basic structure of bacterial chromosomes?

Contributes to the adaptation and evolution of microorganisms

What is the function of a plasmid?

Unidirectional replication that rolls around the circular DNA creating multiple copies

What is the rolling circle mode of replication?

Regions of a gene that code for amino acids

What are exons?

Intervening sequences between exons

What are introns?
(hint: often called junk DNA)

Eukaryotes

Are introns and exons commonly found in prokaryotes or eukaryotes?

N-formyl

What is the initiator codon in bacterial cells?
(hint: it is a modified version of methionine)

Protein splicing

In bacterial translation, what are inteins and exteins used for?

Enables cells to produce multiple copies of a protein simultaneously

What is a polyribosome?
(hint: transcription and translation both happen in the cytoplasm of bacteria so they occur simultaneously)

Contain more than one gene per mRNA

What are polycistronic mRNA?

Provides the usage patterns of various cell types

What is a codon bias table?

1) Transformation 2) Transduction 3) Conjugation

What are the three main ways that bacteria exchange DNA?

Naked uptake of DNA

What is Transformation in bacterial exchange of DNA?

Phage moves genes

What is Transduction in bacterial exchange of DNA?
(main method of horizontal transfer)

Bacterial sexual reproduction

What is Conjugation in bacterial exchange of DNA?

A protein tube that connects an F+ recipient to an F- recipient during bacterial sex

What is a pilus?

Bacterial donor cell with the F factor integrated into its chromosome

What is a high frequency recombination (HFR) cell?

Able to fix carbon through reduction reactions

What are autotrophs?
(hint: convert carbon dioxide into sugars)