Exam 1 Flashcards
This man was the first to develop a lens powerful enough to view microbes
Antonie van Leeuwenhoek
This man was the first to demonstrate a connection between a single isolated microbe and known human disease
Rober Koch
Modern taxonomy relies heavily on
Comparing the nucleic acids (DNA or RNA) or proteins from different organisms
_____ ____ created a tree with three domains above the level of kingdom
Which included
Carol Woese nnnnnar
Archaea
Bacteria
Eukarya
The genus part of the name is always
capitalized
followed by the epithet name (not capitalized)
always italicized
Microorganisms are found in each of the three domains of life:
Archaea
Bacteria
Eukarya
Bacteria and Archaea are ______ (their cells lack a nucleus)
prokaryotes
Eukaryotes have or do not have a nucleus?
DO
Bacteria are prokaryotic because their genetic material DNA is _____ housed within a true nucleus
NOT
Common bacteria shapes include:
Bacillus
Coccus
Spirillum
Spirochete
Vibrio
______ are also unicellular prokaryotic organisms
Archaea
______ are found in nearly every habitat on earth, even extreme environments
Archaea
The domain Eukarya contains all eukaryotes, including uni- or multicellular eukaryotes such as :
Protists
Fungi
Plants
Animals
Two examples of Protists are
Algae and Protozoa
Protists such as ____ can be unicellular or multicellular
Algae
______ move with help from hair like structures called cilia and flagella and pseudopods (false feet)
Protozoa
Yeasts are multicellular or unicellular fungi?
Unicellular
Multicellular parasitic worms called
Helminths
______ are acellular microorganisms which means they are not composed of cells.
Either DNA or RNA but never ______
Viruses
Both
Refraction occurs when
Light waves change speed and direction as they pass from one medium to another
The power of a microscope can be defined in terms of its
Magnification and Resolution
A _____ microscope has a much higher resolution than a light microscope since it uses an electron beam with very short wavelength.
Electron
__________ was credited with the first observation of microbes
Antonie van Leeuwenhoek
Was the first to describe cells ( looked at dead cork cells )
Robert Hooke
Uses lenses to focus light on specimen to produce and image
Light Microscopy
Produce a dark image on a bright background
Brightfield
Total magnification =
Ocular magnification x Objective magnification
____ scatters the light rays
Air
_____ can be used to fill the space between the specimen and an oil immersion lens
Oil
Oil has the refractive index very similar to _____ thus increasing the light collected and resolution of the image
glass
Shows bright objects on a dark background
Darkfield
_______ is useful for viewing live specimens without the use of stains
Darkfield
_____ use refraction and interference to create high contrast and high resolution images WO staining
Phase contrast
____ _____ ____ use interference patterns to enhance contrast between different features of a specimen using two beams of light
DIC
Differential Interference Contrast
Absorb energy from light source then emits this energy as visible light
Fluorescence
Microscopy technique that is used to identify certain disease causing microbes by observing whether antibodies bind to them.
Immunofluorescence
uses a laser to scan multiple z planes successively
Confocal
_______ microscopy focuses electrons on the specimen using magnets.
Uses short wavelength electron beams rather than light.
Electron
_____ _____ _____ requires that the beam and specimen be in a vacuum and that the specimen be very thin.
Transmission Electron Microscope (TEM)
____ ____ ____ form images of surfaces of specimens
Scanning electron microscope (SEM)
____ ____ ____ produces images of even greater magnification by measuring feedback from sharp probes that interact with the specimen.
Scanning probe microscopy
Two types of microscopes that observe individual atoms on surfaces
Scanning tunneling microscope
Atomic force microscope
___ ____ ____ to properly prepare a slide for microscopy.
Smear
Heat fix
Stain
___ ____ (acid stains) absorbed by the background not by the negatively charged cell.
Produces a silhouette of the organisms against a _____ background
Negative stains
Colorful
___ ____ (basic stains) stick to the cell walls of negatively charged cells
Positive cells
Two types of staining:
Simple (one stain)
Differential (two stains)
Crystal violet, a primary stain, is applied to a heat fixed smear, giving all of the cells a ______ color
Purple
_____ _____ (a substance used to set or stabilize stains or dyes) in this case, it traps the cystal violet in the cell by making the complex clump
Gram’s Iodine
___ _____ (ethanol or an aceton solution) Cells with thick peptidoglycan layers ( Gram Positive Bacteria) are less affected and retain the crystal violet dye and remain ______.
Decolorizing agent
Purple
The decolorizing agent more easily washes the crystal violet out of cells with thinner peptidoglycan layers in gram negative bacteria leaving them _______
colorless
_____ ______ (_____) is added. This stains the decolorized cells pink and is less noticeable in the cells that still contain the crystal violet dye.
Secondary Counterstain (safranin)
The purple, crystal violet stained cells are referred to as _________ while the red safranin dyed cells are ________
Gram positive
Gram negative
________ bacteria tend to be more resistant to certain antibiotics than _______ bacteria
Gram negative
Gram positive
____ ______: a negative staining technique
Capsule staining
Acid fast staining ______ ____ is the primary stain
Waxy acid fast cells retain the carbol fuchsin even after a _____ _____ is applied.
____ ___ is then applied which renders non acid fast cells blue
Carbol Fuchsin
Decolorizing agent
Secondary counterstain, methylene blue
- Uses heat to push the primary stain into the endospore
- Washing with water decolorized the cell, but endospore retains green stain.
- Cell is then counterstained pink with safranin.
Endospore staining
Endospore staining techniques are important for identifying ____ and _____
Bacillus and Clostridium
_______ ______: life arose from nonliving matter
Spontaneous generation
______ _____ disproved the theory of spontaneous generation with his famous swan neck flask experiment
Louis Pasteur
____ _____ proposed that “life only comes from life”
Louis Pasteur
Cell theory (cork under a microscope)
Robert Hooke
“all cells arise from cells”
Rudolf Virchow
_________ theory states that mitochondria and chloroplast have their origins in bacteria.
Endosymbiotic
Eukaryotic organelles (mitochondria and chloroplasts) are of prokaryotic origin is the hypothesis created by
Lynn Margulis
_______ and _______ are structurally similar to bacterial ribosomes, rather than to the eukaryotic ribosomes of their hosts.
Mitochondrial
Chloroplasts
Binary fission of these two organelles strongly resemble binary fission of bacteria as compared with mitosis performed by eukaryotic cells.
Mitochondria
Chloroplasts
Germ theory of disease
Diseases may result from microbial infection
Founder of the Germ Theory
Louis Pasteur
____ ____ began using carbolic acid (phenol) spray during surgery
Joseph Lister
______ proposed the cause of a specific disease could be attributed to a specific microbe.
Robert Koch
______ _____ occurs because of differences in the concentration of solutes on opposing sides of a semipermeable membrane.
Osmotic Pressure
For ______ and _______ their genetic material is contained in a _____ rather than a membrane bound nucleus.
Bacteria and Archaea
________ cells lack membrane bound organelles
Prokaryotic
Prokaryotic cells may contain extrachromasomal DNA in _______ which often carry genes such as antibiotic resistance.
Plasmids
______ ____: site of protein synthesis and have size of _____
Prokaryotic ribosomes
70S
Clinically significant Gram-Positive bacteria that can form endospores:
Bacillus
Clostridium
Cell envelope =
Plasma membrane + cell wall
______ ____ are composed of phospholipids
Plasma membranes
Prokaryotic cell walls may be composed of ______ (found only in bacteria)
Peptidoglycan