BIOL20/20N - Exam 1 (Chapters 1-4, & 9)

Hippocrates

-"Father of Western medicine"
-Believed that diseases had natural, not supernatural, causes.

Thucydides

Observed that survivors of the Athenian plague were subsequently immune to the infection

Marcus Vero

-Proposed that disease could be caused by certain minute creatures
-Thought swamps might have tiny, disease-causing animals

Antoine van Leeuwenhoek

First to develop a lens powerful enough to view microbes (or animalcules)

"wee little beasties"

Louis Pasteur

-Fermentation
-Pasteurization
-Vaccines for the treatment of diseases, including rabies, in animals and humans
-Swan-neck flask experiment

Robert Koch

-First to demonstrate the connection between a single isolated microbe and a known human disease
-Established a protocol to determine the caused of infectious disease. Both scientists contributed significantly to the acceptance of the germ theory of disease
-Koch postulates
-Anthrax
-Cholera
-Tuberculosis

fermentation (anaerobic respiration)

Process by which simple sugars are converted into alcohol

Carl Linnaeus

-"Father of Binomial Nomenclature"
-His original classification of the natural world consisted of plants, animals, and minerals

Three Major Domains

Bacteria, Archaea, Eukarya

Kingdoms of Eukarya

Protista, Fungi, Plantae, Animalia

Prokaryotes - Bacteria

-Genetic material (DNA) is not enclosed within a true nucleus
-Most have cell walls that contain peptidoglycan

Coccus

What's the shape of this bacteria?

Bacillus

What's the shape of this bacteria?

Vibrio

What's the shape of this bacteria?

Coccobacillus

What's the shape of this bacteria?

Spirillum

What's the shape of this bacteria?

Spirochete

What's the shape of this bacteria?

Prokaryotes - Archaea

\-Found in every habitat on earth (including extreme habitats)
**-Lack peptidoglycan cell walls
-No known human pathogen**

Eukaryotes

-Cells contain a nucleus
-Uni- or multicellular

Protists

-Eukaryotes that are not plants, animal, or fungi
-Algae and Protozoa

Algae

-Plant-like protists
-Cellulose cell walls
-Use photosynthesis for energy

Protozoans

-Animal-like protists
-May be motile via pseudopods, cilia, or flagella
-Some are pathogens

Fungi

-Yeast and Mold
-Cell walls are usually made of chitin

Viruses

-Don't fall under any of the Domains
-Acellular (not composed of cells)
-DNA and RNA core

Bacteriaology

Study of bacteria

Mycology

study of fungi

Protozoology

study of protozoa

Virology

study of viruses

Pathology

study of protozoa and parasitic worms

Brightfield Microscopes

When using this, microorganisms will appear colored against a bright background

Darkfield Microscopes

When using this, the field will be dark and the organism will be outlined by the dark field

Electron Microscopes

-Uses beams of electrons for energy
-Uses a vacuum as a medium
-Uses magnets for objectives
-Image is shown on a screen

Differences between Light & Electron microscopes

1) Energy; LMs use plain white light while EMs use beams of electrons
2) Medium; LMs use air while EMs use a vacuum
3) Objectives; Glass lens in LMs while magnets in EMs
4) Image display; LMs have ocular lens to see the image while EMs use a screen to show the image

Transmission Electron Microscope (TEM) & Scanning Electron Microscope (SEM)

Types of electron microscope

Transmission Electron Microscope (TEM)

Used to view thin specimens through which electrons can pass generating a projection image

Scanning Electron Microscope (SEM)

Uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens

Reflection

The bouncing back of a wave when it hits a surface through which it cannot pass

Transmission

Lightwave travels through a material

Absorbance

Material captures the energy of a light wave

Opaque

When most (or all) of the light is absorbed

Transparent

Allowing all the light to pass through

Refraction

The bending of light when it passes through one medium to another

Refractive Index

a measure of the light-bending ability of a medium

D

Which letter represents a refracted ray of light?

C

Which letter represents a reflected ray of light?

Magnification

the ability of a lens to enlarge the image of an object when compared to the real object

Resolution

-Ability to tell that 2 separate points are separate
-Affected by wavelength and numerical aperture

Shorter wavelengths have more energy while longer wavelengths have less energy

What is the correlation between energy and wavelength on the light spectrum?

Robert Hooke

-Coined the term "cell"
-Observed dead cork cells under a microscope

Zaccharias and Hans Janssen

-May have invented the telescope, the simple microscope, and the compound microscope
-Historical evidence is inconclusive

1) Eyepiece
2) Revolving nose piece
3) Objective lens
4) Coarse focus
5) Fine Focus
6) Stage
7) Illuminator
8) Condenser and Diaphragm
9) X-Y mechanical stage knobs
10) Rheostat

Label the following with the following terms:

Coarse focus
Condenser
Diaphragm
Eyepiece (ocular lens)
Fine focus
Illuminator
Objective lens
Revolving nose piece
Rheostat
Stage
X-Y mechanical stage knobs

Condenser

Gathers the light coming in from the illuminator and concentrates that light into a light cone on the specimen

Diaphragm

Controls the amount of light passing through the opening of the stage and, consequently, the numerical aperture of the condenser

Rheostat

Controls the intensity of the light source on the microscope

10x, 40x, 100x

What are the magnifications of the 3 objectives in a microscope?

Total Magnification

Objective lens X Ocular lens

Oil Immersion Lens

Improves resolutions by reducing refractive index

1000x

What is the total magnification of an object viewed using a 10x ocular lens and a 100x objective lens on a brightfield microscope?

High numerical aperture and short wavelength

What is needed to see a clear image under a microscope?

Stains

Used to increase contrast between the cells and the background, making them easier to see under the microscope

Simple, differential, special

Three types of staining techniques

Simple stains

Will generally make all of the organisms in a sample appear to be the same if the sample contains more than one type of organism

Differential stains

Two organisms in a differentially stained sample may appear to be different colors

E.g. endospore staining, flagella staining, and capsule staining

Acidic, Basic, Gram, & Acid-fast

Special stains (4)

Acidic stain

Negatively charged stain
-Stains positively charged molecules and structures like proteins
-Result can be either a positive or negative stain, depending on the cell's chemistry

Basic stain

-Positively charged stain
-Stains negatively charged molecules and structures like nucleic acids and proteins
-Results in a positive stain

Crystal violet, Iodine, alcohol, safranin

What is the Gram stain order?

Scanning Tunneling Microscope (STM)

-Uses a probe passed horizontally at a constant distance just above the specimen while the intensity of the current is measured
-Can map the structure of surfaces at the atomic level
-Works best on conducting materials but can also be used to examine organic materials such as DNA, if fixed on surface

Atomic Force Microscope (AFM)

-Can be used in several ways, including using a laser focused on a cantilever to measure the bending of the tip or a probe passed above the specimen while the height needed to maintain a constant current is measured
-Useful to observe specimens at the atomic level and can be more easily used with nonconducting samples

AFM

This image was probably achieved with what type of microscope?

STM

This image was probably achieved with what type of microscope?

Iodine

What mordant is used in gram-staining?

Alcohol

What decolorizer is used in gram-staining?

Safranin

What is the last thing that is added when doing gram-stains?

Blue/Purple

What color are gram-positive cells?

Red/Pink

What color are gram-negative cells?

Coccus

Describe the bacteria

Diplococci

Describe the bacteria

Streptococci

Describe the bacteria

Straphylococci

Describe the bacteria

Tetrad

Describe the bacteria

Bacillus

Describe the bacteria

Streptobacilli

Describe the bacteria

Monotrichous

Describe the following

Ampithrichous

Describe the following

Lophotrichous

Describe the following

Peritrichous

Describe the following

Theory of Spontaneous Generation

Stated that organisms arose from nonliving matter as long as it had "breath"

Francesco Redi

Demonstrated that maggots were the offspring of flies, not products of spontaneous generation with his "meat in a jar" experiment

Miasma Theory

Before the discovery of microorganisms, scientists believed diseases came from particles in decomposing matter that spread through the air "poisonous air"

Germ Theory

States that diseases result from microbial infection. Microbes in the air cause disease and can spoil food. The way to prevent these diseases is by washing your hands

John Needham

Heated broth in sealed flasks. When the broth became cloudy with microorganisms, he mistakenly concluded that they developed spontaneously from the broth

Lazzaro Spallazani

Recreated Needham's experiment and obtained results that countered Needham's.

Swan Flask Experiment

Louis Pasteur did this experiment to refute the long-disputed theory of spontaneous generation.

Theory of Biogenesis

states that only living organisms can produce other living organisms

Schleiden

Described plant tissues as being composed of cells

Schwann

Observed cells in animal tissue

Schleiden's and Schwann's Observation

Laid the foundation for the idea that cells are the fundamental components of plants and animals

Rudolf Virchow

Popularized the cell theory in an 1855 essay entitled "Cellular Pathology"

Robert Remak

Came up with the idea that all cells come from pre-existing cells