BIO 230: Exam #1

What are microbes?

microorganisms and infectious agents too small to be seen by the naked eye

Germ Theory of Disease

microorganisms cause disease

Koch’s Postulates Purpose

Set of criteria that establishes whether a microbe causes a diease

Koch’s Postulates

1. Microbe must be present in all diseased organisms

2. microbe must be isolated from a diseased organism

3. when introduced into a healthy organisms, the cultured microbe must cause disease symptoms

4. microbe must be re-isolated from diseased organisms

Edward Jenner

Developed the first successful smallpox vaccine

Lous Pasteur

used the curved-necked flask to disprove spontaneous generation

Abiogenesis/Spontaneous Generation

living organisms arise from non-living matter

Biogenesis

living organisms arise from pre-existing life

Alexander Fleming

discovered penicillin from mold in his lab

What are the three types of cellular junctions?

communication, occluding, anchoring

Selective Permeability Property

Property of the cell membrane permits an unequal distribution of ions across the membrane

Infectious Diseases

disorders caused by organisms such as bacteria, viruses, fungi, or parasites

Emerging Infectious Diseases (EIDs)

infections that are new, have recently appeared within a population or those who range and will increase rapidly and that will threaten to increase in the future

Recombinant DNA Technology

process of combining DNA from different sources to give an organisms new traits

Major Groups of Microorganisms

bacteria, archaea, fungi, protozoa, algae, viruses, prions, multicellular parasites

Three-Domain Systems

Bacteria, Archaea, Eukaya

Anton Van Leeuwenhoek

first to observe microbes using a microscope

Robert Koch

developed criteria for determining whether a microbe causes a disease If yi

If you leave a piece of rae meat outside for several days. Eventually maggots appear on the meat. Which explanation sounds more reasonable?

the maggots came from preexisting living organisms

All microbes are living organisms? True or False

False

Fungi are more closely related to humans than bacteria? True or False

True

Properties of Light

Reflection, transmission, absorption, refraction

Reflection

light bounces off a surface at the same angle it arrives

Transmission

light passes through a material without being absorbed

Absorption

light energy is taken up by the material and converted into heat

Refraction

the bending of light as it passes through from one medium to another density

Resolution

Ability to distinguish between two nearby objects are separated

Dark-Field Microscopy

observation on unstained or difficult to stain organisms

Phase Contrast

detailed observations of internal structure of living unstained organisms

Bright-field Microscopy

generally used for stained or pigmented organisms

Electron Microscopy

uses of beam of electrons instead of a beam of light

Transmission Electron Microscopy (TEM)

passes through specimen

Scanning Electron Microscopy (SEM)

passes on surface of a specimen

Fluorescence Microscopy

uses specific wavelength of light to excite molecules to emit light of different wavelenght

Differential Stains

Gram and Acid-Fast Stain, positive charge, stains bacteria, attracted to negative charge bacteria

Special Stains

Capsule Stain, Endospore Stain, Flagella Stain, negative charge, repelled by negative charge bacteria, repelled by negative charge bacteria, stains background

Why don’t we heat fix during capsule staining?

capsule shrinks after heat application

Endospores

dormant, tough, non-reproductive that is produced in the bacteria

Mordant

helps dyes adhere to a substrate

Gram Stain

classifies bacteria into gram-positive or gram negative

Gram Positive

have cell walls that consists of a thick peptidoglycan layer and smaller pores

Gram Negative

thin layer of peptidoglycan and an outer membrane of lipopolysaccrides (LPS)

Acid Fast Stain

has a waxy layer that is very difficult for molecules to get through

Numerical Aperture (NA)

how much light is getting concentrated by the condenser and capture by the objective lenght

Magnification

how much lager an image appears compared with the actual specimen

Taxnomy

putting organisms into categories or taxa to show