Microbiology Test #1

Microbiology

Unable to be seen with the unaided eye, the study of the hidden and microscopic world

How do microbes affect our lives

There would be no plant life, animal life, fermentation, nutrient breakdown, no carbon and oxygen

Carolus Linnaeus

In 1735 he developed scientific nomenclature

• each organism is assigned a 2 part name → genus and the species

Carl Woese

Developed the three-domain system that organizes life

• bacteria: prokaryotic microbes

• archaea: prokaryotic microbes with extreme environments

• eukarya: protists, fungi, plants, animals

Robert Hooke

In 1665 observed cells in cork, beginning cell theory

Anton van Leeuwenhoek

1670s, the first to observe living microbes

Pasteur

Disproved spontaneous generation and linked microbes to fermentation and food spoilage

Lister

Used phenol to prevent surgical infections and worked to progress sanitization

Semmelweis

Discovered handwashing reduced fever

Vaccination History People

• 1796, Jenner creates smallpox vaccine using cowpox

• 1900s, Ehrlich develops the first synthetic drug

• 1928, Fleming discovers penicillin, used in 1941

Bacteria

• prokaryotic, single-celled

• cells walls made of peptidoglycan

• reproduce via binary fission

• nutrition from organic/inorganic sources or photosynthesis

Archaea

• prokaryotic but distinct from bacteria

• lack peptidoglycan in cell walls

• found in extreme environments

Fungi

• eukaryotic, have a true nucleus

• cell walls made of chitin

• yeasts (unicellular), mold and mushrooms (multicellular)

• absorb organic materials for energy

Protozoa

• eukaryotic

• may move use pseudopods, cilia, or flagella

• can be free-living or parasitic

Algae

• eukaryotic, cell walls contain cellulose

• use photosynthesis for energy

• found in aquatic and soil environments

Viruses

• acellular (not cells)

• DNA or RNA core, surrounded by protein coat

• only replicate inside living host cells

Cell Theory

All living organisms are composed of cells and arise from preexisting cells

Recombinant DNA

Combines genes from different sources

Bioremediation

Microbes clean oil spills, remove toxins, and degrade sewage

Biotechnology

Uses microbes to produce drugs, enzymes, and vaccines

Normal Microbiota Functions

Microorganisms that live on/in the human body without causing disease

• compete with pathogens

• produce essential vitamins

Biofilms

Microbial communities that stick to surfaces

• biofilms are resistant to antibiotics and disinfectants

Taxonomy

Science of classifying organisms

• identification, nomenclature, and classification

Binomial Nomenclature

The system of having two names for each organism

Domain Bacteria

prokaryotic, peptidoglycan cell walls

Domain Archaea

prokaryotic, unique chemistry, often extreme environments

• methanogens

• extreme halophiles

• hyperthermophiles

Domain Eukarya

eukaryotic cells with nucleus

• animals, plants, fungi, protists

Taxonomic Hierarchy

Domain→Kingdom→Phylum→Class→Order→Family→Genus→Species

Methods of identifying microorganisms

• bergey’s manuel: reference system

• staining: gram-stain, acid-fast stain

• biochemical tests: enzyme activity

• morphology: shape and structure

Classification of eukaryotes

• protists: diverse, autotrophic or heterotrophic

• fungi: chemoheterotrophs, chitin cell walls

• plants: photosynthetic, cellulose cell walls

• animals: multicellular, no cell walls

Endosymbiotic theory

eukaryotic cells evolved from prokaryotic cells living inside one another as endosymbionts

Acid

A substance that dissociates into one or more H ions and one or more negative ions (proton donor), 0-7 on pH scale

Base

Dissociates into one or more negatively charged hydroxide ions (OH) and one or more positive ions (proton acceptor), 7-14 on pH scale

Salt

A substance that dissociates in water into cations and anions

Solute

A substance dissolved in another substance

Buffer

A substance that tends to stabilize the pH of a solution

Carbohydrates

serve as energy sources and structural components

• include monosaccharides (glucose), disaccharides (sucrose), and polysaccharides (starch, cellulose)

Lipids

key component of cell membranes

• include triglycerides (energy storage), phospholipids (membranes), and steroids (hormones and membrane fluidity)

Protein

Made of amino acids, serve as enzymes, structural components, and signaling molecules

• primary, secondary, tertiary, quaternary

• can denature under extreme conditions

DNA and RNA

DNA carries genetic information and RNA helps build proteins

• DNA = double helix, RNA = single strand

Compound Microscope

Has a series of lenses and uses visible light as its source of illumination

• can examine very small specimens as well as their fine detail

Darkfield Microscope

used to examine live microorganisms that either are invisible in ordinary light microscopes, cannot be stained, or are distorted by staining so their characteristics are obscured

Fluorescent Microscope

uses UV light to excite fluorochromes that bind to specific targets, like pathogens

Confocal Microscope

produces 3D images using lasers, excellent for biofilms and detailed cell imaging

Transmission Electron Microscopy

views thin slices of specimens, ideal for internal structures

Scanning Electron Microscopy

Scans surfaces to create 3D images, excellent for external cell structures

• used to examine structures too small to be resolved w/light microscopes

• always black and white

• short wavelengths

What does the term compound in compound light microscope mean?

It refers to the multiple lenses to magnify an object →objective lens and an eyepiece lens

Refractive Index

A measure of the light-bending ability of a medium

Negative Staining

A procedure that results in colorless bacteria against a stained background

What is a mordant?

A substance added to a staining solution to make it stain more intensely

What genus is being identified with acid-fast stain?

Mycobacterium

What 2 types of organisms produce spores that can be identified with a spore stain?

Bacillus and clostridium

What is the purpose of a flagella stain?

Helps microbiologists identify motile bacteria and classify them based on the number and arrangement of flagella