Microbiology CH 1

UMKC Fall 2026 - Dr. Fischer idk

culture

cells grown in/on nutrient medium

medium

liquid/solid mixture containing all required nutrients

cytoplasmic membrane

barrier that separartes the inside of cell from the outside environment

cytoplasm

aqueous mixture of macromolecules, small organics, ions, and ribosomes inside cell

ribosomes

protein-synthesizing structures

prokarytoes

bacteria and archaea, no organelles, no nucleus

eukaryotes

plants, animals, algae, protozoa, fungi. has organelles, DNA enclosed in memb-bound nucleus. has mitochondria and chloroplasts

genome

cells full set of genes

eukaryotic DNA

linear chromosomes within the nucleus

larger and has more DNA

prokaryotic DNA

single circular chromosome that forms the nucleoid

can have plasmids

small

plasmids

extrachromosomal DNA

confer special properties (antibiotic resistance)

properties of ALL microbial cells (4)

structure

metabolism

growth

evolution

properties of SOME microbial cells (4)

differentiation

communication

motility

horizontal gene transfer

morphology

cell size and shape

physical characteristics

morphology measurements

1 micrometer (um) - 1/1×10^6 meters

morphology advantage

the smaller the cell the more surface area relative to volume

coccus (cocci)

spherical or ovoid

rod / bacillus (bacilli)

cylindrical

spirillum

flexible spiral (~)

spirochete

rigid spiral (-)

3 major domains or microbial life

bacteria

archaea

eukarya

bacteria

prokaryotes, usually single-celled, >80 phyla

archaea

prokaryotes, historically associated with extreme environments, >12 phyla

eukarya

plants-animals-fungi, originally were unicellular, ~6 kingdoms, most diverse group

viruses

not cells, cant carry out metabolism or cell division, small genomes of double-stranded/single-stranded DNA/RNA

take over infected cells to replicate

first cells on earth

anoxygenic

phototrophs

use energy of light for metabolism

anaerobes

do not use O2

extremophiles

live in habitats too harsh for other life forms

microbial ecology

study of mhow microbes affect animals, plants, global ecosystems

industrial microbiology examples:

pharmaceuticals and brewing

biotechnology

genetically engineered microbes to make high-value products in small amounts

biofuel examples:

methane and ethanol

bioremediation

cleaning up pollutants

biofilms

growth of submerged surgaces

Robert Hooke

first to describe microbes w/ mold structures

Antoni van Leeuwenhoek

first to see bacteria

light microscope

resolution

ability to distinguish two adjacent objects as distinct and separate

limit of resolution for light microscope

-0.2μm

compound light microscope

uses visible light to illuminate cells

condenser

focuses light

how many lenses to form the image

two sets

two types of lenses are called:

objective lens, ocular lens

total magnification

multiple objective and ocular magnification (max mag. is 1000x)

basic dyes

positively charged, binds strongly to negatively charged cell components

differentail stains

render different kinds of cells different colors (more than one dye)

example of differential stain

gram stain

gram-positive

purple

gram-negative

pink

steps for gram stain procedure (4)

dye with crystal violet

use iodine

decolorize with alcohol → clear = -, purple = +

apply safranin; pink and purple

phase-contrast microscopy

improves image contrast of unstained live cells

phase ring

amplifies difference in refractive index

dark-field microscopy

light reaches specimen from the sides, only light scattered by speciment reaches the lens

fluorescence microscopy

used to visualize specimens that emit light, cells glow w filters

used in clinical diagnostic microbio

differential interference contrast (DIC) microscopy

two distinct beams of polarized light, giving 3D appearance

confocal scanning laser microscopy (CSLM)

computerized fluorescent microscope w/ laser source to get 3D image

electron microscopes

use electrons to image cells/structures

2 types

electron microscope types (2)

transmission electron microscopes (TEM)

scanning electron microscopes (SEM)

transmission electron microscopes (TEM)

greater resolving power (0.2nm) than light microscope

visualization of structures at molecular level

electron cryotomography (cryo ET) TEM - to get 3D images at low temps

scanning electron microscopy (SEM)

specimen is coated in thin film of heavy metal

electron beam scans object

scattered electrons collected/projected to produce image

magnification can reach 100,000x

aseptic technique

collecition of practices that allow prep and maintenance of sterile media/solutions, used to maintain pure cultures

pure cultures

cells from only a single type of microorganism

Pasteur

discovered alcoholic fermentation; disproved spontaneous generation

swan-necked Pasteur flask → sterilization of food/preservation

Koch

link between microbes and infectious diseases

identified causative agents of anthrax, turberculosis, and cholera

Koch’s postulates

definitively link cause/effect in infectious disease

1-suspected pathogen must be present in all cases of disease and absent from healthy animals

2-suspected pathogen must be grown in pure culture

3-pure culture cells must cause disease in healthy animals

4-suspected pathogen must be reisolated and shown to be the same as original

microbial diversity

nonmedical aspects and metabolic processes of microbes in soil/water

Winogradsky

demonstrated that specific bacteria are linked to specific biogeochemical transformations

proposed concept of chemolithotrophy (oxidation of inorganic compounds to yield energy)

Beijerinck

enrichment culture technique, encourages growth of specific organisms

first to observe a virus

Griffith

discovered some substance can be transferred between microbes, conferring new properties (transformation)

Avery-MacLeod-McCarty experiment

discovered that DNA is a transforming agent

R, rough colonies doesnt kill mice

S, smooth colonies kills mice

R+S-killed, R transformed to S, kills mice

James Watson, Francis Crick, Rosalind Franklin

structure of DNA

ribosomal RNA (rRNA)

present in all cells made it possible to build first tree of life

Woese

realized rRNA seq. could be used to infer evolutionary relationships

named new group: Archaea

phylogenetic tree

depicts phylogeny of all cells

LUCA (last universal common ancestor)

bacteria, archaea, eukarya

metagenomics

microbial genomes/fragments can be recovered from environmental DNA samples