mcb

what is mircrobiology?

study of mircobes and the interacting bewteen microbes and environment, humans, and how they can be used by humans

Acellular

cell free -not organisms

cellular

prokaryotes and eukaryotes

prokaryote mircobes

archaea, bacteria, cyanobacteria

eukaryotes mircobes

algae, protozoa, fungi

acellular

viroids, prions, viruses

define cellular life

metabolism, growth, reproduction, genetic variation, response/adapt to external environments, homeostasis

what are the 4 macromolecules?

polypeptides, nucleic acids, lipids, polysaccharides

polypetides made of? function? drywell?

amino acids; catalyze majority of biochemical reactions;50-55 (most abudant in a cell)

nucleic acids made of? function? drywell?

dna-2-5, rna 15-20; dna provides instructions for assembly and reprodcution; many functions involved in production of polypetides

lipids made of? function? drywell?

fatty acids; cellular membrane form physical boundary between cell and surrounding things; 10

polysaccharides made of? function? drywell?

sugar; strucutal and energy stroage; 6-7

carl woese

compared small ribosomal rna genes rRNA learning more variation in rRNA more distant bewteen species —> EVOLUTIONARY DISTANCE, ALSO created three of life

three domains?

bacteria (prokaryotic), archaea (prokaryotic) , eurkaray (complex nucleus)

do the three domains have universal ancestor?

yes last universal common ancestor

order of branching?

bacteria archaea eukarya

bacteria

prokaryotes, single celled, no nuclear membrane, peptidoglycan cell wall(sugar), binary fission, mostly beneficial

Archaea

lacks peptidoglycan, HAS pseudopeptidoglycan, live in extreme environements, no disease

eukaryotic cells

nucleus , cell membrane/single or multicellular, algae, protozoa, fungi

algae

eukaryote, cellulose cell walls, photosynthesis energy, produces molecular oxygen and organic compounds, multicellular/unicellular

protoza

eukaryote, UNICELLULAR, ingest organic chemicals, moves thru pseudopods cilia or flagella, ameba moving with actin and myosin, live in water, some live in animal host

Fungi

eurkaryotes, chitin cell walls, nuclear membrane, organic chemicals for energy, molds mushrooms multicellular, yeast unicellular

helminths

eukaryotes mulitcellular animals, not microograisms but have microscopic stages in life

helminths process

a person drinks water that is infected in worm larvae which is inside a water fleas. then it gets ingested into their stomach and it goes to their abdominal tissues where it grows. the felmales move to lower limbs and create blisters. when it touches water immature larvae will go to the pond/water and then it will be eated by water flea that will grow in the water fleas

viruses

seen only in microscope, acellular, consists of dna or RNA, can only reproduce in a host, protein coat

carl linnaeus

naming nomenclature organisms

naming rules

italicilze/or underline; first the genus (caps) second word species name not caps

marine microbes

more viruses than bacteria , produces most atomspheric oxygen , recyle chemical elements

soil microbes

helps break down wastes and incorporate nitrogen gas

normal microbiota

microbes normally present in and on the human microbes, mostly found in the gut, can change through your life time because of the change in your immune system

commensalism

one organism benefits and the other is unaffected

staphylococcus epidermidis

commensalism on our skin cause no harm

mutualism

both organisms benefit

e coli

mutualism breaks down food in the gut

parasitism

one organism does not benefit while the other one does

H1N1 virus

parasitism; in your respiratory tract and can damage cells in that area

biofilms

Most microbes live in biofilms, extracellular matrix found in microbes protective bubble; can have multiple different microbes

black death

killed thrid of the population caused by yersinia pestis

yersinia pestis

bacterium that infects rodents and humans; infects into the espongense of the humans in biofilms

recombinant dna techniques

dna can be incorporate into linearized plasmid then form a recombinant plasmid and be introduced into bacteria and then bacteria can express

robert Hooke

created cell theory and learned that living things are made of little boxes, cells

cell theory

all living things are composed of cells and come from preexisting cells

antonie van leewenhoek

a pioneering microbiologist known for his work with microscopes and discovering single-celled organisms. Using microscopes was able to large the cells and. FIRST person to use microscope

franceso redi

against spoentous thoery; when decaying meat was kept isolated from files maggots never developed

john Needham

boiled nutrient broth and then pour it into a sealed flask and saw microbial growth -WRONG cuz it put it into a dirty flask.

Lazzaro Spallanzani

agaisnt spontenous theory; Redid John Needham experiment and saw no microbial growth

lousi pasteur

microorganisms are present in the air which exlpains the “vital forces” people were talking about

-boiled infusions long enough to kill everything an did not seal - used s-shape necks, allowed air to enter but no dust and other microbes into broth no microbial growth

-showed that microbes responsible for fermentation

-created solution to spoilage problem: pasteurization -heat beer and wine just enough to kill most bacteria but does not evaporate alc in wine

-germ theory

-created first rabies vaccination transforming treatment of viral disease

john tyndalll

explained how dust carries mircroorganisms, also showed existence of heat resistant forms of bacteria

Ferdinand Cohn

heat resistant bacteria could produce endospores

ignaz semmelweis

hand washing preventing childbed fever from one pateitn to the other

joseph lister

chemical disinfectant to prevent surgical wound infections; clean wounds after surgery

Florence nightingale

established aseptic techniques in nursing Mother of modern nursing

Robert Koch

specific microbes cause specific disease explained using kochs postulates

-saw sick cows, isolated bacteria called bacillus anthracis from cow, injected into healthy animals showing it caused diesease

kochs postulates

specific experimental steps; find mircobe isolate it from host and grow on culture, inject into ealthy animals find it and isolate again

fanny Hesse

agar gel derived from red algae

limitations of koch postulates

some cant be grown in pure culture, cant use humans in experiment, molecular and genetic evidence can be used instead, not all pathogens cause diesases in host

Kochs work led to

-agar (fenny)

-Petri dish (Richard Petri)

-nutrient broth and nutrient agar

-methods for isolating microorganisms

-aseptic technique

edward jenner

vaccine collected scraping from cowpox, scratched it into a healthy boy hand, boy got sick and recovered, then gave boy small pox and boy did not get it

John snow

study of how things are transmitted; stopped the cholera outbreak by seeing how things are transmitted and stop the cause of how people got the disease—> epidemiology

epidemiology

agencies that monitor, track, and respond to infectious disease

stan miller

organic molecules forming from inorganic molecules

experiment: The Miller experiment simulated early Earth oceans and atmosphere (liquid water, methane, ammonia, and electrical spark discharge), producing amino acids that assemble into peptides and proteins.

RNA World Hypothesis

• RNA was the initial genetic material because it stores genetic information and catalyzes reactions.

• Single-bilayer micelles formed protective structures around early genetic material before DNA replaced RNA due to superior stability.

Endosymbiotic Theory

eukaryotic organelle origin: ancestral cells engulfed microorganisms that evolved into mitochondria and chloroplasts, evidenced by double membranes, circular DNA, independent ribosomes, and autonomous replication

Alexander Fleming

• penicillin in 1928 when Penicillium mold contaminated a Staphylococcus aureus culture plate near an open window and inhibited bacterial growth.

cm

10^-2

mm

10^-3

macrometer

10^-6

nanometer

10^-9

Refraction Principle

Light bends as it transitions between media. Directing refracted light into the objective lens prevents image fuzziness and increases clarity

light microscopy

using visible light to obseve specimens; image from 2 lens:objective (4x-100x) and ocular lens(10x)

bending of light

• Light travels as oscillating electromagnetic waves; entry into a new medium slows the wave and bends light (refraction).

Focal point

is where light rays converge; focal plane/length is the distance from the lens center to the focal point; shorter focal length → higher magnification

Magnification rule

•  A shorter focal length produces higher magnification.

RI refractive indices

measure how greatly a substance slows the velocity of light, higher RI=slower light travels

refractive indices

how much light bends through multiple medium higher Ri=more bending

total mag

objective lens magifcation *ocular lens magifcation

Resolution

 ability of a microscope to distinguish two distinct points; Shorter light wavelengths yield higher resolution; longer wavelengths yield lower resolution and blurry images.

Bright Field Microscope

• Uses a solid cone of light.

• Generates a dark image against a bright background.

• Best for dead or stained specimens (e.g., staphylococcus aureus, erythrocytes

Dark Field Microscope:

• Uses an opaque stopper to produce a hollow cone of scattered light.

• Light enters the objective lens only when reflected by the specimen, generating a bright image against a dark background.

• Ideal for living, unstained specimens (e.g., Borrelia burgdorferi, the causative agent of Lyme disease).

Phase Contrast Microscope:

• Utilizes an annular ring and changes in refractive index to pass light through specimens at varying speeds.

• Enhances internal structural contrast in living, unstained cells (e.g., Paramecium).

• BEST ONE FOR ALIVE AND UNSTAINED

Differential Interference Contrast (DIC) Microscope:

• Directs two separate light beams through the specimen, creating an optical illusion of a 3D image.

• Excellent for high-resolution imaging of live, unstained cells and internal structures.

Fluorescence Microscope:

• Uses a high-energy light source (e.g., UV light) to excite fluorophores or markers, causing the specimen itself to emit light.

• Used on non-living specimens to track target proteins, cell structures, or pathogens via immunofluorescence (antibody binding).

Confocal Microscope:

• Uses fluorescent dyes and computer-controlled optics to take sequential image slices from the bottom to the top of a specimen.

• Constructs a true, rotatable 3D image of internal and external structures

Electron Microscopy

Employs electron beams with extremely short wavelengths to achieve superior resolution for viewing viruses and minute cellular structures.

looking at viruses not other things

Transmission Electron Microscope (TEM):

• Passes an electron beam directly through ultrathin, chemically fixed, and stained non-living specimens.

• Visualizes internal structures (e.g., inside staphylococcus aureus, influenza, or bacteriophages).

Scanning Electron Microscope (SEM):

• Scans an electron beam across the outer surface of a specimen.

• Provides 3D surface images and is optimal for visualizing complex microbial interactions and biofilms.

• Good at looking at how microbes interact with the environmental or each other

• see the surface

Culturability

mircroorganisms cultured in lab

Growth Media

Mixtures of nutrients formulated to support microbial growth in artificial environments (available in broth, agar plates, and agar slants).

Aseptic Technique

• Practices designed to prevent contamination:

  • Sterilizing instruments (e.g., heating inoculation loops until glowing in a Bunsen burner flame).

  • Decontaminating workspace surfaces.

  • Wearing personal protective equipment (PPE), including gloves, lab coats, and eye protection.

Streak Plate Method (T-Streak):

 A technique used to isolate pure cultures from mixed samples by spreading cells across an agar plate until individual colonies form

Colony Forming Unit (CFU

• An individual bacterial cell that replicates to produce a distinct, visible colony.

• Smear Preparation & Heat Fixing:

• Liquid microbial sample is spread onto a glass slide.

• Sample must fully air-dry (prevents cell boiling and lysis).

• Slide is briefly passed through a flame to heat-fix cells to the glass

Basic Dyes

• Positively charged chromophores that bind to negatively charged bacterial cell surfaces (e.g., crystal violet, safranin, methylene blue).

Acidic Dyes

• Negatively charged chromophores that are repelled by cell surfaces, staining the background.

Simple Staining

• Uses a single dye to reveal basic cell size, shape, and arrangement without distinguishing cell types.

• cant tell the difference between two microbes

Differential stains

• gram stain or acid fast

gram stain

hans christian gram

• gram neg gram pos

gram postive

thick cell wall made by peptidoglycan, etains crystal violet-iodine complex ($purple$). Penicillin is typically effective against this group. stains purple

gram neg

• Contains a thin peptidoglycan layer and an outer membrane; decolorizes and counterstains with safranin ; two membranes

• Acid-Fast Staining

• Used for bacteria with thick, waxy mycolic acid cell walls that resist Gram dyes.

• Requires heat to drive carbol fuchsin (red dye) into the cell wal