Micro exam 1

What is microbiology?

The scientific study of microorganisms

What are considered microorganisms?(6 major groups)

• Fungi

• Algae

• Virus

• Bacteria

• Protozoa

Careers in microbiology

• Medical

• Industrial

• Immunology

• Environmental

• Public health and epidemiology

• Agricultural

Medical Career In microbiology

Diagnose & treat infections

Environmental career in microbiology

Studies how microbes interact with the environment

Agricultural career in microbiology

Microbes and food productions

Public Health and Epidemiology career in microbiology

track disease spread

Industrial career in microbiology

used to make products with microbes

Immunology career in microbiology

studies how the immune system responds

Immune defense vs microbes

What was Koch known for

• Koch Postulates (Germ Theory)

• determined that a bacillus was responsible for anthrax in farm animals

• Discovered sporulation

• Developed methods of staining

• Determined causative agents for many bacteria/ infections

• Discovered how to grow tuberculosis in culture

Koch Postulates

1. Disease always in sick, not in well individuals. (the microorganisms must be found in abundance in all organisms suffering from the disease, but should not be found in health organism)

2. isolate microorganisms (the microorganisms must be isolated from a diseased organism and grown in pure culture)

3. Infection with pure microbes result in disease (the cultured organisms should cause disease when introduced into a health organism)

4. Re-isolate microorganisms from infected individuals (the microorganisms must be re isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent)

Fracastoro

early version of germ theory

He said that disease could spread from

• Direct contact

• Indirect contact

• Through air

He did not conduct any experiments

Pauteur (Pasteurized)

He was mainly known for the swan neck experiment

• Disproved spontaneous generation with swan neck flask experiment

• Developed a vaccine for anthrax and rabies

• Discovered microbial fermentation with spillage in beer and wine

Swan Neck Flask experiment

• Put broth in swan neck flask so no outside air can enter

• Boil the broth to kill any microorganisms

• When you break the flask, bacteria enters the sterile broth and organism growth occurs

Lister

• Ward fever

• Use carbolic disinfectant during surgery

• Aseptic technique

He tracked death rate of surgeries before and after using carbolic acid on open wounds, surgical tools, and bandages

Hooke

• Named cell

• Observed cork cell under microscope

Leeuwenhoek

• First person to accurately describe living microbes

• Used a simple microscope

Bacteria

• Prokaryotic

• usually unicellular

• Cell wall contains peptidoglycan

• Reproduced by binary fission

• Can be beneficial(gut bacteria) or pathogenic

• Can by many different shapes (cocci, bacilli, & spirilla)

• Some form endospores (super resistant)

• Can exchange DNA

• EX- E. coli & Streptococcus

Fungi

• Eukaryotic

• Cell walls made of chitin

• Include yeasts (unicellular) and molds/mushrooms (multicellular)

• Absorb nutrients from the environment by absorption

• Reproduce by spores

• Important decomposers; some cause disease (athlete’s foot, ringworm)

• Grow as hyphae forming a mycelium

• Not photosynthetic

• Ex- Yeast:Candida. Molds:Penicillin

Viruses

• Not living cells

• Made of DNA or RNA never both

• protein coat (capsid); some have envelopes

• Obligate intracellular parasites (must infect a host cell to reproduce)

• Much smaller than bacteria

• Cause diseases like influenza, HIV, COVID-19

• Extremely small

• No metabolism of their own

• Replicate only inside host cells

Algae

• Eukaryotic

• Cell wall (often cellulose)

• Photosynthetic (contain chlorophyll)

• Mostly aquatic

• Can be unicellular or multicellular

• Produce a large amount of Earth’s oxygen

• Not plants (lack true roots, stems, leaves)

• Ex- diatoms & green algae

Protozoa

• Eukaryotic

• Unicellular

• Usually motile (flagella, cilia, or pseudopodia)

• Heterotrophic (consume organic material)

• Many are free-living; some are pathogenic (malaria, amoebic dysentery)

• No cell wall

• Many are parasitic

• Complex life cycle

• Live in water or host

archaea

• Prokaryotic, but genetically different from bacteria

• Cell walls lack peptidoglycan

• Often live in extreme environments (hot springs, salty lakes)

• Rarely pathogenic

• Important in evolution and ecology

• Unique membrane lipids

• unicellular

• a sexual

Helminths

• Eukaryotic, multicellular

• Not microscopic as adults, but eggs/larvae are

• Include roundworms, tapeworms, flukes

• Parasitic lifestyle

Kingdom & Domain

From broadest → most specific:

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

Dear King Philip Came Over For Good Spaghetti

When did Prokaryote and Eukaryote appear

Prokaryotes 3.5 billion years ago

Eukaryotes 2.1-1.8 billion years ago

(Earth 4.6 billion years ago & Humans 1.2 billion years ago)

What organisms are considered prokaryotes

• Bacteria

• Archaea

Does Bacteria have a nucleus ?

No

Does Bacteria have a mitochondria ?

No

Does Bacteria have a Golgi apparatus?

No

Does Bacteria have chloroplast ?

No

Does Bacteria have a endoplasmic reticulum ?

No

Does Bacteria have Linear chromosomes?

No

Does Bacteria have a capsule ?

Only some

Does Bacteria have a flagella ?

Only some

Does Bacteria have Pili/ Fimbriae

Only some

Does Bacteria have plasmids?

Only some

Does Bacteria have endospores?

Only some

Does Bacteria have photosynthesis ?

Only some

Does Bacteria have oxygen use virus ?

only some

Does Bacteria have pathogenicity

Only some

Does Bacteria have a small size?

Yes

Does Bacteria have a cell wall present?

only some (peptidoglycan)

Does Bacteria have a cell membrane ?

Yes

Does Bacteria have ribosomes ?

Yes 70s

Is bacteria unicellular?

Yes

How does bacteria reproduce?

Asexually by binary fission

Does Bacteria have genetic material?

Yes singular or circular DNA molecule

Does Bacteria have cytoplasm ?

Yes

Does Bacteria have a prokaryotic or eukaryotic structure?

Prokaryotic- no membrane bound organelles or nucleus

Is Glycocalyx (Capsule & slime) prokaryotic or eukaryotic feature? and what is it’s function ?

Prokaryotic-Outer coating – not all bacteria

• Protects against desiccation (drying out)

• Prevents phagocytosis by host immune cells

• Helps bacteria adhere to surfaces (biofilms)

• Increases virulence in pathogenic bacteria

• Can fit tight or loosely and diffuse

• Lies outside the cell wall

Made of Made of

• polysaccharides or proteins

Is Flagella prokaryotic or eukaryotic feature and what is it function

Prokaryotic-Motility & attachment structures

Flagella

Features

• Long, whip-like structures

• Made of flagellin

• Anchored in the cell envelope

Functions

• Movement (chemotaxis)

• Helps bacteria move toward nutrients or away from toxins

Is Fimbriae (Pili) a prokaryotic or eukaryotic feature and what is it function?

Prokaryotic-Motility & attachment structures

Features

• Short, thin, hair-like projections

• More numerous than flagella

• extends from cell surface

• helps in adhesion to other cells and surfaces

Functions

• Attachment to surfaces or host cells

• Sex pili allow DNA transfer during conjugation

Is a cilia a prokaryotic feature?

No-True cilia are NOT found in bacteria (they are eukaryotic).

Is cell membrane a prokaryotic or eukaryotic feature and what is it’s function?

Prokaryotic-Plasma Membrane

Features

• Phospholipid bilayer

• No sterols (except Mycoplasma)

• May contain enzymes for respiration

Functions

• Selectively controls entry and exit of substances

• Site of metabolic processes (e.g. ATP production)

• Maintains internal environment

Is a cell wall a prokaryotic or eukaryotic feature and what is it’s function?

Prokaryotic-Present in most bacteria

Features

• Rigid outer layer

• Made of peptidoglycan

• Gram-positive: thick layer

• Gram-negative: thin layer + outer membrane

Functions

• Maintains cell shape

• Prevents osmotic lysis

• Provides protection

What feature does this and is it prokaryotic or eukaryotic ?

Only in some bacteria)

Features

• Dormant, thick-walled structures

• Contain DNA and minimal cytoplasm

• Highly resistant to heat, chemicals, radiation, dehydration

Functions

• Survival in harsh conditions

• Germinate when conditions improve

Endospores & Prokaryotic

What feature does this and is it prokaryotic or eukaryotic ?

Features

• Single, circular DNA molecule

• Not enclosed by a nuclear membrane

• Located in nucleoid region

Functions

• Contains essential genes

• Controls metabolism, growth, and reproduction

Bacterial Chromosome / Nucleoid & Prokaryotic

What feature does this and is it prokaryotic or eukaryotic ?

Optional genetic elements

Features

• Small, circular DNA molecules

• Replicate independently of chromosome

Functions

• Carry non-essential but advantageous genes

• Often encode antibiotic resistance or virulence

• Can be transferred between bacteria

Plasmids & Prokaryotic

What feature does this and is it prokaryotic or eukaryotic ?

Features

• 70S (50S + 30S subunits)

• Free in cytoplasm

Functions

• Protein synthesis

• Tiny particles that is made of protein and RNA

Ribosomes & Prokaryotic

What feature does this and is it prokaryotic or eukaryotic ?

(Storage structures)

Features

• Granules in cytoplasm

• May store glycogen, lipids, phosphate, sulfur

Functions

• Nutrient and energy storage

• Help survival during nutrient scarcity

Inclusions/Granule & Prokaryotic

coccus

What is this ?

coccus

bacillus

what is this?

bacillus

what is this ?

coccobacillus

coccobacillus

What is this?

spirillum

spirillum

What is this?

vibrio

vibrio

What is this?

spirochete

spirochete

Pair of two coccus ?

cocci

Group of 4 or more cells in a square

Tetrad

Cluster of cocci ?

staphylococcus

pair of two cocci ?

diplococcus

chain of cocci?

streptococcus

chain of rods?

streptobacillus

diplococcus

Tetrad

streptococcus

staphylococcus

streptobacillus

Thick peptidoglycan layer

Teichoic & lipoteichoic acid

Stains purple

Gram + or -

Gram +

• Single, thin sheath of peptidoglycan

• Outer membrane

– LPS (outermost)

– Lipoprotein (innermost)

Stains pink/red

Gram + or - ?

Gram -

Chemotaxis

Stimulus	Chemicals
Directional?	Yes
Positive response	Toward nutrients
Negative response	Away from toxins
Common in	Many bacteria

Phototaxis

Stimulus		Light
Directional?		Yes
Positive response		Toward light
Negative response		Away from intense light
Common in		Photosynthetic bacteria

Mycoplasma cell membrane

High concentration of sterols > rigidity

Archae cell membrane

Hydrocarbons instead of fatty acids

Plasma Membrane

Very thin (5-10 nm)

• Contain primarily phospholipids and proteins

• Provides a site for functions such as energy reactions, nutrient

processing, and synthesis

• Regulates transport (selectively permeable membrane)

• Secretion

Prokaryotic and Eukaryotic similarities

• Cell (plasma) membrane

• Cytoplasm

• DNA as genetic material

• Ribosomes (protein synthesis)

• Carry out metabolism

• Can reproduce and grow

Differences between prokaryotic and eukaryotic

Prokaryotes-small, no nucleus, DNA is circular, single cellular, no histones except archaea, and no membrane bound organelles

Eukaryotes-large, nucleus, Linear DNA, multi cellular, histones, and membrane bound organelles

Evidence of Endosymbiotic theory

circular DNA, 70S ribosomes, double membrane, binary fission

What does the Endosymbiotic theory explain?

• Origin of eukaryotic cells

• Why mitochondria and chloroplasts resemble bacteria

• Why eukaryotic cells are more complex and energy-efficient

What is the Endosymbiotic theory

that mitochondria and chloroplasts originated as free-living prokaryotes that were engulfed by a larger ancestral eukaryotic cell, forming a mutualistic (symbiotic) relationship

eukaryotic organelles?

Nucleus, mitochondria, ribosomes, Rough and Smooth ER, Golgi apparatus, Lysosomes, Chloroplast , vacuole, and centrioles

centrioles

only in animal cells

Organize spindle fibers during cell division

Cylindrical microtubule structures

eukaryotic

Vacuole

eukaryotic

• Large central vacuole in plant cells

• Smaller or absent in animal cells

• Storage

• Maintains turgor pressure

• pH and ion balance

Chloroplasts

plants & algae only

• Double membrane

• Thylakoids and grana

• Chlorophyll

• Own DNA and ribosomes

Photosynthesis