Microbiology test 1

Prokaryotic cell

-single circular chromosome in nucleoid
-no nucleus
-Inn some microorganisms

Eukaryotic cell

-multiple rod-shaped chromosomes
-Plant and animal cells
-In some microorganisms

Prokaryotic microoranisms domains

-Archaea (extremophiles)
-Bacteria

Eukaryotic organisms domain

-Eukarya

Eukaryotic vs Prokaryotic cells

-Eukaryotic cells are larger

Plasmid

-double stranded circular DNA molecule in bacteria cells that can be antibiotic resistant

Round cell shape

Coccus

Rod cell shape

Bacillus

Curved rod cell shape

Vibrio

Short rod cell shape

Coccobacillus

Spiral cell shape

Spirillum

Long, loose helical spiral

Spirochete

Pair of two cocci

Diplococcus

Group of 4 cells in square

Tetrad

Chain of cocci

Streptococcus

Cluster of cocci

Staphylococcus

Chain of rods

Streptobacillus

Cytoskeletal elements that maintain cell wall

Proteins

Prokaryotes

-bacteria
-archaea

Eukaryotes

-plants
-fungi

Isotonic medium

-No net movement of water particles, equal

Hypertonic solution

Water particles move out of cell

Hypotonic solution

Water particles move into cell (osmosis)

Osmotic pressure

-Water passes through semipermeable membrane, solutes can not

Shriveling of the cell

Crenation
With cell wall: plasmolysis

Prokaryotic chromosomes

-Circular
-Haploid- 1 copy of every gne

Nucleoid

DNA and proteins

NAP

-prokaryotic DNA interacts with nucleoid-associated proteins
-assist with packaging of chromosome

Histones

In bacteria, function similar to NAP
-DNA-organizing proteins found in eukaryotic cells

Archaea, nucleoid is organized by either

NAPs or histone-like DNA organizing proteins

Plasmids

-extrachromosomal DNA in prokaryotic cells
-circular, double-stranded
-commonly found in bacteria
-antibiotic resistant

Ribosomes

-structures responsible for protein synthesis
-Pro Small unit: 30S
-Pro Large unit: 50 S
-Pro Complete ribosome: 70S
-Constructed from proteins and ribosomal RNA
-Prokaryotic ribosomes are found in cytoplasm
-Eukaryotic have size of 80S
-S- Svedberg unit (sedimentation in an ultracentrifuge)

Inclusions

-prokaryotic cells have ability to store extra nutrients
-reduces buildup of osmotic pressure
-Stores glycogen and starches
-Supply carbon

Inclusion: Volutin granules (metachromatic granules)

-Store polymerized inorganic phosphate
-Can be used in metabolism and assist formation of biofilms
-Microbes to contain: archaea Methanosarcina, bacterium Corynebacterium diphtheriae, unicelllular eukaryotic alga Chlamydomonas

Inclusion: Sulfur granules

-found in sulfur bacteria of genus Thiobacillus
-store elemental sulfur, used for metabolism

Inclusion: Polyhydroxybutyrate (PHB) granules

-surrounded by phospholipid monolayer
-produced by species of Bacillus and Pseudomonas
-used as a source of biodegradable polymers for bioplastics

Inclusion: Gas Vacuoles

-Accumulations of small, protein-lined vesicles of gas
-prokaryotic cells alter their buoyancy
-Can adjust location in water column

Inclusion: Magnetosomes

-Magnetic iron oxide or ion sulfide surrounded by lipid layer
-Found in Magnetospirillum magnetotacticum

Carboxysome inclusion

-Composed of protein subunits
-Interior is filled with Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO, helps plants take CO2 and convert to sugars)
-Carbonic anhydrase
-Found in cyanobacteria (Anabaena cylindrica)
-Some prokar. cells possess carboxysomes called proto-organelles: compartmentalize compounds or chemical reactions

Endospores (inclusion)

-protect bacterial genome when conditions are unfavorable
-Can not reproduce
-Helps bacteria survive during exposure to chemicals, extreme temps, radiation

Endospore cycle

Vegetative cell gets irritated->sporulation
Endospore-> germination

Sporulation

-binary fission
-environmental conditions are unfavorable
-Formation of septum in vegetative cell and divides cell (copy of cells chromosome) asymmetrically
-DNA forespore separates from mother cell
-Cortex forms around forespore (calcium and dipicolinic)

Germination

-Occurs after living conditions improve

Pathogenic endospore formers

-Clostridium perfringens (Gas gangrene)
-Clostridium botulinum (Botulism food poisoning)(anaerobic)
-Tetanus (Clostridium tetani) (Anaerobic)
-Clostridioides difficile (Pseudomembranous colitis) (Anaerobic)

-Bacillus anthracis (Anthrax) (Aerobic)
-Bacillus cereus (Food poisoning) (Aerobic) (Found in rice) (Boiling does not kill)

-Genus is first part, species is second part

B. thuringienis

-bt corn when can is all extra smashed

Plasma Membrane

-Composed of a phospholipid bilayer
-Glycoprotein (carbohydrate protein, glyco lipid)
-Glycolipid: acts as receptors
-Proteins allows things to move in and out of membrane

Archael membrane

-Phospholipids are formed with ether linkages
-Have branched chains
-Some can be formed of lipid monolayers

Membrane proteins

-Cell-to-cell communication: chemical signals, attach to other receptors
-Sensing environmental conditions: temp, salt levels
-Pathogenic virulence factors: how diseases are caused, characteristics, toxins

Simple diffusion

-molecules moving from higher conc to lower conc along gradient
-aka passive transport
-Goes through lipid bilayer

Facilitated diffusion

-used for charge molecules, large molecules
-form of passive transport
-has to pass through protein channel

Active transport

-molecules moving across cell membrane to a higher conc requiring energy
-ATP (adenosine triphosphate)

Peptidoglycan (murein)

-bacterial cell walls
-Composed of NAG and NAM which form glycan chains
-Tetrapeptides are chain bridges between NAM subunits

Gram-negative bacteria

-tetrapeptide chains directly cross-linked

Gram-positive bacteria

-tetrapeptide chains are linked by pentaglycine cross-bridges
-The petidoglycan subunits (nam and nag circles) are made inside the bacterial cell
-Antibiotics interfere with peptidoglycan synthesis
-Certain cells can recognize bacteria by detecting peptidoglycan

Gram positive cell walls

-Bottom to top: cell membrane, peptidoglycan sheets, sheets embedded with teichoic acids (carbohydrate chains), lipoteichoic acid, cell wall
-Techoic acids enhance ability to casue infection (streptococcus, staphylococcus)

Family Mycobacteriaceae

-External layer of waxy mycolic acids: makes them acid-fast (detects presence of cell walls that are rich in mycolic acid)
-Mycobacterium tuberculosis (leprocy)

Gram-negative cells

-Have thinner layer of peptidoglycan
-Gel-like matrix occupies periplasmic space(around pepglyc sheets)
-Outer membrane attached to peptidoglycan by murein lipoprotein
-Membrane made up of Phospholipid on bottom and lipopolysaccharide on top
-Lip A is toxic (endotoxin)- fever, spetic shock
-Proteins go in membrane or stop there

Lippopolysaccharide

-Bottom to top:
-Lipid A
-Core polysaccharide
-O side chain (sugar like molecules) or O antigen (special proteins that cause diseases

O side chain

-Can be detected using serological or immunological tests
-Identifies specific pathogenic strains like Escherichia coli

Archael cell walls

-Contain pseudopeptidoglycan
-Lack cell walls

Glycocalyx

-sugar
-have a polysaccharide coat (2 types)
-Capsule: organized layer located outside of cell wall and usually composed of polysaccharides or proteins
-Slime layer: loosely attached to cell wall. composed of polysaccharides, glycoproteins and glycolipids
-Glycocalyces allow cells to adhere to surfaces. aids in formation of biofilms

Biofilms

-form in layers on surfaces
-Give some protection from environment like predation (some viruses can make bacteria sick)
-Hold water to prevent moisture loss
-Resists action of antibiotics and disinfectants
-Biofilms give advantages to microbes

Capsules

-can make it more difficult for phagocytic cells to kill microbe
-Examples: streptococcus pneumonia (smooth, disease causing), S-strain is very pathogenic (rough)
-In these cases, capsule is a virulence factor- allows bacteria to be more disease causing

S-layers

-Another type of outer cell structure
-Composed mixture of structural proteins and glycoproteins
-In some archaea this layer serves as cell wall
-Helps cell withstand osmotic pressure
-May help certain pathogens evade host immune system

Filamentous appendages

-protein appendages embedded within cell wall
-Attach to other surfaces
-Transfer DNA
-Locomotion
-Fimbriae, pili, flagella

Fimbriae

-Bristle like proteins projecting from cell surface
-Enable bacteria to attach to surfaces and to other cells
-Adherence to host cells is important for colonization, infectivity, and virulence ( how disease causing something is), and biofilm formation

Pili

-Longer and less numerous protein appendages
-Aids attachment to surfaces

F pilus

-specialized pilus important in the transfer of DNA between bacterial cells
-allows 2 cells physically transfer or exchange parts of their respective genomes

Conjunction

-transfer of DNA from one bacteria cell to another
-F-plasmid makes F pilus
-Between F+ and F-, f pilus forms
-Both are antibiotic resistant and are toxins

Flagella

-Functions like propellers
-Stiff spiral filaments
-Spin in solutions (motility)
-Composed of basal body (motor) in plasma membrane
-Hook- connects basal body to filament (flagellin subunits)
-Gram + and Gram - have different basal bodies

Electron transport chain->Proton motive force

-cell membrane on bottom
-basal bottom in middle (cylinder)
-proteins side by side next to basal body
-Hook on top of basal body
-filament connecting to hook
-peptoglycan on top
-Hydrogen atoms outside of cell
-1200 rpm
-Proton want to be inside the shell

Monotrichous (flagellar arrangements)

-single flagellum at one end
-Vibrio cholerae

Amphitrichous

flagella at both poles of the cell
-Spirillum minor

Lophotrichous

cluster of flagella at one end
-Pseudomonas aeruginosa

Peritrichous

-flagella that cover entire surface of a bacterial cell
-Escherichia coli

Movement toward an attractant or away from repellent

-Increasing length of runs. Counterclockwise direction and move forward. In peritrichous bacterium, flagella are bundled together (efficient movement)

-Decreasing length of tumbles. Clockwise. Splayed out, creates looping motion, prevents forward movement, toward direction of attractant (higher concentration)

-When no chemical gradient exists, length of runs and tumbles are more equal, movement is more random

Prokaryotes

-Are everywhere
-Found in hot springs, antarctic ice, deep ocean

Human body prokaryotes

Thrive in the mouth, nasal cavity, throat, ears, armpits, groin, behind ears

Prokaryotes in soils

-Important for stability and thriving of ecosystems
-Part of soil formation and stabilization
-Breakdown of organic matter and development of biofilms
-one gram of soil contains up to 10 billion microorganisms
-Bacteria use substances from plant roots as nutrients (acids and carbohydrates)
-Bacteria metabolize the plant substances and release metabolic products and form humus and increase fertility of soil

Salt lake prokaryotes

-Halobacteria decomposes dead brine shrimp
-Halobacterium salinarum archael species that live in dead sea (nourishes shrimp)

Metabolic diversity (prokaryotes)

-Glucose and lactose
-Switch from one energy source to the other
-Prokaryotes fix and recycle elements
Ex: CO2 -> sugars
-Nitrogen fixation: conversion of atmospheric nitrogen into ammonia
-Some plants use ammonia to form biomolecules for survival

Rhizobium

-Nitrogen-fixing bacteria
-Live in roots of legume plants such as alfalfa and peas
-Ammonia produced helps plants make nucleic acids
-Symbiotic relationships w/ plants
-Plants may be eaten by animals

Bioremediation

-microbes have ability to break down toxic pollutants
-Provide nutrients to microbes already present in polluted sites to increase metabolism

Disease and spoilage

-Most microbes play positive role
-Some cause spoilage of food or foodborne illness
-Less than 1% of prokaryotes are thought to be human pathogens, responsible for large number of diseases that afflict humans

Population

-A group of individuals that belong to the same species and live in the same area

Population interactions

Cooperative- benefit the populations
Competitive- one population competes with another for resources

Symbiosis

-Interaction between species in community
-Opposition and cooperation

Mutualism

-benefitted, benefitted

Amensalism

-harmed, unaffected

Commensalism

-benefitted, unaffected

Neutralism

-unaffected, unaffected

Parasitism

-benefitted, harmed

Microbiome

-all prokaryotic and eukaryotic microorganisms in one certain organism

Human microbiome

-resident microbiota: microbes that constantly live in/on our bodies. Different microorganisms for different areas of body.
-Transient microbiota: temp found in human body, may include pathogenic microorganisms.
-Hygiene and diet can alter both of these

Human mouth

-Commensal and mutualistic species
-Bacteria on tongue, internal surface of cheeks (least diverse microbiota bc of exposure to oxygen), front of back teeth/gums
-Microbiome can change over time
-flora microbes at birth, additional ones are acquired from healthcare providers, parents, relatives

Resident microbiotas

-Important for human health
-Occupy niches that might be taken by pathogenic microorganisms
Ex: Lactobcillus spp. (antibiotics) is the dominant bacterial species of the normal vaginal microbiota for most women at child-bearing stage

Fermentation

-Sugar (glycogen) -> Acids
-If bacteria is absent, then fermentation is impossible and pH levels rise (can get yeast infections)
-Opportunistic pathogens: resident microbes
-Skin: Staphylococcus(genus) epidermis(species)
Ex: candida albicans --> pathogenic yeast

Binary Fission

-Cell replication of bacteria
-Starts at ori (where chromosomes are attached to inner cell membrane)
-Replication continues in opposite directions along chromosome, and goes until terminus is reached
-Center of enlarged cell constricts until two daughter cells are formed
-Each daughter cell receives complete copy of parental genome
-Division called cytokinesis

Cytokinesis

-directed by protein called FtsZ
-FtsX assembles into Z ring on cytoplasmic membrane
-Z ring is anchored by FtsZ-binding proteins
-This defines division plane between two daughter cells

Divisome

-Structure formed by Z ring and additional proteins required for division
-Produces peptidoglycan cell wall and build a septum
-Daughter cells are separated by division septum