2420 micro bio tcc southeast Dr. Marlyn Brookins ch 3 (from slides)

Spontaneous generation (abiogenesis)

the idea that life can arise from non-living material; proposed by early thinkers such as Jan Baptista van Helmont who believed mice could arise from rags

Biogenesis

the principle that life only comes from other life

Francesco Redi's experiment

showed that meat isolated from flies did not develop maggots while meat exposed to flies became infested; proved maggots arise from fly eggs and not spontaneous generation

John Needham's experiment

corked broths became turbid after heating; seemed to support spontaneous generation but the heating was later shown to be insufficient

Lazzaro Spallanzani's experiment

modified Needham's experiment with more thorough heating and sealing; concluded spontaneous generation does not occur and that Needham had not sufficiently killed all microbes

Louis Pasteur's swan-neck flask experiment

showed that after boiling the contents of a curved-neck flask remained free of microbial growth despite access to air; supported the theory of biogenesis

Ignaz Semmelweis

observed a decreased death rate in the midwives' ward compared to the doctors' ward; linked puerperal fever to "cadaver particles" and developed preliminary aseptic techniques

Joseph Lister

credited with the first aseptic surgical techniques; advanced the idea of antisepsis using carbolic acid (phenol) solution; known as the "Father of Antiseptic Surgery"

Germ Theory of Disease

the principle that specific diseases are caused by specific kinds of microbes; developed through the work of Pasteur Koch Snow and Semmelweis

Robert Koch

studied the etiology (microbial cause) of diseases such as anthrax tuberculosis cholera bubonic plague and malaria

Etiology

the microbial cause of a disease

Pasteurization

process developed by Louis Pasteur to kill harmful bacteria in liquids without affecting quality

Fermentation (Pasteur's discovery)

demonstrated that fermentation is caused by specific microorganisms such as alcoholic fermentation by yeast and lactic acid fermentation by bacteria

Pasteur's vaccination work

created vaccines for chicken cholera anthrax and rabies

Microbial metabolism (Pasteur's discovery)

discovery that different microbes have different metabolic processes

Aseptic techniques (Pasteur's contribution)

emphasized the importance of sterilization and hygiene in medical and laboratory practices

Koch's postulates

criteria developed by Robert Koch for identifying the causative agent of a disease

Robert Koch's other contributions

included simple staining techniques photomicrography of bacteria techniques for estimating CFU/ml sterilization with steam use of Petri dishes and techniques to transfer bacteria

Ancient Greeks (miasma theory)

proposed that disease was caused by "bad air" or miasma

Fracastoro (1546)

began an early version of germ theory in his work De Contagione et Contagiosis Morbis

Robert Hooke (1665 timeline)

observed cork cells under a microscope and was first to identify and name cells

Antonie van Leeuwenhoek (1674 timeline)

observed single-celled organisms using improved lenses

Ignaz Semmelweis (1847 timeline)

demonstrated that hand washing reduces puerperal infections

John Snow (1854)

demonstrated that cholera bacteria were transmitted through contaminated drinking water

Louis Pasteur (1856 timeline)

discovered microbial fermentation while studying the causes of spoilage in beer and wine

Louis Pasteur (1862 timeline)

disproved spontaneous generation using the swan-neck flask experiment

Joseph Lister (1867 timeline)

began using carbolic acid as a disinfectant during surgery

Robert Koch and his workers (1876-1906)

determined the causative agents for many bacterial infections

What principle states that microorganisms cause diseases?

Germ Theory of Disease

Assume the theory of spontaneous generation is TRUE. Predict the result if you were to repeat Pasteur's experiment.

Microbes would grow in the flask

Cell theory

states that all organisms are made of cells; all existing cells are produced by other living cells; and the cell is the most basic unit of life

Robert Hooke's contribution to cell theory (1665)

first to identify cells and named them

Antonie van Leeuwenhoek's contribution to cell theory (1674)

made better lenses and observed cells in greater detail

Matthias Schleiden's contribution to cell theory (1838)

first to note that plants are made of cells

Theodor Schwann's contribution to cell theory (1839)

concluded that all living things are made of cells

Rudolf Virchow's contribution to cell theory (1855)

proposed that all cells come from other cells

Properties of life

include cells and organization; energy processing; response to environmental changes; regulation and homeostasis; growth and development; reproduction; and evolutionary adaptation

Prokaryotic cells

cells that include bacteria and archaea

Eukaryotic cells

cells that include animals plants fungi and protists

Central Dogma theory

describes the flow of genetic information from DNA to RNA (transcription) to protein (translation); occurs in all living cells

Features shared by prokaryotes and eukaryotes

include DNA existing as a chromosome; RNA (messenger transfer and ribosomal); proteins; a plasma membrane; ribosomes; and cytosol/cytoplasm

Fluid mosaic model

describes the plasma membrane as a mosaic of different proteins embedded in a fluid matrix of the lipid bilayer

Amphipathic

term describing phospholipids that have both a hydrophilic (polar) head and hydrophobic (nonpolar) tail

Membrane fluidity and saturation

saturated hydrocarbon tails pack together making the membrane more viscous while unsaturated tails prevent packing and increase fluidity

Hopanoids

lipid molecules found in bacterial membranes that help stabilize the membrane in place of cholesterol

Passive transport

movement of substances down a concentration gradient without the cell expending energy

Active transport

movement of substances against a concentration gradient that requires the cell to expend energy from ATP

Bulk transport

energy-requiring process in which large molecules or particles are transported across the plasma membrane via vesicles

Exocytosis

process in which large molecules are secreted when a vesicle fuses with the plasma membrane

Endocytosis

process in which large molecules are taken into the cell when the plasma membrane pinches inward to form a vesicle

Simple diffusion

passive movement of molecules from higher to lower concentration directly through the membrane without any energy input

Facilitated diffusion

passive transport of molecules down a concentration gradient using a membrane carrier protein or channel without energy input

Osmosis

movement of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration

Osmotic pressure

the pressure needed to stop the movement of water across a membrane

Aquaporin

channel protein through which most water passes across a biological membrane

Tonicity

the strength of a solution relative to the strength of a solution on the other side of a membrane

Isotonic solution

solution in which water concentration is equal inside and outside the cell so rates of diffusion are equal in both directions

Hypotonic solution

solution in which there is a net diffusion of water into the cell; cells with a cell wall become turgid while cells without one may swell or lyse

Hypertonic solution

solution in which there is a net diffusion of water out of the cell; cells with a cell wall undergo plasmolysis while cells without one shrink and become distorted

Plasmolysis

shrinking of the cell membrane away from the cell wall due to water loss in a hypertonic solution

Crenation

shrinking and distortion of a cell without a cell wall when placed in a hypertonic solution

Prokaryotes (characteristics)

cells that lack a nucleus and membrane-bound internal structures; are small (about 1.0 micrometer in diameter); have a simple structure; and are composed of bacteria and archaea

Eukaryotes (characteristics)

cells that have a true nucleus and internal membrane-bound organelles; are larger (10-100 micrometers in diameter); have a more complex structure; and are composed of algae protozoa fungi animals and plants

Bacteria (domain characteristics)

ubiquitous organisms whose cell walls contain peptidoglycan though some lack cell walls

Archaea (domain characteristics general)

organisms that inhabit harsh environments and have cell walls composed of polymers other than peptidoglycan

Binary fission

process of bacterial cell division involving DNA replication protein synthesis and cytoplasm expansion followed by septum formation and cell division

Coccus

round-shaped bacterium

Bacillus

rod-shaped bacterium

Coccobacillus

short rod or oval-shaped bacterium between a coccus and bacillus in shape

Vibrio

curved rod-shaped bacterium

Spirillum

rigid helical/corkscrew-shaped bacterium

Spirochete

long loose flexible helical/spiral-shaped bacterium

Pleomorphism

trait that allows bacteria to display different shapes under different physiological or environmental conditions

Diplo arrangement

pairing of cells that remain attached after division in one plane

Strepto arrangement

chain of cells that remain attached after division in one plane

Tetrad arrangement

group of four cells formed by division in two planes

Sarcina arrangement

cube-like group of eight cells formed by division in three planes

Staphylococci arrangement

grape-like cluster of cells formed by division in random planes

Palisade arrangement

cells that remain attached side by side or end to end forming a fence-like pattern

V shape arrangement

cells that remain attached forming a V shape after division

Cytoplasmic membrane (bacterial)

thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of substances in and out of the cell

Bacterial chromosome/nucleoid

condensed DNA that directs heredity and codes for proteins

Ribosomes (bacterial)

structures composed of protein and RNA that are the site of protein synthesis

Cytoskeleton (bacterial)

protein fibers that encircle the cell just inside the membrane and contribute to the shape of the cell

Cytoplasm (bacterial)

the cytosol plus all other components contained within the cell membrane

Fimbriae

fine hairlike bristles extending from the cell surface that help with adhesion

Outer membrane (bacterial)

membrane containing LPS external to the cell wall that controls the flow of materials in and out of the cell

Cell wall (bacterial)

structure made of peptidoglycan that provides structural support and shape for the cell

Pilus

hollow appendage used to transfer DNA to other cells

Capsule

layer of molecules external to the cell wall that is protective adhesive and involved in receptor functions; also called the slime layer or glycocalyx

Inclusion/granule

stored nutrients deposited in dense crystals within the cell

Plasmid

double-stranded circular piece of DNA that is extrachromosomal and can provide adaptive advantages

Flagellum

specialized appendage attached to the cell by a basal body that provides motility

Endospore

dormant body formed by some bacteria that allows for survival in adverse conditions

Cytosol

gelatinous solution contained by the cell membrane that is 70-80% water and a complex mixture of sugars amino acids and salts

Nucleoid

region housing the bacterial DNA as a single circular haploid chromosome held together by DNA-binding proteins with an origin of replication

Ribosome (function)

complex of protein and rRNA responsible for protein synthesis; exists as 70S in bacteria and 80S in eukaryotes; a selective target for antibiotics

Streptomycin

antibiotic used to treat tuberculosis (with isoniazid and rifampin); given by injection or orally; can damage kidneys and inner ear

Gentamicin and other aminoglycosides

antibiotics used to treat antibiotic-resistant and hospital-acquired infections often together with other drugs; given by injection or applied topically for burns; can cause varying degrees of kidney and inner ear damage

Tetracyclines

antibiotics used to treat a broad spectrum of bacterial infections and some fungal infections; given orally; can stain teeth cause gastrointestinal symptoms and lead to superinfections