HEAL 4300 Microbiology Exam #1

microorganism (microbes):

- ubiquitous (found everywhere)

- integral role in energy and nutrient flow on earth

- produce CO2, NO, and CH3

- can evolve into larger organisms

characteristics of prokaryotes

Bacteria = single celled, no true nucleus

Archaea = single celled, no true nucleus, distinct from bacteria

- 10x smaller than eukaryotes

- lack of organelles

- all are microorganisms

characteristics of eukaryotes

- predominantly single celled

- have a nucleus

develop into highly complex, multicellular organisms

- larger in size

- a small minority compared to bacteria and archaea

characteristics of viruses

- most abundant inhabitants of the oceans

- not independently living cellular organisms

- exist at the level of complexity somewhere between large molecules and cells

- composed of a small amount of hereditary material surrounded by a protein coat and sometimes a membrane

characteristics of prions

- smaller and simpler than viruses

- no nucleic acids, only protein, act like infectious microorganisms

sizes of microorganisms

eukaryote 10,000nm (10 micrometers)

bacterium/archaeon 1,000nm (1 micrometer)

viruses 100 nm

prions 10nm

pathogens:

microbes that cause disease

infectious diseases are important causes of death worldwide

human actions can play a role in the emergence or reemergence of pathogenic microbes

genetically modified organisms:

manipulates the genetics of microbes, plants, and animals for the purpose of creating new products and genetically modified organisms (GMOs_

bioremediation:

uses microbes already present or introduced intentionally to restore stability or clean up toxic pollutants

recombinant technology:

makes it possible to transfer genetic material from one organisms to another and deliberately alter DNA

abiogenesis:

spontaneous generation, belief that invisible vital forces present in matter led to the creation of life

biogenesis:

living organisms arise only from others of the same kind

Louis Pasteur

- studies role of microbes in fermentation of beer

- invented pasteurization

- conduced the first studies linking human disease to infection

- swan-necked flask experimentation disproved abiogenesis

Joseph Lister

used aseptic techniques in surgery, which greatly reduced the number of post-surgical infections

Robert Hooke

- studies household objects, plants and trees

- described cellular structures and drew sketched of living cells

Antonie van Leeuwenhoek

- constructed over 150 small microscopes that could magnify 300x

- manufactures simple microscopes to study fabrics

Robert Koch

developed a series of logical steps that established whether an organisms is pathogenic and which disease it caused

organism classification

the orderly arrangement organisms into a hierarchy

taxonomy

the science of classifying living things

nomenclature

the assignment of scientific names to the various taxonomic categories and to individual organisms

binomial system:

genus species (g. species)

classification

the orderly arrangement of organisms into a hierarchy

domain

kingdom

phylum (division)

class

order

family

genus

species

organic vs inorganic

organic - carbon based

inorganic - non-carbon based

amino acids

- when combined, make proteins, the predominant organic molecules in cells

- about 20 different types

structure of amino acids

primary: type, number, and order of amino acids

secondary: arises when various functional groups interact by forming hydrogen bonds

tertiary: created by additional bonds between functional groups

quaternary: when more than on polypeptide forms a large, multiunit protein

carbohydrates

combinations of carbon and water

contribute to structural support and protection; serve at nutrient and energy stores

-ose

types of carbohydrates

monosaccharides

disaccharides

polysaccharides (cellulose, agar, chitin, peptidoglycan, glycocalyx)

lipids

- important storage

- triglycerides: glycerol bound to 3 fatty acids (saturated or unsaturated)

- yield twice as much energy per gram as other storage molecules

types of lipids

steroids: complex ringed compounds found in cell membranes and as animal hormones cholesterol: reinforced the cell membrane in animal cells and cell-wall-deficient bacteria

wax:

- ester formed between a long-chain alcohol and a saturated fatty acid

- found in the cell wall of bacteria that causes TB/leprosy, contributing to disease-causing potential

- natural waterproofing

phospholipids

structure of phospholipids

(charged/polar) hydrophilic head - phosphate with functional alcohol

(nonpolar) hydrophobic tail - fatty acid

plasma membrane organization

nucleotides

building blocks of DNA and RNA

purines: adenine and guanine

pyrimidines: cytosine, thymine, and uracil

types of nucelotides

DNA: contains genetic coding material for each organism's heredity

RNA: responsible for carrying out DNA's instructions and translating the DNA program into proteins that can perform life functions

types of RNA

mRNA: copy of a gene that provides the information for the order and type of amino acids in a protein

tRNA: carrier that delivers the correct amino acids for assembly

rRNA: major component of ribosomes (16S rRNA in small subunit, 23S and 5S rRNA in large)

ribosomes

site of protein/RNA synthesis

bacteria and archaea ribosome = 70S (50s + 30s)

inoculating:

introducing a small sample (inoculum) into media to culture microbes

incubation:

a controlled environment to encourage the growth of microbes to a macroscopic level

isolation:

based on the concept that if cells are separated on a nutrient surface, they will produce distinct colonies

ex. streak plate method

inspection:

assessing appearance (shape/size), cellular metabolism, nutrient requirements, products/enzymes, genetic/immunologic characteristics

identification:

using appearance (shape/size), cellular metabolism, nutrient requirements, products/enzymes, genetic/immunologic characteristics to identify culture growths

three physical forms of lab media

liquid

semisolid

solid

what is agar and why is it useful?

solid @ room temp, cam liquify at 100F, flexible/moldable

not digestible nutrient for most microorganisms

colony:

a macroscopic cluster of cells appearing on a solid medium arising from the multiplication of a single cell

types of cultures (physical, chemical, functional)

pure culture:

mixed culture:

contaminated culture:

general purpose media:

grow as broad spectrum of microbes as possible

generally complex

enriched media:

contains complex organic substances (blood, serum, hemoglobin, special growth factors) or the growth of hard to grow (fastidious) microbes

used in kab to encourage growth of pathogens

defined/synthetic media:

precisely chemically defined

contain in/organic compounds

molecular content specified by means of an exact chemical formula

complex media:

one or more components are not chemically defined

contains extract of animals, plants, or yeasts (blood, serum, meat extract/infusions, milk, yeast extract soybean digests, and peptone)

selective media:

contains one or more agents that inhibit the growth of certain microbes

used to isolate a specific type of microbes from a sample containing dozens

speed up isolation by suppressing unwanted ones for the growth of desired ones

differential media:

allow multiple types of organisms to grow by display visible differences in how they grow

variations in size/color/bubbles come from chemical in the media with which microbes react

microscope characteristics

magnification: real (formed by objective) and virtual image (projected through microscope)

resolution: capacity of an optical system to distinguish two adjacent objects or points from one another

contrast: degree of bending the light undergoes as it passes from one medium to another (refractive index)

bright field:

forms its image when light is transmitted through the specimen

dark field:

brightly illuminated specimens surrounded by dark field; used for live and unstained specimens

phase contrast:

transforms subtle changes in light waves passing through the specimen into differences in light intensity, best for observing intracellular structures

fluorescence:

modified compound microscope furnished with UV radiation source that causes it to give off light forming its own image against a black background (infections and pinpointing particular cellular structures)

types of staining

any procedure that applies colored chemicals to specimens

dyes

simple

differential

positive stain" dye sticks to specimen to give it color

negative: does not stick to specimen but settles on outer boundary forming silhouette

dyes for staining

basic dyes (cationic) have a + charge

acidic dyes (anionic) have a - charge

simple staining:

only require a single dye and is uncomplicated

cause all cells to appear more/less the same color regardless of type = only reveal shape, size, and arrangement

differential stains

use 2 different colored dyes (primary + counterstain) to distinguish cell types/pats

requires additional chemical reagents to produce desired reaction

gram

acid-fast

endospores

gram staining (differential):

emphasizes differences in structure of cell wall and how it reacts to series of reagents applied to cells --> diagnose infection and guide drug tx

gram positive bacteria

bacteria that have a thick peptidoglycan cell wall, and no outer membrane.

They stain very darkly (purple) in Gram stain.

gram negative bacteria

bacteria that have complex cell walls with less peptidoglycan but with lipopolysaccharides (endotoxin)

more toxin and harder to kill

staining procedure order

crystal violet: added to cell in a smear, stains them all purple

iodine: stabilizer that causes dye to firmly attach to thicker gram + walls

alcohol: dissolves lipids in outer membrane and removes dye from gram - cells

safranin (red): dye counterstains the gram - bacteria after alcohol removes the violet

acid-fast staining (differential):

differentiates acid-fast (pink) from non acid-fast (blue) bacteria

used for bacteria, fungi, and protozoa

endospore staining (differential):

forced by heat into resistant bodies called endospores

distinguishes between endospores and vegetative cells

(gram positive, spore forming members of bacillus and clostridium)

shapes of bacteria

cocci - spherical (1um)

bacillus - rods (2um x 1 um)

spirochete - spiral

types of appendages

flagella

fimbriae

pili

glycocalyx

s-layer

flagella

primary function is motility

external

internal - spirochete

structure: filament, hook (sheath), basal body

flagellar chemotaxis

+ : movement towards a favorable chemical stimulus (nutrient)

- : movement away from a repellant

run: rotation of flagellum counterclockwise, resulting in a smooth linear direction

tumble: reversal of direction of flagellum (clockwise), causing stop and changing course

fimbriae

small fibers off the surface allowing tight adhesion between cells allowing colonization and infection of host cell

pili

used in conjugation between bacterial cell to transfer DNA

glycocalyx

:coating of repeated polysaccharide/glycoprotein units

slime layer: loose, protects against water and nutrient loss

capsule: tightly bound sticky character to colonies on agar protecting against phagocytosis

biofilms: colonies of bacteria conjugated together on a surface

s-layer

single layers of thousands of copies of a single protein linked together

only produced when bacteria are in a hostile environment

cell envelopes

cytoplasmic membrane

cell wall (peptidoglycan)

outer membrane

endospores

forms slowly in response to nutrient depletion --> produced a dormant cell that can survive until nutrients and growth can resume

resistant to many environmental conditions (heat, UV, radiations, disinfectants)

cytoskeleton

protein filaments that form functional filaments that extend to inner dimensions of the cell

- gives structure and maintains shape

- moves intracellular material

nucleoid

location of bacterial DNA

supercoiling and nucleoid proteins aid in folding and structure

essential nutrients

: any substance that must be provided to an organism

macronutrients: required in large quantities and play principal roles in cell structure and metabolism

micronutrients: present in smaller amounts and are involved in enzyme function/maintenance of a protein

organic nutrients

contain C and H, usually products of living things

can be molecules (methane)) or polymers (carb, lipids, proteins, nucleic acids)

inorganic nutrients

an atom or simple molecule that contains a combination of atoms other than C and H

cytosol makeup

70% water

proteins

organic compounds

autotrophs

organisms that are able to make their own food

energy: sunlight, in/organic molecules

carbon source: CO2

heterotrophs

organisms that cannot make their own food

energy: sunlight, metabolism, parasites

carbon source: organic

parasites

derive their nutrients from a living host (cells or tissues)

range from viruses - helminths

passive diffusion

movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy

facilitative diffusion

solute combines with a transporter protein in the membrane

osmosis

diffusion of water through a selectively permeable membrane

active transport

energy-requiring process that moves material across a cell membrane against a concentration difference

endocytosis

: cell encloses a substance in its membrane and engulfs it

phagocytosis: accomplished by amoebas/WBCs, ingests whole cells or large matter in a vacuole

pinocytosis: ingestion of liquids such as oils or molecules in solution in a vesicle

temperature ranges for bacterial growth

psychrophiles: -20-15

psychrotolerant: 5-35

mesophile: 10-50

thermophile: 45-80

extreme thermophile: 65-135

pH ranges for bacteria growth

acidophiles: < 7

alkalinophiles: > 7

halophiles

grow best in salty conditions

barophiles

grows best in high pressure environments

presence of O2 for bacteria growth

aerobes: requires O2 for metabolism

microaerophiles: require O2 at a lower concentration than atmosphere

facultative aerobes: can live with/out O2

anaerobes: does not require O2 for metabolism, die in its presence

aerotolerant anaerobes: does not require O2 for metabolism, can survive in its presence

bacterial fission

A special type of asexual reproduction performed by bacteria

parent cell enlarges and splits into two cells

generation time/doubling time:

time required for a compete fission cycle, from a parent cell to two daughter cells

generation:

increases the population by a factor of two

Nt = (N)2^n

growth curve

: predictable growth of bacteria

lag: flat period of growth while adjusting

exponential: growth increases geometrically and will continue is conditions are optimal

stationary: cell birth and death rates are equal d/t depleted nutrients

death: cells begin to die at an exponential rate d/t buildup of waste depending on conditions

endergonic reactions

require the input of energy (ATP)