Microbio - Exam 1

chpt. 1-5

acellular microorganisms

prions, viruses

cellular microorganisms

bacteria, archaea, eukaryotes

ubiquitous

“found everywhere,” used to describe microbes’ presence

biotechnology

the use of microbes for commercial or industrial purposes

genetic engineering

area of biotechnology that manipulates the genetics of microbes/plants/animals to create new products and GMOs

recombinant DNA technology

makes it possible to transfer genetic material and alter DNA → GMO design

bioremediation

the use of present or introduced microbes to restore stability of an ecosystem or clean up toxic pollutants

pathogens

disease-causing microbes

infectious disease

any disease caused by a microorganism

smaller

bacterial and archaeal cells are about 10xs ___ than eukaryotic cells

types, metabolic capabilites

The Human Microbiome Project has demonstrated that the ___ of microbes found in and on humans are diverse, but the ___ are similar

cellulose

a long, fibrous polymer that provides plants and many microscopic algae cell walls with strength and rigidity

chitin

a polysaccharide similar to cellulose that makes up the exoskeleton of some fungi

peptidoglycan

a network of polysaccharide chains that provide structural support, protection, and nutrient/energy storage

the main sourceof structural support to the bacterial cell wall

glycocalyx

an outer coating on many cells that acts as a protective layer and also plays a role in attachment of the cells to other cells or surfaces

eukaryotes, bacteria, archaea

___ have organelles while ___ & ___ lack organelles

6 types of microorganisms

archaea, fungi, helminth, bacteria, protozoa, viruses

eukaryotic microorganisms

helminth, fungi, protozoa

prokaryotic microorganisms

bacteria, archaea

5 I’s of Microbiology

1. inoculation
2. incubation
3. isolation
4. inspection
5. identification

inoculation

a sample is placed onto a media to culture a microbe

(5 I’s)

incubation

placing the medium container into a temperature-controlled chamber to encourage growth

(5 I’s)

pure culture

only one type of species in a culture

mixed culture

two or more species in a culture

contaminated culture

a pure or mixed culture plus an unwanted microbe in a culture

media classification

1. physical state (liquid, semi-solid, solid)
2. chemical composition
3. functional type

general purpose media

media type that promotes growth in a broad spectrum of microbes

enriched media

media type that contains complex organic compounds for the growth of fastidious (having complex/precise nutrient requirements) microbes

selective media

media type that inhibits the growth of certain microbe(s) to isolate the particular microbe of study

differential media

media type that allows multiple types to grow but displays visible differences in how they grow

isolation

separating an individual bacterial cell to create a colony

(5 I’s)

inspection & identification

looking at the microscopic appearance, determining nutrient requirements, products given off during growth, and other characteristics

(5 I’s)

virus size

20-400 but up to 800-1500 nm

bacteria size

200 nm-750micro-m

protozoa size

100-300micro-m

principles of light microscopy

1. magnification
2. resolution
3. contrast

objective lens, ocular lens

magnification occurs in 2 phases, first in the ___ and second in the ___

oil immersion lens (100x)

lens that reduces scatter to increase resolution

bright-field microscopy

• most widely used type of light microscope
• forms image when light is transmitted through specimen
• can be used for live, unstained/preserved, and stained materials

dark-field microscopy

• adapted from bright-field microscope by adding a “stop” to block light from entering the objective lens
• used to visualize living cells that would be distorted by drying or heating or cannot be stained by usual methods

phase-contrast microscopy

• used to observe intracellular structures such as organelles, endospores, etc.

fluorescence microscopy

• uses a specially modified compound microscope with a UV light
• the use of certain dyes show fluorescence
• specimen is first coated/placed in contact with fluorescence source
• used to diagnose infections and pinpoint particular cellular structures

confocal microscopy

• uses a laser beam to scan various depths of the specimen
• used on fluorescently stained specimens or to visualize live unstained cells/tissues

transmission electron microscope (TEM)

• transmits electrons through specimen
• used to view detail structure of cells and viruses
• dark areas = denser areas

scanning electron microscope (SEM)

• specimens are metal-coated while electrons scan back and forth over it
• color is always added after, actual images are black and white

simple stain

stain that requires only a single dye and caused all the cells to appear the same color which reveals its shape, size, and arrangement

differential stain

stain type that uses 2 differently colored dyes (primary dye and counterstain) to distinguish cell types or parts

gram stain

differential stain type

• gram positive = purple
• gram negative = pink

acid-fast stain

differential stain type

• acid-fast = reddish/purple
• non-acid-fast = blue

endospore stain

differential stain type

• endospores = green
• vegetative cells = pink

capsular staining

• used to observe an unstructured protective layer surround the cells of some bacteria and fungi
• cell is negatively stained with India ink

flagellar staining

• used to reveal tiny, slender filaments used by the bacteria for locomotion
• these filaments are enlarged by depositing a coating on the outside of the filament and then staining it

bacteria vs eukaryote differences

• DNA packaging; bacteria lack nucleus and histones
• cell wall makeup (peptitoglycan - bacteria)
• internal structures; bacteria lack membrane-bound organelles

• cytoplasmic membrane
• cytoplasm
• ribosomes
• chromosomes

all bacterial cells have ___ (4)

• cell wall
• glycocalyx

most bacterial cells have ___ (2)

• flagella, pili, fimbriae
• outer membrane
• plasmids
• endospores

some bacterial cells have ___ (4)

cocci, rod/bacillus

the two most common bacteria shapes are ___ & ___

diplocci

pairs of cocci

staphylococci

clusters of cocci

streptococci

chains of cocci

flagella and axial filaments

external bacterial structures (2) used for motility

fimbriae

small, bristle-like fibers that sprout off the surface of many bacterial cells and allow for adhesion between cells, allowing bacteria to colonize and infect host tissues

pili

used in cell-to-cell contact between bacterial cells (usually for the transfer of genetic material)

capsule

a type of glycocalyx that is formed by many pathogenic bacteria to protect against phagocytosis and produces a sticky character to colonies on agar

biofilms

groups of bacteria attached to a particular coating

ex: plague on teeth

cell envelope

part of bacterial cell that lies outside the cytoplasm

composed of: cell wall, cytoplasmic membrane, and (sometimes) outer membrane

bacterial cell wall

determines the shape of a bacterium, provides support and protection, composed of peptidoglycan (contributes rigidity)

gram-positive cell wall

cell wall that lacks outer membrane

crystal violet

1st step of Gram staining

all cells appear purple

Gram’s iodine

2nd step of Gram staining

the mordant (stabilizer) causes the dye to form large complexes in the cell wall

alcohol

3rd step of Gram staining

dissolves the lipids in the outer membrane and removes dye from the gram-negative cells

all appear purple (+) or colorless (-)

safranin (red dye)

4th step of Gram staining

dyes colorless (-) cells to make their presence apparent

cytoplasm

internal bacterial structure

composed of sugars, amino acids, and salts and is 70-80% water

ribosomes

sites of protein synthesis

composed of rRNA (60%) and protein (40%)

endospores

dormant bodies that can resist extremes of heat, drying, freezing, radiation, chemicals, etc.

exist in either a dormant or vegetative stage

Bergey’s Manual of Systematic Bacteriology

classification system for bacteria and archaea that is based on rRNA sequencing

Bergey’s Manual of Determinative Bacteriology

classification system for bacteria and archaea based on phenotypic characteristics

chitin, no cell wall

fungi cell walls are made of ___ while protozoa and helminths have ___

nucleus

internal eukaryotic structure that contains DNA and is separated from the cytoplasm by an envelope

endoplasmic reticulum

eukaryotic internal structure that is a series of membrane tunnels used in transport and storage

may be smooth or rough

Golgi body

eukaryotic internal structure that is the site of protein modification and shipping

vacuoles

internal eukaryotic structure that are sacs containing fluid or solid particles

mitochondria

internal eukaryotic structure that generates ATP for the cell

cytoskeleton

internal eukaryotic structure made of protein strands for structure, movement, and transport

yeasts

a type of fungal cell

• round-oval shape
• asexual reproduction (budding)

hyphae

long, threadlike cells found in the bodies of filamentous fungi

makes up the mycelium

mycelium

woven, intertwining mass of hyphae that makes up the body or colony of a mold

pseudohypha

chain of yeast cells

three types of fungal disease in humans

1. community-acquired infections
2. hospital-associated infections
3. opportunistic infections

trophozoite

motile feeding stage of protozoa that requires ample food and moisture to stay active

cyst

dormant, resting stage of protozoa when conditions in the environment become unfavorable

helminth life cycle

fertilized egg, larva, adult

human genome

8% of the ___ consists of sequences that come from viruses

active/inactive

terms used to describe viruses instead of alive/dead

properties of viruses

• ubiquitous in nature
• ultramicroscopic in size
• not cells, compact and economical structure
• do not independently fulfill characteristics of life
• basic structure: protein shell capsid that surrounds nucleic acid core
• nucleic acid that is either DNA or RNA (not both)
• lacks enzymes for most metabolic processes and lacks machinery for synthesizing proteins

capsid

a protein shell that surrounds viral nucleic acid

spikes

projections from the nucleocapsid or envelope of a virus that allows it to dock with host cells

virion

a fully formed virus that is able to establish an infection

helical, icosahedral

two types of viral capsids

phases of viral replication

1. adsorption
2. penetration
3. uncoating
4. synthesis
5. assmebly
6. release