microbio exam 1

mbio 3401

Microbes occur spontaneously

False

Florence Nightingale

sanitation correlates with mortality

Loise Pasteur

microbial fermentation produces lactic acid or alcohol

Antonie Van Leewenhock

microbes observed under microscope

Hess

Developed agar for streak plates

(Robert) Koch Postulate

Germs cause disease

Edward Jenner

Cowpox vaccination prevents smallpox

Variolation

Using actual virus for immunization

Vaccination

Using a safer version for immunization

Alexander Fleming

Penicillin the successful antibiotic isolated from fungus

Roseline Franklin

Overall structure of DNA identified by X-ray diffraction analysis as double helix

Watson & Crick

bonding AT and GC base pairs

Resolution

smallest distance which two objects can be separated and still be distinguished (think minecraft FOV)

Detection

ability to determine presence of object

Magnification

increase in size of image

Bacillli

Rods

Cocci

spheres

Spiral forms

spirochetes

sprilla

Light is part of

electromagnetic radiation

Visible light

400-750nm

Electromagnetic radiation

Contrast between object and medium

Wavelength

Magnification

Do virus’ have color?

No but can be maybe, we just can’t see

Absorption

Photons energy is acquired by absorbing object

Reflection

wavefront bounces off surface of object

Refraction

bending of light, slows its speed

Scattering

wavefront interacts objects smaller than wavelength of light

Magnifications requires bending of light rays (refraction)

True

Wavefront of light shift direction as they enter higher refraction index

Parabolic curvature bends light rays to intersect at a focal point

Empty magnification

magnification wo increasing detail (blurry)

Compound microscope

system of multiple lenses designed for aberration

total magnification

magnification of ocular multiplied by that of the objective

Wet mount preparation

observe microbes by placing them in a drop of water on a slide with coverslip

advantage of wet mount

observation in natural state

disadvantage of wet mount

little contrast between cell and background

dries out

Fixation

cells are made to adhere to slide in fixed position

Staining

cells are given distinct color

Simple stain

adds dark color to cells

Methylene blue is most commonly used stain

True

Gram Stain

devised in 1884, differentiates gram+ and gram-

Acid fast stain

carbolfuchsin used to stain mycobacterium species

spore stain

malachite green used to detect spores of bacillus and clostridium

negative stain

colors the background which makes capsules more visible

excitation wavelength

absorbs light of a specific wavelength

emission wavelength

emits light at a longer wavelength

Flurosphere

chemical affinity

labeled antibodies

dna hybridization

gene fusion reporter

Dark field microscopy

enables visualized as halos of bright light against darkness

Phase contrast microscopy

exploits differences in refractive index between cytoplasm and surrounding medium or between different organelles

Electron microscopy (EM)

observes shapes of macromolecular structures (les expertise)

X-ray crystallography

tool for atom level detail of macromolecule

Electron behave like light waves

True

dilution streaking

loop dragged across agar plate

spread plate

tenfodl serial dilutions are performed on a liquid culture

complex media

nutrient rich but poorly defined

minimal defined media

nutrients essential for growth of given microbe

enriched media

specific blood components added

selective media

favor the growth of one organism over another

differential media

exploit differences between two species that grow equally well

growth factors

specific nutrients not required by other species

petroff hausser counting chamber

direct counting method

fluorescence activated cell sorter

AI tech direct counting

bacteria undergo cell differentiation

endospores, heterocysts, fruiting bodies, aerial hyphae

dehydration reaction

monomer joins another molecule of water is released that leads to a covalent bond. required investment of energy

hydrolysis reaction

polymer broken down to molecules of water used for each bond broken. required release of energy

competitive binding

irreversible binding to prevent binding of substrate

non comp binding

binding to allosteric site to change conformation of enzyme to reduce activity but does not affect affinity

uncomp binding

binding to allosteric site to change conformation to affect affinity

factors that influence diffusion

temp

solubility

surface area

concentration

structural support

used to anchor appendages such as flagella

hold on different layers of the cell envelope together

attachment to cytoskeleton

ion transport

manages ion gradient between interior and exterior cell will generate a gradient to store energy

cytoplasm

gel like network

cell membrane

encloses cytoplasm

cell wall

rigid structure external to cell membrane

nucleoid

non membrane bound area of the cytoplasm that contains the chromosome in the form of looped coils

flagellum

external helical filament whose rotary motor propels the cell

cell fractionation

method used to separate cellular components such as membranes, ribosomes, and flagella

How do prokaryotes protect the cell membrane?

cell envelope includes

at least one structural supporting later

bacterial cell wall

helps withstand turgor pressure, most are made up of peptidogylcan

sacculus

consists of a s single interlinked molecule

gram positive bacteria

thick cell wall (phylum firmicutes)

gram negative bacteria

thin well wall (phylum proteobacteria)

myobacteria

complex, multilayered cell wall (phylum actinobacteria)

the capsule

made of polysaccharide glycoprotein

protects cells from phagocytosis

S-layer

additional protective layer

bacteria undergo mitosis or meiosis

FALSE

septation

dna synthesis terminates and cell divides

managed by divisome

eukaryotic cells have a well defined nucleus

true

prokaryotic cells have a nucleoid that extends throughout the cytoplasm

true

bacteria has two kinds of daughter cells

one stationary one mobile

TipN

landmark protein correctly marks the site of a new cell pole and polar placement of flagella

isolated microbial cells carry proteins and nucleic acids

attractors of partner heterotrophs

phage decoys

vehicles for DNA transfer

thylakoids

folded intracellular membranes found in photosynthetic bacteria

carboxysomes

polyhedral bodies packed with enzyme rubisco for CO2 fixation

gas vesicle

protein bound gas filled structure increase buoyancy

storage granules

glycogen

sulfur globules

chemotaxis

movement of a bacterium in response to chemical gradients

CCW rotation

“random walk”