Lab practical micro

What are the cultural characteristcs in broth?

- sediment, turbid, pellicle

What Typical disinfectants used in the laboratory?

1. Halogens - sodium hypochlorite (bleach) 2. Phenolics - Lysol 3. Quats (quaternary ammonium compounds) - Zephiran chloride 4. Alcohols - isopropanol

When does agar melt?

100 c

What wavelength is used to have maximum lethality?

265 nm. wavelength used in lab experiments was 254 nm

When does agar solidify?

40 degrees c

What is the agar holding temperature?

50 c (temperature of water bath)

What temperature do you pour agar?

>40 C and < 50 C

What are the cultural characteristics agar plates?

A. colony shape, margin, size, elevation, pigmentation (color, diffusible or non-diffusible), ecophenotypic variation.

What does Trypanosoma gambiense cause? Kingdom? Domain?

African sleeping sickness. Protista. eukarya

From where does agarose component come?

Agarose is purified from marine algae

. Circle the correct choice for each of the following statements: As wavelength decreases/increases, energy increases. As wavelength decreases/increases, energy decreases. Shorter/longer wavelengths have higher energy. Shorter/longer wavelengths have lower energy. Therefore, wavelength and energy are directly/inversely proportional.

As wavelength decreases, energy increases. As wavelength increases, energy decreases. Shorter wavelengths have higher energy. longer wavelengths have lower energy. wavelength and energy are inversely proportional.

Endospore bacteria are members of what two genera?

Bacillus and Clostridium

Example of each Obligate Aerobe: Grows only at the surface Microaerophile: Grows just below the surface Facultative Anaerobe: Grows throughout, but greatest growth at surface. Aerotolerant Anaerobe: Grows with or without oxygen. Dispersed equally throughout the medium. Obligate Anaerobe: G

Bacillus subtilis is an obligate aerobe is a microaerophile is a fucultative anaerobe is an aerotolerant anaerobe is an obligate anaerobe

Why is Woese's taxonomic method of classification superior to Whittaker's method for determining relatedness of living organisms?

By comparing the molecular sequence of nucleotide bases (A,U,G,C) in ribosomal ribonucleic acid (rRNA), a highly conserved molecule that very rarely changes, Woese classified all living organisms into three domains

What does UV light do to DNA?

Causes Thymine and Cytosine dimers

List two (2) pathogens that are spore-formers and identify the diseases that they cause

Clostridium tetani, causative agent of tetanus, Bacillus anthracis, the causative agent of anthrax

As magnification increases: Field of view increases/decreases (Circle one.) Length of objective increases/decreases (Circle one.) Working distance increases/decreases (Circle one.) Amount of light required increases/decreases (Circle one.) Depth of field increases/decreases (Circle one.) Resolution increases/decreases (Circle one.)

Decreases field of view Increase in length of objective decrease in working distance increase in amount of light required decrease in depth of field increase in resolution

Penicillum notatum, what disease can they cause? Kingdom? Domain?

It is often non pathogenic but it could cause mycosis. Kingdom fungi. eukarya

What does Saccharomyces cerevisiae cause? Kingdom? Domain?

It rarely causes disease but malignancy can occur. Fungi. eukarya

State a consequence of pouring a plate at too low a temperature.

It will probably turn into a solid so it won't pour and lumps will occur.

Why is it important for microbiologists to understand the ubiquity of microbes?

Microorganisms are ubiquitous, but they do not generate spontaneously. It is the ubiquity of microorganisms that makes it so important to use sterile technique when working in the laboratory with sterile media or pure cultures.

Acid-fast bacteria that are members of what two genera?

Mycobacterium and nocordia

What could mycobacterium and nordia cause?

Mycobacterium could cause tuberculosis Nocordia causes nocodiosis

Differentiate between 'resident' normal flora and 'transient' flora.

Normal (resident) flora are microorganisms that are always present on or in a person and usually do not cause any disease. For instance, a lot of staphylococci inhabit your skin. ... Transient flora are episodic microorganisms found on or in a person.

What do the terms parfocal and parcentric mean?

Parfocal. This means that the focus for each lens is very similar. ex) Microscopes are designed to be parfocal. It will remain in focus as you change to other magnifications. Parcentric. This means that an object in the center of the field of view at one magnification is in the center of the field of view at any of the other magnifications.

What is a simple stain?

Procedure: Methylene Blue for 1 min., then rinse with tap water Demonstrates shape and arrangement only

.Name one genus and species that produces pigmented colonies when plated on agar

Pseudomonas Aeruginosa

What disease can mixed diatoms cause? Kingdom? Domain?

Some dinoflagellates produce neurotoxins that affect fish and shellfish and cause neurological disease in humans that consume them. Protista. eukarya

How is total magnification calculated when viewing a microscopic specimen?

To get the total magnification take the power of the objective (4X, 10X, 40x) and multiply by the power of the eyepiece, usually 10X

What does Trichinella spiralis cause? What kingdom does it belong to? What does it look like? Domain?

Trichinosis, animalia, eukarya

Which is the most energetic color in the visible light spectrum? Least energetic?

Violet is the most energetic while red is the least energetic

What does the index of refraction (refractive index) measure?

a measure of how light propagates through a material

What component in agar makes it solid?

agarose

Aspergillus niger disease how do they look like? kingdom? domain?

aspergillosis can be caused by aspergillus niger

What is Brownian movement?

continuous random movement of small molecules dissolved in liquid or gas

What are the cultural characteristics in agar slants?

even, irregular or spreading growth.

Rhizopus nigircans... how do they look like?

fungi... eukarya

What are other alternatives to determine bacterial motility

hanging drop - places a drop of culture onto a cover slip that is then inverted into the well of a depression slide and observed under a microscope. Once again, the organisms are given freedom to move around. motility agar- it is inoculated with microorganisms from a single stab of an inoculating needle, their motility can be observed by determining whether growth occurs outward from the inoculation site.

Common units of measurement in microbiology include 'mm', 'µm', and 'nm.' These are abbreviations, what is the full term for each. How are each of these mathematically related to 1 meter?

nm means nanometer 1 m = 1e+9 nm mm means milimeters 1 m = 1000 mm µm means micrometers 1 m =1,000,000

Where does rRNA function in the cell?

nucleolus

Define ubiquitous.

present, appearing, or found everywhere

How do disinfectants work?

protein denaturation, membrane permeability.

What is the purpose for heat fixation?

purposes are to kill the microorganisms and to induce adherence to the slide

Which of these properties of light are most important in microscopy?

refraction

What does 'X' mean, as in 10'X' or 100'X' Oil?

the magnification

What does crystal violet stain in a bacterial cell?

the peptidoglycan.

State a consequence of pouring a plate at too high a temperature.

to avoid a large amount of condensation forming on the lid of the petri dish when the hot agar is poured into a cold plate. Cooling also prevents hot agar from killing the microorganisms that were added to the plate

What is the function of the condenser lens? What is the function of the diaphragm?

to focus the light onto the specimen. to control the amount of light that enters the condenser.

Why is oil immersion necessary to view very small organisms, such as bacteria?

to reduce/eliminate refraction (bending) of light (Fig 1A.1), and thereby increase resolution of light, as it passes through the glass slide and into the glass 100X objective lens.

What is a means of directly determining motility?

wet mount