Gram Staining, Lab Terms, and Microorganisms Flashcards
What is the gram + cell wall made up of ?
thick layer of peptidoglycan
- associated with teichoic acids
Why is staining the cells important ?
ensure we can see all the neccessary cells
Is the cell wall thicker in the Gram + or - ?
gram +
What cell retains the crystal violet ?
gram +
What cells retains the safranin which turns it pink ?
gram -
In the gram staining process what causes the forming of the large molecule ?
the application of the iodine (mordant) to the crystal violet
- 2nd step
What is the purpose of the application of crystal violet ?
to permeate the bacterial cells
In the gram + why does the molecule formed, because of the crystal violet and iodine , not able to exit the cell ?
because the cell wall is so thick
- easy for crystal violet to get in but once joined it can’t get out
What is the gram - cell wall made up of ?
thin layer of peptidoglycan
- has a outer membrane with periplasmic spaces
Why is the crystal violet and iodine molecule able to get out of the Gram - cell ?
because it has a outer membrane with periplasmic spaces
- can escape when decolorized
What happens if you leave the decolorizer on for too long ?
can cause the purple of the gram + to lighten up which we don’t want
What is the primary stain ?
crystal violet
What is the mordent ?
gram’s iodine
What is the decolorizer ?
acetone alcohol
What is the counter stain ?
safranin
What is the purpose of applying the acetone alcohol ?
causes the stain to escape some bacterial cell wall rendering them unstained/colorless
- turns gram - clear
What is the purpose of the safranin ?
adds color to the cells that were decolorized
- colorizes the gram - pink
What is the purpose of the grams iodine ?
binds with the stain inside the cell wall making a larger molecule
Is there periplasmic spaces in both gram + and - ?
- present in all gram - which allows things to move out of gram -
- present in some gram +
What is the effect of penicillin on the cell wall ?
inhibits the production of the peptidoglycan layer
Is penicillin more effective on gram + or - ?
gram +
- except for staphylococci
Why is penicillin less effective on gram - ?
outer membrane prevents penicillin from reaching the peptidoglycan layer
What determines the effectiveness of penicillin on the cell wall ?
the composition of the cell wall
What are the 3 modes of transmissibility of an infectious disease ?
- contact transmission
- vehicle transmission
- vector transmission
What is contact transmission ?
- direct: person to person (kissing, touching, sexual, etc)
- indirect: one host to another by fomites (inanimate objects)- needles, toothbrushes, drinking glasses, doorknobs, etc
- droplet: droplet of mucus that exit mouth/nares during coughing, sneezing or exhaling (cold and flu)
What is vehicle transmission ?
spread of pathogens via air, drinking water, and food
- also blood and body fluids handled outside the body
- airborne, waterborne, blood and body fluids
What is vector transmission ?
animals that transmit diseases from one host to another
- biological: vectors affecting human are biting arthropods (mosquitos ticks, lice, fleas)
- mechanical: vectors passively carry pathogens to new hosts on their feet or other body part (houseflies, cockroaches)
What is a epidemic ?
appearance of infectious disease or condition which attacks many people at the same time in same geographical location
- flu, food poison
What is a pandemic ?
epidemic that occurs simultaneously with on more than one continent
- AIDS, COVID
What is a endemic ?
a disease peculiar to and recurring continuously in a particular locality or population
- Histplasmosis-Ohio Valley
What does contagious mean ?
communicable disease that is easily transmitted from a reservoir or person
- common cold, legionnaires disease
What is epidemiology ?
study of the occurence, distribution, and spread of disease in humans
- Bird flu, seasonal flu, tracking SARS
What does incidence mean ?
the number of new cases of a disease in a given area or population during a given period of time
What does prevalence mean ?
the total number of cases, new and existing in a given area of population during a given period of time
How are microorganisms our foe ?
- leading cause of illness and death
- costs us billions of dollars in health care costs
- causes the rise of infectious diseases
What are some reasons for the rise in infectious diseases ?
- travel
- lax in vaccinating children because disease is no longer common
- use of medication to make life longer
- development of drug resistance
How are microorganisms our friends ?
- breakdown of food in the gut
- produce foods like yogurt, cheese, wine, breads
- used to make vitamins, insulin, drugs
- decompose waste
- recycle nutrients back into Earth
- used as food source for other organisms
- make chemical products like acetone, glycerin, enzymes, alcohols
- agriculture
What is a broth ?
liquid medium that contains various nutrients and is used to culture bacteria and other microorganisms in culture
What is a Agar ?
gelatinous material derived from algae, specifically used as a culture medium of bacteria and other cells for diagnostic or laboratory experiments purposed
- melts are 85 C
What does deep mean ?
used for culture where you need a deep inoculation into solid medium (gelatin or agar) that is used especially for the growth of anaerobic bacteria
What are slants ?
a culture made on the slanting surface of a solidified medium (agar based) in a test tube that has been tilted to provide a greater area for growth
What are plates ?
petri dish that contains a solid growth medium, typically agar plus nutrients used to culture small organisms such as microorganisms
What is incubation ?
act of maintaining controlled environmental conditions for the purpose of favoring growth or development of microbial cultures
What is a colony ?
visible mass of microorganisms all originating from a single mother cell, therefore a colony constitutes a clone of bacteria all genetically alike
What is picking colonies ?
selecting a colony from a plate and transferring it to another media or a slide
What is a loop ?
simple tool used mainly by microbiologists to retrieve an inoculum from a culture of microorganisms
- used for cultivation of microbes on plates by transferring inoculum for streaking
What is a needle ?
used in the field of microbio to transfer and inoculate living microorganisms
What is a Bunsen Burner ?
small adjustable gas burner used in labs
