exam 1 content Flashcards
From a human standpoint, what are some negative things that microorganisms do?
disease, spoilage, and infection
what are some positive things that microorganisms do?
make antibiotics, make foods/beverages, waste decomposition, nutrient cycling
What are the major groups or categories of microorganisms? How are they similar to one another? How are they different from one another?
- Viruses, bacteria, archaea, fungi, and protists. - All of them are of microscopic size, they can all be found in almost every environment on the Earth, and they play key roles in nutrient cycling, decomposition, and food chains.
- They differ in that bacteria and archaea are prokaryotic and single-celled. Fungi and protists are eukaryotic. Viruses are non-living and require a host cell to reproduce.
What are the usual sizes of prokaryotic cells, eukaryotic cells, and viruses?
Prokaryotic cells are small between 0.1-5 micrometers, eukaryotic cells between 10-100 micrometers, and viruses between 20-400 nanometers.
How do you do metric system unit conversions; and what do the prefixes in metric system nomenclature stand for (milli-, micro-, nano-, etc.) ?
Millimeter (mm) – one 1/1000 of a meter
Micrometer (um)– one 1/1000 of a millimeter
Nanometer (nm) – one 1/1000 of a micrometer
who Introduced agar-agar as a solidifying gel in culture media.
Walter and Fanny Hesse
who Demonstrated that the disease anthrax is caused by a bacterium and devised postulates for establishing causative relationship between a microbe and a disease
robert koch
Developed a microbial control technique for preserving food and liquid.
louis pasteur
who Developed the first chemotherapeutic agent, for treating syphilis.
paul erlich
who published first work on antiseptic surgery
joseph lister
who Developed staining method for differentiating between groups of bacteria.
christian gram
Compounds unique to bacteria or certain other microbial groups can be detected by “alarm systems” in the body.
True
In a cytoplasmic membrane, the lipid tails are ______ and face towards the inside of the cell, while the phosphate heads are ______, and face towards the environment.
hydrophobic, hydrophilic
The cytoplasmic membrane of prokaryotic cells plays a crucial role in transforming energy. This means that the membrane is directly involved in ______.
converting the energy of sunlight or food into ATP
When there are more ions inside a cell than are present in the extracellular environment, a mechanism that can be used to move more ions into the cell requires ______ the cell, and moves the ion ______ the concentration gradient.
energy from, against
Cells use a process called _______
to move certain enzymes and other proteins they synthesize out of the cell.
secretion, protein secretion, or exocytosis
Bacterial components unique to bacteria are potential targets for antibacterial medications used to treat infectious diseases.
true
Differences in cell wall structure can be used to identify two groups of bacteria:
gram-positive (thick PG wall) and gram-negative (thin PG wall and outer layer with periplasmic space between filled with periplasm (proteins, enzymes)
energy transformation for prokaryotes`
cytoplasmic membrane plays a critical role in transforming energy
energy transformation for eukaryotes`
membrane bound organelles transform energy
Moving a substance against the concentration gradient means
moving it from a region of low concentration to high concentration
Some secreted proteins will act as _______
outside of the cell and catalyze the breakdown of large macromolecules.
enzymes
the function of the cell wall is
to prevent the cell wall from bursting
In archaea, the cell wall is composed mostly of ______, while in bacteria, the cell wall contains ______.
pseudopeptidoglycan, peptidoglycan
In a bacterium, pili are typically ______ than flagella.
shorter and thinner
Movement of substance against the concentration gradient involves energy in the form of _____ or ______.
ATP; proton motive force
The bacterial chromosome ______.
is a double helix in the shape of a circle
bacterial fimbriae are involved in
attachment
Bacterial gas vesicles are composed of ______.
a protein coat
a typical bacterium possesses
a single, circular chromosome
Gas vesicles found in ______ bacteria are essential for adjusting ______.
aquatic, buoyancy
The eukaryotic ribosome found outside the mitochondria is best described as ______.
40S + 60S = 80S
The ribosomes of ______ are 70S whereas the ribosomes of ______ are 80S.
bacteria, eukaryotes
Light microscopes that are routinely used in the laboratory can magnify images about ______.
1,000X
Eukaryotic flagella and cilia are ______.
flexible structures, covered by cytoplasmic membrane, composed of long microtubules
A bright-field microscope ______.
transmits light through a speciman
Select three specimens that could be viewed using a compound light microscope.
bacteria, protozoa, and cells
A(n) _______
force microscope uses a very sharp scanning probe to produce detailed images of surfaces with a very high resolving power.
atomic
Immunofluorescence involves using
an antibody with a fluorescent dye attached to it
Compared to an electron microscope, the atomic force microscope has ______.
a higher resolving power and does not require special sample preperation
Which of the following statements about immunofluorescence is FALSE?
uses the dye methylene blue
what is an angstrom and what fraction of a meter is it
o.1 nm, 10^-10 meter
relative size of subatomic particles
10^-15 m
relative size of atoms
0.1-0.5 nm
relative size of molecules
0.1`-0.275 nm
relative size of macromolecules
100-10,000 angstroms
relative size of viruses
20-400 nm
relative size of prokaryotic cells
0.1-5 um
relative size of protists
protozoa - 10-1000 um
algae - 10-500 um
relative size of fungi
yeast - 5-30 um
mold cell - 5-100 um
relative size of eukaryotic cells
5-100 um (some 200 um)
Rank the size categories listed above, from smallest particles to largest particles
- Subatomic particles
- Atoms
- Molecules
- Macromolecules
- Viruses
- Prokaryotic cells
- Yeast
- Mold cell
- Eukaryotic cells
- Algae
- Protozoa
How does yeast differ from molds (also called filamentous fungi)?
Yeast is single-celled while molds are formed by networks of cells. Yeast is a bidding fungus and mold grows as multiple tubular branches.
What types of microscopes (if any) would be useful to visualize these different particles, molecules, or microbes?
compound or simple
What microbes are the exceptions (that we talked about in lecture) to these general size ranges? What are the scientific genus names of the two unusually large prokaryotes mentioned in lecture?
Prokaryotes thiomargarita namibiensis (200 um) and thiomargarita magnifica (1.0 cm long) and epulopiscium.
What are mimiviruses, and why are they unusual?
Mimiviruses are considered giant viruses and typically infect amoebae. Size range – 370-600 nm. Have 1-2 millions base pairs
What are pandoraviruses, and why are they unusual?
They are as big as bacteria with complex genomes (only 30% if genes match that of existing genes) . Can get up to 1000 nanometers in size (1 micrometer
What is the estimated size range of viral particles of the SARS covid-19
60-140 nm
For the N95 particle mask shown on the PowerPoint slide in lecture, what size of particles will be filtered out and with what percent efficiency?
95% of particles 0.3 microns or bigger
What is the diameter of a methanethiol molecule in nm? In angstroms? Will such a gas be filtered out/retained by a N95 mask?
0.4 nm
4 angstroms
NOT filter it
colonization
the act of a microorganism growing and multiplying in/on a host without interaction between them (no immune/clinical response)
infection
when a microorganism enters the body and multiplies
subclinical
an infection/diseases that is not detectable through symptoms or usual tests
infectious disease
a microorganism-caused disease that spreads to a person
symptoms
changes in the body that a person feels or experiences that could be linked to infection or a disease
signs
the objective, observable, and measurable indicators of the presence of microorganisms
primary pathogen
a microbe capable of causing disease in a host regardless of the host’s immune system or microbiota.
opportunistic pathogen
– a microbe capable of causing disease in a host that was a weakened immune system.
virulence
the ability of a microorganism to cause damage to a host
virulence factors
specific molecules produced by a pathogen that enable it to infect a host, establish itself within the body, and cause disease through specific mechanisms.
communicable/contagious disease
an illness that can be spread through blood-blood contact, breathing in an airborne virus, or being bitten by an insect.
infectious dose
– the amount of a pathogen required to cause infection
incubation period
the time it takes for symptoms to appear
illness
– condition when a microorganism damages the body’s normal status
convalenscence
– the final stage of infection when person recovers from an illness
acute infection
short-term illness`
chronic infection
long-term illness
latent infection
virus present in the body that is no longer producing more virus, typically asymptomatic
localized infection
an infection confined to only a specific area of the body
systemic infection
an infection now in the bloodstream and affecting other parts of the body or the entire body.
bacteremia
a medical condition where bacteria are present in the bloodstream
sepsis`
the body’s extreme (improper) response to an infection
shock
a condition where the body is in circulatory failure leading to inadequate oxygen delivery.
toxemia
– a condition where toxins are present in the bloodstream
viremia
– a condition where viruses are present in the bloodstream
What is the estimated average number of human eukaryotic cells in a human being?
30 trillion
What is the estimated average number of human prokaryotic cells in a human being?
38 trillion
microbiome
community of microorganisms in a particular development
virome
a collection of viruses in a particular development
What is the rule of thumb for the estimated number of virus particles versus cells on Earth/in most environments?
there are 10 times more viruses present than cellular microbes
How many different human viruses on average are present in each human individual?
71
How many herpes viruses are present in over 90% of the population of the United States?
12
What is meant by “Germ Theory” of disease? What is meant by the “Terrain Theory” of disease?
Germ theory – A pathogen is the principal cause of the disease while eother factors such as environmental & hereditary factors also influence the severity of the disease.
Terrain theory – Diseases are results of our internal environment and its ability to maintain homeostasis against outside threats
Give a definition of “Terrain” as it relates to disease
the internal environment of our body
taxonomy
the study of organizing, classifying, and naming living things
- What are the 3 Domains or Superkingdoms of the Woese scheme for classifying cellular life?
Prokaryotic domains are 1) bacteria and 2) archaea and all ofther cellular life is 3) eukarya
What are some general key traits/major characteristics of microorganisms that are mentioned in Topic 2
Reproduce by asexual reproduction, able to reproduce quickly, large numbers found in many environments, can undergo genetic change through mutation or gene transfer events, many communication by producing/receiving specific molecules/chemicals, and only a small number of microbial species can be grown in isolation in the lab.
vibrio cholerae (cholera
gram-negative
causes profuse diarrhea by producing extracellular
toxin, dehydration, electrolyte imbalance.
transmitted by fecal-oral route by contaminated water/food
site of infection - SI
treatment - oral rehydration to replace water and electrolytes, antibiotic therapy
how long have prokaryotes been present on Earth, how does this compare to how long humans have been on Earth?
around 3.8 billion years ago; Humans have only been present about 190,000-200,000 years ago. Less than 0.01% of Earth’s history
What type of prokaryotes left fossil remnants in some soft shale rocks that are about 3.5 billion years old?
cyanobacteria (blue-green algae)
When was the existence of microbes first noted by humans using a microscope?
Around 1676 by Antoni van Leeuwenhoek
What is Black Death (plague), what causes it, and why is it considered to have had a major effect on human history?
A devastating pandemic caused by the bacterium, Yersinia pestis, and potentially wiped out 30-60% of Europe’s population.
What types of microbes did van Leeuwenhoek observe and describe
bacteria, protozoans, and yeast
what did van Leeuwenhoek use to to observe these microbes
glass lenses, specimen holder, focus screw, and handle to make a microscope
What infectious disease did Semmelweis try to control or eradicate in the hospital facilities he had authority over?
puerperal fever (childbed fever)
what method did Semmelweis use to attempt to control childbed disease
directed medical students to wash their hands with calcium hypochlorite when switching tasks
which bacterium caused childbed fever
streptococcus pyogenes
What infectious disease did Snow try to control or eradicate in an area of London?
cholera
what method to Snow use to try controlling cholera spread
remove the pump’s hand and disable the pump
name of bacterium that caused cholera
vibrio cholerae
what are of study did Snow help establish
epidemiology
What infectious disease did Jenner try to control or eradicate in an area of London? What type of microbe causes this disease? What method did he use to attempt disease control?
He developed a vaccine against smallpox by inoculating people with cowpox virus. Smallpox microbes are variola virus.
What were the major experiments that Pasteur carried out which led to major discoveries in Microbiology?
Pasteur developed pasteurization that kills harmful microbes in food, disproved spontaneous generation using his swan-neck flask, identifying fermentation process, and created vaccines preventing fowl cholera, anthrax, and rabies.
What are the details and significance of Pasteur’s experiments involving: alcohol fermentation to produce beer and wine; spontaneous generation; silkworm disease; rabies vaccine
we use these processes now
Which of Pasteur’s experiments pointed out the significance of airborne microorganisms?
Swan-neck flask experiment that showed that his instrument prevent dust particles containing microbes from reaching the broth.
What were the major techniques that Koch and his co-workers devised to enable them to study microorganisms, especially some culturable bacteria?
The major techniques were solid agar media and pure cultures, straining techniques, animal inoculation, and microphotography.
what are Koch’s postulates?
A set of 4 criteria used to determine if a microorganism is responsible for a disease
how are the postulates carried out
- The microorganism must be present in people who have the disease, but not in people who are healthy.
- The microorganism must be isolated from a person who has the disease.
- The microorganism must cause the disease when introduced to a healthy person
- The microorganism must be re-isolated from the person who became sick after being introduced to it, and it must be the same microorganism that was originally isolated.
what materials are need to the postulates
rats, petri dishes, instrument to inoculate test subjects
Using the postulates, which pathogenic bacteria did Koch determine to cause which specific infectious diseases?
Bacillus anthracis causes anthrax
Vibrio cholerae causes cholera
Mycobacterium tuberculosis causes tuberculosis
What method did Koch and his coworkers use to obtain pure cultures of bacteria?
Plate technique which involved growing bacteria on a solid agar medium in a petri dish, allowing colonies to form and isolating them to cultivate a single, pure bacterial strain.
What were some of the common research interests that Pasteur and Koch shared?
Identifying the causative agents of infections diseases and developing methods to understand and combat them through vaccination
Why was surgery before Lister a more dangerous, uncertain procedure than it is today for patients?
Many people died from post-operative infections due to lack of medicinal preventions.
What influence did Pasteur’s work have on Lister’s?
Pasteur’s work on microorganisms causing infections/diseases convinced Lister than microorganisms were causing postoperative infections on surgical patients.
How did the ability of certain chemicals to remove foul odors affect Lister’s ideas and work?
Carbolic acid removed foul orders from sewage so Lister believed it could kill the microorganisms causing postoperative infections
How were Lister’s steps to carry out antiseptic surgery later modified to enable aseptic surgery?
Using phenol (carbolic acid) as a mist in air surrounding the procedure and socked surgical instruments/dressings, surgeon hands in phenol.
Which steps involved in aseptic technique are related directly to the work that Semmelweis, Pasteur, Koch, and Lister carried out?
Semmelweis promoted handwashing with antiseptic solutions now used in aseptic techniques. Pasteur laid the groundwork for understanding that microorganisms play a role in disease and preventable infection, making the aseptic technique needed to be created. Koch did research on bacterial growth and control, we sterilize instruments/equipment using heat or chemicals before use to prevent bacterial growth. Lister used carbolic acid to disinfect wounds and instruments which is a part of the aseptic technique
what is phylogeny, phylogenetic tree
- evolutionary relatedness
- archaea, bacteria, and eukarya
How does Whittaker’s 5 Kingdom scheme differ from Woese’s 3 Superkingdom (3 Domain) scheme?
Was based on obvious morphological differences and does not reflect recent genetic insights of rRNA data indicating plants and animals more closely related than archaea and bacteria.
How does Whittaker’s 5 Kingdom scheme differ from Woese’s 3 Superkingdom (3 Domain) scheme?
Was based on obvious morphological differences and does not reflect recent genetic insights of rRNA data indicating plants and animals more closely related than archaea and bacteria.
How does complementary base pairing account for the secondary structure of tRNA and rRNA?
Allows the single-stranded RNA molecules to fold back on themselves, formed hydrogen bonds between bases
What are the major traits of procaryotic (also spelled “prokaryotic”) cells?
o DNA not enclosed within a nuclear membrane
o No membrane-bound organelles
o Domain bacteria cell walls usually made of peptidoglycan (PG)
o Cells usually divide by binary fission
o Ribosomes are 70S in size
S = Svedberg unit affected by size, mass, & shape of particle
What are the most common shapes for prokaryotic cells to have?
o Spherical/coccus
o Cylindrical
o Coccobacillus
o Spiral
Cell wall & cytoskeleton determine cell shape
What are some of the most common arrangements of prokaryotic cells?
Tetrads, diplococci, streptococci
How does cell arrangement sometimes indicate what the planes of cell division in cocci are? What are some of the common arrangements of cocci?
o The cell arrangement indicates the typical division the cocci takes.
Staphylococcus – irregular bunches
Streptococcus - chains
Diplococcus - pairs
Sarcina – packets of eight or more
Tetracoccus – four cells & more in a sheet
How do spirilla differ from spirochetes?
Spirochetes are flexible spirals with axial filaments (periplasmic flagella) inside sheath, can have 3-70 helical turns. Spirilla are rigid helix with polar flagella, rotate like corkscrews, can have 1-20 helical turns.
What is peptidoglycan (PG)? What is it composed of?
Carbohydrate backbone (glycan chains), peptide cross bridge.
NAM and NAG
What are peptides, what are they composed of, and what type of bond is found in peptides to join amino acids together?
Peptide bonds are short chains of amino acids linked together by covalent bonds
What chemical linkages do penicillin & lysozyme affect in PG?
Penicillin – an antibiotic, inhibits peptide bond formation in growing cells.
Lysozyme – an enzyme in tears, mucus, saliva; causes hydrolysis of glycosidic bonds
cylindrical (rod) bacteria arrangements
single, pairs, chains, or palisade
vibrios
bent rods, comma shaped
difference between gram positive and negative bacterial walls
positive - thick PG layers, very sensitive to lysozyme, penicillin
negative - thin PG layer, shielded by OM, less sensitive to lysozyme, penicillin
one vaccine that Louis pasteur developed
afforded protection against rabies
In the five kingdom classification scheme of Whittaker, the kingdom Protista
includes the protozoa and algae
2,500 micrometers (µm) is equal to how many millimeters (mm)?
2.5
If the holes in a piece of latex rubber are 200 manometers (nm) in diameter, which of the following are
most likely to pass through the rubber?
viruses
The range of wavelengths of the electromagnetic spectrum which are visible to the human eye extend
from approximately
400 to 800 nm
Crystal violet is a basic dye because
its colored ion (chromophore) is cationic
A microscope with a total magnification ability of 1,900.0 X and a 20 X ocular would need to have an objective of
95 X
How does the wavelength of electromagnetic radiation used for microscopy affect the resolution?
the shorter the wavelength, the better the resolution
The Svedberg unit (S) values for complete ribosomes are
70S for prokaryotic ribosomes and 80S for eukaryotic non-organeller ribosomes
peptidoglycan is found only
the cell walls of the prokaryoties, eubacteria
How are transmission electron microscopy (TEM) and scanning electron microscopy (SEM) similar?
both use magnets to focus electrons, and both usually only view dead specimens in a vacuum
Procaryotic spirilla differ from spirochetes in that
motile spirilla are rigid and have flagella to allow movement; spirochetes are more flexible
and have axial filaments.
Penicillin damages peptidoglycan by
inhibiting peptide bond formation.
Which of the following environments has the overall same concentration of solutes as that of the cytoplasm of a cell in that environment?
isotonic environment
Which of the following is part of a Gram negative eubacterium, but not of a Gram positive eubacterium?
outer membrane
Which of the following components of the Gram negative eubacterial cell is most likely to cause fever in humans?
lipid A - endotoxin
Bacterial protoplasts differ from bacterial spheroplasts in that
protoplasts have had all the cell wall material removed, whereas spheroplasts have some cell
wall material remaining.
light microscope
uses visible light of 400-800 nm wavelength
upper limit is 1500-2000 X magnification; res of 200 nm
simple - 1 lens
compound - 2 lenses
compound light microscope - bright-field
transmits light through the specimen
electron microscope
uses electron beams
uses magnets instead of glass lenses for focus
magnification up to 100,000X, res of 0.5nm
image viewed through fluorescent screen
electron microscope - scanning electron
electrons bound off metal-treated specimen’s surface, are collected, and create 3D image
mag - 100,000-300,000 X, resolution of 2 nm
electron microscope - transmission electron
electrons pass through thin metal treated specimen and 2D image formed
Mag - 1,000,000 X. Res - 0.2nm
streptococcus pyogenes
bacteria (prokaryote)
coccus (sphere), non-motile, in pairs or chains
gram-positive
colonies are beta-hemolytic in blood agar plate
streptococcus pyogenes can cause
Scarlet fever
-Rheumatic fever
-Necrotizing fascitis
-Impetigo
-Puerperal fever
-Toxic shock syndrome
- Streptoccal Pharyngitis (Strep throat)
what did john snow do
edward jenner
