Exam 1
Some pathogens can have more than one portal of entry. Pick the pair of words that will make the following sentence correct. HIV can be transmitted via the _____ route during sexual contact or via the _____ route during needle sharing.
urogenital; parenteral
Match the following historical figures to his/her accomplishment.
Louis Pasteur: Helped disproved spontaneous generation, preservation of beverages, rabies vaccine, discovered fermentation carried out by microbes Joseph Lister: First to routinely use disinfectant during surgery, and is considered the father of antiseptic surgery Ignaz Semmelweiss: Linked puerperal fever to "cadaver particles," advocated washing hands before examining next patient, implemented preliminary aseptic techniques Alexander Fleming: Discovered lysozyme and linked bacterial growth inhibition by the mold Penicillium Robert Koch: Developed postulates to confirm the germ theory of disease Robert Hooke: Constructed the first microscope, and was first to observe and describe cells in Micrographia, coined the term "cell" Antonie Leeuwenhoek: Cloth merchant, developed more powerful microscope enabling him to first see and describe bacteria, called them "animalcules" Edward Jenner: Developed first small pox vaccine by administering cowpox to patients after observing milk maids were often immune to small pox
These three graphs show the incidence of three vaccine-preventable diseases in the United States. Which of the following statements is true?
Measles and mumps have shown a general decline over time, while pertussis has recently increased.
Which of the following correctly explains how archaea differ from bacteria and eukaryotes?
No archaea are currently known to be capable of pathogenesis.
Select all the bacteria that have a waxy mycolic acid in their cell wall.
Norcardia asteroides Mycobacterium leprae
Typhoid Mary was a female cook in the New York region in the early 1900s. She was found to be a carrier of typhoid and spread it through her cooking. She was known for being quite unhygienic, not washing her hands after bowel movements, often causing many of the patrons to become ill with typhoid, too. What type of infection cycle does this illustrate?
vehicle transmission
Consider the figure below. The arrow pointing from cyanobacteria to plants and algae indicates that, according to the endosymbiotic origin of eukaryotic cells, cyanobacteria ...
were internalized by early eukaryotic cells to form the chloroplast present in plants and algae.
A disease that can spread to humans from nonhuman animals is known as a ________ disease.
zoonotic
Koch's Postulates
· 1st postulate: microorganism or pathogen must be present in all cases of disease and that that organism must not be found in healthy animals · 2nd postulate: pathogen must be isolated from the diseased host and grown in a pure culture · 3rd postulate: Pathogen from the pure culture must cause the same infectious disease when it is inoculated into a new healthy susceptible animal · 4th postulate: pathogen must be reisolated from the new host and shown to be the same as the originally inoculated pathogen
exceptions to Koch's postulates
· Asymptomatic infectious disease · Not all microbes can be grown in-vitro · More than one microbe produces the same disease · Diseases caused by combinations of pathogens · One microbe that causes multiple diseases · Strictly human diseases with no animal model · Diseases in which pathogens have been ignored
How do humans use microorganisms?
· Food / beverage production · Antibiotics · Industrial o Acetone, alcohol · Biotechnology / Genetic engineering o Bioremediation - unicellular organisms · Why are microorganisms especially useful in research? o Share important features of larger organisms o Simple structures o Reproduce quickly o Large number of offspring o Reasonable cost o Minimizes animal testing o Genetic code universal
"universal precautions"
· Handwashing · Barrier precautions - PPE · Needlestick precautions · Decontamination of equipment · Discard single use materials o Biohazard · Healthcare workers with draining skin or mucous membrane lesions must refrain from handling patients
The organism shown here as drawn by Robert Hooke is a(n) ....
eukaryote
Laura has a bacterial infection in her urethra, most likely Escherichia coli. How are the bacteria able to stay attached to the urethra, even during the full force of urination?
fimbriae
Which of the following is NOT a function of the cell membrane?
RNA production
The image below shows the effects of cholera toxin on intestinal cells. Which numbered arrow indicates the step of the toxin entering a cell via endocytosis?
2
Identify three factors that may influence the rate of membrane transport.
- mass of molecules - temperature - solvent density - distance traveled
In the photo, you see aerosolization of a person's sneeze. The secretion particles are called droplet nuclei and are laden with bacteria or viral pathogens from the respiratory tract. These nuclei can be inhaled via direct contact transmission. How far away would someone need to stand to best limit the chance of exposure to these droplet nuclei?
10-15 feet
Koch's postulates are listed below. What is their correct order? 1. Same pathogen is isolated from newly diseased host 2. Pathogen is present in every case of disease 3. Pathogen is isolated from diseased host and grown in pure culture 4. Pathogen introduced into healthy susceptible host and the same disease occurs
2-3-4-1
Which of these is the best description of a microbe?
A living organism that requires a microscope to be seen
a) Differentiate spontaneous generation (abiogenesis) and biogenesis. b) Explain the argument supporters of the idea of spontaneous generation put forth, which led to Pasteur's experiment and how the piece of equipment shown in the image here was used to disprove the theory of spontaneous generation.
A) Spon: The idea that living things can come from non-living matter, an idea that lasted for 2000 years. Bio: The idea that life can only come from other life B)
A) Describe the plasma membrane fluid mosaic model. Discuss all major components of this structure and how they are arranged. B) What does the term amphipathic mean? Which molecule in the plasma membrane is amphipathic? How does it contribute to the spontaneous formation of a bilayer when placed in a aqueous solution?
A) A plasma membrane is composed of a phospholipid bilayer, embedded with proteins, lipoproteins, glycoproteins and sterols (or hopanoids in prokaryotes). B) The term amphipathic refers to a molecule that has both hydrophilic (polar) and hydrophobic (nonpolar) regions. Phospholipids are an example of amphipathic molecules. The phospholipid bilayer spontaneously forms due to hydrophobic/hydrophilic interactions between the amphipathic phospholipids. The phosphate head of the phospholipid interacts with the aqueous cytosol and extracellular fluid, while hydrophobic tails are pointed towards the center of the membrane.
Compare and contrast archaea, bacteria, and eukaryotes.
Archaea o Unicellular prokaryotes o Different ribosomal RNA sequence o Cell walls are made of Pseudomurein o Lipids found in the plasma membrane that are not found in eukaryotes or bacteria o Typically inhabit extreme or harsh environments such as in: o Steam vents and mud pots o Methane rich environments like swamps Bacteria o Unicellular o No membrane bound organelles or nucleus o Genetic material is found in the nucleoid o Cell wall is peptidoglycan o Important environmentally, commercially, and for our health o Crucial for boosting for immunity, keeping our digestive system running smoothly as well as keeping hormone levels balanced Eukaryotes o Have a true nucleus o Membrane bound organelles o Divided into super group that contain all of the protists, animals, plants, and fungi o Super groups are monophyletic (organisms in the same group have a common ancestor) o Excavata o Chromalveolata o Rhizaria o Archaeplastida o Amoebozoa o Opisthokonta
Which of the following is NOT a eukaryotic organism?
Archaean
Select ALL of these that are prokaryotic organisms? (Mark all that apply)
Archaeans Bacteria
A child with a violent paroxysmal cough has an impeded mucociliary escalator. If it were possible to look at tracheal epithelial cells in this child, you would see something similar to this image. The cell attached to the cilia are ______.
Bordetella pertussis
Match the signs and symptoms described to the correct disease.
Cholera: Bacterial infection that causes "rice water stools", severe dehydration, and shock. Lyme disease: Induces a bull s eye type rash at site of bite, chronic infection may induce arthritis, lupus, and neurological symptoms. Syphilis: Sexually transmitted infection that presents in three distinct phases, with the tertiary phase consisting of gummas and neurodegeneration. Tuberculosis: Caused by an acid fast positive bacterium that most often infects the lungs, diagnosed with a positive PPD test or chest x-ray. Trachoma: An intracellular pathogen that lacks a cell wall and may induce this infection in the eye
The information shown in this figure was obtained by using a technique known as _____.
DNA sequencing
Mitochondria are now known to be separate organelles within the cytoplasm of a cell. However, in the past, mitochondria were believed to be bacteria that were engulfed by larger eukaryotic cells for protection. In return, the bacterium/mitochondrion provided energy for the eukaryotic cell. What is this evolutionary process called?
Endosymbiosis
How does the cell wall protect bacterial cells from osmotic shock?
Forming a rigid cage that withstands turgor pressure.
Consider the case of Lyme disease, caused by the bacterium Borrelia burgdorferi, and Koch's postulates. Regarding B. burgdorferi, what would have to occur in order to satisfy Koch's second postulate?
It would have to be isolated from a host suffering from Lyme disease and grown in pure culture.
a) Koch's postulates have their limitations and so may not always be the last word. Identify two exceptions to Koch's postulates. b) Explain a potential problem with satisfying Koch's third postulate in practice?
Koch's postulates are criteria used to define the causative agent of an infectious disease (validates the Germ Theory of Disease). Koch's postulates state: The bacteria must be present in every case of the disease. The bacteria must be isolated from the host with the disease and grown in pure culture. The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host. The bacteria must be recoverable from the experimentally infected host. a) There are several exceptions to Koch's postulates: Asymptomatic infectious disease Not all microbes can be grown in-vitro More than one microbe produces the same disease Diseases caused by combinations of pathogens One microbe that causes multiple diseases Strictly human diseases with no animal model Diseases in which pathogens have been ignored
Match each organelle with the correct description.
Nucleoid: Site of the genetic material in a prokaryotic cell Cytoskeleton: Network of microtubules and microfilaments that serve as structural components within cells Flagella: Organelle used for motility Smooth ER: Organelle that produces phospholipids, detoxifies the cell and may store calcium Peroxisome: Vesicular organelle that houses oxidative enzymes Golgi apparatus: Flattened membranous sacs that modify, store and route products of the rER Glycocalyx: Polysaccharide/polypeptide substance external to the bacterial cell wall Nucleolus: Site of ribosome synthesis in a eukaryote
Which of the following substances would be expected to cross directly through a phospholipid bilayer (i.e., without transport proteins) the fastest? (See Section 4.5 in your text for more information.)
Oxygen gas (O2)
Pathogen A has an LD50 of 100, and pathogen B has an LD50 of 1175. Which of the following statements is true?
Pathogen A is more virulent than pathogen B.
List and describe the function of five different bacterial virulence factors. (Be specific)
Pili (adhesions) - are long adhesions. If the bacteria is able to adhere onto a cell it is more likely to aid in the prorogation of more bacteria. Fimbriae - are small hairlike structures on the surface of bacteria. They also help with the adhesion to other bacteria and the target organism. Capsules - if the bacteria has example an outer coting, it makes it hard for white blood cells to get to the bacteria. Sometimes even encapsulating the bacteria causing abscess. Toxins - if the bacteria is able to produce toxins they can help transfer the disease to the organism by secretion or shed the toxins form the membrane of the bacteria. Enzymes - are released by the bacteria which helps to damage and break down the hosts tissues. For example it may release Collagenase which breaks down collagen, thus breaking down connective tissue. 1. Bacterial capsule. Thick mucilaginous slime layer that is external to the bacteria's cell wall. Blocks phagocytosis by host cell. 2. Antiphagocytic chemicals. Prevent fusion of lysosome and phagocytic vesicles therefore the bacterium can remain within the cell reproducing within the phagosome. 3. Collagenase. Enzyme breaks down and damages the protein collagen which is found in connective tissue. This allows the organism to invade and spread through the tissues. 4. Coagulase. Enzyme that coagulates the protein fibrinogen in plasma leading to the formation of a fibrin clot. Can prevent phagocytosis. Temporarily limits the spread of organism allowing organism to multiply within the fibrin clot increasing the size of the infecting dose.
Match the organelle/structure with the type of cell that may possess it.
Plasma membrane Both prokaryotes and eukaryotes 70S ribosome Prokaryotes only Endomembrane system (endoplasmic reticulum, Golgi, vesicles) Eukaryotes only Nucleus Eukaryotes only Nucleoid Prokaryotes only Cell wall Both prokaryotes and eukaryotes Cytoplasm Both prokaryotes and eukaryotes Cytoskeleton Both prokaryotes and eukaryotes
Which of the following shows the correct path a secreted protein takes in a eukaryotic cell?
Rough ER, Golgi complex, vesicle, cell membrane
Which of the following demonstrates correct scientific notation of a bacterial organism?
Staphylococcus epidermidis
Kerri has a urinary tract infection. Bacteria were cultured from Kerri's urine and found to be Gram-positive staphylococci. Several species of Staphylococcus are human skin microbiota. Would the bacteria causing Kerri's disease be considered a primary or opportunistic pathogen? Explain your answer.
Staphylococcus would be a opportunistic pathogen. The reason for this is that our body already has these species of bacteria in our own normal flora. Another reason would be that they do not have a moderate to high virulence therefore they are not a primary pathogen.
What is happening in the figure shown below?
The mold on the right is producing a compound that inhibits the growth of the bacterial colonies on the left.
Many of your personal daily habits have an impact on your susceptibility to disease. The photo shows Ebola hemorrhagic fever, a highly contagious disease. What is the MOST simple behavior that you can do in everyday life to drastically decrease your susceptibility to disease and pathogens?
Wash your hands frequently. Correct Answer: e. Wash your hands frequently.
Some bacteria respond to attractants or repellents (usually chemical in nature) in their environment. This response is called chemotaxis. If the bacterium has one flagellum or more, the bacterium must coordinate its flagellar movement to move toward or away from the stimulus. This is called negative chemotaxis. What is a type of repellent that a bacterium would respond to by moving away?
Waste products
CASE HISTORY - Jennifer, age 23, had just graduated from college with a Fulbright fellowship to study sociology in Africa. Before leaving the US, she obtained a routine physical exam at a large city hospital. Upon returning home from the hospital, she developed a swelling in her leg. When she returned to the hospital, she was told that the swelling represented an allergic reaction and was given antiinflammatory agents. The swelling grew, and within a day the skin ruptured with a bloody discharge. Upon return to the emergency room, Jennifer at last received the correct diagnosis of methicillin-resistant staphylococcus infection (MRSA). A nurse commented that hospital visitors can acquire MRSA; the infectious agent is endemic at many hospitals in the US and is very difficult to eradicate. She showed Jennifer a micrograph of the bacteria, Staphylococcus aureus, which septate in alternating division planes, thus forming clusters of cells. Jennifer required many weeks of treatment with the antibiotics doxycycline and clindamycin (inhibits protein synthesis) before the infection resolved, and she had to postpone her fellowship for a year. Methicillin, the antibiotic to which MRSA is characteristically resistant, targets the cell wall. a) Describe in detail the structure of the cell wall in a bacterial cell like those of MRSA. b) How can antibiotics target the bacterial cell wall without harming the patient?
a) MRSA is a gram-positive cocci bacteria. It is mostly composed of peptidoglycan. b) The bacterial cell wall is targeted by using specific antibiotics. For example, penicillin is used to fight bacteria because its property to prevent peptidoglycan synthesis. Thus leaving the bacteria to burst.
The key characteristic that differentiates a prokaryote from a eukaryote is the ...
absence of membrane-bound organelles.
How do bacteria, such as Escherichia coli, stay attached to body cells, tissues, or other surfaces? Bacterial Attachment to Human Cells - 3D micrograph showing a small cluster of bacteria (Escherichia coli) attached tightly to human cells. Note that these bacteria are rod-shaped.
adhesins
In the image below, the circles and squares indicate molecules. The energy released by the transport of the circles out of the cell is used to drive the import of the squares into the cell. This is an example of ...
antiport coupled transport.
What determines whether an individual will contract a particular infectious disease?
both the host's susceptibility to the pathogenic agent and the virulence of the pathogenic agent
Which of the following statements does NOT provide evidence in support of the endosymbiotic origin of eukaryotic cells?
c. Mitochondria are capable of free-living outside of a eukaryotic cell.
Which of the following is depicting a lophotrichous bacterium?
d
The molecule shown in this figure is a ...
double-stranded nucleic acid called DNA.
he low level of disease noted in this figure by an asterisk illustrates a(n)
endemic disease.
Nitrogen-fixing bacteria can sometimes live as ________ inside plant cells.
endosymbionts
What theory emerged from the work of Robert Koch?
germ theory: microorganisms known as pathogens or "germs" can lead to disease. these small organisms, too small to see without magnification, invade humans, other animals, and other living hosts
What characteristic do hemorrhagic viruses, such as Marburg and Ebola, have that causes such widespread bodily damage and rapid death?
invasiveness
in some parts of the world, human immunodeficiency virus is endemic. Endemic diseases require a reservoir to serve as a source of pathogen. The reservoir for HIV is ________.
humans
Read section 4.5 in your textbook and watch the animation Osmosis and Water Balance. This figure illustrates a cell in a solution. The dots represent solute the yellow line represents the plasma membrane. The solution is _______ (hypertonic or hypotonic) in relation to the cytoplasm of the cell.
hypertonic
Colonization occurs during the __________ phase of an infectious disease.
incubation
Which of the following has the stages of infectious disease in the correct order?
incubation phase, prodromal phase, illness phase, decline phase, convalescent phase
What properties would you look for in the cell envelope of Gram-negative bacteria that is not present in Gram-positive bacteria?
lipopolysaccharide, periplasm
Throughout history, more soldiers have died from ________ than anything else.
microbial infections
A mutualistic relationship exists between human hosts and ...
microbiota.
The two images show a link between deforestation and malaria. The highest incidence of malaria (locations marked in red and orange in the panel on the left) corresponds to areas suffering from the greatest increase in deforestation between 1997 and 2006 (light tan spots in the panel on the right). In this instance, malaria can be thought of as an emerging infectious disease. What factors are connected to emerging infectious disease?
more humans moving into areas that were once wild
According to the endosymbiotic origin of eukaryotic cells, the ancestor of the chloroplast is a _______.
photosynthetic bacterium
The human protein transferrin sequesters iron away from bacteria. Transferrin attempts to interfere with which fundamental attribute of a successful pathogen?
nutrient acquisition
17) List and describe Koch's postulates, as well as some practical obstacles in applying Koch's postulates.
o 1st postulate: microorganism or pathogen must be present in all cases of disease and that that organism must not be found in healthy animals o 2nd postulate: pathogen must be isolated from the diseased host and grown in a pure culture o 3rd postulate: Pathogen from the pure culture must cause the same infectious disease when it is inoculated into a new healthy susceptible animal o 4th postulate: pathogen must be reisolated from the new host and shown to be the same as the originally inoculated pathogen o Asymptomatic infectious disease o Not all microbes can be grown in-vitro o More than one microbe produces the same disease o Diseases caused by combinations of pathogens o One microbe that causes multiple diseases o Strictly human diseases with no animal model o Diseases in which pathogens have been ignored
11. Describe various forms of membrane transport.
o Active transport - molecules move against the concentration gradient, requires carrier proteins and energy input, helps maintain ion gradients across the cell membrane o Passive - the diffusion of a substance across a biological membrane Transport directly through the membrane, from high to low concentration, with/down concentration gradient No ATP required, driven by kinetic energy Dynamic equilibrium - equal movement in and out of the membrane, no net movement when this occurs Gases move through plasma membrane via passive transport, in the lungs oxygen diffuses from alveoli into capillaries due to higher (O2) in alveoli than in the blood, and then from blood into cells o Facilitated - With the concentration gradient - high to low Requires membranous transport protein No ATP required Examples Ion channel - facilitate the diffusion of ions - highly specific Aquaporin o Osmosis - diffusion of a substance across a biological membrane
5) Compare the roles of animal endosymbionts and plant endosymbionts
o Animal endosymbionts o Plant endosymbionts
6. Identify flagellar arrangements.
o Atrichous - without flagella o Montrichous - having a single flagella o Amphitrichous - having a flagella on each of the ends
13. How are bacterial ribosomes different than eukaryotic ribosomes?
o Bacterial (prokaryotic) ribosomes are 70's o Eukaryotic ribosomes are 60's and 40's = 80's
12. Identify three mechanisms of infection control.
o Break connection between source and susceptible individuals o Reduce number of susceptible individuals o Reduce or eliminate source or reservoir
1. Describe the function of all eukaryotic organelles.
o Cell membrane: protective barrier to the uncontrolled flow of water o Cell wall - (plants only) provides and maintains the shape of the cells and serves as a protective barrier o Chloroplast - (plant cells only) converts sunlight energy into sugars o Smooth ER - organelle that produces phospholipids, detoxifies the cell and may store calcium o Rough ER - protein synthesis o Flagellum - used for motility o Golgi apparatus - flattened membranous sacs that modify, store and route products of the Rough ER o Mitochondria - the site of ATP synthesis o Nucleus - Stores genetic material and controls all activities of the cell, the cell brain o Vacuole - intracellular digestion and the release of cellular waste products o lysosomes - membranous sac of hydrolytic enzymes found in most eukaryotes o peroxisomes - vesicles that contain specialized enzymes
3. Differentiate positive and negative chemotaxis/phototaxis.
o Chemotaxis - is the movement of a cell or organism in response to a chemical stimulant § Toward = positive § Negative = away o Phototaxis - is the movement of an organism either towards or away from a light source § Toward = positive § Negative = away
1. Compare and contrast infectious disease, noninfectious disease, communicable infectious disease and noncommunicable infectious disease. Provide an example of each.
o Communicable Disease (Infectious disease) § Are diseases, pathogens, or illnesses that can be easily spread from individual to individual through means of touch or air. · Examples: influenza, covid-19, staph infections § They are also generally spread through bacteria, virus, or even yeast o Non-communicable (non-infectious disease) § Diseases that are not spread from person to person and may be related to lifestyle, environment, and genetics · Examples: cancer, congenital heart disease, urinary tract infection, food poisoning, and diabetes
1. List and describe structures common to all bacteria.
o DNA organized in the nucleoid o No intracellular endosymbiotic organelles o Chromosomes replicate and segregate during cell growth o Rotary flagella for motility, driven by proton motive force o Few intracellular membranes o Cell wall is composed of peptidoglycan
10) List the taxonomic categories from least specific to most specific.
o Domain o Kingdom o Phylum o Class o Order o Family o Genus o Species
11. Differentiate the terms endemic, epidemic, and pandemic. Provide an example of each.
o Endemic - maintains a relatively steady, low level frequency at moderately regular intervals § Examples - o Epidemic - when a sudden increase in the expected number of cases o Pandemic - if the disease become global and expands beyond a single population becoming either worldwide or transcontinental
4) Evaluate endosymbiosis as an explanation for mitochondria and chloroplasts.
o Endosymbiosis is when one symbiotic organism lives within another o Both mitochondria and chloroplasts are similar in size and morphology to bacterial prokaryotic cells o They both have their own DNA and ribosomes, they are also similar to prokaryotic versions o They both have their own cell membranes; and actually, have double membranes o They both replicate independently of the cell during binary fission o Comparative ribosomal sequencing prove that both are related to bacteria
4. Differentiate exotoxins and endotoxins. Provide examples of each.
o Exotoxins - are toxins secreted by a live cell § Examples: neurotoxins, cytotoxins, enterotoxins, hemolysins o Endotoxins - are not secreted, but are released from the cell membrane when the cell dies § Examples: Lipid A (LPS) - "held responsible for the toxicity of gram-negative bacteria"
4. Differentiate the function of bacterial fimbriae and pili.
o Fimbriae - enable the cell to adhere to surfaces of the host or other cells. They are mainly used for attachment and help to set up colonies o Pili - attachment and gene transfer (by conjugation)
20) State some uses of microbes in medicine and industry.
o Food and beverage production o Antibiotics o Industrial - acetone and alcohol o Biotechnology/Genetic engineering - bioremediation - unicellular organisms
7) Identify two useful and two pathogenic microbes.
o Fungi o Bacteria
10. Describe the functions of the cytoplasmic membrane.
o Gelatinous solution that contains the cell membrane o Cytosol and organelles o Mainly water with complex mixture of sugars, proteins, and salt
2. Identify the general shapes and arrangements of bacteria.
o General shapes - § Coccus - diplococcus, streptococcus, tetrad, sarcina, and staphylococcus § Bacillus - Streptobacillus, coccobacillus § Spiral - Vibrio, spirillum, spirochete
7. List and describe the differences between Gram-positive and Gram-negative bacteria cell walls.
o Gram positive bacteria (purple/violet) have a thick peptidoglycan layer and no outer lipid membrane whilst Gram negative bacteria (pink/red) have a thin peptidoglycan layer and have an outer lipid membrane.
9. Define healthcare-associated infection, list common types and causative agents.
o Healthcare-associated pathogen - hospitals acquired infections from pathogen within a hospital or clinical care facilities that may have gotten the pathogen from another patient. § UTI's, surgical wounds, respiratory infections § Causative agents - · a medical professional moving from one patient to the next without proper sterilization · the same cart of food may have been used for one patient and the pathogen was brought into the next patients room without being properly cleaned · anything that may have entered the room could be a causative agent for the spread of a pathogen within a hospital
3. Define ID50 and LD50, and explain its role in establishing infection.
o ID50: stands for the infectious dose 50. This means that the particular pathogen will infect at least 50% in a experimental group. o LD50: stands for the lethal dose 50. This means that the pathogen kills 50% of the experimental animals o Both are specified by a specific time and help to show the virulence for pathogens.
8. Describe how the outer membrane of Gram-negative contributes to pathogenicity.
o In Gram-negative bacteria the outer membrane is usually thought of as part of the outer leaflet of the membrane structure and is relatively permeable. It contains structures that help bacteria adhere to animal cells and cause disease o Lipid A (LPS) - is an endotoxin that is released from the outer membrane
10. Differentiate between the term's incidence/morbidity, prevalence, and mortality.
o Incidence - is the number of new cases during a specific time o Morbidity - is the number of affected by a disease during a set period in relation to the total number of the population o Prevalence - is the number of total cases of a diseas in a given area and a given time o Mortality - the number deaths due to the epidemic in a certain time period
16) Describe what constitutes a pure culture and how to obtain one.
o Is a population of microbes that are growing without any other microbes o Bacteria or microbes is by getting the sample and placing it on a solid medium.
12. Differentiate the impact of isotonic, hypotonic and hypertonic solutions cells with and without a cell wall.
o Isotonic - there will be no net flow of water into or out of the cell, and the cell's volume will remain stable o Hypotonic - (into the cell) having a lower osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid. o Hypertonic - (out of the cell) having a higher osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid.
tonicity
o Measure of the effective osmotic pressure gradient, as defined by water potential of two solutions separated by a semipermeable membrane
2) Identify where microbes live and list examples of microbes.
o Microbes are ubiquitous, meaning that they can be found anywhere and everywhere
1. Describe the endosymbiotic theory.
o Mitochondria, hydrogenosomes, and chloroplasts are all thought to have evolved from bacterial cells that invaded or were ingested by early ancestors of eukaryotic cells o Evolved from free-living prokaryotes that were engulfed by other cells thus subsequently became obligate endosymbionts
1. Describe the secretory pathway.
o Nuclear envelope o Endoplasmic reticulum o Vesicles/vacuoles o Golgi apparatus o Vesicles/vacuoles o Lysosomes
21) Identify fields that employ microbiology.
o Nursing o Physician assistant o Medical microbiology o Veterinary medicine o Public health o Food and industrial microbiology o Agricultural microbiology o Environmental microbiology o Forensic microbiology o Experimental microbiology
1) What types of organisms are studied by microbiologists?
o Organism that requires to be seen with a microscope
7. Differentiate types of reservoirs, providing examples of each.
o Plants, humans or animals, fomites, soil and water are considered reservoirs § Examples - · Humans can harbor the bacterium Treponema pallidum (Syphlilis) and can transfer the bacterium directly to another host · Ticks are a reservoir for the pathogen Rickettsia rickettsii
In Gram-negative bacteria, peptidoglycan is found in the ...
periplasm
1. Compare and contrast characteristics of prokaryotic and eukaryotic cells.
o Prokaryotic - Small cell size - DNA organized in nucleoid throughout the cytoplasm - Small genome (0.5-15 million base pairs) - Circular chromosome (usually), although may have multiple circular and linear chromosomes - Chromosomes replicate and segregate during cell growth - Few intracellular membranes (such as thylakoids of photosynthetic bacteria) - No intracellular endosymbiotic organelles - Cell wall composed of peptiodoglycan - Rotary flagella for motility, driven by proton force o Eukaryotic - Wide range of cell sizes, from very small to very large (usually 0.2 micrometers-1mm) - DNA contained in the nucleus, enclosed by nuclear membrane - Wide range of genome size, including very large (0.5 million- 20 billion pairs) - Linear chromosomes (in nucleus); mitochondria (derived from bacteria) have one circular chromosome - Chromosomes segregate by mitosis and meiosis, after replication during interphase - Many types of intracellular membranous organelles (such as endoplasmic reticulum, Golgi, and lysosomes) - Mitochondria and chloroplasts are organelles that evolved from endosymbiotic bacteria - Cell walls of plants and fungi composed of various carbohydrates (such as cellulose or chitin), but never peptidoglycan - Whiplike flagella for motility, with microtubule contraction driven by ATP
13. How are archaeal cells different than bacterial cells?
o S layer o Pseudomurein
8. Differentiate modes of horizontal transmission, providing an infectious disease spread by each.
o Shaking hands - Covid-19 o Sex - STD's like syphilis, gonorrhea, and chlamydia o Kissing - infectious mononucleosis, covid-19, and germs that may cause gum disease o Contract with bodily fluids - § Hepatitis B - which can be contracted through saliva, vaginal fluids, semen, and blood § Hepatitis C (HIV) - which can be contracted through breastmilk, semen, blood, and vaginal fluids
6) Why are microbes useful in research?
o Share important features of larger organisms o Simple structures o Reproduce quickly o Larger number of offspring o Reasonable costs o Minimizes animal testing o Genetic code universal
1. List similarities and differences between eukaryotic and bacterial cytoplasmic membranes.
o Similar - Both have phospholipids and both have same function of being selectively permeable o Differences - Eukaryotic cells have sterols which makes them more stable
2. Identify areas of the body that have abundant resident flora and areas of the body are generally microbe free.
o Some areas of the body that have an abundance of resident flora may be the mouth, nose, stomach and intestines. Areas that should generally remain microbe free is the circulatory system, the brain and the lungs.
5. Describe the features of the glycocalyx and its role in biofilm formation.
o Support o Protection o Recognition and communication
what are the features of living organisms
o Unicellular or multicellular o Grow o Reproduce o DNA genome o Responsive o Metabolism o Adaptable - Homeostasis
5. Describe virulence factors, and summarize their actions.
o Virulence factors - is the degree or the severity of a disease that it causes to the host § The more virulent a pathogen, the more deadly to put it short. The less virulent, then the less deadly it may be. The factors described in the power points are "adaptations to invade and establish infection in the host," and "the degree of tissue damage that occurs." Some specific things that shows a pathogen to be more virulent are: the binary fission time or replication time, having fimbriae, and the way they may secrete toxins.
11) What are the five kingdoms of the Whittaker system of classification? Three domains identified by Woese?
o Whitakers five kingdoms are - plants, animals, fungi, Protista, and Monera o Woese three kingdoms are - eukaryotes, bacteria, and archaea
9. Explain the structure of plasma membrane fluid mosaic model and how it is formed.
o aka plasma membrane. This model includes phospholipids, cholesterol, proteins, and carbohydrates. The membrane is semi-permeable, which accounts for passive (no ATP required for small molecules, Ex. Oxygen) and active transport (ATP required for larger molecules, Ex. Sodium, Potassium pump)
The links in the chain of infection from left to right in this figure are ...
organism, reservoir, transmission, susceptible host
Imagine a mutation in the genome of a cell; the mutation stops the cell's manufacturing of the proteins embedded within the phospholipid bilayer. Which of the following functions would be most severely compromised?
signaling and transport
Select ALL of these that are potential symptoms of infectious disease. (Mark all that apply)
sore throat nausea
What structure in bacteria is the target of penicillin (the first antibiotic discovered)?
the cell wall
stages of disease graph
· Incubation period (asymptomatic) - time after the pathogen enters the pathogen before the host shows any signs or symptoms · Prodromal stage - there is an onset of signs and symptoms. Typically vague, you know it is coming · Period of illness - signs and symptoms are most severe o Acme - highest point of infection o Fulminating: rapid and severe onset · Convalescence period - once the hosts immune system kicks in the pathogen that induced the infectious disease will start to decline and the host will begin to improve
What is the clinical significance of lipopolysaccharide (LPS)?
· Stability · Negative charge on cell surface · Attachment to surfaces and biofilm formation · Permeability barrier · Protection from host defenses (O antigen) · Endotoxin (Lipid A) - contributes to the pathogenicity of a bacteria
signs and symptoms of disease
· Symptoms o Chills o Pain, ache, soreness o Malaise / Fatigue o Chest tightness o Itching o Headache o Nausea / Anorexia (lack of appetite) o Sore throat o abcess · Signs o Fever o Septicemia, Bateremia, viremia o Bacturia o Chest sounds o Tachycardia o Leukocytosis, Leukopenia o Antibodies in serum o Pathology (Immunopathology) o Inflammation o Lymphadenitis - inflammation in the lymph nodes o Edema - swelling because of the accumulation of fluids within the tissue o Abscess - bacteria and white blood cells being trapped within the tissue known as puss o Granuloma - cannot clear and infection. Influx of white blood cells surrounding the are of infection preventing the infection from spreading · Asymptomatic (subclinical) - patient is infected but is not showing any signs or symptoms · Syndrome - collections of signs and symptoms of the diseases state - down syndrome · Sequelae - the lasting effects that remain after a host has recovered from an infection o Tissue or cell damage of the host
