Final Exam Micro Flashcards
(132 cards)
1
Q
Note Card: We are starting with module 3, so lecture 12!
A
2
Q
What are the trade-offs of sexual vs asexual reproduction?
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3
Q
Explain horizontal gene transfer vs vertical gene transfer? What are the 3 kinds of horizontal gene transfer?
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4
Q
What are the 3 benefits of taking up foreign DNA for a bacteria?
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5
Q
Simply explain the process of the 4 different types of HORIZONTAL GENE TRANSFER.
(transformation, transdusction, conjugation, vesicles and nanotubules.)
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1:
2:
3:
4:
6
Q
What are plasmids? what shape are they?
A
Plasmids are single, circular pieces of DNA.
7
Q
True or false:
Plasmids replicate autonomously
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8
Q
What is the difference between plasmids and secondary chromosomes?
vs primary chromosomes?
A
9
Q
True or false:
Extrachomosomal DNA elements are often MORE mobile between organisms
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10
Q
(slide 11)
What 3 types of organisms are plasmids found in?
A
11
Q
Which of the following is NOT true about plasmids:
(a) They are typically smaller than chromosomes.
(b) The number of copies that a cell has, can vary greatly.
(c) They are circular and negatively supercoiled.
(d) plasmids contain nonessential genes that often play critical roles in certain situations.
(e) All of them are true
A
12
Q
(slide 14)
Describe griffith’s experiment on transformation.
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13
Q
(slide 12)
Describe 3 strategies that a plasmid uses to maintain itself in the host cell (and not be destroyed).
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14
Q
Describe Lederberg’s experiment experiment on recombination.
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15
Q
(slide 15)
What does it mean if a bacteria is naturally Competent?
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16
Q
(slide 15)
Describe the mechanism of transformation.
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17
Q
(writing on slide 15)
Why is single stranded DNA better for transfer?
–>(same reason), why does a ‘competent bacteria’ convert double stranded DNA into single stranded as they take it out of the environment?
A
18
Q
(slide 15)
What is Natural vs Artificial competence in bacteria?
A
19
Q
(slide 17)
What is the evolutionary impact of transformation?
A
20
Q
(slide 17)
True or false;
Transformation is the most efficient method of introducing genetic diversity.
A
False (read slide, finish explaining why here.)
21
Q
(slide 18)
What is vesiduction, how does it relate to transformation?
A
So, transformation can be the uptake of naked DNA or via vesicles; this it the vesicle method (? true?)
22
Q
(slide 19)
Is it gram negative, gram positive, or both bacteria, that can make vesicles?
What is it that is sort of confusing about this? (hint: gram+)
A
23
Q
(slide 20)
What are the 3 reasons to make vesicles for sharing DNA?
A
24
Q
(slide 22)
What is the difference between GENERALIZED TRANSDUCTION and SPECIALIZED TRANSDUCTION?
Describe each one?
A
1:
2:
25
What is a capsid? (it's for viruses)
The part that protects the virus DNA. It is NOT the outer Coat, it is like the equivalent of a nuclear membrane.
26
recap Lytic vs lysogenic bacteriophages
27
(slide 22)
True or false: Specialized transduction occurs ONLY with *lysogenic* phages.
28
(slide 23)
Describe the steps of generalized transduction
1:
2:
3:
4:
5:
29
(slide 24)
what is the mechanism of specialized transduction?
30
(slide 26)
What are the clinical consequences of transduction?
31
(slide 27, writing)
Explain why V. Cholerae causes such bad symptoms if it is not pathogenic itself.
32
(slide 28)
1) Define lysogenization.
2) Define phage conversion.
33
Define prophage
Prophage refers to the genome of the VIRUS that is currently incorporated in the bacteria DNA.
34
True or false: Conjugation must occur between cells that are relatively closely related?
(slide 30)
False.
Conjugation can occur between distantly related cells.
35
What is the conjugation pilus called? and what system is it part of?
(slide 30)
The conjugation pilus is called the F pilus (F stands for fertility), and it's a component of the T4SS.
36
1) In E. coli, what is the F plasmid encoded with?
2) True or False: Conjugative plasmids exist in bacteria only.
(slide 30)
1: In E. Coli, the F plasmid is encoded with a plasmid.
2: False, conjugative plasmids also exist in Archaea.
37
Explain F+ and F- cells.
(slide 30)
38
What are the 3 simple steps of the conjugation of the F plasmid?
(Slide 31)
39
What does Hfr strain stand for, and what does it do?
(Slide 33, and writing)
40
True or false: The F plasmid is not an episome?
(Slide 33)
(explain what that means)
41
Describe: How does the plasmid integrate into the chromosome?
(slide 34)
42
(slide 34)
How does the plasmid integrate into the chromosome?
43
What is an F' vs an Hfr cell?
(slide 35, but idk if it says exactly)
44
What is the F' plasmid, and an F' cell?
(slide 35)
45
What happens if a cell tries to transfer it's whole genome over with the plasmid?
Why would this happen?
(Slide 36)
46
When a cell donates part of it's whole chromosome, will this donor cell lose any DNA, or will it be able to replicate the whole synthesized strand over again, and still have all its genes?
(slide 37)
Spoiler: yes it does synthesize it again
47
^Does recombination have to occur here?
(slide 37)
Spoiler: yes (i think so)
48
What are the 5 steps of how DNA from the Hfr cell can integrate into the donor cell?
1:
2:
3:
4:
5:
49
Give a summary definition of
1) Conjugation
2) Transduction
3) Transformation
(Slide 38)
1:
2:
3:
50
Give the definition for Genome
(slide 40)
51
Define Chromosomal Islands
(slide 42)
51
Tell me about genomes varying in size
(slide 41)
52
What are the 3 reasons why chromosomal islands are considered to be of foreign origin?
(slide 42)
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Describe Pan Genome vs Core Genome.
(slide 43)
54
What are the 4 chromosomal genetic islands that can increase fitness?
(slide 43)
55
Why do we metaphorically compare the chromosomal islands to the chimera in greek mythology?
(slide 44)
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Why do we say "the gut is a boiling cauldron of HGT"?
(Slide 45)
57
(spare card)
58
Note Card: Now we are on LECTURE 13!!!
.
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Define Microbiome
(slide 4)
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1) Define Microbiota
2) What is actually the difference between microbiome and microbiota.
(slide 4)
2) Microbiome is more of the genomes of the microorganisms.
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True or false: our bodies have as many bacterial cells as human cells.
(slide 5 lec. 13)
True.
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(slide 6)
True or false: the nostrils of two different people (in terms of bacteria) are more similar than different body parts on the same person.
True.
63
(slide 6)
True or false: even though there is a huge diversity in bacteria amounts in different body parts, their metabolic pathways are very similar.
True. (it's that graph thing with all the colours, see the slide).
64
(slide 8)
1) Describe the different microbial microhabitat in the skin, the general characteristics of the microbiota present. Names of microorganisms are not necessary.
(so, the 3 microenvironments, and the 3 composition-influencing factors.)
2) why is skin difficult to colonize?
1) There are 3 microenvironments
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(slide 9)
1) what are the two layers of skin and their properies?
2) what type of bacteria (gram positive or negative) are mostly found on the skin?
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(slide 11)
General recap the skin interactions with s. aureus.
(the things that the skin does to kill s. aureus).
* Antibiotic production by a different bacteria
*
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(slide 14)
Describe the different microbial microhabitat in the oral cavity and airways, the characteristic
of the microbiota present and what mechanisms the oral cavity and airways have to clear or
contain the microorganisms present. Names of microorganisms are not necessary.
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(slide 15)
1) T or F: The oral cavity is a really diverse microhabitat
2) T or F: saliva can increase bacteria amounts.
1) True.
2) FALSE. Saliva has antimicrobial properties.
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(slide 15)
1) T of F: the lower respiratory tract has a limited microbiota.
2) what moves particles up and out of the lungs?
70
(slide 16)
1) as ____ emerge, other bacteria start growing. (in oral cavity).
2) what are the two sub-regions of the oral cavity?
71
(slide 17)
1) How does bacteria in lower respiratory tract compare to the upper respiratory tract?
2) what is the mucociliary escalator?
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(slide 18)
1) Describe why the lungs need to be very careful about their immune responses, with surgeon-like precision.
2) True or false: the epithelial cells of the lungs can defend themselves, largely on their own.
1) the lungs are fragile basically, and a strong immune response could cause tissue damage that could be lethal.
2) True!
73
(slide 18)
As we said above, the elithelial cells of the lungs can defend themselves, so tell me about how they do that!
* Secretion of mucus:
* Secretion of Surfactants: The soapy secretions that decrease surface tension, but can also be microbicides (things that inhibit growth of microorganisms).
* they can detect pathogens and secrete microbicidal polypeptides or cytokines such as IL-25 and IL-33.
~~ They also have Macrophages that will do phagocytosis to eat the pathogens.
74
(slide 22 of lec. 13)
1) True or false: The kidney and bladder normally have microbes.
2) Altered conditions can cause potential pathogens in the _______ (such as E. Coli) to multiply and cause disease.
3) True or false: Urinary tract infections are really common and can affect like 100 million people each year.
1) FALSE. The kidney and bladder are normally STERILE!
2) Altered conditions can cause potential pathogens in the __Urethra__ (such as E. Coli) to multiply and cause disease.
--> [ The urethra is a tube-like structure in the human body that carries urine from the bladder to the outside of the body. ]
3) True. it's in the top 10 most common reason for contacting a gp.
75
(slide 23)
1) What are STIs and UTIs?
2) True or false: STIs primarily affect the urogenital system and are an important cause of patient morbidity.
3) What age do people usually get an STI?
1) an STI is a Sexually transmitted infection/disease. A UTI is a urinary tract infection, sometimes STIs are included under this term.
2) True.
3) Age 15-24
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(slide 24)
1) The vagina of thew adult female is weakly ______ and contains significant amounts of _______.
2) What is the resident microorganism in the vagina that ferments the glycogen, producing lactic acid?
3) What is the local acidic environment of the vagina, maintained by lactic acid?
4) when does L. acidophilus first colonize the vagina, and when does it leave? what does this do to pH?
5) What can infect the vagina when L. acidophilus isn't there to protect the mucosa anymore?
1) The vagina of thew adult female is weakly __Acidic__ and contains significant amounts of __Glycogen__.
2) Lactobacillus acidophilus is the resident microorganism in the vagina that ferments the glycogen, producing lactic acid.
3) around pH 5.
4) it colonizes during puberty, and leaves after menopause. When it is not present, the pH is neutral.
5) yeast infections.
77
(slide 25)
1) True or false: the male genital microbiota is understudied.
2) _____ has the largest influence on penis microbiome. (and how does it affect)?
1) True!
2) __Circumcision__ has the largest influence on penis microbiome.
--> It decreases the microbiome.
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(slide 25)
3) True or false: gut microbiota are found on penis
4) True or false: female and male partners tend to share genital microbiota.
3) True. Bacteroidetes and firmicutes.
4) True.
79
(slide 27)
1) Humans are ______ and _________.
2) True or false: gut microbes affect early development, health, and predisposition to disease.
3) When does gut microbe colonization begin?
4) what are the 3 parts of the gastro-intestinal tract?
1) Humans are __monogastric__ (one stomach) and __omnivorous__.
2) True.
3) gut microbe colonization begins at birth.
4) stomach, small intestine, large intestine.
80
(slide 28)
1) How many hours from stomach to large intestine, and how many hours from mouth to anus?
2) out of stomach, small intestine, and large intestine, order them from lowest to highest pH.
1) 1-4h from stomach to large intestine, and 24h from mouth to anus.
2) Stomach is most acidic at pH2.
Small intestine at pH 4-6.
Large intestine at pH 7.
81
(slide 29)
1) What are the 3 major phyla of all human gut phylotypes?
2) So, as we established above, there are only 3 major gut bacteria phyla. But, tell me about the species diversity.
3) True or false: Archaea, fungi, and yeast are also prominent in the gut.
1) * Firmicutes
* Bacteroidetes
* Proteobacteria
2) There is actually a lot of gut bacteria SPECIES diversity!!
like 200-1000 different ones in a single individual.
3) FALSE. Archaea and yeast and fungi are absent from or only a very little part of the microbiota in the gut.
82
(slide 30 of lec 13)
1) Why is the stomach so hard to colonize?
2) what is the bacteria that causes gastric ulcers?
3) What is decreased stomach acidity called? and what causes it?
1) because of acidity. pH is 2.
2) H. pylori causes gastric ulcers. it can survive pH 1 and it burrows into gastric lining.
--> likes to dwell in the gastric mucosa, and it is found in about 50% of the population!
3) decreased stomach acidity is called Hypochlordia. it is caused by malnourishment.
--> it can allow Vibrio cholorae to survive the stomach and cause infection in the less acidic small intestine.
83
(slide 31)
1) How much bacteria per /gm of feces is in the large intestine?
2) What's the ratio of anaerobes to facultative ones?
3) what consumes the small amount of oxygen that diffuses into the intestinal lumen?
1) 10^11 to 10^13 bacteria/gm of feces.
2) 1000:1
3) facultative bacteria like E. coli.
84
(slide 31)
1) True or false: There's not many *essential* metabolic reactions that occur with the intestinal microorganisms.
2) The colon is essentially an in Vivo _______ vessel. (anoxic so no respiration using O2 as final electron acceptor, with the microbiota using nutrients derived from digestion of food.
3) Most microorganims are in the lumen of the intestine, but some are found in the _____ layers.
1) FALSE.
Intestinal microorganisms carry out a variety of metabolic reactions that produce various compounds.
2) The colon is essentially an in Vivo __Fermentation__ vessel. (anoxic so no respiration using O2 as final electron acceptor, with the microbiota using nutrients derived from digestion of food.
3) Most microorganims are in the lumen of the intestine, but some are found in the __mucosal__ layers.
85
(slide 32)
Which of the following is false about anatomy of the gut?:
a) small and large intestine anatomy is different.
b) the epithelium is one layer of cells.
c) the immune system underlines the epithelial layer and is integrated in the epithelium too.
d) the mucus layer is an important barrier separating microbes from the epithelium
e) all are correct.
e) all are correct!
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(slide 33)
87
(slide 34)
what is the GALT?
The GALT (Gut-Associated Lymphoid Tissue) refers to the specialized lymphoid tissues in the gut that play a crucial role in the immune system's defense against pathogens while maintaining tolerance to beneficial microorganisms and food antigens. The GALT is an important component of the mucosal immune system, which protects the mucosal surfaces of the body, including those in the intestines.
87
(slide 35)
In terms of the gut microbiota, tell me some things the microbes do for us, for each of the following categoties:
1) Energy source
2) Physiological barrier
3) immune development
1) Energy source:
* Diegestion of carbs that humans cannot digest, like plant carbs.
2) Physiological barrier:
* protects epithelial barrier by stimulating mucous secretion.
* protects against microbial invasion. It has pattern recognition across species ('cross-protective immunity').
3) immune development:
* Stimulates tolerance
* stimulates inflammation
88
(slide 37)
Tell me about gut microbiota as a source of energy.
* Gut microbiota can metabolize a diverse number of carbs.
* proportion of bacteria genome coding for carb degradation is larger than ours.
* This symbiosis could have been an advantage when we were hunter-gatherers and our caloric intake was much more limited.
89
(slide 38)
Tell me the 3 ways gut microbiota may act as a physical barrier.
1: DIRECT INHIBITION: Bacteria X may secrete antimicrobial effectors that inhibit the growth of bacteria Y.
2: NUTRIENT COMPETITION: Bacteria X can use up nutrients so that bacteria Y doesn't have any.
3: IMMUNE STIMULATION: Bacteria X can activate the immune system to produce mucous, IgA antibodies, bacteriotoxins, inflammation.
89
(slide 40-41)
What is local vs systemic immune development?
Local Immune Development:
Local immunity refers to the immune response that occurs at the site of infection, such as in the gut or lungs. It involves mucosal tissues like the Gut-Associated Lymphoid Tissue (GALT), where immune cells like IgA-producing B cells and T cells are activated to fight pathogens before they spread. Local immunity is crucial for preventing infections from worsening and for maintaining tolerance to harmless substances like food and beneficial bacteria.
Systemic Immune Development:
Systemic immunity involves the immune response throughout the body when pathogens spread beyond local areas. It is activated in central lymphoid organs like the bone marrow and thymus, and involves immune cells such as B cells, T cells, and antibodies that circulate in the blood and lymph. Systemic immunity helps eliminate infections that have spread and forms long-term memory for faster responses to future infections.
90
(slide 43)
1) Recent evidence suggests that the microbiota begins to develop ________.
2) What might the source of those microbes be ^?
3) What additional benefit do the first early colonizing microbes have for a baby, and are they obligate or facultative anaerobes?
4) True or false: babies have more diverse microbiomes than adults.
1) Recent evidence suggests that the microbiota begins to develop __before birth__.
2) possibly the Placenta.
3) A source of vitamins! and they tend to be facultative.
4) TRUE!
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(slide 44)
Vaginally born vs C-section infants?
it's thought that vaginally born infants have more of a microbiome from their mother and the C-section ones.
At 12 months the difference between the two is smaller, but still visible.
92
(slide 46)
Breast-fed vs bottle fed infants?
Breast-fed infants have more commensal bacteria because breast milk has more complex oligosaccharides that promote their colonization.
at 4 months, infants who were breast-fed have more probiotic and gut lining bacteria, and immune system education.
93
(slide 47)
1) T or F: Adult microbiota does not change much throughout life, typically.
2) T or F: firmicutes and proteobacteria are less stable.
3) T or F: early parental transmission of gut bacteria can have affects for the rest of life.
4) T or F: aging is associated with decreased microbial diversity
1) true!
2) true.
3) true!
4: true
94
(slide 49)
When we die::
1: what happens in the first few days to week?
2) T or F: in the first 24-48 hours, the microbiota stays stable.
3: after 48 hours, what happens to the microbiota?
1: bacteria and fungi participate in purification (tissue breakdown) and act as decomposers.
2: True!
3: after 48h, the microbial ecology alters to the point that it is no longer recognizable as a human gut microbiota.
95
Note CARD: We are on LECTURE 14 NOW!
.
96
(slide 4)
1) True or false: a medical description of a healthy gut microbiome does not exist.
2: what are the benefits of gut symbiosis (and thus, the things that are negatively impacted by dysbiosis).
3: Give me a list of things that can affect Symbiosis or dysbiosis.
2) True.
2: * Metabolic benefit
* Colonization resistance
* Interstital barrier protection
* immune function regulation
3: Diet, drugs, sex, age, genetics, bmi, infections, antibiotics, pre-existing conditions, microbial diversity, environment (rual, pets... etc.)
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(slide 6)
Describe how pathogens can cause dysbiosis and disease.
Pathogens can cause dysbiosis and disease by disrupting the balance of the microbiota in the body. Dysbiosis refers to an imbalance or disruption in the composition of the microbiota, often caused by factors like infection, antibiotic use, or a poor diet. When pathogenic microbes invade, they can outcompete beneficial bacteria for resources, leading to a reduction in the diversity of the microbiota.
*Dysbiosis: Either the barrier is not as tight as it should be, the mucus layer is not as thick as it could be, or a specific species takes over and secretes enzymes that can digest these barriers and get inside where your immune system has to kick in.
--> Bacteria will sometimes get into the blood stream which causes infection, and can lead to arthritis, type I diabetes, Athsma, etc.
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(slide 7)
Describe the criteria for an immune response to a gut infection.
(at least one of the bullet point questions must be present):
1: There must be stimulation of the innate cells.
* Physical barriers must be broken
* there must be an imbalance between healthy microbiota and pathogenic ones, so pathogens take over.
* Deregulation of the innate system favorable to pathogens.
2: Severity of the pathology causes consequence to the host
* virulance is high enough that immune response is stimulated
*
.... Left this one, it was giving me a headache.
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(slide 13)
Difference between crohns disease and ulcerative colitis?
-Crohn's can affect any area all along the whole GI tract, from the mouth to the anus.
-Ulcerative Colitis occurs in the large intestine.
100
(slide 14)
What are potential causes for increase in bowel disease (crohns and UC) in western countries?
* breastfeeding vs not, C-section, hygene hypothesis
* Antibiotic use killing gut bacteria
* western diet rich in animal proteins and food additives that can produce harmful metabolites. high fiber diet seems beneficial.
101
(slide 15)
1) Is IBD (inflammatory bowel diseased - crohns, Ulcerative colitis) transmissible between people?
2) what are the 3 main symptoms caused by this?
1) yes, it can be.
2) * presence of adaptive T cell response when there should not be
* lower gut microbiome diversity.
* absense of anti-inflammatory stimulating bacteria
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(slide 17)
What does your Microbiome-Gut-Brain-Axis affect?
* secretes dopamine
* compounds associated with fear
* 3 genera of firmicutes associated with depression
* influence cravings
* linked to neurogenetive disease.
103
(slide 27)
Tell me about obesity and gut microbiome
* obese mice and humans have a less diverse microbiome.
* having more firmicutes can increase chance of obesity.
* it may be species-speciifc bacteria, more than phyla-specific.
104
(slide 28)
We use mouse models to study the human microbiota (germ free mice, etc.)
But what are the limitations of these studies?
* Many human microbiota never colonize the mouse gut, inducing bias.
* The number of human donors is low, so not representative of diversity.
* anatomy of mouse gut is totally different.
* human causes of dysbiosis cannot be replicated in mice.
105
(slide 30)
What are the two ways that microbiota seems to influence obesity?
1: Harvesting energy from ingested foods
2: Triggering of intestinal inflammation
106
(slide 30)
When gut microbes digest things for us, what do they produce?
they produce short chain fatty acids.
The amounts and ratios of these SCFAs are said to influence obesity.
107
(slide 31)
Label each of these Short Chain Fatty Acids as either pro or anti obesity.
1: Acetate
2: Butyrate
3: Propionate
4: and what about archaea?
1: Acetate: pro-obesity
2: Butyrate: anti-obesity
3: Propionate: both.
(so, remember this, the a for acetate and anti, do *NOT* go together.)
4: archaea may tilt the balance towards a pro-obesity microbiome.
108
(slide 32)
Rank the mice from least to most fat:
Germ-free, higher Bacteroidetes, higher firmicutes & proteobacteria
Germ-free are the least fat,
higher Bacteroidetes 'Normal' mice have more fat
higher proteobacteria have the most fat, these are the obese mice.
109
(slide 33)
explain the role of dietary fibers in metabolic disorders.
This is chat gpt's answer:
Dietary fibers play a significant role in preventing and managing metabolic disorders, such as obesity, type 2 diabetes, and cardiovascular diseases. Fiber is classified into two main types: soluble and insoluble. Both types of fiber have beneficial effects on metabolic health:
Soluble fiber: Found in foods like oats, legumes, and fruits, soluble fiber dissolves in water to form a gel-like substance. This helps to slow down digestion and absorption of sugars, which can lead to better blood sugar control. By reducing the rate at which glucose is absorbed, soluble fiber helps to prevent spikes in blood sugar levels, which is particularly beneficial for people with or at risk of type 2 diabetes. Additionally, soluble fiber can lower blood cholesterol levels by binding to cholesterol molecules and removing them from the body, thus reducing the risk of cardiovascular diseases.
Insoluble fiber: Found in whole grains, vegetables, and seeds, insoluble fiber does not dissolve in water but adds bulk to stool, promoting regular bowel movements and preventing constipation. It also helps in maintaining a healthy gut microbiota, which is essential for overall metabolic health. A healthy gut microbiota can influence inflammation and insulin sensitivity, both of which play roles in metabolic disorders like obesity and diabetes.
110
(slide 34)
Describe the link between obesity and dysbiosis.
Obese people have::
*chronic low-grade inflammation (impacts energy metabolism because it's a stress response).
*LPS from gram-negative species promote inflammation
* a high fat diet can promote LPS absorbtion
* LPS stimulate TLR4 receptor, which increases inflammatory cytokines and oxygen-reactive species production
111
what do cytokines have to do with obesity?
Cytokines are signaling molecules that help regulate immune responses. In obesity, excess fat tissue can lead to chronic inflammation, which causes the release of pro-inflammatory cytokines. These cytokines can interfere with normal metabolic processes, such as insulin signaling, leading to insulin resistance. This can contribute to the development of type 2 diabetes, heart disease, and other obesity-related health problems.
112
(slide 35)
Can we treat obesity and diabetes with a FMT?
No, fecal matter transplants cannot treat these yet.
* it's hard to change adult microbiome
*exactly what to transfer isn't clear yet
113
(slides 40-43)
Discuss probiotics vs prebiotics and their limitations
Probiotics are LIVE organisms that have a health benefit for the host. They are THOUGHT to help with antibiotic-related diarrhea, ulcerative colitis remission, and can help survival of pre-term infants.
--> Limitation: most are destroyed by acid pH in stomach and ileum
--> They are usually obligate anaerobes, so oxygen will kill them between manufacture date of product, and expiry date.
--> IF they work, it is thought to be temporary only. They would get swept out with feces when you stop eating them.
Prebiotics: typically CARBOHYDRATES that provide nutrients to gut bacteria, to promote growth of good bacteria.
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NOTE CARD: Now, we are on LECTURE 15!
.
115
(slide 5)
Primary vs opportunistic pathogens
Primary pathogens cause disease in healthy individuals, as they have specific mechanisms to bypass the immune system.
Opportunistic pathogens, on the other hand, typically don't cause disease in healthy people but can do so when the immune system is weakened or the normal balance of microorganisms is disrupted.
116
(slide 6) define pathogenicity and what are the 2 ways of measuring it
Pathogenicity is an organism's overall ability to cause disease. It is measured by the following:
* Infectivity: how easily an organism causes disease.
* Virulance: how severe the disease is.
117
(slide 7)
Tell me about virulance meaning, and ID50 vs LD50.
Virulance is the relative ability of a pathogen to cause disease.
Virulance is measured by the following:
ID50: The infectious dose. number of pathogen cells / virions needed to cause infection in 50% of hosts.
(a lower number would obviously mean MORE infectious).
LD50: The Lethal dose. number of cells/virions needed to KILL 50% of hosts
(again, lower numbers mean MORE lethal!)
118
(slide 9)
Discuss Immunopathogenesis.
Immunopathogenesis is "friendly fire" by our immune system reacting to a pathogen, and can cause major tissue or organ damage.
The term "immunopathogenesis" applies when the immune response to a pathogen is a contributing cause of pathology and disease.
119
(slide 10)
1) Describe infection cycles.
2) what are the two routes of transmission (hint: similar to bacteria terms).
1) Infection cycle describes the route of transmission of an infectious organism.
2) * Horizontal transmission: passage of one person to another (or animal), that is not parent to child during birth.
* Vertical: passage from mother to her fetus during pregnancy or birth.
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