microbiology Flashcards
1
Q
bacteria
A
they are single-celled, prokaryotic, and members of two domains: eubacteria and archaea
most bacteria is decomposers
2
Q
prokaryotes vs. eukaryotes
A
prokaryotes- bacteria, protozoans, fungi, plants
- ribosomes (but smaller) - cell wall
eukaryotes- animal
- nucleus - organelles - ribosomes - cell walls (some)
3
Q
anaerobes
facultative
microaerophiles
A
anaerobes- without oxygen
facultative- with or without oxygen
microaerophiles - reduce oxygen levels
4
Q
thermophiles
mesophiles
psychrophiles
A
thermophiles- elevated temperatures
mesophiles- moderate temp
psychrophiles- cold temp
5
Q
halophiles
A
halophiles- grow at elevated salt concentration
6
Q
cyanobacteria
A
photosynthetic and produce O2
7
Q
bacterial shape
A
cocci- round
bacilli- rod-shaped
spirals- including vibrios which are half spiral and spirochetes which are tightly wounded spirals
8
Q
bacteria cell wall
A
rigid layer outside of their plasma membrane - cell wall
made up of peptide cross-bridges called peptidoglycan (two forms)
- gram-positive- are thick with many peptidoglycan layers
- gram-negative- have a small amount of peptidoglycan with an outer membrane of lipopolysaccharide ) LPS_
9
Q
flagella
A
for movement
10
Q
fimbrae
A
hair like structures for attachment to surfaces
11
Q
pilli/sex
A
pilus for exchange of DNA
12
Q
glycocalyx
A
sugar containing the outer layer, which protects bacteria or helps attach it to surfaces.
example-capsule on some bacteria protect against phagocytosis
13
Q
single chromosomes
A
circular and free-floating within a cell and no membrane-bounded organelles
14
Q
plasmids
A
some have circular piece of DNA that replicates independently of the chromosomes and may carry genes (R factor) for antibiotics resistance
plasmids can move between bacteria
15
Q
endospore
A
(Bacillus and Clostridium) make very tough survival structure
16
Q
ribosomes of bacteria
A
slightly smaller and function slightly differently
17
Q
gram stain
A
the most widely used. It involves a decolorization step with alcohol that removes the color from cells with the thinner gram-negative cell wall. the gram-positive cells hold the purple primary stain and gram-negative cells are counterstained pink after being decolorized
18
Q
a group of gram-negative rods
A
enteric or coliform bacteria, includes E. coli, salmonella, and shigella, cause a variety of infections in the GI tract, also serves as an indicator of pollution since they are only found in the gut and feces
19
Q
gram-positive cocci
A
staphylococcus and streptococcus cause a wide variety of infections in the skin, respiratory tract, and elsewhere. a deadly disease caused by stroptococcus pneumoniae is pneumococcal pneumonia
20
Q
gram-positive rod
A
a spore-forming anaerobic gram-positive rod is clostridium the cause of dangerous diseases including tetanus, botulism, clostridum difficle infection and gas gangrene.
Mycobacterium has an outer layer of wax/lipid (referred to as acid fast because of how they stain and causes the lung diseases tuberculosis, characterized by coughing
21
Q
bordatella
A
causes pertussis, commonly known as whooping cough, where a toxin damages the airways
22
Q
borrelia
treponema
A
two spirochetes are Borrelia, the cause is Lyme disease-transmitted by a tick and Treponema, the cause of the STD syphilis
23
Q
protozoans
A
eukaryotic, single-celled, they move by a variety of means including flagella, cilia, or amoeboid motion
24
Q
survive protozoans stage
A
very complex, many can make a tough survival stage called cyst, which is often the stage that transmits disease (such as giardia, cryptosporidium, or Entamoeba)
remainder of the time they are in a form called trophozoite
25
location protozoans
found in water or in moist areas, some are photosynthetic (Euglena) many are predators (paramecium or Amoeba, some absorb nutrients
26
malaria
protozoans disease, complex life cycle and mainly infect the RBCs in humans and the digestive tract of mosquitos,. the symptoms of malaria are associated with the destruction of RBCs
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protozoan disease of the intestines include
amebiasis, giardia, and cryptosporidium. Trypanisoma causes the disease known as sleeping sickness, which goes from the blood to the brain and is transmitted by the Tse Tse fly. Toxoplasma has a complex life cycle that involves cats-the fetus can be infected if a woman gets the disease during pregnancy
28
Fungi general characteristic
- both single-celled and multicellular
- major role-decomposers-they grow on, break down and absorb nutrients from dead material
- reproduce by-asexual or sexual spores-spores contained specialized structure known as a fruiting body
- spores can transmit fungal disease and are one of the most common causes for respiratory allergies
29
fungi- mold
multicellular fungi-composed of strands (hyphae) of cells all joined into one mass-some have chitin in their cell walls
example: Penicillium and mushrooms (the visible part of a mushroom is the fruiting body)
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fungi-yeast
single-celled fungus- can carry out fermentation economically important for the production of bread, wine, and beer
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Fungi-lichens
a symbiotic relationship between a fungus and algae. The algae provide "food" via photosynthesis, the mold attaches to the surface and absorbs the nutrients
32
Fungal disease
| dermatophytes
most common site is skin
dermatophytes- break down keratin in your skin-
Example: ringworm- occurs at various areas of the body such as the head and feet. Cause by fungi such as Epidermophyton and Trichophyton
33
fungal disease
| yeast Candida
can infect the mouth, intestines, or vagina, and is often seen in immunosuppressed patients (HIV infection, or patients on cancer chemotherapy)
34
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Parasitic worms (Helminths)
general characteristics
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two major groups
flatworms- flukes, and tapeworms
roundworms- hookworm, pinworm
typically lay large numbers of eggs, and some form cysts inside the tissue of the host, which can be involved in disease transmission
35
parasitic diseases
- common site for parasitic worms is intestines- example: Ascaris, hookworms, pinworm, and tapeworms.
- Trichinella- acquired from eating un/undercooked pork leaves and intestines and forms cysts in the muscles
- The fluke Schistosoma and the roundworm Hookworm are unusual in that they enter the body by drilling through the skin
- tapeworms are acquired by eating un/undercooked beef, pork, or fish
36
Microorganisms: Viruses
| general characterisitc
- a very unusual group
- extremely small- smaller than all other organisms
- very simple structure- consist only of a protein coat (called capsid) and nucleic acid (can be RNA or DNA) known as genome
- some have an outer membrane called the envelope that has protein spikes on it
37
Microorganisms: Viruses
| Obligated intercellular parasites
- are not cells- no cell wall, no cell membrane, no nucleus, no organelles- are neither prokaryotes nor eukaryotes
- All viruses must live inside some sort of host cell because viruses can not make metabolic energy, protein, and carry out cellular function
38
bacteriophage
a virus the infects bacteria- they have a polyhedral head with a tubular/helical tail with fivers at the bottom used for attachment
39
Replication of viruses
synthesis and assembly of subunits- many copies of the parts of the virus are made within the host cell and then put together to make many viruses
40
replication of viruses steps
- attachment- which is host and tissue-specific
- penetration- the virus enters the host cell by endocytosis or fusion of the envelope
- uncoating- the genome is released from inside the capsid
- synthesis/biosynthesis- the host cell makes viral proteins and nucleic acid
- maturation/assembly- the viral subunits are put together
- release- the virus exist the host cell
41
Latency
some viruses do not complete replication but exist as DNA inserts into the host's DNA. The virus may reactivate and continue replicating at a later time
Example: herpes, HIV, and chickenpox/shingles
42
Atypical viruses
include
viroids: made up only of small pieces of RNA and no protein
prions: made only of proteins with no DNA or RNA
Prions cause destruction of the brain- example: BSE "made cow disease"
43
Viral Disease
can infect anywhere in the body
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viral diseases-respiratory tract
in the respiratory tract, they cause influenza and the common cold
influenza virus is that it changes its surface proteins often by mutations that sometimes switching genetic material with birds or pig influenzas and so avoids the immune responses and can infect you repeatedly
45
viral disease- on the skin
- measles, rubella, and variety of disease associated with herpes simplex virus.
- Varicella (chicken pox) establishes a latent infection in nerve ganglia and can recur later in life as shingles
- Warts are caused by Human Papilloma Viruses (HPV) and trigger hyperplasia (excessive growth) of skin cells
46
viral diseases- digestive tract
liver infection hepatitis occurs in different forms caused by different viruses (hepatitis A, B, C), mumps, and gastroenteritis
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viral diseases- nervous system
| and other areas....
- palio, encephalitis, and rabies, which is transmitted by mammals such as raccoons and bats.
- other areas we see mononucleosis which infects B cells, and viral fevers such as yellow fever
48
retrovirus family
includes HIV, uses the enzyme reverse transcriptase to convert their RNA genome into DNA after entering the host
49
epidemiology
study of disease transmission. pathogens (disease-causing microbes) can be transmitted by: contact, respiratory, enteric, environmental, or by vectors (living things as ticks and mosquitos)
most come from other humans, although a few (zoonoses) come from animals, the environment, and even the hospital (nosocomial)
50
Normal Flora
refers to microbes that live in and on certain areas of the human body normal and are not harmful, in fact beneficial.
Example: gut bacteria is considered to be a mutualistic as both benefits. Benefits humans include the production of vitamins such as vitamin K by gut flora
51
damages seen in bacterial diseases
damages seen in bacterial disease is often due to the effects toxins
- exotoxins- which are secreted by certain bacteria such as tetanus toxin, pertussis toxin
- endotoxins, which are part of the cell wall of gram-negative bacteria. A small amount can lead to a protective inflammatory response, a large amount can cause Disseminated Intravascular coagulation (DIC), and fatal septic shock.
52
damages seen in viral diseases
viral diseases the damage viruses do while replicating inside host cells or the immune response itself are major contributors of symptoms
53
controlling microbes and infections
| physical methods
include heat:
- boiling
- autoclaving (achieves sterility)
- pasteurization (reduce microbial numbers but does not achieve sterility) which denatures proteins
- ionizing radiation (x-rays and gamma rays) which creates toxic free radicals inside cells
- UV radiation (damages DNA)
54
controlling microbes and infections
| Chemical methods
most chemicals denature proteins
- antiseptic are used on living tissue
- disinfectants are used on inanimate objects such as equipment or surfaces Example: alcohol, iodine, chlorine, and phenolics.
Hydrogen peroxide (H2O2) is most effective against anaerobic bacteria
55
controlling microbes and infections
| antimicrobial drugs
the basis for antimicrobial drugs is selective toxicity-finding a target that is only found in microbe and not human host
in synergy, two drugs used together are more effective than the sum of their effects
56
controlling microbes and infections
antimicrobial drugs
antibacterial drugs
inhibit peptidoglycan synthesis and damages the cell wall (penicillins, cephalosporins, and bacitracin)
- most effective against gram-positive bacteria
- those that interfere with protein syntheses (tetracycline, erythromycin)
- sulfa drugs- which block DNA and RNA synthesis by mimicking enzyme substrates (sometimes referred to as based analogs or competitive inhibitors)
57
controlling microbes and infections
antimicrobial drugs
antiviral drugs
antiviral drugs such as acyclovir (used for herpes) and reverse transcriptase inhibitors like AZT (use for HIV) work by resembling nucleotides and blocking enzymes involved in DNA synthesis
58
controlling microbes and infections
antimicrobial drugs
antifungal drugs
antifungal drugs such as the polyenes and azoles target the plasma membrane of fungi
59
Immunology function
protection against diseases. used in Medicine for vaccines and diagnostic testing
60
Immunology function categories
- natural active immunity
- natural passive immunity
- artificial active immunity
- artificial passive immunity-
61
vaccines
first for smallpox used in Europe by Edward Jenner, artificially create immunity by exposing the person to antigens on a killed microbe, antigens on a live, weakened (attenuated) microbe, or a piece of microbe (hepatites B surface)
62
- natural active immunity
type produced in response to an infection
63
- natural passive immunity
the protection produced by the mother and passed through the placenta to the developing child
64
- artificial active immunity-
- the type produced in response to intentional exposure to antigen via vaccination/immunization
65
artificial passive immunity-
artificial passive immunity- giving the patient antibodies (also known as gamma globulin or antitoxin) produced by injecting an animal with materials such as botulinum toxin or rattlesnake venom
66
Immunology components
include blood and certain organs
Blood- contain fluid and cells
Lymphoid organs
67
Immunology components
| blood
```
leukocytes (WBCs):
- neutrophils
- eosinophils
- basophils
- lymphocytes
- monocytes
Plasma
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- neutrophils
most abundant protects against bacteria mainly
69
- eosinophils
- contain toxic granules, protects against parasites
70
- basophils
- contain granules full of histamine and other mediators that cause inflammation
71
- lymphocytes
T and B cells involved in specific immunity and NK cells are involved in nonspecific immunity
72
- monocytes-
can do both phagocytosis or kill infected cells
| they leave the bloodstream and become macrophages or dendritic cells
73
Plasma
the fluid portion of the blood contains antibodies and complement,
complement triggers inflammation via the production of anaphylatoxins, enhances phagocytosis, and kills target cells such as bacteria
74
Immunology components
| lymphoid organs https://www.brainscape.com/packs
Lymph nodes found in a network throughout the body
- protects particular area or regions of tissue
- acts as a site for interaction between various cells of the immune system and foreign matter (antigen)
- Thyms- the site where T cells mature
- Spleen- largest lymphoid organ, contains a variety of leukocytes, protects bloodstream instead of tissue -also removes old RBCs
- bone marrow-site where all bloods are made (WBCs and RBCs)
75
Functional categories
specific immunity - adaptive
| nonspecfic immunity- innate
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nonspecific (innate) defense
| innate barriers
innate barriers- (1st line of defense) various types such as skin, mucus lining the respiratory and Gi tacts, and stomach acid
77
nonspecific (innate) defense
| innate mechanism
Innate mechanism- the second line of defense
- phagocytosis- ingestion, and destruction
- inflammation- protects against infection, repairs damage
- fever-inhibit viral or bacterial replication
- interferon- block viral replication inside host
78
inflammation
- a key mechanism for immunity and tissue repair, multiple cells and mediators that can trigger inflammation including histamine
- increases blood vessel diameter and permeability which increases the blood flow to the inflamed area, deposits fluid in the inflamed area, and triggers migration of phagocytes out of the circulation to destroy invading bacteria
79
inflammation and diseases
inflammation can be destructive as well as protective. Example rheumatoid arthritis and asthma... examples of harmful inflammation, for treatment antihistamines and corticosteroids
80
Specific (adaptive) defenses
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the third line of defense involves the recognition and memory- the response is stronger when the immune system in re-exposed to a particular material. the substance (usually protein) that the specific response recognizes and reacts to are called antigens
involves:
T cells-
Control mechanism
B cells
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81
T Cells
carry out cell-mediated responses- function by producing signaling molecules like cytokines- T cells mainly protect against, viral, fungal, and parasitic infections
different types:
Helper T cell
Cytotoxic T cells
82
Helper T cell
also known as CD4
| activate other T cells, B cells, macrophages, and NK cells
83
Cytotoxic T cells
CD8
kill virus-infected or cancer cells by binding to them and exposing them to toxins and perforins and triggering apoptosis
84
NK cells
natural killer cells
| kill virus-infected or cancer cells, but do so nonspecifically. Macrophages play a role in mediated immunity as well
85
control mechanism
preventing Th and Tc cells from being activated inappropriately and causing damage. Helper T cells require multiple
activation signals
Antigen is ingested by the Antigen Presenting Cell and a fragment displayed on the surface of the cell along with a class II MHC marker (which are found on cells involved in immune responses). Cytotoxic T cells must recognize antigen in an infected cell along with a class I MHC marker (which are found on virtually all cells in the body)
86
B cells
humoral response- produce antibodies-(known as immunoglobulins or Ig) bind specifically to antigens
antigen binding sites are at the end of the "arms" of the Y shaped molecule and the bottom "tail" portion functions to signal or activate other parts of the immune system such as complement of phagocytes
When B cells are activated, some become plasma cells, which are short-lived cells specialized and secrete antibodies
87
5 classes of antibodies
different function and are found in different places in the body-all antibodies bind to foreign material or cells and trigger their destruction or removal
IgA, IgG, IgD, IgE, and IgM
88
IgA,
IgA- protects mucous membranes and therefore the respiratory and digestive tract, it is present in milk so can protect infants
89
IgG
IgG- gamma globulin- most common immunoglobulin in serum, protects you against toxins, and is the one that can cross the placenta (maternal antibody) to protect infants the first 5-6 months
90
IgD
the surface of B cells
| role in maturation and antigen recognition
91
IgE
- surface of mast cells and basophils, (level in blood are normally very low)
- protects against parasitic infections
- found in allergies such as hay fever and food allergies
92
IgM
largest immunoglobulin and is mainly in the bloodstream. It is the first to be produced when the immune system reacts to an antigen for the first time
93
Autoimmunity
when the immune system doesn't recognize self and non-self and attacks the self
immune system attacks and damages some part of the body
- rheumatoid arthritis (IgM attacking IgG triggers joint inflammation)
- systemic lupus erythematosus (the immune system produces anti-nuclear antibodies)
- graves disease (the immune system attacks the thyroid)
94
hypersensitivity
the immune system responds to harmless material (milk, pollen, penicillin, or latex) and reaction cause death or hypersensitivity disorder including hay fever, asthma, hives, food allergies, Rh disease, and contact dermatitis
95
Immunodeficiency
part of the immune system is missing or does not work
- recurrent infections
can be genetic, malnutrition, infecting.
influenza, causes immunosuppression which can lead to secondary bacterial infection, which can be fatal
