Exam 3 Flashcards
1
Q
Transformation
A
Uptake of free DNA from environment, discovered by Griffith
2
Q
Fred Griffith
A
Used nonvirulent and virulent encapsulated Streptococcus pneumoniae cultures on mice to discover transformation
3
Q
Competent cells
A
Can naturally take up DNA and be transformed (some are specific in origin)
4
Q
Gram + competent genera
A
Bacillus and Streptococcus
5
Q
Gram - competent genera
A
Haemophilus, Neisseria and Acinetobacter
6
Q
Artificial transformation
A
Makes naturally non-competent cells transform (Ex. Escherichia coli)
Occurs via two techniques: CaCl2 (increases permeability), and electroporation (high-voltage currents form temporary holes in cell wall/plasma membrane)
7
Q
During transformation, ____ DNA is taken up and converted into ____ DNA, which is incorporated into the genome via a ____
A
double-stranded, single-stranded, nuclease
8
Q
Protein that integrates DNA by homologous recombination
A
RecA
9
Q
Mobile DNA
A
Consists of transposable elements that move via transposition
10
Q
Deinococcus radiodurans
A
Mesophilic, extremely resistant to radiation and desiccation (drying out) via DNA repair mechanism, commonly found in tetrads
11
Q
Thermus aquaticus
A
Thermophile, grows in hot springs, source of Taq polymerase for PCR
12
Q
Phylum Cyanobacteria
A
Primary producers in many ecosystems
* Carries out oxygenic photosynthesis (produces O2, water is e- donor, 2 photosystems, generate ATP and NADPH for dark rxns)
* Contains thylakoids with chlorophyll, carboxysomes with C fixation enzymes
13
Q
Phylum Cyanobacteria, Genus Spirulina
A
- Alkaliphile (soda lakes)
- High [carotene], food additive, protein, vitamin-rich
14
Q
Phylum Cyanobacteria, Genus Anabaena
A
Aquatic bacterium carrying out oxygenic photosynthesis and atmospheric N fixation to ammonia for use by cells (nitrogenase enzyme sensitive to O2
15
Q
Heterocysts
A
Differentiated from Anabaena vegetative cells that remain devoid of O2, form every 10th cell
16
Q
Phylum Chlamydiae
A
Gram-, obligate intracellular bacteria (pathogenic to animals and humans)
17
Q
Pathogenic bacteria of phylum Chlamydiae of the genus Chlamydia
A
- C. pneumoniae
- C. trachomatis (causes #1 reported bacterial STI in U.S.)
18
Q
Chlamydia reproduction steps
A
- Attachment of infectious, dormant Elementary Body (EB) via endocytosis
- Inside cell, EB develops into reproductive, non-infectious Reticulate Body (RB) and divides
- RBs differentiate back into EBs, which then are released by host cell lysis
19
Q
Phylum Spirochaetes
A
- Flexible, helical shape
- Flagella reside within the periplasm (axial filaments), which rotate and move the whole cell
- Some types are pathogenic (ex. Treponema pallidum - Syphilis, Borrelia burgdorferi - Lyme Disease (from ticks) - identified by Erythema Migrans (bullseye rash))
20
Q
Phylum Bacteroidetes, Genus Bacteroides
A
- Obligate anaerobes
- Degrade complex dietary polysaccharides
- Important to intestinal tract of humans, indicator of human health (makes up 30% of bacteria cultured from feces)
21
Q
Phylum Proteobacteria (Gram -)
A
Largest group with diverse cell forms and metabolism, broken up into classes:
* Alpha
* Beta
* Gamma
* Delta
* Epsilon
22
Q
Alpha Proteobacteria
A
Some are photoheterotrophs, using method of anoxygenic photosynthesis (bacteriochlorophyll) (ex. Rhodospirillum)
Others include:
* Rhizobium - root nodules, fixes N2 for plant symbiont
* Rickettsia - obligate intracellular bacteria in animals (pathogen), causative agent of Rocky Mountain Spotted Fever (ticks)
* Agrobacterium - infect plants
23
Q
Agrobacterium tumefaciens
A
- Causes crown gall disease in plants
- Has tumor-inducing (Ti) plasmid
24
Q
How does A. tumefaciens infect a host plant cell?
A
A piece of the Ti plasmid T DNA is transferred via conjugation from the bacterium into the plant cell, where it integrates into the plant genome and expresses bacterial Ti genes
25
T DNA function in plant cells
1. Directs plant to overproduce phytohormones, uncontrolled growth forms gall (tumor)
2. Stimulates plants to make opines, a C and N source used only by *A. tumefaciens*
26
How are genes for T DNA transfer activated in *Agrobacterium tumefaciens*?
*A. tumefaciens* senses environmental compounds released by wounded plants via a two-component system (**histidine kinase**)
(membrane sensor protein VirA, cytoplasmic response regulator protein VirG)
27
Class Alpha *Proteobacteria*, Genus *Caulobacter* (Gram stain & definition)
Gram -, aquatic, and is dimorphic (two distinct morphological cell types)
28
*Caulobacter* cell division generates ___
* Motile swarmer cell
* Non-motile stalked cell
29
Functions of a *Caulobacter* stalk
* Attachment via holdfast (tip)
* Increased surface area for nutrient uptake (increases in length when limited nutrients)
30
*Caulobacter* Life Cycle
1. Monotrichous swarmer cell cannot replicate its genome
2. Swarmer ejects flagellum, grows a stalk to become a stalked cell that can replicate
3. Stalked cell gives rise to motile swarmer and non-motile stalked cell ("**hedge-betting**" on environmental conditions)
31
Beta *Proteobacteria*
* Some are chemolithotrophs (ex. *Nitrosomonas*, oxidizes ammonia to nitrite in nitrification)
* Some are human pathogens (ex. *Neisseria meningitidis*, *gonorrhoeae*, *Burkholderia cepacia*)
32
*Burkholderia cepacia*
*Beta Proteobacteria*, plant pathogen (onion) and also human respiratory pathogen (causes cystic fibrosis)
33
Gamma *Proteobacteria*
Include "Enterics" (intestine)
* Facultative anaerobes (ex. *E. coli*, *Salmonella*)
Also includes "Non-enterics"
* *Pseudomonas aeruginosa* (Cystic Fibrosis, burn wound patients) ,*Vibrio cholerae* (cholera), *Shewanella* (mudwatt)
34
Myxococcus fruiting body assembly
Under nutrient-poor conditions, 1000s of myxococcal cells assemble into a multicellular fruiting body (via **signal aggregation**), which produces dormant myxospores that rise to the top to spread and germinate
35
Epsilon *Proteobacteria*
Smallest group of proteobacteria, some members cause gastrointestinal illness in humans:
* *Helicobacter pylori* - peptic ulcers
* *Campylobacter jejuni* - gastroenteritis
36
Phylum *Firmicutes* (Low GC Gram+)
Includes pathogens (ex. *Staphylococcus* (MRSA) and *Streptococcus*)
Also contains "good" bacteria (ex. *Lactobacillus*, *Lactococcus*) which undergo fermentation to form lactic acid for probiotics, cheese, and yogurt
37
The genera ________ and ________ within the phylum *Firmicutes* are **spore formers**
*Clostridium* and *Bacillus*
38
*Clostridium* members include
* *C. tetani* - tetanus
* *C. botulinum* - botulism, produces neurotoxin (Botox)
* *C. difficile ("C. diff")* - colitis, inflammation of colon
39
*Bacillus* members include
* *B. subtilis* - non-pathogenic soil bacterium
* *B. anthracis* - anthrax
* *B. thuringiensies* - produces insecticidal toxin, used in GMO Bt corn
40
Sporulation in *Bacillus*
* Survival mechanism triggered by a lack of nutrients
* Spore forms within the mother cell, which lyses to release the mature spore
* The spore is dormant, heat and stress resistant, but can germinate and become and actively growing cell
41
How do *Bacillus* sense stress to initiate sporulation?
Two-component histidine kinase systems
42
Phylum *Actinobacteria* (High GC Gram+)
Contains genus *Streptomyces* and acid-fast genus *Mycobacterium*
43
Genus *Mycobacterium*
Acid-fast cell walls with waxy lipids (requires acid-fast staining to ID), contains human pathogens such as:
* *M. tuberculosis* - tuberculosis
* *M. leprae* - leprosy
44
Genus *Streptomyces*
* Forms hyphae and mycelia
* Makes chemical Geosmin (smell of moist soil after rain)
* Source of **many** antibiotics
45
Eukaryotic microorganisms are grouped into ____ and ____, make up ____ of top 20 most frequent microbial causes of death
Protists, Fungi, 6
46
Eukaryotic cells features include:
* Sexual/Asexual reproduction
* Meiosis & mitosis
* Membrane-bound nucleus and organelles
* Plasma membranes, cell walls
47
Endoplasmic Reticulum
Involved in protein synthesis (rough) and transport (smooth)
48
Golgi Apparatus
Chemical modification, protein packaging and secretion
49
Mitochondria generate ATP via ____ transport and ____ ____
electron, oxidative phosphorylation
50
Mitochondria
Powerhouse of the cell, generates ATP and is the site of the TCA cycle
51
Algae are ____ and protozoa are ____
(metabolism)
photosynthetic, chemoorganotrophic
52
Protists serve as an important ____ in food chains, and are involved in reef formation, beach sand, and limestone
link
53
General features of protists include:
* In domain *Eukarya*
* >60,000 species
* Mostly unicellular (ex. algae, slime molds, protozoa)
* Terrestrial or aquatic
* Some can be parasitic
* Motile via cilia, flagella, or pseudopodia (cytoskeletal rearrangements)
* Sexual and/or asexual reproduction
54
Micronucleus
The "true" nucleus, involved in mitosis
55
Macronucleus
Thousands of short, linear chromosomes, 1-2 genes each (responsible for growth and feeding), **transcriptionally active**
56
Solid nutrients enter protists via ____ (engulfment), and soluble nutrients enter via ____ diffusion and ____ transport
phagocytosis, facilitated, active
57
Encystment
Development into a dormant stage (cyst), plays a role in protection and transmission
58
Excystment
Escape from cyst to metabolically active, motile form (**trophozoite**)
59
*Chlamydomonas* "Clammy"
* Protist unicellular green algae (chlorophyll)
* Cell walls of cellulose, carries out oxygenic photosynthesis (potential biofuel)
* Motile via two flagella ("beating action")
* **Stigma** (eyespot) filled with photoreceptors and allows for phototaxis
60
*Dictyostelium* Cellular Slime Mold
* Eats bacteria via phagocytosis
* Free living, aggregate in response to cAMP signal
* Forms **motile slug**
* Becomes fruiting body with spores (like *myxococcus*)
61
*Giardia*
Protozoan parasites responsible for the human pathogen, Giardiasis ("backpacker's diarrhea)
* Ingest cysts, trophozoites attach to intestine (using **sucking disc**), disrupting nutrient and water flow
62
*Naegleria fowleri*
"Brain-eating amoeba"
* Thermophile, eutrophic lakes in summer
* Trophozoite form enters nose, travels to brain and destroys tissue
* Causes Primary Amebic Meningoencephalitis (**PAM**)
63
*Alveolata*
Includes:
- Dinoflagellates
- Ciliates
- Apicomplexans
64
Dinoflagellates
Found in marine plankton, responsible for phosphorescence, have two characteristic flagella (girdle, sulcus), covered with cellulose plates, releases trichocyst proteins when threatened
65
Ciliates
Protists with 2 types of nuclei (micro and macro nucleus) and coated in cilia
Inhabit both benthic and planktonic communities in marine and freshwater systems, use cilia for locomotion and feeding, arranging them either in rows or spirals
66
Apicomplexans
All are parasites to animals, distinguished by the formation of their apical complex (use calcium and enzyme release to penetrate host cells)
Ex. Cryptosporidiosis, Toxoplasmosis, Malaria
67
Oocysts
* Small, not easily filtered
* Chlorine resistant
* Stable for months
* Just 8-10 needed for infection
* Undergo excystment after infection to become trophozoites
68
Cryptosporidosis
Caused by oocysts of *Cryptosporidium* transmitted in contaminated water
* Common cause of waterborne disease (ex. Milwaukee '93)
69
Toxoplasmosis
Caused by oocysts of *Toxoplasma* in raw or undercooked meat, also in cat feces
* Mice are a natural reservoir, those infected lose fear of cats (required for sexual cycle)
* Ingested oocysts becomes tachyzoites, localize in neural and muscle tissue
70
Malaria
Caused by 4 species of *Plasmodium*
* Apicomplexans
* Transmitted by bite of infected female *Anopheles* mosquito
* ~300 million cases per year
71
Malaria life cycle in humans
1. In liver cells, sporozoites become merozoites
2. Merozoites infect red blood cells
3. Parasite forms "knobs" on RBC surface, causing them to stick to blood vessels and prevents them from reaching the spleen
72
Clinical symptoms of Malaria
* Periodic chills and fever (with each infection cycle)
* Anemia - disrupted blood flow due to knobs formed on RBCs, blood vessels get clogged with "sticky" RBCs
* Liver hypertrophy - enlargement of liver/liver failure
73
Malaria control/prevention methods
* Mosquito control (wetland drainage, insecticides, netting)
* Chloroquine - blocks parasite from polymerizing toxic heme formed from hemoglobin degradation
* Malarone - blocks e- transport and pyrimidine synthesis (used prophylactically)
74
Fungi general features
* In domain *Eukarya*, kingdom *Fungi*
* Vastly vary in size
* Lack chlorophyll
* Have plasma membrane and chitin cell walls
* Sexual/asexual reproduction
* Saprophytes - digest food (dead organic matter) via enzymes before eating it
75
Fungi are known as the ____ ____
Great Decomposers
## Footnote
Can break down many complex organic molecules, necessary for CO2 cycling
76
Mycology
The study of fungi
77
Mycoses
Diseases caused by fungi
78
Mycotoxicosis
Poisoning by a fungal toxin (ex. Aflatoxins, Ergot alkaloids)
79
Aflatoxins
* Type of mycotoxicosis from *Aspergillus*
* Carcinogen, interlacate between DNA bases which cause mutation
80
Ergot Alkaloids
* Type of mycotoxicosis from *Claviceps*
* Mimics LSD structure, causes delusions and convulsions
* Used to treat migraines and induce labor
81
Fungal mutualist associations include:
* Lichens (fungi and cyanobacteria)
* Mycorrhizal fungi and plants (80% of all land plants, fungus provides nutrients and water, plant provides carbohydrates)
82
Yeasts
Unicellular fungi
* *Saccharomyces cerevisiae* - ferments to make bread, beer, wine
* *Candida albicans* - microflora of mouth, vagina, and intestinal tract, causative agent of thrush (Candida infection of mouth)
83
Molds
Multicellular fungi
* Form hyphal filaments and mycelium
* Aseptate (no cross walls, one nucleus) or septate (cross walls, many nuclei)
* Some fungi change from yeast to mold form ("YM shift")
84
Fungi asexual reproduction
Occurs by 3 mechanisms:
* Binary fission
* Budding
* Spore production
Ex. Conidiospores, Sporangiospores
85
Fungi sexual reproduction
Often occurs under environmental stress
* Meosis forms haploid spores
* Haploids of opposite mating types (+/-) fuse to form genetically intermediate offspring (2-nuclei dikaryon -> fuse to form diploid zygote)
* **Pheremones** signal between types
86
4 Fungal Subclasses (of 7)
* *Chytridiomycetes*
* *Zygomycetes*
* *Ascomycota*
* *Basidiomycota*
87
*Chytridiomycetes*
Simplest fungi
* Aquatic, motile, flagellated zoospore
* Chytridiomycosis - skin infection of frogs, devastating to global populations
88
*Zygomycetes*
Have sexual zygospores, asexual sporangiospores
* Ex. *Rhizopus* (bread mold, tempeh)
* Used in meat tenderizer, birth control agents
* Plant pathogen - Rice Seedling Blight
89
Does *Rhizopus* toxin cause Rice Seedling Blight?
No, formed by *Burkholderia* (alpha proteobacterium) inside *Rhizopus*
90
*Ascomycota*
Sac fungi - ascus
* Sexual ascospores, asexual conidiospores
* Ex. *Saccharomyces*, *Aspergillus*, *Penicillium*, *Cordyceps* - (insect pathogen, infection of ant leads it to climb to a specific height to release spores)
* Pathogenic members include *Histoplasma capsulatum*, *Pseudogymnoascus*
91
*Histoplasma capsulatum*
Causative agent of histoplasmosis
* Mold spores (conidia) are inhaled
* Germinate into yeast in lung, yeast grows in human macrophages
92
*Pseudogymnoascus*
Causative agent of White Nose Syndrome in bats
* Psychrophile
* Infects skin of hibernating bats, leading to large-scale deaths
93
*Basidiomycota*
Club fungi characterized by basidium (bears sexual basidiospores)
* Ex. Mushrooms, *Cryptococcus neoformans* (cryptococcal meningitis)
94
*Basidiomycota*, Genus *Agricus*
Edible mushrooms
95
*Basidiomycota*, Genus *Amanita*
Toxic mushrooms, including death angel
- Contain amanitin
96
Amanitin
Peptide toxin that targets RNA polymerase, inhibits transcription and RNA synthesis
97
*Cryptococcus neoformans*
* Member of *Basidiomycota*
* Fungal pathogen via inhalation of basidiospores
* Infects lungs and CNS (can cross blood-brain barrier)
98
Virulence Determinants
The characters of suspected pathogenic microbes that enable virulence (ex. capsules, pigments)
99
Two virulence factors of *C. neoformans* are the polysaccharide ____ and the ____ pigment
capsule, melanin
100
Metagenomics
Analysis of genetic material derived from microbial communities, a **culture-independent** approach
101
Drawback of a culture-dependent approach
Media will not be able to culture all bacteria present
102
Metagenomic Approach Steps
1. Isolate total DNA from an environment
2. Use PCR to amplify SSU rRNA genes (16S rRNA)
3. Clone and sequence amplified DNA
4. Compare to database for known genes, checking for hits
103
Human Microbiome
The collection of all microorganisms living in association with the human body
- studied by the NIH's Human Microbiome Project (2007)
104
Gut microbiota make signaling molecules called ____ that affect brain development and behavior
neurotransmitters (ex. Short Chain Fatty Acids (SCFAs))
105
The large intestine has the largest bodily microbial community (how many species, ratio?)
Over 1000 different bacterial species present, metagenomic profile in healthy adults includes:
* 60-80% *Firmicutes* (Gram +)
* 20-40% *Bacteroidetes* (Gram -)
106
The __ nerve connects visceral organs and the brain, allowing for gut microbiota to influence the brain and behavior via the "__ - __ - __ Axis"
vagus, microbiota-gut-brain
107
Dysbiosis
Disruption in the microbiome that is assocciated with disease
* Gain or loss of community members
* Change in relative abundance of microbes
108
Mutualism
A type of symbiotic relationship in which both partners benefit
109
Mutualism examples include:
* Mycorrhizal fungi and plants (~80% of land plants)
* Hawaiin Bobtail Squid and *Vibrio fischeri*
* Coral and Zooxanthellae
110
*Vibrio fischeri* uses ____ ____ to control light production; cells produce light only if they are at a high density
quorum sensing
111
Autoinducer
Density-dependent signaling molecule used in quorum sensing
* Diffusable, moves in and out of cells
- Low cell density = movement out of cell
- High cell density = movement into cell (genes activated)
112
Important components of the *V. fischeri* quorum sensing process include:
* LuxR - transcription factor protein which binds autoinducer to activate *lux* operon
* *lux* operon - controls expression of genes for luciferase (bioluminescence)
113
Most corals obtain energy and nutrients from ____ that live within the coral's tissues
Zooxanthellae
114
Zooxanthellae
Photosynthetic algae that are Dinoflagellates (protists), form mutualist relationship with coral
115
Zooxanthellae use energy from photosynthesis to fix ____ into ____ and donates it to the coral which produces ____, ____, and ____
CO2, carbohydrate
nitrogen, phosphate, CO2
116
The immune system is a complex of widely distributed ____, ____, and ____ that neutralizes or destroys foreign substances
cells, tissues, and organs
117
Antigens
Foreign substances that provoke immune response (any type of molecule)
118
Antibodies
**Proteins** produced bu B cells that bind antigens, inactivate or eliminate them
119
The immune system protects against four classes of pathogen:
1. Bacteria
2. Viruses
3. Fungi
4. Protists
120
The immune system participates in disease through
* Allergies
* Autoimmunity (breakdown of what is self and non-self)
* Transplant rejection
* Graft vs Host Disease
121
The mammalian immune response consists of ____ and ____ immunity
innate, adaptive
122
Innate Immunity
The non-specific first line of defense
* Fast acting with no antigen memory
* Cells include macrophages, neutrophils, and dendritic cells
* Components include anatomical features, complement, toll-like receptors, cytokines (signaling molecules)
123
Cells responsible for both innate and adaptive immune responses are the ____, all of which originate from pluripotent stem cells in the bone marrow
leukocytes
124
The five major types of leukocytes:
1. Basophils
2. Eosinophils
3. Neutrophils
4. Monocytes (mature into macrophages or dendritic cells)
5. Lymphocytes (T, B, and NK cells)
| 1-4 from common myeloid progenitor cell, 5 from lymphoid progenitor cell
125
Macrophages (definition and functions)
From monocytes in blood, enter and reside in the tissue, have 3 main functions:
1. Phagocytosis of pathogens
2. Antigen presentation
3. Make cytokines
126
Macrophage phagocytosis steps:
1. Pseudopodia used to engulf bacterial pathogens
2. Phagosome forms, microbe is contained within
3. Lysosome bonds, forming a phagolysosome
4. Pathogen is degraded via ROS (H2O2) and RNS (NO)
127
Professional Antigen Presenting Cells
Macrophages, Dendritic cells, and B cells
(can take in and process protein antigens to present peptide fragments bound to MHC molecules to T cells)
128
Innate immune response physical barriers:
* Skin and mucous membranes
* Normal microflora protect by competing with potential pathogens
129
Innate immune response chemical barriers:
* Acidic pH of stomach
* Lysozyme in tears and breast milk
* Defensins (antimicrobial peptides)
Other components include complement, toll-like receptors, and cytokines
130
The complement system is made up of >____ serum proteins activated by ____ ____, "complements" the activity of antibodies
30, enzymatic cleavage
131
The complement system includes:
* Opsonins
* Chemotactic factors
* Membrane Attack Complex (MAC)
132
Toll-like Receptors
* Pattern recognition receptors
* At least 10 distinct receptors
* Bind Pathogen-Associated Molecular Patterns (PAMPs/MAMPs)
133
PAMP Examples for TLRs
* TLR4 - LPS
* TLR2 - Peptidoglycan
* TLR3 - dsRNA (RNA viruses)
* TLR5 - Flagellin (flagellar filament proteins)
134
The binding of TLR to PAMP initiates a ____ ____ ____, activating NFkB that activates cytokine-producing genes
signal transduction cascade
135
Cytokines such as ____ and ____ bridge the innate and adaptive immune responses
Interleukins (stimulate cell growth), Tumor Necrosis Factor (TNF, increases vascular permeability, induces fever, activates B and T cells)
136
Cytokine types:
* Chemokines - Stimulate cell migration to infection sites
* Endogenous pyrogens - Induce fever, circulate to brain and induce neurons to make prostaglandins
* Interferons - Produced in response to viruses, block viral replication and assembly
137
Vasodilation
Widening of the blood vessel to allow neutrophils into tissue to respond to pathogen, initiated by cytokines
138
Adaptive Immune Response
* Can descriminate between self and non-self
* Has specificity and memory
* Slower than innate
139
Adaptive immune response components include:
* Antibodies, antigen receptors, Major Histocompatibility Complex (MHC)
Main cell types are B and T lymphocytes
140
Adaptive immunity has two branches:
Humoral and Cell-mediated
141
Humoral Adaptive Immunity
Involves antibodies (made by B cells), defends against **extracellular** pathogens
142
Cell-mediated Adaptive Immunity
Involves T cells, largely defends against **intracellular** pathogens, destroys own cells to eradicate them
143
While innate immune responses are inititated at the site of infection, adaptive immune responses are initiated in the ___ ___ and ____, which are all connected via the ____ system
lymphoid organs and tissues
lymphatic
144
Primary Lymphoid Organs/Tissues
Where lymphocytes mature (ex. bone marrow (B cells), thymus (T cells))
145
Secondary Lymphoid Organs/Tissues
Where lymphocytes engage antigen (ex. spleen and lymph nodes)
146
B Cells
* Make antibodies
* Are Professional Antigen-Presenting Cells
* Activate by antigen or T cells (recognizes just one antigen)
* Develop into plasma cells or memory cells
147
Plasma Cells
B cell descendant that produces and secretes antibodies for a specific antigen (>1000/sec)
148
Memory Cells
B cell descendant that lasts for decades, activated upon the second exposure to an antigen
149
Antibodies (Immunoglobulin)
* Free-floating **proteins** made by B cells
* Defend against extracellular pathogens by binding to them (on epitopes on surface)
* Can **neutralize** or **opsonize** an antigen
150
Affinity
The strength that an antibody binds to an antigen
151
Epitopes
Parts of an antigen that antibodies bind to
152
One antigen can have ____ epitopes, each binds to a ____ antibody
several, single
153
Opsonins
Coat microbes for phagocytosis (ex. C3b, read by C3b receptor)
154
Chemotactic factors assist in ____
PMN migration from blood to infection (ex. C5a)
155
Membrane Attack Complex (MAC)
Series of complement proteins combine to form a pore in the microbial membrane
