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110 Cards in this Set
- Front
- Back
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Biology |
The study of living organisms |
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Microbiology |
The study of microbes (microscopic living organisms and certain non-living entities) |
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Living Microbes |
Cellular microbes Types: bacteria, archaea, some algae, protozoa, and some fungi |
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Non-living Microbes |
Acellular microbes or infectious particles Types: viroids, prions, and viruses
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Pathogens |
The scientific term for disease causing microbes |
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Non-pathogens |
Microbes that do not cause disease (the vast majority of microbes are this type) |
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Indigenous microflora |
Microbes that live on and in our bodies |
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Opportunistic pathogens |
Microbes that can cause disease, but usually do not; they are awaiting the opportunity to cause disease |
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Pathogens cause which two categories of disease? |
1. Infectious disease: organisms multiply in the body and cause symptoms
2. Microbial intoxication: person ingests toxin produced by a microbe |
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Which microbes produce more of the oxygen in our atmosphere than plants? |
Photosynthetic algae and bacteria |
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Saprophytes |
Organisms that live on dead and/or decaying organic matter |
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Bioremediation |
The use of microbes to clean up toxic wastes and other industrial waste products |
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Which microbes serve as food for tiny animals? |
Algae and Bacteria |
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What do microbes that live in the intestinal tracts of animals aid in? |
The digestion of food and they produce beneficial substances |
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Which major industries use microbes? |
Food, beverage, chemical, and antibiotic industries, as well as genetic engineering |
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Genetic engineering |
a gene or genes from one organism is inserted into a bacterial or yeast cell; that cell is then capable of producing the gene products coded for by the new genes |
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Biotechnology |
The use of living organisms or their derivatives to make or modify useful products or processes |
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Anton Van Leeuwenhoek (1632-1723) |
-Father of microbiology -not a trained scientist -made simple single lens microscopes -first person to observe "animalcules" (bacteria and protozoa) |
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Louis Pasteur (1822-1895) |
-French chemist -disproved theory of abiogenesis (spontaneous generation) -Investigated different fermentation products -Developed pasteurization (disinfection process that kills only pathogens, not all microbes) -discovered anaerobes and aerobes -developed several vaccines, including rabies and anthrax
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Rudolf Virchow
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Proposed theory of biogenesis (life can arise only from preexisting life) |
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Alexandre Emil Jean Yersin |
Discovered etiologic agent of plague |
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Robert Koch (1843-1910) |
-German physician -Made significant contributions to the germ theory of disease -Developed methods of fixing and staining bacteria -Developed methods to cultivate bacteria |
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What are Koch's Postulates? |
1. A particular microbe must be found in all cases of the disease and must not be present in healthy animals or humans. 2. The microbe must be isolated from the diseased animal and grown in a pure culture in the lab. 3. The same disease must be produced when cultured microbes are inoculated into a healthy animal. 4. The same microbe must be recovered from the infected animal and grown again in a pure culture. |
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1. Bacteriology 2. Phycology 3. Protozoology 4. Mycology 5. Parasitology 6. Virology |
The study of: 1. Bacteria 2. Algae 3. Protozoa 4. Fungi 5. Arthropods, helminths, and certain protozoa 6. Viruses |
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Ecology |
The systematic study of the interrelationships between organisms and their environments |
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Most relationships between microbes and humans are... |
Helpful rather than harmful |
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Indigenous Microflora |
Microorganisms that are present on and in our bodies
(between 500 and 1,000 different species) (includes bacteria, fungi, protozoa, and viruses) |
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Symbiosis |
Two dissimilar organisms living together in a close association |
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Neutralism |
Symbiotic relationship in which neither symbiont is affected by the relationship |
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Commensalism |
Symbiotic relationship that is beneficial to one symbiont and of no consequence to the other
(Most indigenous microflora of humans are considered to be commensals) |
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Mutualism |
Symbiotic relationship that is beneficial to both symbionts
(example is the relationship humans have with the intestinal bacterium Escherichia coli) |
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Parasitism |
Symbiotic relationship that is beneficial to one symbiont (the parasite) and detrimental the the other symbiont (the host) |
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Which parts of the body are sterile (i.e. contain no microorganisms)? |
Blood, lymph, spinal fluid, and most internal tissues and organs |
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Micorflora of the skin |
-Primarily bacteria and fungi -30 different types, most common is Staphylococcus spp., Corynebacterium, Propionibacterium -number and variety depend on moisture, pH, temperature, salinity, presence of chemical wastes and other microbes |
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Microflora of the Ears and Eyes |
-Middle and inner ear are sterile -Outer ear contains same microbes as skin -Eye is lubricated and cleansed by tears, mucus, and sebum - few microorganisms are present |
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Microflora of the Respiratory Tract |
-Divided into upper and lower tract -Upper (nasal passages and throat) have an abundance of microbes, many are harmless -Carriers are people that harbor virulent pathogens in nose or throat and spread the disease to others -Lower tract is usually free of microbes |
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Microflora of the Oral cavity |
-Shelter for numerous anaerobic and aerobic bacteria -Most common organisms are various species of alpha-hemolytic streptococci |
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Microflora of the Gastrointestinal Tract |
-Colon contains the largest number and variety of microorganisms of any colonized area of the body, 500-600 species, primarily bacteria -Colon is anaerobic -Many of the microflora of the colon are opportunists -Escherichia coli - endosymbiont, mutualistic relationship, opportunist
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Microflora of the Genitourinary Tract |
-Kidney, ureters, and urinary bladder are usually sterile -Distal urethra and its external opening harbor many microbes including bacteria, yeasts and viruses -Vagina is the only part of the female or male reproductive system that is not sterile |
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Examples of health benefits from indigenous microflora: |
Vitamin B12 secreted by intestinal bacteria
Vitamin K (E. Coli in a mutualistic relationship) |
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Microbial Antagonism |
- Microbe vs. Microbe -Many members of our indigenous microflora prevent other microbes from becoming established -Production of antibiotics and bacteriocins |
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Oppurtunistic Pathogens |
Microorganisms that "hang around" and wait for an opportunity to cause infection. (E. coli) |
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Biotherapeutic Agents |
Bacteria and yeasts used to stabalize the microbial balance (also called probiotics) |
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Microbial communities |
-Biofilms -Complex communities of assorted organisms -Biofilms are very resistant to antibiotics and disinfectants |
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Synergistic Infections |
Two or more organisms "team up" to produce a disease neither could produce by itself |
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What is a cell? |
The fundamental unit of any living organism because it exhibits the basic characteristics of life |
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Eukaryotic Cell |
-Contains a true nucleus (nucleoplasm, chromosomes, and a nuclear membrane) -Contain organelles -Cell membrane w/ selective permeability -Microbes: algae, protozoa, fungi |
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Nucleus |
- Command center of cell -DNA, RNA, rRNA, tRNA -Human diploid cells have 46 chromosomes |
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Cytoplasm |
-Semi fluid, gelatinous nutrient matrix -contains storage granules and organelles -Where most metabolic reactions occur |
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Ribosomes |
-Consist of rRNA and protein -a cellular structure that is also present in prokaryotic cells -The site of protein synthesis |
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Endoplasmic Reticulum |
-System of membranes arranged to form a transport network in cytoplasm -Rough ER has ribosomes attached to it; manufactures membrane and secratory proteins -Smooth ER has no ribosomes; functions in synthesis of lipids |
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Golgi Complex |
-Connects and communicates with ER -Completes transformation of newly synthesized proteins -Packaging center |
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Lysosomes and Peroxisomes |
-Originate in Golgi complex -contain lysozyme and other digestive enzymes -Peroxisomes are membrane bound vesicles where H2O2 is generated and broken down |
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Cytoskeleton |
-System of fibers through the cytoplasm -Microtubules, microfilaments, intermediate filaments -Support and maintain cell shape, anchor organelles, movements of the cytoplasm |
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Cell Wall |
-Some eukaryotic cells contain external structure to provide shape, protection, and rigidity -Chitin found in walls of fungi -Cellulose in cell walls of algae and plants |
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Flagella |
-Long whiplike organelles of locomotion -Cells may possess more than one flagella
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Cilia |
-Organelles of locomotion, shorter and thinner than flagella -Hair like projections -some species of protozoa and certain cells in human bodies -Not found in bacterial cells |
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Mitochondria |
-Powerhouse of cells -Production site of ATP during cellular respiration
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Plastids |
-Membrane bound structures containing photosynthetic pigments -Sites of photosynthesis -Chloroplasts are a type of plastid |
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Cell Walls Present: |
Plants (cellulose), algae (cellulose), fungi (chitin), most bacteria (peptidoglycan) |
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Cell Walls Absent: |
Animals, Protozoa, mycoplasma species |
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Prokaryotic Cells |
-No true nucleus -No organelles except ribosomes -10 times smaller than eukaryotic cells -reproduce by binary fission -All Bacteria |
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Cell membrane |
-Selectively permeable -Metabolic reactions take place here with attached enzymes |
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Chromosome |
-Usually consist of a single, long, super coiled circular DNA molecule as the control center -All bacterial cells have 1 or more chromosomes -Plasmids are small circular molecules of DNA that are not a part of the chromosome |
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Cytoplasm |
-Semi liquid that consists of water, enzymes, waste products, etc required for metabolic function -cytoplasmic particles, mostly ribosomes |
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Bacterial Cell Wall |
-Rigid exterior that defines the shape of bacterial cells - chemically complex -Main constituent is peptidoglycan -Mycoplasma spp. do not have cell walls, they are pleomorphic |
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Gram positive bacteria |
Have a thick layer of peptidoglycan -final color blue to purple during gram staining |
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Gram negative bacteria |
Thin layer of peptidoglycan -final color red to pink during gram staining |
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Gram variable bacteria |
Neither consistently purple or pink after gram staining
Often identified using acid fast staining |
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Purpose of Domain Bacteria Staining procedures |
- Add contrast for better visualization -Three major categories 1. Simple Staining procedure 2. Structural staining procedures (capsule, spore, flagella staining) 3. Differential staining procedure (gram and acid-fast staining) |
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Fixation process during staining: |
- Kills organism and preserves their morphology - anchors smear to slide - two most common techniques: 1. heat fixation 2. methanol fixation (preferred) |
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Glycocalyx (slime layer and capsules) |
- Some bacteria possess - slimy gelatinous material secreted outside cell wall - Two types: 1. slime layer - lacks organized structure, loosley attached, allows bacteria to "glide and slide" 2. capsule - highly organized, firmly attached, serves an antiphagocytic function (by WBC) |
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Flagella |
-Motile bacteria possess flagella - Composed of threads of protein called flagellin -Number and arrangement of flagella characteristic of a particular species
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Peritrichous bacteria |
Flagella over entire surface |
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Lophotrichous bacteria |
Tuft of flagella at one end
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Amphitrichous bacteria |
One or more flagella at both ends |
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Monotrichous bacteria |
Single polar flagellum |
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Pili (also called fimbriae) |
-Thin hair like appendages -Not for locomotion -Composed of protein called pilin -Enable bacteria to adhere to surfaces -Some bacteria possess a sex pilus for conjugation (bacterial mating) |
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Spores (endospores) |
A few genera are capable of forming thick walled spores as a means of survival
-process of formation: sporulation -can survive for many years -highest resistance to chemical and physical control -endospores can be visualized using a spore stain |
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Binary fission |
Prokaryotic cells reproduce by this method
-one cell splits into two daughter cells -time it takes is called generation time |
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Taxonomy |
Science of classification of living organisms |
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The five kingdom system of classification |
1. Bacteria and archaea - Kingdom Prokaryotae 2. Algae and Protozoa - Kingdom Protista 3. Fungi - Kingdom Fungi 4. Plants - Kingdom Plantae 5. Animals - Kingdom Animalia
(viruses are not included because they are acellular) |
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Sequence of Taxa |
1. Kingdom 2. Division 3. Class 4. Order 5. Family 6. Genus 7. Species (King David Came Over For Good Spaghetti) |
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Microbial Classification |
- Each organism is given 2 names - genus and th specific epithet - Abbreviation sp. is used for a single species and spp. for more than one species |
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Three domain System of classification |
1. Archaea (prokaryotic) 2. Bacteria (prokayotic) 3. Eucarya (all eukaryotic organisms)
Based on differences in the structure of certain ribosomal RNA molecules |
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Bacteria are divided into three major phenotypic categories:
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1. Gram negative w/ cell wall 2. Gram positive w/ cell wall 3. Those that lack a cell wall (Mycoplasma spp.) |
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Three basic categories of bacteria based on shape: |
1. Cocci/Coccus (round) 2. Bacilli/Bacillus (rod shaped) 3. Curved and spiral shaped bacteria
Cocci may be seen singly or in pairs, chains, clusters, or packets of 4 or 8 |
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Bacilli |
-Often referred to as rods -May occur singly or in pairs, in chains, in long filaments or branched -medically important bacilli: Escherichia, Klebsiella, Proteus, Pseudomonas, Haemophilus, and Bacillus spp. |
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Curved and spiral shaped bacteria |
- curved: Vibrio spp., Campylobacter spp., Helicobacter spp. - spiral shaped: Treponema spp., Borrelia spp. |
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Unique Bacteria |
Rickettsias, Chlamydias, and mycoplasmas are bacteria that do not possess all the attribures of typical bacterial cells
Rickettsias - leaky membranes Chlamydias - energy parasites |
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Mycoplasmas |
- Smallest of the cellular microbes - Lack a cell wall so can assume many shapes (pleomorphic) - In humans they can cause primary atypical pneumonia and genitourinary infections - resistant to drugs that attack cell walls - produce tiny "fried" egg colonies on artificial media
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Charles Darwin (1809-1882) |
- British naturalist - Wrote "On the Origin of Life" - theory of branching pattern of evolution - Natural selection - Impact on microbiological thinking was negligible |
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Which microbes are acellular? |
Viruses, viroids and prions |
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Virions |
Complete virus particles |
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A typical virion consists of: |
- A genome of either DNA or RNA, surrounded by a protein coat (capsid) which is composed of protein units called capsomeres
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Enveloped virus |
A virus that has an outer envelope composed of lipids, and polysaccharides |
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5 distinguishing characteristics of a virus |
1. possess DNA or RNA - not both 2. unable to replicate on their own 3. do not divide by binary fission or mitosis 4. lack genes and enzymes necessary for energy production 5. Depend on the organelles of a host cell for protein and nucleic acid production |
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Viruses are classified by: |
- type of genetic material (DNA or RNA) - shape and size of capsid - number of capsomeres - presence or absence of an envelope - type of host it infects - disease it produces - target cells - immunologic / antigenic properties |
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Types of viruses based on the type of nucleic acid that they possess: |
1. Double stranded DNA viruses 2. Single stranded RNA viruses 3. Single stranded DNA viruses 4. Double stranded RNA viruses (most viral genomes are circular molecules but some are linear) (most viral genomes are first two types) |
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Bacteriophages |
Viruses that infect bacteria
Two categories: virulent and temperate bacteriophages
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Virulent bacteriophages |
- always cause the lytic cycle - ends with destruction of the host cell
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Lytic Cycle |
1. Attachment 2. Penetration 3. Biosynthesis 4. Assembly 5. Release |
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Animal Viruses |
Multiply similarly with two differences: 1. Whole virus enters the cell, not just injected DNA 2. Between Penetration and biosynthesis is a step called "uncoating" which releases the DNA
Animal viruses escape from their host cell by lysis of the cell or budding. Viruses that escape by budding become enveloped viruses |
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What is a key feature of all viral infections? |
The separation of the viral nucleic acid from the capsid |
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Latent virus infections |
Viral infections in which the virus is able to hide from a host's immune system by entering cells and remaining dormant.
ex. Herpes viral infections
Once acquired they never completely go away |
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Antiviral agents |
Antibiotics are not effective against viral infections
Antiviral agents are drugs used to treat viral infections
They interfere with virus specific enzymes and virus production |
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Oncogenic viruses or oncoviruses |
Can cause cancer
Examples: Epstein-Barr virus, human papillomaviruses, and human T-lymphotrophic virus type 1 |
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Human Immunodeficiency virus (HIV) |
- Virus that causes AIDS - Is enveloped, single stranded RNA Virus -Primary targets for HIV are CD4+ cells, those having CD4 receptors on their surface |
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Viroids |
- Smaller, less complex infectious particle - Short, infectious, naked fragments of single stranded RNA which can interfere with the metabolism in plant cells - Transmitted between plants in the same manner as viruses ex. Potato spindle tuber and citrus exocortis |
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Prions |
- Smaller, less complex infectious particles - Cause fatal neurologic diseases in animals - Of all pathogens prions are most resistent to disinfectants - Method by which they cause disease is unknown ex. Scrapie, Mad cow disease and Creutzfeldt- Jacob disease |
