Dr. Dannelly’s Bio274 Test Questions – Flashcards
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| General characteristics of viruses |
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| Obligatory intracellular parasites(not truly cells) Contain DNA or RNA(one or the other) No ribosomes No ATP-generating mechanisms(gets ATP from your cells Contain a protein coat(use cell machinery to make protein coat) It has to infect a cell and go inside cell to replicate Some viruses are enclosed by an envelope Some viruses have spikes-protein spikes Most viruses infect only specific types of cells in one host Host range is determined by specific host attachment sites and cellular factors |
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| What is the biggest virus known? |
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| Ebola |
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| Virion structure |
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| Nucleic acid -DNA or RNA Capsid(protein coat) -Capsomeres(triangle shape on virus) Envelope(lipid bilayer) Spikes(made of protein. aka "landing gear" it recognizes the cell with these) No envelope=naked virus |
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| Phage |
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| Virus |
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| Virus that infects bacteria |
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| Bacteriophage |
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| Taxonomy of viruses |
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| Family name ends in a -viridae Genus name ends in a -virus Viral species:a group of viruses sharing the same genetic information and ecological niche(host) Common names are used for species Subspecies are designated by a number(H1N1=flu virus) Herpesviridae(whole family of herpes) |
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| The lytic cycle |
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| Attachment:phage attaches by tail fibers to host cell Penetration:phage lysozyme opens cell wall; tail sheath contracts to force tail core and DNA into cell Biosynthesis: production of phage DNA and proteins (at this point, virus has taken over normal cell- no normal cell activity, it is only producing stuff for virus) Maturation: assembly of phage particles Release: phage lysozyme breaks cell wall |
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| Viral one-step growth curve |
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| Eclipse period=virus is inside cells trying to replicate more viruses, can't detect many viruses during this time Acute infection lasts 3-7 days AIDS-acute infection happens(flu like symptoms) around a month before you can even tell that you have the disease,doesn't produce any antibiotics in blood stream |
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| Multiplication of animal viruses |
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| Attachment: virus attach to cell membrane Penetration: by enocytosis or fusion-most cases, the whole virus goes inside cell Uncoating by viral by host enzymes Biosynthesis: production of nucleic acid and proteins Maturation: nucleic acid and capsid proteins assemble Release by budding(doesn't lysis cell)(enveloped viruses) or rupture(lysis) If it doesn't bind to right receptor, the cell will not let the virus in. If a virus is not enveloped, doesn't have membrane around virus |
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| Entry of herpesvirus by fusion |
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| Herpesvirus has envelope around virus Viral protein in membrane-recognizes receptors Membrane of virus and cell membrane fuse together-think of two bubbles in a bubble bath that come together. The come together and join as one bubble, now virus would be in the big bubble without small membrane around it. |
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| Budding of an enveloped virus |
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| Spikes have been put in membrane of the invaded cell When the virus first starts to push on the side of the cell to exit the cell, this is called "blebbing out" Virus leaves with a piece of your cell |
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| Cancer |
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| Activated oncogenes transform normal cells into cancerous cells Transformed cells have increased growth, loss of contact inhibition, tumor-specific transplant antigens, and T antigens The genetic material of oncogenic viruses becomes integrated into the host cell's DNA Not many cells cause cancer, cancerous cells=transformed cells Oncogenic=cancer causing viruses DNA virus=incorporate into chromosomes-can't get rid of-cancer causing has to be DNA virus exception=HIV(called retrovirus) RNA virus-makes DNA out of RNA-therefore, it can incorporate DNA virus into cell Retro=reverse transcriptase Take RNA-->DNA Comes with prepackaged enzyme |
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| Oncogenic viruses |
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| Oncogenic RNA viruses -Retroviridae -Viral RNA is transcribed to DNA, which can integrate into host DNA -HTLV-1 -HTLV-2 These are all lenta viruses |
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| Latent and persistent viral infections |
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| Virus remains in asymptomatic host cell for long periods -Cold sores, shingles Disease process occurs over a long period; generally is fatal -Subacute sclerosing panencephalitis(measles virus) AIDS=goes on for years(persistent) Herpes=no replication in between acute outbreaks(latent) Shingles=latent |
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| Pathology |
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| The study of disease, any kind of disease |
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| Etiology |
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| The study of the cause of a disease Name of the organism is the etiology |
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| Pathogenesis |
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| The development of disease How it developes |
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| Infection |
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| Colonization of the body by pathogens Not normal flora, PATHOGENS |
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| Disease |
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| An abnormal state in which the body is not functioning normal |
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| Disease |
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| An abnormal state in which the body is not functioning normal State in which body is removed from health |
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| Transient microbiota |
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| May be present for days, weeks, or months Staph areus- in summer months it takes over due to sweat, goes away in the winter |
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| Normal microbiota |
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| Permanently colonize the host Staph epidermides protect us from pathogens Normal flora crowds skin so there is no room for transient microbiota Protect the host by: -Occupying niches that pathogens might occupy -Produce acids -Producing bacteriocins-protein antibiotics-inhibit other microbes |
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| Symbiosis |
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| Is the relationship between normal microbiota and the host They live off my byproducts, in return, they protect me from the other pathogenic microbes |
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| Symbiosis |
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| In COMMENSALISM, one organism benefits, and the other is unaffected-some normal flora, don't benefit you In MUTUALISM, both organisms benefit In PARASITISM, one organism benefits at the expense of the other-parasite being harmed by organism Many normal microbiota are opportunistic pathogens When they get displaced(cut yourself and normal flora gets in wound) they will infect you, they are no less pathogenic than any other pathogens E. coli(normal flora of intestines) if it gets in bladder,most causes of bladder infections- it can kill you if it gets too far |
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| Normal flora and the human body |
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| Mouth to anus is not sterile Normal flora=eyes, mouth, throat, skin, large intestine, some in small intestine, opening of urinary tract=if it gets up in the urinary tract, you will have a UTI, vagina, opening of urethra. Mucus plug(at cervix)-stops normal flora from going any farther Bladder infection=your own fecal material infects you |
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| Microbial antagonism |
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| A competition between microbes |
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| Probiotics |
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| Live microbes applied to or ingested into the body, intended to exert a beneficial effect Example=Clostridium difaceal-given antibiotic, and it wipes out normal flora of the gut, gets worse with more antibiotic, so they end up having to give the patient a fecal transplant, it works. |
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| Symptoms |
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| A change in body function that is flet by a patient as a result of disease Can't be measured, can feel it, but can't measure |
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| Sign |
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| A change in a body that can be measured or observed as a result of disease Can be measured, temperature, redness... |
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| Syndrome |
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| A specific group of signs and symptoms that accompany a disease Every disease has a syndrome Collection of signs and symptoms that characterizes disease |
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| Communicable disease |
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| A disease that is spread from one host to another |
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| Contagious disease |
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| A disease that is easily spread from one host to another |
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| Noncommunicable disease |
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| A disease that is not transmitted from one host to another Anthrax-can't catch it from another patient |
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| Incidence |
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| NEW CASES of a disease in a population during a specified time period-epidemic |
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| Prevalence |
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| TOTAL CASES of a disease in a population at a given time |
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| Sporadic disease |
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| Disease that occurs occasionally in a population Not an epidemic |
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| Endemic disease |
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| Disease constantly present in a population Common cold(virus dies outside body, so if it wasn't in someone's body at all times, it would die off) |
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| Epidemic disease |
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| Disease acquired by many hosts in a given area in a short time Fairly small area(one country/continent) |
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| Pandemic disease |
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| Worldwide epidemic AIDS |
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| Herd immunity |
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| Immunity in most of a population It won't spread |
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| Reported AIDS in the United States |
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| First million cases were from 1981-2007 1993 highest number of cases recorded, they came up with better ways to detect cases, and a new definition of AIDS HIV=infected with virus-->leads to AIDS AIDS=lowers white blood count to 200 WBC's per microliter of blood, which is extremely low, should be 10,000 When you get this low, you are like an open petri dish, you are getting stuff a normal person with normal immune system would never let you catch. |
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| Acute disease |
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| Symptoms develop rapidly Cold, flu |
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| Chronic disease |
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| Disease develops slowly |
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| Subacute disease |
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| Symptoms between acute and chronic |
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| Latent disease |
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| Disease with a period of no symptoms when the causative agent is inactive Herpes |
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| Local infection |
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| Pathogens are limited to a small area of the body Infection on finger, local to finger |
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| Systemic infection |
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| An infection throughout the body Carried or replicated by blood High fever Immune system responding |
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| Focal infection |
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| Systemic infection that began as a local infection Bad infection on leg-very infected-in hospital, gotten in blood stream, filtered by the kidney, can get infection in kidney(from leg) The kidney infection is the focal infection |
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| Sepsis |
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| Toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection Body is responding to infection, don't have to have a blood infection |
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| Bacteremia |
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| Bacteria in the blood Get everytime you brush your teeth or have a wound |
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| Septicemia |
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| Growth of bacteria in the blood Replicates in blood stream Lupus=Auto immune disease where your immune system loses mechanism to recognize "self" |
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| Toxemia |
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| Toxins in the blood |
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| Viremia |
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| Viruses in the blood |
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| Primary infection |
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| Acute infection that causes the initial illness |
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| Secondary infection |
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| Opportunistic infection after a primary(predisposing) infection Ex: flu in elderly, flu gets down into lungs, gives rise to walking pneumonia or bacterial pneumonia, a lot of times it is the last thing they get, very bad news |
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| Subclinical disease |
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| No noticeable signs or symptoms(inapparent infection) Carrier(strept throat) |
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| Predisposing factors |
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| Make the body more susceptible to disease -Short urethra in females -Inherited traits, such as the sickle cell gene -Climate and weather(Cold weather slows down cilliated cells in lungs, making you more susceptible for catching cold) -Fatigue, and nutrition -Age(immune system declines after 70 years of age) -Lifestyle -Chemotherapy(wipes out immune system, can make immune system go lower than that of AIDS patient) |
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| The stages of a disease |
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| Incubation period(no signs or symptoms) Prodromal period(mild signs or symptoms) Period of illness(most severe signs and symptoms) Period of decline(signs and symptoms) Period of convalescence(you aren't contagious anymore) |
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| Reservoirs of infection |
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| Continual sources of infection -Human: AIDS, gonorrhea --Carriers may have inapparent infections or latent disease -Animal: rabies, Lyme disease --Some zoonoses may be transmitted to humans -Nonliving: botulism, tetanus --Soil Stop infection by finding where it started from |
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| Transmission of disease |
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| Contact -Direct: requires close association between infected and susceptible host(touching between people) -Indirect:spread by fomites(inanimate object) -Droplet:transmission via airborne droplets |
