Microbiology Test Questions and Answers – Flashcards
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Unlock answers| What percentage of bacteria cause disease? |
| Less than 1% |
| Are Bacteria prokaryotic, eukaryotic, or acellular? |
| Prokaryotic |
Are Viruses prokaryotic, eukaryotic, or acellular?
|
| acellular |
| Who was the first to observe microorganisms and term them animalcules? |
| Antonie van Leeuwenhoek |
| What is a biofilm? |
| Bacteria that are stuck to a surface living as a community: offering greater immunity and protection from antimicrobials. |
| What is bioremediation? |
| The use of bacteria to Clean up pollution or other messes |
| What stains are used for the Gram's staining procedure? |
| Crystal Violet and Safronnin |
| Other agents of gram staining |
| Decolorizer (ethanol) and iodine |
| Do bacteria have a nucleus? |
| NO bacteria are prokaryotic (no nucleaus) |
| How many chromosomes in a bacteria? |
| One circular chromosome |
| Name specific structures for Gram Positive |
Thick Petidoglycan Lipo-teichoic acids teichoic acids ; ; |
| Name structures for gram negative organisms: |
Thin Petidoglycan LPS (Lipopolysaccharides) Two membranes (pg surrounded by outter) Lipoproteins |
| What are flagella used for? |
| Swimming/ motility /movement |
| Small extra chromosomal pieces of DNA are called: |
| Plasmids |
| Site of protein synth? |
| Ribosomes |
| Most resistant biological structure |
| Endospore |
| Obligate anaerobes |
| A bug that dies upon exposure to oxygen |
| Selective medium |
| Has a component in it that kills something undesireable.; |
How do bacteria divide? ; |
| By binary fission |
| Sterilization of medical instruments |
| Autoclave: kills most microorganisms and even some endospores |
| Disc diffusion assay with a large zone of inhibition |
| The treatment is effective: such as an antibiotic or chemical germicide.; |
| DNA from DNA process |
| Replication |
| What is mRNA from DNA |
| Transcription |
| Protein from mRNA |
| translation |
| During replication one old and one new strand what is the term? |
| Semi-conservative |
| What are the three types of base Substitutions? |
Missense: One AA change (bad or no change) Non-sense: early stop codon (usually bad) Silent: same AA coded for by chance (no change not bad) |
| what happens when you get a frameshift mutation? |
| Almost always deliterious, the entire reading of a codon is shifted over and destroys everything after.; |
| What is the spontaneous mutation rate of a bacteria? |
| One in a million |
| What is an auxotroph? |
When it doesn't make something it needs. Could be an AA or vitamin/cofactor |
What is the uptake of naked DNA? Where exogenous DNA is drawn in and used within a bacterium |
| Transformation |
| What is transduction? |
| Process whereby a virus transfers DNA from one bacterium to another. |
| What is conjugation? |
| Process with the sex pilus (involving an F+ cell) |
| which is more pathogenic capsulated or non? |
| Capsulated is more pathogenic |
| Virus' can contain DNA or RNA but not both |
| True |
| Protein coat of a virus |
| capsid, composed of capsomeres |
| A virus that can cause cancer |
| Oncovirus, oncogene, oncogenic virus |
| What is a pandemic? |
| A worldwide / global disease that has spread |
| Zoonotic disease? |
| One that you can get from other animals (transfered) |
| Tick carries a virus from a deer to a human. the tick is considered? And the deer is? |
Tick: Vector Deer: resevoir |
| What is an example of a parental port of entry? |
| A needlestick, cut with a knife, anything that injects beneath skin.; |
LD50: ID50: And? |
Lethal for 50% of test population Infectious for 50% of population Very Low LD50or ID50 indicates high pathogenicity |
| List the ways a pathogen evades host immunity |
lyse host cells antigenic variation biofilms capsules m-proteins |
| 1st line of defense |
| Skin, normal flora, mucous membranes |
| 2nd line of defense |
| Phagocytes, inflammation, fever, antimicrobial substances |
| 3rd line of defense |
| T and B cells: adaptive immune system |
| What are some physical factors for innate immunity? |
| Cillia, presence of musous, urine flow, tears |
| What are some chemical immunities of the human body? |
| pH, lysozymes, urea, sibum |
| Complement immunity? |
| Helps out innate and adaptive systems |
| Antiviral proteins produced by infected cells are called? |
| Interfereons: this alerts other cells nearby to make their own antiviral proteins.; |
| What is the first class of antibodies produced during infection? |
| IgM (good marker for recent infection) |
| Where do antibodies come from? |
| B-Cells activation to plasma cells: synthed on surface |
| B-cells mature where? |
| Bone Marrow |
| T-cells mature where? |
| Thymus (but originate in the bone marrow) |
| What are peyer's patches? |
| Lymphoid in the intestine: (lymphatic tissue) they are like traps for GI bugs. |
| What is the difference between bacterialstatic and bacterialcidal? |
Bacterialstatic: stops growth Bacterialcidal: kills |
| Is Rabies a virus, a bacteria, or worm? Where does it originate? |
| Rabies is a virus that infects the PNS then the CNS before causing death. |
| What bacteria can cause peptic ulcers? |
| Helicobacter pylori |
| Who is Barry Marshal? |
| A doctor who infected himself with h.pylori to prove his theory. |
| Who did the first work on bacterial transformation? |
| Frederick Griffith -1928 |
| What enzymes do viruses lack? (hint: why can't they live outside a host cell?) |
| Protein synthesis and ATP generation |
| What is host range? |
| the spectrum of host cells a virus can infect |
| How is host range determined? |
| The receptors on the host cell surface |
| What is the typical size of a virus? |
| 20-1000 nm |
| What is the typical size of a eukaryotic cell? |
| ~10 um; |
| What is the typical size of a bacterial cell? |
| 0.5-5.0um |
| What is a complete fully developed and infectious viral particle composed on nucleic acids and surrounded by a protective protein coat? |
| Virion |
list the three main morphological characteristics of viruses |
Helical: may be enveloped Polyhedral: may be enveloped Complex |
| What makes enveloped viruses difficult to treat? |
| usually the spikes on the surface change to evade host defenses |
| How are viruses cultivated? |
| A host is required which makes culturing more difficult |
| What is the easiest way to identify a virus? |
| Genetic identification |
| What is the difference between latent and persistent viral infections? |
Latent resides within a host for a long time without producing disease where as persistent infection occurs gradually over a long time and is often fatal.; Latent: herpes/coldsores Persistent: herpes/epstein barr |
| What are Probiotics? |
Live microbial cultures applied or ingested that intend to exert a beneficial effect.; Lactobacilus acidophilus |
| What are prebiotics? |
| Substances that are intended to promote the existing beneficial bacteria within the host (i.e. gut flora) |
| Who identified the cause of Anthrax? |
| Robert Koch |
| Identify koch's postulates |
The same pathogen must be present in every case of the disease The pathogen must be isolated and grown in pure culture The grown pathogen must cause disease when innoculated into a healthy susceptiple animal. Lastly, the pathogen must then be isolated from new host and shown to be the original organism. |
| What is the difference between communicable disease and contagious disease? |
Communicable is one that can spread from one host to another Contagious means that it Easily spreads hosts. |
| What does the term endemic disease mean? |
| That it is constantly present within a population such as the common cold |
| What is sepsis? |
| The inflammatory condition arising from the spread of microbes from a focus of infection. |
| What is speticemia? |
the presence of pathogens multipling in the blod. Also: bacteremia, toxemia, viremia |
| What is a Primary infection? |
| Acute infection caused by an initial illness |
| What is a secondary infection? |
| infection caused by opprotunistic pathogen steming from a weakened immune system (from primary). |
| Name the development steps of disease (infection) |
Incubation period: time between infection and appearance of symptoms/signs Prodromal period: Early and mild symptoms Period of Illness: disease is most severe: patient either gets better or dies. period of decline: signs/symptoms decline period of convalescene: body returns to pre-diseased state. |
| What is a reservoir of infection? |
May or may not exhibit signs of illness: carriers harboring a pathogen without disease. Also Zoonoses: disease passed animals to humans. Also non-living in soil and water |
| What is a nosocomial infection? |
| Infection resulting from a hospital stay |
| What helps bacteria with adherence and resists phagocytosis? |
| M-protein |
| What is mycolic acid? |
| A waxy lipis that resist phagocytosis: seen in M. tuberculosis |
| What do coagulase, collagenase, and IgA proteases do for bacterial pathogens? |
| Form blood clots to resist phagocytosis, digest host connective tissue(food), and digest host antibodies (evasion). |
| What is antigenic variation? |
| The changing of surface proteins on a pathogen in order to evade host defenses. |
| What does listeria monocytogenes do to succeed in a host? |
| Forms actin rockets to spread to other cells and evade host defenses. |
| What is a limiting factor in using host nutrients and what do pathogens secrete for this? |
| Iron: siderophores sequester it from host. |
| What is the difference between exotoins and endotoxins? |
Exotoxins are released from an bacterial cells *gram Positive cells Endotoxins are apart of the cell wall and released when lysed *apart of LPS in gram negative cells. |
| How are complement proteins named? |
Big C and number for complement protein C3 C5 After activation they split into 2-named with lowercase 'a' or 'b' C3a & C3b |
| How do complement proteins enhance: Inflammation? |
| They stimulate histamine production |
How do complement proteins enhance: phagocytosis? |
| Activated proteins coat pathogens and encourage opsinozation |
How do complement proteins enhance: cytolysis? |
| Activated proteins bind to pathogens and poke holes in membranes |
| How do interferons work? |
| They bind to healthy cells and stimulate AVP (antiviral proteins) production |
| What is the host counterpart to siderophores? |
Ironbinding proteins transferrin in blood lactoferrin in milk ferritin in the liver/spleen/marrow hemoglobin in blood |
| List three modes of action for AMPs (antimicrobial peptides) |
1. Inhibit cell wall synthesis 2. form pores in pathogen membrane 3. destroy pathogen's DNA / RNA |
| What is the difference between humoral and cellular immunity? |
Humoral: involves B-cells and Ab production (extracellular pathogens) Cellular: involves T-cells and chemical messenger production (mainly for viruses/intracellular pathogens) |
What is the term used to describe the antigen binding site? (the antigenic determinant) |
| epitope |
| name the parts of a Generic Antibody |
heavy chains in the center connected by the lightchains ont he outter sides. Ag binding site on the tips of the 'Y' and a constant region on the stem. |
| Who discoved the process of vaccination by injecting cowpox for immunity from smallpox? |
| edward, jenner - 1770 |
| What was Alexander Flemming most famous for? |
| Discovery of the enxyme Lysozyme and antibiotic pennicillin |
| Name the four types of and list their energy requirement (or lack of) |
Diffusion and facilitated diffusion: no energy required Active transport and group translocation: energy required |
| What enzyme is responsible for adding nucleotides during replication? |
| DNA polymerase |
| Name 4 required components for transcription the process of creating complementary RNA copy of DNA |
1. RNA polymerase 2. Promoter 3. RNA nucleotides 4. Terminator |
| Pathogens have what to bind to specific host receptors? |
| Adhesins or ligands |
| Name the two types of adaptive immunity |
| Humoral and cellular |
| Which T-cells help activate macrophages and secrete cytokines? |
| T-helper cells |
Which T-cells would be used to help activate the cells used to kill large parasites? |
| T-helper cells |
| Which T-cells kills target cells? |
| Cytotoxic T lymphocytes CTLs |
| What do CTLs target? |
| Viral infected cells and some tumor cells (considered non-self) |
| What do Natural Killer cells do? |
| used to attack parasites and tumor cells: Ab-dependent cell mediated cytotoxicity |
| Parasites might engage which immune cells? |
Eosinophils, macrophages, NKs, and T-helper cells. (but mainly eosinophils and NKs) |
| Which type of T cell is responsible for killing host cells infected with virus? |
| CTLs, Tc, or cytotoxic t lymphocytes |
| A mother passing antibodies to a baby is what kind of immunity? |
| Naturally aquired: Passive |
| Antigens introduced by a vaccine is what type of immunity? |
| Artifically aquired: Active |
| Antibodies introduced into a host is what type of immunity? |
| Artificially acquired: Passive |
| Antigens that happen to come into the body and induce Ab production is what type of immunity? |
| Naturally acquired: Active |
| What does a static titer indicate in a patient? |
| The patient has been exposed at some time to a pathogen and so has antibodies for it. |
| What does an increasing titer indicate? |
| The patient has an active infection and is producing antibodies for it. |
| Which cells does HIV target? |
| The Aids virus destroys T4 lymphocytes (T-helper cells) |
| What does penicillin target? |
| cell wall synthesis |
| What causes strep throat? |
| Streptococcus pyogenes |
| What causes skin infections including folliculitis and sty? |
| staphlococcus aureus |
| What causes impetigo and Toxic shock syndrome if released into the blood? |
| Staphylococcus aureaus |
| What is the disease name for a skin infection that results in rapid tissue destruction, often requiring amputation |
| Necrotizing fasciitis |
| Swimmer's ear, catheter infections, burn wounds infections are most commonly caused by _______ |
| Pseudomonas aeruginosa |
| varicella is? |
| Chickenpox, a herpes virus |
| Herpes Zoster... |
| Is also known as shingles |
| Rubeola |
| Aka: Measles |
| What is causes a yeast infection? |
Candidaisis albicans Mouth: thrush Also in the genitouriary tract |
What causes pinkeye?
|
| Haemophilus influenzae |
Menegitis: encephalitis: menigoencephalitis: |
Inflammation of the meninges Inflammation of the brain Inflammation of both |
| What causes bacterial meningitis? |
| Neisserria meningitidis |
| What is hepatitis? What causes it? |
| Inflammation of the liver: the hepatitis virus (A-E) |
After recover you confer lifelong immunity to this virus. There is no specific treatment but there is a vaccine. Virus is shed and spread through the fecal oral route. |
| Hep A |
A virus transmitted parentally and sexually. No treatment but there is a vaccine. |
| Hep B |
| What causes pus discharge from the penis and often little to no symptoms in women. Caused by what bacteria? |
| Gonorrhea; Neiserria gonorrhea |
| What causes chlamydia often a co-disease with gonorrhea. |
| chlamydia trachomatis |
| What causes Syphilis? |
| treponema pallidum |
| Name the four stages of syphilis. |
Primary: small hardbased chancre sore (highly infecious) Secondary: Skin rash - especially on palms and soles (normally uneffected regions) Latent stage: asymptomatic and not contagious Tertiary: Gummas - rubbery tissue masses (death)
|
| What causes genital warts? |
HPV human palliomavirus
|
| Why isnt' there a vaccine for the common cold? |
| because there are so many different types of viruses that cause it. |
