Microbiology Exam 2 Questions and Answers

Microbiology Exam 2 Questions and Answers Are Viruses Living or Nonliving? They are only considered living when they are inside of a host cell, using their resources and energy. Outside of a host they are considered intert. When are Viruses considered to be "alive"? When they are inside of a host cell. When inside, their nucleic acid (ONLY RNA OR DNA) become active. *Virus replicates Obligatory Intracellular Parasites Require livinghost cell in order to multiply - Such as Viruses. Defining a Virus 1) Contains 1 Nucleic Acid (DNA or RNA) 2) Protein coat surrounds the DNA or RNA 3)Multiply within host using host machinery ---because they don't have the ways of making/obtaining their own nutrients. like ATP or enzymes. Virus Characteristics *Some are enclosed by an envelope which consists of lipids, proteins, carbohydrates *some have spikes *only infect the cells of ONE host. Host Range The spectrum of host cells that a virus can infect. -invertebrates -vertebrates -plants -protist -fungi -bacteria The virus must be able to attach to a the particular host's cell. **Host range is determined b specific attachment sites on the host cell's surface Bacteriophages Bacteria that is infected by a virus How do Viruses attach to a host cell Through receptors on the host cell's surface. There must be an interaction. Capsid Protein coat that surrounds the Nucleic Acid of a virus. (not the whole virus itself. That's an envelope.) ***Made up of individualized Capsomeres*** *accounts for most of the mass of a viral cell. Capsomeres Protein subunits that make up a capsid (think of tiny balls that come together to make a huge coating around the Nucleic Acid) *capsomeres can be made up of multiple types of proteins or one single type of protein Envelope Surrounds the virus as a whole. *Synonymus to a somatic cell's Plasma Membrane. But around a virus. ***Composed of proteins, lipids and carbs. *Could be covered in spikes NOT ALL VIRUSES HAVE ENVELOPES Spikes Cover the envelope of the cell Composed of protein and carbohydrates. -Used for attachment to the host cell Spikes differ, and can be identified as different virus by the host body. That's why you can get the flu more than once a year, there's a change in spikes. -Can be used for identification for some virsus under microscope. Helical Capsid Long rods that are flexible and rigid These surround the Nucleic Acid. *Capsids are hollow cylinders surrounding the nucleic acid. *CAN OR CANNOT HAVE A ENVELOPE. Without envelope = they look like long noodles, because it's just the capsid and no sphereical shape WITH the envelope = they look like balls, but with their Nucleic acids all tangled inside. Polyhedrical Capsid These are icosahedron, and are 20 triangle shapes, with 12 corners. THEY CAN BE WITH OR WITHOUT ENVELOPE -Without envelope, you can see their individual caposomere and their many different triangular faces of the Capsid WITH envelope, they appear ordinarily spherical, and like a normal cell. (Some have spikes) Complex Capsid They have a variety of weird shapes within the one virus cell, and look just straight up weird. They can be bacteriaphages and just look mutuant Family names suffix for Taxonomy -viridae Ex. Herpesviridae Genus name suffix Taxonomy -virus Genus Simplexvirus Ex. Herpesvirus Viral species A group of viruses sharing the same genetic information and ecological niche (niche=host) Viral species are designated by descriptive common names, such as human immunodeficiency virus (HIV), Subspecies They are determined by the NUMBER that is attached to the specific genus of the family. These are viruses that can affect humans HIV-1, HIV-2 Plaque Areas of clearing where the the virus has killed the bacteria PFU Plaque Forming Unit *Concentrations of viral suspensions measured by the number of plaques Cytopathic Effect CPE This is cell deterioration after a virus infects a monolayer of cells that appears to be growing just fine. The cells clump together as they deteriorate. Virion Complete, fully developed, infectious viral particle composed of nucleic acid and surrounded by protein coat that protects it from the environment and is a vehicle of transmission from one host cell to another. **AKA MATURE PHAGE Lytic Cycle The cycle that bacteriophages use to multiply. WHERE THE CYCLE ENDS WITH LYIS AND DEATH OF HOST CELL. Lysogenic Cycle The cycle that bacteriophages use to multiply. Where the host cell remails alive after the cycle. Phage Lysozyme Enzyme released by the bacteriophage tails to break down bacteria cell wall so they can enter the bacteria. Lytic Cycle of a T-Even Bacteriophage 1) ATTACHMENT to bacteria cell wall by tail fibers to complementary receptor sites 2) ENTRY of viron DNA inside the bacteria, and the protein capsid is left outside of the bacteria cell 3) BIOSYNTHESIS goes underway to use the host machinery to interfear with host DNA synthesis, and makes the phage DNA instead 4) MATURATION is undergone when capsids are assembled around the DNA, and the "assembly line" happens to form the virions 5) RELEASE or LYSE happens when the new virions are released to infect other cells. The host cell does not survive through this cycle. Prophage The Virus and the bacteria's DNA combined into one. Oncogene a gene that can bring about malignant transformation *Also called a cancer causing gene Pathology Scientific study of disease "Patho" disease/suffering - Logos "study of/science" =Concerned with the changes brought by the disease and change it has on the body. Pathogenesis The MANNER in which a disease DEVELOPS Eitology The study of the CAUSE of the disease Koch's Postulates 1) Same pathogen must be present in EVERY CASE of the disease (aka to be consistant) 2) Pathogen must be isolated from the disease host and grown in pure culture 3)Pathogens from the pure culture must cause the disease when it is incoulated into a healthy, suspetible lab animal and then cause disease 4) The pathogen must be isolated from the inoculated animal and must be shown to be the original organism - Both organisms infecting both host must match the kind of organism that is grown and extracted. Koch's Postulates Used to determine the causative agent for bacterial diseases Symptom SUBJECTIVE A change in a body function that is felt by a patient as a result of disease. -Subjective and not measurable by empircial data: PAIN. Sign OBJECTIVE A change in a body that can be measured and obsterved -Anything empirical: Lesions, fever, swelling Syndrome A specific group of signs and symptoms that accompany a specific disease Communicable Disease Any disease that spreads from one host to another, directly or indirectly. Contagious disease A communicable Disease that is EASILY spread from one person to the next. Non-communicable disease Not spread from one host to another *the microbes exist outside the body, and only produces disease when introduced inside TETANUS Incidence of a disease Number of people who DEVELOP and contract this disease within a certain period of time. *Diagnosed cases of HIV in 2009 alone Prevalence of a disease Number of people EXISTING WITH the particular disease at a given time. *Known cases of HIV at the point of year 2009 TAKES INTO ACCOUNT OLD AND NEW CASES FROM YEARS BEFORE Sporadic Disease Occurs only OCCASIONALLY *Typhoid fever within the US Endemic disease A disease that is constantly present in a population *Common cold Epidemic Disease If many people in a CERTAIN AREA acquire a certain disease in a relatively SHORT PERIOD of time. *Influenza, AIDS Pandemic Disease An epidemic disease that occurs worldwide *A worldwide Influenza, and AIDS Acute Disease A disease that develops rapidly but only last for a short period of time *influenza Chronic Disease Develops slowly, and the body's reactions might be less severe, but the disease is likely to continue to recur for long periods of time. Subacute Disease Symptoms between acute and chronic diseases - in the middle *Infection and bronchitis. Latent Disease Causative agents are inactive for long periods of time, then becomes active to produce symptoms *any latent viruses of the Herpesvirus family. Such as shingles or chicken pox that lay on the nerve cells. Herd Immunity When many immune people are present in a community When the number of people vaccinated goes UP, The chance of the risk to encounter the disease goes DOWN. Local infection Invading pathogens are limited to a small area of the body. *Boils and absecesses Systematic (generalized) infection Spread THROUGHOUT the body bu blood or lymph *measles Focal Infection Systematic infection that BEGAN as a local infection *Local infections can enter blood or lymphatic vessels and can spread to other specific parts of the body *can arise in areas such as teeth, tonsils, or sinuses Sepsis Toxic inflammatory condition arising from the spread of microbes from a focus of infection Septicemia Blood poisoning *multiplication of pathogens within the blood Bacteremia Bacteria in the blood Toxemia Presence of toxins within the blood Viremia Presence of virus in the blood Primary Infection Acute infection that causes an initial illness Secondary Infection Caused by opportunistic pathogen after immune system weakened by primary infection. Pneumonia is a consequence of AIDS, and is a secondary infection. Predisposing Factors Makes the body more suspectible to diease and may alter the course of disease. *gender (females have higher incidence of UTIs *genetic background ( inherited genes from parents like sickle cell anemia) *Lifestyle/Occupation *Climate/Weather Stress/Fatigue Subclinical Disease An infection that doesn't cause any noticiable illness Poliovirus and hepatitis A. You can carry it but you never contract it. Reservoirs of infection Can be human, animal, or nonliving carriers Those who carry the pathogens and transmit them to others without exhibiting any sign of illness Zoonoses Diseases that occur in wild and domestic animals and can be transmitted to humans *rabies *Lyme disease Noliving Reservoirs of Infection Soil AND Water. Bacteria strands can be found within them and contaminate them and then they can infect humans 3 means of disease transmission 1) Contact (by means of direct contact, indirect contact, or droplet transmission) 2) Vehicle (Transmission via a medium like food, water air, blood, bodily fluids, air) 3) Vectors (animals that carry pathogens to host) 3 types of CONTACT transmission 1) Direct Contact - Kissing touching hugging 2) Indirect Contact-Fomite(something normal infected) 3) Droplet transmission - microbes spread by coughing, sneezing, laughing, talking Pathogenicity The ability to cause disease by overcoming the dfense of the host Mechanical transmission Passive transport (fly landing on burger) Virulence The extent oe degree of pathogenicity AKA DANGER Biological Transport Active process. Mosquito biting an individual, giving malaria. Portals of Entry 1) Mucous Membranes 2) Skin 3) Direct deposition beneith the skin or membranes - (the parenteral route) Epidemiology The study of when/where disease occurs and how disease is transmitted in populations **there is always an epidemiologist at each large hospital to prevent nosocomial diseases and keep them under control. Portal of Entry - Mucos Membrane Lining of GI Respiratory tract Genitoruitary tract, Conjunctiva (eyeball and the lining of it) Most common way is GI and Respiratory tract. Case Reporting Health care workers must report specified disease to local, state, and national offices -by doing this, (by law) this documentation raises awareness so the nation can prevent epidemics or a pandemic from occuring. *examples: AIDS, measles, gonorrhea tetanus, typhoid fever. CAN LEAD TO EDUCATION ABOUT ILLNESSES. ID(subscript)50 ID= Infectious Dose Infectious dose for 50% of population ***How many endospores that are necessary to infect 50% of the population. Nationally Notifiable Diseases Diseases in which physicians are required by law to report. LD(subscript)50 LD=Lethal Dose Lethal Dose (OF A TOXIN) for 50% of population. Morbidity Rate How many people are affected by disease Adhesin Also called a ligand that helps the pathogen adhere to the host cell in order to invade it *Located on the pathogen. Mortality Rate How many people have died resulting from this disease M Protein Surface Protein in Cell wall component of bacteria that helps with bacterial attachment to an epithelia cell Resists phagocytosis of WBC ***INcreases Virulence of the bacteria Microbial antagonism Competition for nutrients ****When normal microbiota can prevent pathogens from causing an infection Mycolic Acid (Waxy Lipid) A cell wall component that can prevent phagocytosis It can even multiply within the phagocyte Coagulases Form blog clots within the blood. An enzyme that a pathogen uses to clot the blood to prevent phagocytosis What causes Staph to be so deadly and prevent blood from flowing to parts of the body Collagenase Enzyme produced by bacteria. It breaks down the protein collagen and breaks down the connectrive tissue of muscles and other body organs and tissue. IgA Proteases Enzymes that the bacterial cell can give off to Destroy antibodies Antigenic Variation Antigens line the ouside of a bacterial cell for the attachment to the host cell. The body makes antibodies to attach to these antigens to destroy them and prevent their wrongdoing However, when pathogens alter their surface antigens, making the antibody that the body made unusable. THIS SNEAKY SNAKE MOVE IS ANTIGENIC VARIATION. By the time the immune response reaches a pathogen, the pathogen has already alters its antigens and is unaffected by antibodies. ***The flu does this Siderophores The iron sealing protein that bacteria use to attach to the iron tigher than the iron within the host cell's