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Microbiology Exam Study Guides 71008 - BIOL 305 - 001
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This 59 page Study Guide was uploaded by Jacqueline Shaia on Thursday January 21, 2016. The Study Guide belongs to 71008 - BIOL 305 - 001 at George Mason University taught by Deborah A Polayes (P) in Fall 2015. Since its upload, it has received 78 views. For similar materials see Biology of Microorganisms in Biology at George Mason University.
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Microbiology Final Study Guide: New Information Specific Immune Response: 1. What is an antigen? What macromolecules are the best antigens? a. Antigen (ag): substance that stimulates an immune response (not self) i. A substance that causes the body to produce specific antibodies or sensitized T Cells ii. May be a protein, polysaccharide, nucleoprotein (nucleic acid and protein) or glycolipid iii. Many antigens on surface of a bacterium: pili, cell wall, proteins of outer membrane, flagella, etc. iv. Other ags are pollen, egg white, blood cells, and surface molecules of transplanted cells b. Macromolecules: foreign proteins and complex carbohydrates 2. What is an epitope? A hapten? An antigenic determinant? a. Epitope: antigenic determinant i. That part of a foreign substance an antibody(ab) reacts with ii. Antigens must be certain size b. Hapten: a foreign substance too small to be antigenic by itself i. Must be combine with a carrier molecule in prdr to elicit an immune response ii. Hapten can bind to an antibody 3. What is the humoral immunity system? a. B Cells and Antibodies b. 3 line of defense c. type of adaptive immunity: induced resistance to a specific pathogen. Involves recognition and has a memory d. each B cell (or clone) produces one specific antibody e. each human synthesize more than 100 million different kinds of antibodies f. mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides g. due to antibodies h. Abs are found in plasma, lymph, tissue fluid i. Abs are produced by B cells (B lymphocytes) j. Abs respond to bacteria, viruses and toxins k. Humoral system: effective against pathogens in the blood 4. Draw the structure of an antibody. Are the 4 proteins chains attached to each toher? How? a. Hinge region: attaches protein chains 5. Where are the IgG abs found? IgA, IgM, IgE, and IgD? a. IgG: blood, lymph, and intestines b. IgM: in blood, in lymph, and on B cells c. IgA: mucosal protection (in secretions) d. IgD: in blood, lymph, and on B cells e. IgE: on mast cells, basophils, and in blood i. Bound to cells by Fc region to specific receptors ii. Allergic reactions 6. What do secretory IgA abs in the intestines do? a. Can proved protection against microbes that multiply in body secretions 7. What role does IgE abs play in allergies? a. Allergic reactions; lysis of parasitic worms 8. Which abs activate the complement system? a. IgG: fix complement 9. What is naturally acquired immunity? How does it differ from passively acquired immunity? a. Naturally acquired active immunity: resulting from an infection i. Antigens enter the body naturally: body produces antibodies and specialized lymphocytes b. Naturally acquired passive immunity transplacental or via colostrum i. Antibodies pass from mother to fetus via placenta or to infant in the mothers milk 10. What is artificially acquired active immunity? How does it differ from artificially acquired passive immunity? a. Active: antibodies are introduced in vaccines; body produces antibodies and specialized lymphocytes: injection of Ag vaccine b. Passive: preformed antibodies in immune serum introduced into body by injection: injection of Ab 11. Example of each of the above four types of acquired immunity: bold ones 12. What cells are involved in the cellmediated IS? a. T cells (t lymphocytes) 13. Where do B cells mature in humans? T Cells? a. B cells: probably mature in bone marrow i. B cells arise from stem cells in bone marrow b. T cells mature in the thymus 14. What does the clonal selection theory say? a. Are millions of ags, hence millions of abs b. Means we need millions of rearrangements of genes to code for the abs 15. What is the significance of Memory Cells? a. Adaptive immunity has a memory b. B cells differentiate into plasma cells and some become memory ells c. T helper cells or T Hcells also differentiate into memory cells d. Allows you to fight an illness more easily when reinfected because your body has made antibodies and has that memory i. Generating an accelerated and more robust antibodymediated immune response in case of reinfection 16. Why are there so many antibodies? a. Diversity comes from the fat that there is a variable region on the light chain and the heavy chain i. Almost 4 million combinations 17. What role does the specific immune system play in inflammation? a. Inflammation: second line of defense b. Activation of complement: causes inflammation and cell lysis 18. What is opsonization? Agglutination a. Antibodyantigen interactions: i. Opsonization and phagocytosis and cell lysis: activation of complement ii. Agglutination: agglutination of particular (cell bound) abds causes ags to be more readily phagocytized 19. What are cytokines? Chemokines? Interleukins? a. Cytokines: small chemical molecules i. Note: overproduction: cytokine storm b. Chemokines: types of cytokine (cell communicates via cytokines) i. Induce the migration of leukocytes c. Interleukin: type of cytokine i. Promote the development and differentiation of T and B lymphocytes 20. What do T helper cells do? T regulatory cells? T cytotoxic cells? a. T helper cells: Cd4+ (also differentiate into memory cells) i. T H1produce IFNy which activates cells related to cellmediated immunity, macrophages, and abs ii. T H2activate eosinophil’s and B cells to produce IgE iii. T H17timulate the innate immune system iv. TF: stimulate B cells to produce plasma cells and are involved in class switching b. T regulatory cells i. CD4 and CD25 on surface 1. Turn off immune response when no ag is present 2. Involved in self maintenance, ie, prevents immune response to self ags c. T cytotoxic cells: Cd8+ or T Ccells i. Target cells are selfcells carrying endogenous antigens ii. Activated into cytotoxic T lymphocytes (CTLs) 1. CTLs recognize Ag + MHC I 2. Induce apoptosis in target cells 3. CTL releases perforin and granzymes 21. What are CD’s and MHC? a. Cell surface receptors designated by CD b. Major Histocompatability Complex (MHC) i. Divided into 3 classes depending on structure and function ii. Class 1: accepts all cells except RBCs, sperm, ovum and cornea 1. Marks cells as “self” directly activates CD8+ cells iii. Class II: activated macrophages, mature B cells and some T cells to interact with Bcells and macrophages iv. Class III encodes factor B and 2 forms of C4 of the complement system 22. How do T helper cells “help”? a. TCRs recognize Ags and MHC II on APC (TCR = tcell receptors) b. TLRs are a costimulary signal on APC and T H c. T Hcells produce cytokines and differentiate into: TH1, TH2, TH17, Memory cells 23. What is an APC: an ag presenting cell? a. Digest antigen b. Ag fragments an APC surgace with MHC i. B cells ii. Dendriteic cells iii. Activated macrophages Vaccines: 1. What is the origin of the word “vaccination”? a. Cow: vacca, therefore vaccination b. 1798: Edward Jenner began a series of experiments to prevent smallpox i. people who survived smallpox did not get the disease again ii. people who had cowpox didn’t get smallpox 1. expose people to cowpox deliberately and see if it prevents smallpox 2. Ab to cowpox were able to neutralize the smallpox virus 2. Why is Jenner the father of Immunology? (#1) 3. List 6 forms of vaccines we use today a. Attenuated, whole agent vaccines b. Inactivated, whole agent vaccines c. Toxoids subunits vaccines d. Conjugated vaccines e. Nucleic acid vaccines 4. What is an attenuated virus? An attenuated bacterium? a. Weakened bacteria or virus b. Able to replicate but not virulent c. “modifiedlive” vaccine 5. What is a toxoid? Why does one protect against its analogous toxin? a. Modified toxins, antigenic but not toxic 6. What is a subunit vaccine? A conjugated vaccine? a. Subunit vaccine i. Contains parts of a M/O or virus ii. Bacterial capsule iii. Viral peplomers 1. People receive recombinant, purified peplomers as a vaccine b. Conjugated vaccine i. Principle: combining a poorly immunogenic antigen with one that elicits a good immune response 7. What is a DNA vaccine? a. Nucleic acid vaccines i. Inject the DNA that codes for the protein wanted as a antigen ii. DNA is expressed in person iii. Thus the protein is synthesized in the person Selected Diseases of the Skin and Eyes: 1. What are the properties of the normal bacteria of the skin? a. Gram +, salttolerant bacteria i. Staphylococci ii. Micrococci iii. Diptheroids b. Grow on oils c. Aerobes on surface i. Corynebacterium xerosis d. Anaerobes in hair follicles i. Propionibacterium acnes e. Yeast i. Malassezia furfur 2. Structure of skin, role mucus membranes, cilia a. Skin: i. Thin outer portion: epidermis ii. Inner, thick portion: dermis iii. Perspiration and sebum contain nutrients iv. Salt inhibits microbes v. Lysozyme hudrolyzes peptidoglycan vi. Fatty acids inhibit some pathogens vii. Antimicrobial peptides: defensins b. Mucus Membranes and Cilia: i. Cells secrete mucus ii. Barrier iii. In eyes, washed by tears with lysozyme iv. Cilia: carry mucus out of body 3. List the 4 virulence factors produced by S. aureus (MERSA) a. Virulence factor: are molecules produced by pathogens and contribute to the pathogenicity of the organism i. Antibiotic resistant ii. Leukocidin iii. Resists opsonization iv. Survives in phagolysosome v. Lysozyme resistant vi. Exfoliative toxin vii. Super antigen 4. What skin diseases do strep cause? a. Streptococcal skin infections i. Streptococcus pyogenes 1. Divide into 3 groups according to their hemolysis (alpha, beta, y) ii. Necrotizing fasciitis iii. Streptococcal toxic shock syndrome 5. What skin diseases does Pseudomonas aeruginosa cause? What virulence factors? i. Pseudomonas dermatitis ii. Otitis extema: swimmer’s ear iii. Post burn infections iv. Opportunistic b. Virulence factors: i. Endotoxin ii. Exotoxin A – stops protein synthesis iii. Exotoxin S – adhesion iv. Fimbriae v. Capsule vi. Proteases 6. What causes acne? Warts? Smallpox? a. Acne: i. Comedonal acne ii. Inflammatory acne iii. Nodular cystic (severe) acne b. Warts: human papilloma Virus c. Smallpox (variola) i. Orthopox virus 7. How does the VZV get into the body? What diseases does this virus cause? a. VZV: varicella – Zoster Virus or human herpes virus type 3 (HHV3): chicken pox i. Transmitted by the respiratory route ii. Shingles 1. Reactivation of latent HHV3 releases virus that move along peripheral nerves to skin 8. What disease does HSV1 cause? HSV2? a. Herpes Simplex i. Human Herpes Virus 1 (HSV1) and 2 (HSV2) 1. Cold sores or fever blisters (vesicles on lips) 2. Herpes gladiatorum (vesicles on skin) 3. Herpetic whitlow (vesicles on fingers) 4. Herpes encephalitis *HSV1 can remain latent in trigeminal nerve ganglia * HSV2 causes venereal herpes transmitted sexually no vaccine to the HSVs 9. How do we prevent measles in the USA? a. prevented by vaccination (3 attenuated viruses (MMR)) 10. What organism causes neonatal gonorrheal opthalmia? Trachoma? a. Neonatal gonorrheal opthalmia or opthalmia neonatorum i. Neisseria gonorrhoeae b. Trachoma: chalmydia teachomatis Diseases of the Nervous System: 1. Name of the Diseases Discussed in class and the diseases of each causes: a. Haemophilus influenza Meningitis: bacterial meningitis b. Neisseria Meningitis: bacterial meningitis (also called meningococcal meningitis) c. Streptococcus pneumonia meningitis: bacterial meningitis (pneumonoccal meningitis) d. Clostridium tetani: tentanus (lock jaw) e. Clostridium botulinum: botulism f. Mycobocterium leprae: leprosy g. Poliomyelitis: polio h. Rhabdovirus: rabies i. Flaviviridae family: West Nile Virus j. Tryponosoma brucei gambiense: African Trypanosomiasis i. Chronic 2 to 4 yrs k. T.b. rhodesiense infection: African Trypanosomiasis 2. What is Meninges? Meningitis? a. Meninges: protective cover of the brain and spinal cord b. Meningitis: inflammation of the meninges 3. What are the bacteria that cause more than 70% of meningitis in children? a. Haemophilus influenza meningitis, Neisseria Meningitis, Streptococcus pneumonia meningitis 4. What does tetanus do? What type of paralysis results? a. Tenanospasmin released from dead cells blocks relaxation pathway in muscles b. Grows dead in wounds c. Lockjaw 5. Where is clostridium tentani found in nature? a. In the soil b. Can also be found in animal and human fecal samples 6. How is tetanus prevented? Treated? a. Prevention by vaccination with tetanus toxoid (DTP) and booster (dt) b. Treatment with tetanus immune globulin 7. How do we prevent botulism in this country? a. Proper canning b. Nitrites prevent endospore germination in sausages 8. What does the botulinum toxin do? What types of paralysis does it cause? a. Botulinal toxin blocks release of neurotransmitter, causing flaccid paralysis – (weakness or paralysis and reduced muscle tone, no nerve impulses therefore muscles cannot contract) 9. Is there a vaccine to prevent tetanus? Botulism? a. Tetanus: yes b. Botulism: no 10. What are the symptoms of Botulism? a. Nausea may proceed neurological symptoms b. Double or blurred vision c. Difficulty swallowing, general weakness d. Infant botulism: results from C. botulism growing in intestines i. Does not compete with normal intestinal flora of adults ii. If symptoms appear slowly: crying, sucks poorly, cant hold up head iii. If symptoms appear rapidly: death due to respiratory failure 11. What is Hansen’s disease? How is it transmitted? a. Treatments/Prevention: i. Leprosy also called Hansen’s disease ii. Transmission requires prolonged contact with an infected person 1. Enters through skin or respiratory tract 2. Most likely due to shedding of organism by respiratory tract iii. Grows in peripheral nerves and skin cells iv. Treatment: dapsone (a sulfa drug) + rifampin (semisynthetic antibiotic but resistant strands have developed) v. Prevention: no real vaccine, BCG: vaccine for M. Tuberculosis, a live vaccine may give minimal immunity 12. How is polio transmitted? a. By ingestion 13. How does the OPV compare to the IVP? Which vaccine is more effective? a. OPV: oral polio vaccine – sabin vaccine (3 live viruses/attenuated) i. Produced in 1963 ii. Contains attenuated polioviruses, viruses can replicate iii. Given orally iv. Intestinal IgAs are produced v. Problem: will virus revert to wild type? b. IPV: inactivated polio vaccine, salk vaccine: inactive i. Boosters needed ii. Developed in 1954 iii. Effective but no intestinal IgAs produced c. EIPV: enhanced inactivated polio vaccine i. Produces a better ab response than IPV ii. Given to immunosuppressed people d. current thoughts: given EIPV first to produce circulating abs then give OPV to produce intestinal abs 14. What causes rabies? Is there a vaccine to prevent this? a. Caused by rabies virus aka rhabdovirus b. Yes there is a vaccine 15. What animals are affected by Rabies in the US? a. Mammals 16. How is a case of rabies in a human treated? Prevented? a. Preexposure prophylaxis: injection of human diploid cells vaccine (HDCV) b. Postexposure treatment: vaccine plus rabies immune globulin (RIG) c. Prevention i. Vaccinate domestic animals ii. Attempts to vaccinate wild animals 17. List some viruses that cause encephalitis? What is encephalitis? a. Encephalitis: inflammation of the brain b. Rabies: West Nile Virus c. Rabies 18. What causes sleeping sickness? a. African Trypanosomiasis: sleeping sickness b. Trypanosome brucei gambiense (chronic 2 to 4 yrs.) c. T.b. rhodensiense infection (acute – few months) d. Transmitted from animals to humans by tsetse fly vector Diseases of the Respiratory System: 1. List names of organisms that causes each of the following diseases: rheumatic fever, scarlet fever, diphtheria, whooping cough, middle ear infection, pertussis, TB, flu, pneumonia a. Rhematic fever: streptococcus pyogenes (bacterial diseases of the URT) b. Scarlet fever: streptococcus pyogenes (bacterial diseases of the URT) c. Diphtheria: Corynebacterium diphtheria (bacterial diseases of the URT) d. Whooping cough: Bordetella pertussis e. TB: Mycobacterium tuberculosis f. Middle ear inection: Streptoccus pyogenes (bacterial diseases of the URT) g. Pertussis (whooping cough): Bordettella pertussis h. Flu (influenxa): virus, influenza virus (orthomyxovirus) i. Pneumonia: pneumococcal neumonia, Haemaphilus influenza pneumonia, mycoplasmal pneumonia, viral pneumonia 2. What 2 diseases can result from an untreated strept thought? a. Middle ear infections, rheumatic fever, tonsillitis 3. What is the major virulence factor of Corynebacteria diphtheria? a. Stops protein synthesis in cells of throat b. Forms psedomembrane of mucus, WBCs, and dead cells c. Cells replicate in throat and secrete exotoxin d. Diphtheria toxin produced by lysogenized C. diptheriae 4. What are the forms of the antigens in the DPT vaccine? a. Diphtheria, pertussis (whooping cough), and tetanus 5. Why is pertussis as contagious as it is? a. Very contagious because bacteria attach to cilia, so can be spread very easily i. Stage 1: catarrhal stage = common cold ii. Stage 2: paroxysmal stage = violent cough, mast contagious iii. Stage 3: convalescence stage= less severe cough 6. Discuss the stages of Tuberculosis a. Acquired organism by inhalation i. Organism goes to lung ii. Is phagocytized by macrophage iii. May be killed by macrophage or iv. If not, other macrophages come to lung v. A tubercle is formed, a granuloma of macrophages, neutrophils, bacteria, and tissue cells in the lung vi. Other macrophages ingest M. tuberculosis vii. Infected macrophages will die and release M/O 1. Form a CASEOUS center (cottage cheese) 2. Do not multiply but lie dormant for years 3. Live bacteria within the center surrounded by tightly packed WBCs trying to “walloff” M/O 4. Eventually calcium deposited see on xray a. Ghon complexes viii. Lique faction: occurs when caseous center enlarges and M/O start to multiply 1. Lesion may rupture allowing M/O to enter tissues and blood 2. Military TB: systematic M. Tuberculosis infection , bones, skin, various organs 7. What is a tubercle? How is a pathogen protected by these structures? a. A round nodule on lungs/small lump i. Granuloma of macrophages, neutrophils, bacteria, and tissue cells ii. Provides protective niche that enables the bacilli to sustain a longterm, persistnen infection 8. What is the main host defense against M. tuberculosis? a. Phagocytosis 9. How does typical pneumonia differ from “atypical” pneumonia? a. Typical: pneumonia caused by Streptococcus pneumoniae b. Atypical: pneumonia caused by other bacteria, fungi, protozoa, and viruses i. Mycoplasma: most common of this category 10. W default number 11. With reference to the influenza virus, what is antigentic shift? Antigenic drift? a. Antigenic shift: i. Charges in HA and NA spikes ii. Probably due to genetic recombination between different strains infecting the same cell 1. 2 antigenically different viruses, there is a assortment of RNA segments 2. during assembly of viruses, there is a reassortment of RNA segments 3. result: antigenically different are produced, these are not neutralized by abs to previous virus 4. reassortment takes place in other animals eg. Pigs b. antigenic drift: i. point mutations in genes encoding HA or NA spikes ii. may involve only 1 amino acid iii. results in a different peplomer to be made iv. virus is antigenically different v. allows virus to avoid mucosal igA antibodies 12. Describe the structure of the influenza virus? a. Hemagglautinin (HA) spikes used for attachment to host cells b. Neutaminidase (NA) spikes used to release virus from cell c. Abs are bilt to H and N peplomers Diseases of the Digestive System : 1. Describe the 2 roles sucrose plays in tooth decay a. Sucrose promotes adherence of S. mutans to tooth b. The glucose of sucrose is fermented to produce lactic acid which breaks doewn calcium phosphate of tooth 2. What is the main organism that causes tooth decay? What is periodontal disease? a. Streptococci: aerototerant anaerobes b. Periodontal disease: i. Infection of gums that support teeth 1. Called gingivitis: inflammation of gums 3. What is dextran (as it relates to tooth decay)? a. Dextran: is a glycocalyz and an adhesion b. Outside of cell, some of the glucose molecules are polymerized to form long chains of glucose molecules called dextran c. Bacteria attach to tooth and to each other forming plaque 4. What is the major virulence factor of Vibria chloerae? a. Produce cholera toxin b. Toxin causes host cells to secrete Cl, HCO, and water c. Cholera is ingested, goes to intestines and adheres to lining of intestines i. Produces an exotoxin which is an enterotoxin called choleragen which causes loss of massive amounts of water and electrolytes 5. How can cholera be prevented? Is there a vaccine for this disease? a. Proper water treatment b. Proper cooking and storage of seafood c. Vaccine: killed cell and part of toxin 6. Where is V. Cholera found in nature? a. Water 7. Are all strains of E. coli nonpathogenic? a. NO some serotypes (distinct variations) are pathogenic BIOL 305 Review Question For Exam 1 (Fall 2014) – YASAMIN RAHMANI Exam will be multiple choice questions. Practice questions can be found at the end of the chapters and on line. 1. Why are microbes important? • Stonewashing: Trichoderma• Cotton: Gluconacetobacter• Debleaching: Mushroom peroxidase• Indigo: E. coli• Plastic: Bacterial polyhydroxyalkanoate 2. When was the microbial world first observed? By whom? What was needed to observe microbes? First microbes observed in 1673 by Antoni van Leeuwenhoek: microscope 3. What was meant by spontaneous generation? Understand why the first experiments “proved” there was spontaneous generation. Spontaneous generation – the hypothesis that living organisms arise from nonliving matter. 4. How was spontaneous generation disproved? Evidence Pro and Con • 1861: Louis Pasteur demonstrated that microorganisms are present in the air. Conditions Results Nutrient broth placed in flask, heated, not sealed Microbial growth Nutrient broth placed in flask, heated, then sealed No microbial growth Spontaneous generation or biogenesis? S shaped flask 5. Who was Louis Pasteur? What did he do for science? Louis Pasteur 1861 – demonstrated that microorganisms are present in the air. ▯ pasteurization, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs 6. Be able to recognize the structures of the 4 major groups of macromolecules and why they are important? Carbohydrates – cell structure and energy source Monosaccharides – simple/single sugar with 3 to 7 carbon atoms. Disaccharides – two monosaccharaides joined in a dehydration synthesis. (broken down by hydrolysis) Oligosaccharides consist of 2 to 20 monosaccharides Polysaccharides consist of tens or hundreds of monosaccharides joined through dehydration synthesis Lipids – primary components of cell membranes, nonpolar and insoluble in water. Membranes made of phospholipids Consist of C, H, and O Proteins – essential in cell structure and function. Enzyme, speed up chemical reaction – lower activation energy Transport proteins move chemicals across membranes Flagella Some bacterial toxins are proteins Made of amino acids (subunits) o Peptide bonds between amino acids are formed by dehydration synthesis Nucleic Acid – consist of nucleotides Pentose (DNA or RNA) Phosphate group Nitrogencontaining (purine – 5 carbons or pyrimidine – 4 carbons) base 7. What is a polymer? A monomer? A disaccharide? A simple lipid? Structure of a protein? Polymer – a large molecule, or macromolecule, composed of many repeated subunits. Monomer – a molecule that may bind chemically to other molecules to form a polymer. Disaccharide a sugar (a carbohydrate) composed of two monosaccharaides. Primary structure – polypeptide chain. Secondary structure – occurs when the amino acid chain folds and coils In a regular helix or pleats. Tertiary structure – threedimensional structure of a protein. Quaternary structure – consists of 2 or more polypeptides. Simple lipid – fats or triglycerides, contain glycerol and fatty acids; formed by dehydration synthesis Saturated fat – no double bonds Unsaturated fat – one or more double bond in the fatty acids 8. List 10 differences between prokaryotic cells and eukaryotic cells. Know how they are similar also. Prokaryote ▯ • One circular chromosome, not in a membrane ▯ • No histones ▯ • No organelles ▯ • Peptidoglycan cell walls if Bacteria ▯ • Pseudomurein cell walls if Archaea ▯ • Binary fission Eukaryote ▯ §§ Paired chromosomes, in nuclear membrane ▯ §§ Histones ▯ §§ Organelles ▯ §§ Polysaccharide cell walls ▯ §§ Mitotic spindle 9. Can you recognize the different shapes of bacteria? bacillus: rod like Coccus: spherical Spiral – Spirillum – Vibrio– Spirochete unusual shaped: star shaped, rectangular bacteria 10.What is a glycocalyx? Glycocalyx – any carbohydrate containing structure outside cell wall. 11.What are the functions of the bacterial capsule? Pili? Fimbriae? Flagella? Cell wall (peptidoglycan layer). Can you recognize them on a diagram of a cell? Capsule function: 1. Serves as an antigen 2. Protects against phagocytosis 3. Prevent dehydration 4. Adhesion 5. Source of nutrients (survival during lack of food in environment) Flagella – motility, including taxis, movement towards or away from an environment. Fimbriae – short, hairlike appendages; used for adhesion Cell wall (peptidoglycan layer) – polymer of disaccharide 12.What does it mean to be motile? Difference between flagella and axial filaments. • Rotate flagella to run or tumble • Move toward or away from stimuli (taxis) • Flagella proteins are H antigens (e.g., E. coli O157:H7) Axial Filaments: • Internal flagella, endoflagella • In spirochetes • Anchored at one end of a cell • Found between cell wall and outer sheath • Rotation causes cell to move Flagella Outside cell wall • Made of chains of flagellin • Attached to a protein hook • Anchored to the wall and membrane by the basal body 13.List differences between Grampositive bacteria and Gramnegative bacteria. Gram – Positive Cells Gram – Negative Cells Thick peptidoglycan layer Thin peptidoglycan layer Peptidoglycan contains No teichoic acid teichoioc acid No outer membrane around Outer membrane around peptidoglycan peptidoglycan 2ring basal body 4ring basal body Disrupted by lysozyme Endotoxin Penicillin sensitive Tetracycline sensitive 14.Know the importance of the various components of a cell wall. 1. Gives shape to cell 2. Gives rigidity to cell 3. Prevents rupture of cell in hypotonic solutions 4. Point of anchorage of flagella 5. The eubacterial cell wall is made of peptidoglycan. 15.How can we damage a cell wall? Lysozyme digests disaccharide in peptidoglycan and essentially create holes in the cell wall. 16.Why do Gramnegative bacteria have an outer membrane? To protect itself from phagocytes, complement, and antibiotics. 17.What two types of molecules are found in the cytoplasmic membrane of all cells? 18.Why are plasma membranes important? 1. Some disinfectants act at this level. 2. Some antibiotics act at this level. 3. Transport a. Passive transport uses no energy. b. Active transport uses energy. 19.How does facilitated diffusion differ from group translocation? Facilitated diffusion: Solute combines with a transporter protein in the membrane Group translocation: Requires a transporter protein and PEP • substrate is modified within the membrane. 20.What is facilitated diffusion, active transport, simple diffusion? Facilitated diffusion – molecules move from area of high concentration to area of low concentration Uses a protein carrier or permease. No energy is involved Substrates binds to carrier, carrier changes shape, and drops substrate off inside cell. Active transport – molecules move against their concentration gradient. Eg: moves from low concentration to high concentration Requires energy Specific carriers or permease Simple diffusion – movement of a solute from an area of high concentration to an area of low concentration No energy or proteins are required 21.Osmosis, what happens to cells in various solutions? Osmosis – movement of water across a selectively permeable membrane from an area of high water to an area of lower water concentration. Isotonic solution – no net movement (but water still moves in and out at an equal rate) Hypotonic solution – lysis occurs (water moves in, and pops the cell) Hypertonic solution – dehydration or plasmolysis occurs, the cell shrinks and dies. 22.What is the cytoplasm? What’s in it? Know the inclusion bodies The substance inside the plasma membrane • Is 80% water. • Contains proteins, carbohydrates, lipids, DNA, ribosomes. • Has no cytoskeleton Inclusion Bodies: ▯ • Metachromatic granules (volutin) ▯ • Polysaccharide granules ▯ • Lipidinclusions ▯ • Sulfur granules ▯ • Carboxysomes ▯ • Gas vacuoles ▯ • Magnetosomes 23.What 2 genera of bacteria form endospores? Bacillus, Clostridium 24.Why are endospores of importance to pathogenic microbiologists? • Resistant to desiccation, heat, chemicals? 25.How are endospores made? • Sporulation: Endospore formation • Germination: Return to vegetative state 26.Compare the structure of the eukaryotic cell flagellum with that of the prokaryotic cell. Flagella in eukaryotic cell ▯ §§ Surrounded by the cytoplasmic membrane. ▯ §§ Contains microtubules in a 2 + (2 x 9) arrangement. ▯ §§ Function: motility ▯ §§ Protozoa and algae. ▯ §§ Only a few per cell ▯ 27.Know the differences and similarity between Prokaryotes/eukaryotes and mitochondria. Eukaryote Vs. Prokaryote §§ EUKARYOTE §§ PROKARYOTE §§ Several chromosomes §§ One chromosome §§ Membranebound organelles §§ No membranebound organelles §§ 80S ribosomes 70S ribosomes 28.What is the endosymbiont theory? §§ Smaller prokaryotes developed first §§ Associated and lived within larger prokaryotes §§ Mitochondria and chloroplasts ~ same size as prokaryotes; divide independently of eukaryotic cell cycle; have double layer membrane §§ Eukaryotes evolved from this symbiotic relationship 29.Why are lysosomes important to us? digestive enzymes 30.What does lysozyme do? Penicillin? Why doesn't penicillin kill humans? FINISH • FUNCTION = Contain HYDROLYTIC ENZYMES • Membranebound spheres, free in cytoplasm • Derived from Golgi apparatus • Enzymes capable of breaking down engulfed bacteria • Important in phagocytosis • Found in large numbers in WBCs 31.What does denaturation mean? Hydrolysis? Dehydration synthesis? hydrolysis: breakdown dehydration synthesis: joining together such as monosaccharide’s 32.List three factors that affect enzyme activity. 1. Temperature 2. pH 3. Substrate Concentration and any inhibitors that may be present 33.What is a competitive enzyme inhibitor? A noncompetitive inhibitor? A competitive inhibitor is an inhibitor that takes the substrates active site, therefore blocking the active site from the substrate. A noncompetitive inhibitor is an inhibitor that binds to a separate spot on the enzyme and changes the shape of enzyme so that the substrate cannot bind to the active site. 34.What is an apoenzyme? A holoenzyme? A coenzyme? Name 3 coenzymes. Apoenzyme: protein Holoenzyme: apoenzyme plus cofactor Cofactor: nonprotein component Coenzyme: organic cofactor + + NAD NADP FAD Coenzyme A 35.Explain metabolic regulation of enzyme activity and compare it to genetic enzyme regulation. What is feedback inhibition? • genetic regulation• The control of enzyme synthesis. • metabolic regulation• The control of enzyme activity following enzyme synthesis . • Allosteric activators increase enzyme activity. • Allosteric inhibitors decrease enzyme activity, e.g., in feedback inhibition, the end product of a pathway turns off the first enzyme of the pathway. 36.Define an oxidation reaction. A reduction reaction. Oxidation Reaction – removal/losing of electrons Reduction Reaction – gain/addition of elections 37.How does catabolism differ from anabolism? Anabolism is the synthesis of molecules in a cell Catabolism is the decomposition reactions in a cell 38.List and define the 3 ways a cell makes ATP. 1. Substrate level phosphorylation: Energy from the transfer of a highenergy PO – to ADP generates ATP 4 2. Oxidative phosphorylation: Energy released from transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP in the electron transport chain 3. Photophosphorylation: §§ occurs in cells that undergo photosynthesis. Light energy is converted to chemical energy, ATP. ▯ §§ Only in photosynthetic cells cells that have chlorophyll, e.g., green plants, algae, and cyanobacter. ▯ §§ Are two types of photophosphorylation: cyclic and noncyclic 39.What is the chemiosmotic mechanism of energy production? A series of carrier molecules that are, in turn, oxidized and reduced as electrons are passed down the chain Energy released can be used to produce ATP by chemiosmosis 40.Which produces more energy? The complete oxidation of a molecule of glucose to form CO and H O o2 the 2 fermentation of a molecule of glucose to form ethanol? 41.How does aerobic respiration differ from anaerobic respiration? §§ Aerobic respiration: the final electron acceptor in the electron transport chain is molecular oxygen (O ) 2 §§ Anaerobic respiration: the final electron acceptor in the electron transport chain is NOT O 2 Yields less energy than aerobic respiration because only part of the Krebs cycle operates under anaerobic conditions 42.What are some electron acceptors in anaerobic respiration? Nitrate, Sulfate, and Carbonate 43.What cells undergo photophosphorylation? occurs in cells that undergo photosynthesis. Light energy is converted to chemical energy, ATP. ▯ §§ Only in photosynthetic cells cells that have chlorophyll, e.g., green plants, algae, and cyanobacter. ▯ §§ Are two types of photophosphorylation: cyclic and noncyclic 44.What are cyclic and noncyclic photophosphorylation? 45.What happen during the CalvinBenson Cycle? Why is it important? § Energy is used in the CalvinBenson cycle to fix CO § 2 §§ Uses CO as2 arbon source §§ Photoautotrophs use energy in the CalvinBenson cycle to fix CO 2 §§ use CO as carbon source 2 Noncyclic photophosphorylation 46.Is oxygen required for glycolysis? No 47.What is glycolysis? What are the end products? What is the preparatory stage? §§ The degradation of glucose in series of enzyme catalyzed reactions. §§ One 6carbon molecule becomes two 3carbon molecules. §§ Free energy released from glucose is conserved as ATP and NADH. §§ Also called the EmbdenMeyerhof Pathway. §§ Is anaerobic in that it requires no oxygen. Preparatory Stage of Glycolysis §§ 2 ATP are used §§ Glucose is split to form 2 glucose3 phosphate ▯ 2 glucose3 phosphate are oxidized to 2 pyruvic acid ▯ 4 ATP are produced ▯ 2 NADH are produced 48.What is the importance of the pentose phosphate pathway? Alternatives to Glycolysis §§ Pentose phosphate pathway ▯ §§ Uses pentoses and NADPH ▯ §§ Operates with glycolysis ▯ §§ Provides intermediates for nucleic acid and amino acid synthesis 49.Why would cells use the EntnerDuodoroff pathway to oxidize glucose instead of the Embden Meyerhof pathway? EntnerDoudoroff pathway§§ glucose is oxidized to pyruvic acid§§ Produces NADPH and ATP§§ Does not involve glycolysis§§ Pseudomonas, Rhizobium, Agrobacterium the Embden Meyerhof pathway (this is another name for glycolysis) 50.What is fermentation? §§ Any spoilage of food by microorganisms (general use) §§ Any process that produces alcoholic beverages or acidic dairy products (general use) §§ Any largescale microbial process occurring with or without air (common definition used in industry) §§ Releases energy from oxidation of organic molecules §§ Glycolysis > pruvate §§ Does not require oxygen §§ Does not use the Krebs cycle or ETC §§ Uses an organic molecule as the final electron acceptor §§ Generates a small amount of ATP§§ Most of energy stored in fermentation products §§ Transfer electrons from NADH, NADPH §§ Electrons transferred to endproducts§§ Generate NAD and NADP + 51.What is the purpose of the Kreb Cycle? What molecule enters the Krebs cycle? Kreb Cycle is the oxidation of acetyl CoA, which produces NADH and FADH . Pyruvic Acid (fro2 glycolysis) is oxidized and decarboxylated. 52.How does homolactic acid fermentation differ from heterolactic acid fermentation? Alcohol fermentation: produces ethanol + CO 2 Lactic acid fermentation: produces lactic acid Homolactic fermentation: produces lactic acid only Heterolactic fermentation: produces lactic acid and other compounds 53.Which do you think first appeared in living cells? Fermentation, aerobic respiration, or anaerobic respiration? Why? Anaerobic respiration: because no organic electron acceptor is used 54.What macromolecules other than carbohydrates are energyrich? 55.Is an energyrich molecule a reduced molecule or an oxidized molecule? 56.Know what a phototroph is, a chemotroph, an autotroph, and a heterotroph. Phototroph – use LIGHT as their energy source Chemotroph – use REDOX as their energy source Heterotroph – use ORGANIC C as their energy source 57.Outline the steps of binary fission. 58.What happens during the phases of growth of a bacterial culture? 1.LAG § Increase in cell size and division § Intense increased metabolic activity § Sensitive to physical & chemical damage 2.LOG/EXPONENTIAL § Maximal growth and cell division Cells doubling at the fastest rate Cell size is slightly decreased § Increased metabolic activity § Sensitive to physical & chemical damage 3. STATIONARY § Growth rate eventually decreases then stops § # of new cells = # of dead cells § Nutrient depletion § Metabolic byproducts 4. DEATH (DECLINE) § Whole culture dies at first slowly then exponentially 59.What is the generation time? Time it takes for a culture to double in size 60.Why do we plot population growth on a logarithmic scale instead of on an arithmetic scale? Use logs so that we can see the minor changes during lag phase and early log phase and the rapid changes during log phase and the death phase all at the same time on the same graph 61.What are the requirements for growth? Temp, pH, osmotic pressure, organic and trace elements, and sometimes oxygen depending on if its an aerobe or not 62.What is a thermophile? A mesophile? A psychrophile? Thermophile – heat loving (4070 °C) Mesophile – moderate temp. (1047 °C) Psychrophile – cold loving (015 °C) 63.Why is pH important for growth? Why is osmotic pressure important/ (what’s a halophile?) 64.Why do cells need nitrogen? Phosphate? Carbon? Sulfur? Nitrogen – amino acids/proteins, nucleic acids, and ATP Phosphate – nucleic acids, ATP, and phospholipids Sulfur – amino acids, vitamins. 65.Why does oxygen kill obligate anaerobes? Why doesn't it kill obligate aerobes? Obligate anaerobes can only grown in the ABSENCE of oxygen Obligate aerobes can only gown in the PRESENCE of oxygen 66.What does superoxide dismutase do? Does a facultative anaerobe have this enzyme? Superoxide dismutase enzyme that catalyzes the dismutation of superoxide (O ) in2o oxygen and hydrogen peroxide. No because anaerobes do not utilize oxygen. 67.How do we measure microbial growth? Number of bacteria/ml = (number of cells counted/volume of area counted) Plate counts, filtration, MPN, direct microscopic count, turbidity, metabolic activity, and dry weight. 68.What is a biofilm? Microbes attach to solid surface and grow into masses. A couple of sample questions: 1. Each of the following is a living microorganism except: a) A bacterium b) A fungus c) A virus d) A green alga e) A protozoan 2. The person who originally proposed that infectious disease was due to little spores or seeds that went from person to person is a) Janssen. b) Fracastoro. c) van Leeuwenhoek. d) Pasteur. 3. Prokaryotic cells have each of the following characteristics, except: a) No membranebound organelles in the cytoplasm. b) No histones associated with the DNA. c) Typically, one circular chromosome consisting of double stranded DNA. d) Endoplasmic reticulum. 4. Which one of the following statements concerning lysosomes is FALSE? a) Lysosomes contain hydrolytic enzymes. b) Lysosomes contain lysozyme. c) Lysosomes are found in procaryotic and eucaryotic cells. d) Upon phagocytosis of a food particle, a phagosome fuses with a lysosome forming a phagolysosome. Study Guide for Exam 2 The Growth and the Control of Microbial Growth 1. How do physical antimicrobial agents act? What do they do to cells? Kills the cell by damaging its physical being such as alteration of the membrane, damage to protein and nucleic acids, and inhibition of cell wall synthesis. 2. Know the definitions for sepsis, asepsis, disinfection, antiseptic, germicide, sterilization Sepsis: refers to microbial contamination Asepsis: the absence of significant contamination o Aseptic surgery techniques prevent microbial contamination of wounds Disinfection: process in which the vegetative microbial forms are destroyed o Does not necessarily include endospores or viruses A substance that is disinfected is usually NOT STERILE Reduction or inhibition of growth but not total destruction of all living forms o Disinfectants are usually chemicals used on inanimate objects Antiseptic: against infection o Chemical disinfection of living tissues o Antiseptics are disinfectants that do not destroy the living tissues Sterilization: process in which all forms of microbial life are destroyed o Includes bacterial endospores and viruses o No degrees of sterility Germicide: chemical agent that kills microbes but not necessarily the endospores o Cide = KILL (kill germs – pathogens) o Bactericide: kills bacteria (bacteriocidal) o Sporicide: kills spores o Virucide: inactivates viruses o Fungicide: kills fungi 3. How does dry heat work? How does moist heat work? Both physical methods of microbial control Dry heat: kills by oxidation Moist Heat: denatures proteins o Boiling: Proteins will coagulate (denature) 100 degrees C at sea level for 10 min breaks the Hbonds in the proteins kills most vegetative cells, fungi, and some viruses **Spores take longer** disinfects does not sterilize o Autoclave: steam under pressure – higher pressure higher temp. Steam replaces the air Steam must contact item’s surface o Pasteurization: use of heat to destroy microbes High temperature shorttime: 72 degrees C for 15 sec Ultra high temp 140 degree C < 1 sec Thermoduric organisms survive 4. List the six major physical methods used to control microbial growth. Moist heat Dry heat Filtration Cold Desiccation Osmotic pressure Radiation 5. Is "cold" bacteriostatic or bactericidal? How about desiccation, filtration, and osmotic pressure? Bacteriostatic: process of inhibiting the growth of bacteria o Inhibits BUT does not necessarily kill the bacteria Bactericidal: agents that kill microorganisms Cold: lowtemp = inhibits growth: bacteriostatic Desiccation: bacteriostatic Filtration: passing a liquid or gas through a material with pores small enough to retain bacteria on the material itself, often used for heatsensitive material. Osmotic Pressure: bacteriostatic 6. How would you sterilize each of the following? Glassware, a heat sensitive vitamin solution, an old book, latex gloves, dental instruments Glassware: autoclave Heat sensitive vitamin solution: filtration Old book – pasteurization Latex glove – autoclave Dental instruments – autoclave 7. Is radiation bactericidal or bacteriostatic? What do ionizing and nonionizing radiation do to cells? Radiation: bactericidal Ionizing: bactericidal Nonionizing: bactericidal 8. What are the principles of effective disinfection? Concentration of disinfectant Organic matter pH Time 9. You have just isolated a chemical from the roots of a bayberry bush. What would you do to determine if the chemical is bacteriostatic or bactericidal? Effectiveness may be evaluated using the filter paper method o Agar plate with microbes spread uniformly o Paper discs containing chemical of interest placed on agar plate o Incubate and observe ZONE OF GROWTH INHIBITION 10. Know chemicals used in control of bacteria Chemical Methods to control growth o Used on living and nonliving surgaces o Many different chemicals, each with a different mode of action o May be bactericidal or bacteriostatic, depending upon conditions o Effectiveness may be evaluated using the filter paper method 11. How do phenols disinfect? Alcohols? The soaps? Halogens? Phenols: (carbolic acid) DISRUPTS PLASMA MEMBRANE o Active for extended periods of time o Bactericidal or bacteriostatic LYSOL – Ophenylphenol (a cresol) Used to disinfect feces, sputum, and pus Phisohex –hexachlorophene Effective versus gram +ve organisms o Bisphenols Hexachlorophene, triclosan Soap: by killing the transit bacteria that are on the surface of the skin, the soap breaks the bacterial membrane. o Antibacterial soap: kills residual bacteria deep in the skin. Halogens o Iodine Tinctures: in aqueous alcohol Iodophors: in organic molecules Alter protein synthesis and membranes o Chlorine: bleach (HOCl) Oxidizing agent Alcohols o Ethanol, isopranol o Dentaure proteins, dissolve lipids, disrupts membranes o Requires water Kill bacteria and fungi Not effective against nonenveloped viruses and endospores Not good antiseptic for wounds Phenols: (carbolic acid) Phenols: (carbolic acid) 12. Why is iodine such a good disinfectant? How does it do what it does? Tinctures in aqueous alcohol, iodophors in organic molecules, alter protein synthesis and membranes. 13. Why is it that bacteria do not develop resistance to the chemical disinfectants or antiseptics? (What is an antiseptic?) Because it doesn’t kill the bacteria, it simply prevents it from infecting a wound Antiseptic antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction 14. What is a germicide? What is a germ? Chemical agent that kills microbes but not necessarily the endospores 15. Know the order of decreasing resistance of microorganisms to chemical microbiocides. (Figure 7.11) 1. Prions (most resistant) 2. Endospores of bacteria 3. Mycobacteria 4. Cysts of protozoa 5. Vegetative protozoa 6. Gramnegative bacteria 7. Fungi, including most fungal spores 8. Viruses without envelopes 9. Grampositive bacteria 10. Viruses with lipid envelopes (least resistant) Genetics 1. What is an organism’s genotype? Its phenotype? Genotype: the genes of an organism Phenotype: expression of the genes 2. If a person is studying "genomics" what is he/she studying? Genomics: the molecular study of genomes o
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