BIOL 302: Bacteria, Viruses and Health - Essay Example

Due BIOL 302: Bacteria, Viruses and Health MULTIPLE CHOICE QUIZ 2 An organism having pili has the advantage over one which lacks pili because it canA. move actively. B. obtain nutrients from beef broth.C. stain easily. D. attach to various surfaces including tissue.E. synthesize glycoproteins.2 The peptidoglycan of a bacteriumA. is located primarily in the spore. B. together with protein is formed in the capsule.C. cannot be synthesized if penicillin is present.D. is associated with the cell membrane.E. is found in Gram-positive bacteria only.

3 Bacteria reproduce by a process known asA. meiosis. B. binary fission.C. mitosis. D. spontaneous generation.4 Spherical organisms arranged in irregular groups of cells that resemble bunches of grapes are referred to asA. staphylococci. B. streptococci. C. bacilli. D. cocci.5 Thin, flowing, loosely bound glycocalyx is referred to as A. capsule B. slime layer C. biofilm D. cell envelope6 Bacterial chromosomes are found:A. in the nucleoid region B. near the flagellumC. in the cell wall D.

in storage granules E. in the pili7 The main difference in between Gram negative bacteria and Gram positive bacteria is:A. the lipids in the plasma membrane B. the cell wall C. sizeD. All of the above8 Attenuated viruses are produced byA. treating viruses with formaldehyde.B. disrupting viruses in a blender.C. passing viruses from culture to culture until a variant evolves.D. irradiating viruses with ultraviolet light.E. forming plaques from viruses.9 Interferons are produced byA.

viruses as they begin replication. B. various body cells on stimulation by viruses.C. bacteria in response to viral infection. D. drug companies for use against bacteria.E. viruses as they complete replication.10 All viruses possessA. a capsid and an envelope. B. DNA as well as RNA.C. a genome and a capsid. D. only DNA. E. only RNA.11 Oncogenes are genes whichA. the virus utilizes to replicate itself. B. convert formaldehyde to formalin in the cytoplasm of a cell.C. encourage recombinations in bacteria.D. transform normal cells to cancer cells.E. influence ongoing protein production.

12 Viral envelopes are usually acquired byA. budding through the membrane of the cell. B. synthesizing envelope lipids under direction of the virus.C. an outgrowth of the genome membrane.D. reaction with interferon protein.E. interaction between gene and oncogene.13 Which of the following is an essential feature in viral replication?A. The viral capsid must enter the host cell cytoplasm.B. The viral envelope must fuse with the cell membrane.C. The viral genome must be uncoated in the cell cytoplasm.D. The viral genome must fuse with the host cell membrane.E. The viral capsid must contain capsomeres.

14 The human immunodeficiency virus (HIV) can synthesize DNA from RNA because it containsA. the necessary glucose molecules. B. envelope proteins that provide receptor sites.C. the enzyme reverse transcriptase. D. cytoplasm within its genome.E. an indwelling bacteriophage in a lysogenic state.15 Inactivated viruses used in vaccinesA. multiply in the body at a low rate.B. contain lysogenic proviruses that induce antibody formation.C. act like drugs in the body.D. cannot replicate in the body.E. are produced by multiple transfers in tissue culture media.

16 The togaviridae cause equine encephalitis and other diseases. These RNA viruses have a symmetrical capsid with 20 equilateral triangles with 20 edges and 12 points. Such a capsid is an example of a(n)A. helical capsid. B. icosahedral capsid.C. simple capsid. D. ovoid capsid.17 For many years it was not understood how an RNA virus could transform its host cell, causing a tumor to develop. This dilemma was solved with the discovery ofA. chromosomal-bound RNA. B. RNA polymerase.C. reverse transcriptase. D. DNA polymerase.

18 You have isolated an animal virus whose capsid is a tightly would coil resembling a corkscrew or spring. Such a capsid is referred to as a(n)A. icosahedron. B. helix.C. complex virion. D. capsomere.19 Because viruses have neither a cell wall nor metabolism, they are not susceptible toA. antibodies. B. interferon. C. antibiotics. D. attenuation.20 Prions were identified in association with which of the following;A. brain cells B. lung cells C. bacterial cells D. muscle cells21 One of the limitations of use of the autoclave is thatA.

some plasticware melts in the high heat. B. distilled water cannot be sterilized.C. glassware melts in the high heat. D. spores are not destroyed.E. protozoal cysts are not destroyed.22 An advantage of filtration is thatA. it combines the use of pressure with a physical barrier.B. it can be used on heat-sensitive solutions.C. kills microbes by disrupting the nucleic acid components of their cytoplasm.D. fluids do not pass through the filter.E. it traps viruses but not bacteria.23 The principle effect of ultraviolet light on bacterial cells takes placeA.

in the cell membrane. B. in the DNA of the cell.C. in the peptidoglycan layer of the cell wall. D. in the flagella of the cell.E. in the ribosomes of the cell.24 A substance that has been pasteurizedA. contains no microbial life. B. has no bacterial spores.C. may contain pathogenic bacteria. D. is not considered sterile.E. is probably dangerous to ones health.25 One drawback to the use of ultraviolet light as a sterilizing agent is itsA. failure to kill microorganisms in the air. B. failure to penetrate liquids or solids.C. failure to generate enough heat. D. failure to change water molecules to ions.E. failure to kill bacteria.

26 Sterilization refers to the:A. complete destruction or removal of all forms of life.B. elimination of pathogens only.C. destruction of microbial spores only.D. killing of bacteria only.E. killing of all microbes except for viruses.27 What type of radiation causes electrons and protons to jump out of molecules?A. X-rays B. visible light.C. ultraviolet light. D. gamma rays.E. both A and D28 Low temperature can be used toA. sterilize objects. B. denature proteins.C. slow microbial reproduction. D. eliminate microbial populations.

29 Mercury is rarely used in antiseptics in the modern era becauseA. mercury does not kill microorganisms. B. mercury is insoluble in water.C. mercury reacts violently with copper. D. mercury has a very high phenol coefficient.E. mercury is very toxic to body tissues.30 Drawbacks to the use of ethylene oxide as a sterilant include the fact thatA. it is a gas. B. it cannot be used in a closed chamber.C. it is explosive and toxic. D. it will not mix with inert gases.E. it is useless for plastics.

31 The two major drawbacks to the use of penicillin areA. loss of hearing and impairment of sight.B. kidney damage and immune complex formation.C. allergic reactions and development of drug-resistant bacteria.D. aplastic anemia and anaphylactic hypersensitivity.E. loss of hearing and cytotoxic hypersensitivity.32 Cephalosporins act byA. inhibiting protein synthesis. B. interfering with cell-wall biosynthesis.C. competitively inhibiting folic-acid biosynthesis. D. inhibiting RNA synthesis.

33 Tetracycline antibiotics interfere withA. protein synthesis. B. RNA synthesis.C. cell-wall biosynthesis. D. DNA replication.34 All the following apply to endotoxins exceptA. they are composed exclusively of protein. B. they are part of the bacterial cell wall.C. they are present in Gram-negative bacteria. D. they often damage the circulatory system.E. they are released upon disintegration of the parasite.35 An example of opportunistic organisms are those thatA. cause typhoid fever.B. inhabit the intestine but are incapable of causing disease.C. convert sugar to alcohol.D. inhabit the lungs and cause disease when body defenses are suppressed.E. require an intermediary host.

36 The organisms that infect individuals with AIDSA. are always viruses.B. are all known to be serious pathogens.C. have a high degree of virulence.D. produce exotoxins as well as endotoxins.E. are examples of opportunistic organisms.37 Invasiveness refers to the ability of a parasite toA. produce aggressive factors.B. add to its virulence by transduction.C. penetrate tissues and cause structural damage.D. multiply only within anaerobic environments.E. convert toxins to toxoids.38 A disease that is usually present at a low level in a certain geographic area is said to beA.

epidemic. B. pandemic. C. endemic. D. ubiquitous.39 An inanimate object that carries disease organisms is called a(n)A. carrier. B. fomite. C. reservoir. D. object of virulence.40 All the following are possible antigens exceptA. components of bacterial flagella. B. hemoglobin molecules.C. polysaccharides from bacterial capsules. D. milk proteins.E. glucose molecules.Match the Term or Concept with its Definition/AssociationReference: List of bacterial structuresSelect one of the following three choices for each of the options below:Term or ConceptA.

endospore B. flagellum C. glycocalyx D. pilusDefinition/Association41 B-rigid filament that permits motility42 A-forms when stress is encountered in environment43 D-aids transfer of genetic material among bacteria44 A-extremely resistant to heat45 A-formed by Clostridium and Bacillus species46 C-coating found outside cell wallMatch the Term or Concept with its Definition/AssociationReference: List of viral structuresSelect one of the following three choices for each of the options below:Term or ConceptA.

viral capsid B. viral nucleic acid C. viral envelope D. viral spikesDefinition/Association47 B-combined with capsid, it is called the nucleocapsid48 C-acquired by “budding”49 D-help to “dock” virus onto host cell 50 A-called the genome_________________________________ Your NameAnswer Table1D11D21A31C41B2C12A22A32B42A3B13C23B33A43D4A14C24D34A44A5B15D25A35D45A6A16B26A36E46C7B17C27E37C47B8C18B28C38C48C9B19C29E39B49D10C20C30C40B50A ESSAY/SHORT ANSWERQ.

Explain the oncogene theory for the emergence of a cancer and indicate how viruses may play a role in this process. Developed and proposed by Huebner and Todaro, oncogene theory suggests that most cells of the vertebrates carry in them oncogenic viruses, which are often invisible and harmless. These viruses are transmitted to their carrier hosts via natural evolutionary inheritance. Though inactive, these viruses occasionally get activated by endogenous and exogenous factors (such as chemical carcinogens, radiation, or the normal process of aging) and cause cancer through the destruction of the normal "repressor system" (Gross 2015).

Noteworthy, the repressor system maintain the "endogenous virogenes" (genes that produces type-C viruses) and the "oncogenes” (portion of the virogenes that transform normal cells into tumor cells) in an unexpressed form in the normal cells throughout the inactive phase. Q. Discuss the concept of lysogeny explaining how it comes about and some of its implications and effects. Lysogeny is a viral reproduction mechanism that characterizes the infection and the subsequent integration of the bacteriophage into a host cell’s chromosome via its genome and replicates in concert with it.

In this process, the genome of the bacteriophage (a collection of genes in the form of nucleic acid) becomes part of the host cells, but it assumes a dormant status and so does not affect the cell functioning. However, the viral nucleic acid becomes active at some point upon the host’s exposure to certain stimuli (such as ultraviolet radiation), after which the virus detaches itself from the host cell’s genetic material, annexes the functioning of the cell and begins production of progeny viruses.

The release of new virus particles ultimately destroys the host cell with a consequential effect of new cell infections (Canchaya, et al. 244-257). Lysogenic cycle introduces disease causing viral genes into the host cells via nonlethal viral transduction and further affords greater frequency to post-infection processes. This is the process that herpes and HIV viruses enters and multiplies into the human body. The discovery of the lysogenic cycle also laid the groundwork for much of the modern day genetic engineering.

Work cited:Canchaya, C., Proux, C., Fournous, G., Bruttin, A. and Brüssow, H. "Prophage genomics". Microbiol. Mol. Biol. Rev. 67.2 (2003): 238–76. Print. Gross, L. Facts and Theories on Viruses Causing Cancer and Leukemia. Proc. Nat. Acad. Sci. USA 71. 5 (1974): 2013-2017. Print.