Questions

REVIEW

Exam #1

• Wed, Oct 8, 1:30 pm, E 135

• MCQ – 80 questions

• Some questions require to choose the best answer

• “none of the above” is a legitimate choice

• Not many “numbers” included

• Material covered - 3 sets of slides (intro, bacteria, viruses/fungi/prions/protozoa)

• 2 versions, A and B – different sequence of questions and different sequence of responses

• Ethics - professional conduct

• Viruses are acellular organisms

• Bacteria are acellular organisms

• Fungi are acellular organisms

• Opportunistic infections are infections which are predominantly on the skin

• Koch postulates were about infectivity of cholera bacteria (Vibrio cholerae)

• First postulate of Koch was that the same infective agent need to be isolated from all infected animals

• Germ theory was developed by …… and it meant that ………

• Measles is one of the 5 most deadly infectious diseases

• A disease which has been eradicated from the globe is polio

• The importance of washing hands was discovered by….

• 100 000 people die yearly in US due to HAI

• Small pox vaccination was introduced by Luis Pasteur

• First epidemiological study were conducted in … by …

• Major advancements in culturing techniques were made by ...

• In case of outbreaks, WHO, Health Canada and CDC may have detailed guidelines on precautions to be applied in health care setting.

• Bacteria belong to a kingdom, Protista

• Major differences between prokaryotes and animal eukaryotes

– Membrane of the nucleus

– Cell wall

– Ribosomes

– Golgi apparatus

– Cell membrane

– Presence of DNA

• 10-6 meter is one µm

• 10-9 meter is one nm

• One mm has ……µm, …….nm

• A typical size of bacteria is in nanometers scale

• Development of vaccines against some of the inf diseases may not be economically viable

• In a healthy person, propagation of Clostridium difficille in the GI track is inhibited by symbiotic bacteria living in the GI track

• Listeria monocytogenes can cause CNS infections (meningitis, brain abscesses)

• Insulin can be produced by genetically engineered bacteria

• 80% of antibiotics are used in livestock industry

• Giving small doses of antibiotics over a long period of time to live stock to enhance growth, is the major contributor to development of antibiotic-resistant bacteria

• Use of bacteria to clean oil spills is an example of Bioremediation

diamonds, copper, gold, zinc, lead, uranium Tourism is a major contributor (14.5%) to Namibia's GDP ??

• Small pox disease has been eradicated from the globe • Small pox vaccination was known in India and China for over 1000

years • The small pox vaccine, developed by Edward Jenner, included killed

small pox viruses • Ebola virus causes hemorrhagic fever • Mortality rate of Ebola varies between 47 – 90% • Men, who are survivors of Ebola infection, can carry Ebola viruses in

their semen for up to 2 month • Washing hands saves lives • If I were a bacteria my name would be written as

1. Urszula Kosecka 2. urszula kosecka 3. Urszula kosecka 4. Urszula kosecka 5. urszula Kosecka 6. Urszula Kosecka 7. Urszula kosecka

• Pasteurization is a process of fermenting foods • H1N1 Spanish flu killed 50 - 100 mln people • H1N1 – the letter H and N relates to places where the outbreak has

happened • The 3rd Koch postulate says: the microb is able to produce the

original infection (even after several generations in culture) • Tuberculosis belongs to reemerging diseases • Scanning microscope produces 3D-like images • In order to identify Mycobacterium bovis, the simple stain is the

stain of choice • Over prescription of antibiotics is one of the reason for

development of antibiotic resistance • Bacteria belonging to normal flora may produce vitamin B • Bacteria belonging to normal flora may produce vitamin K • Bacteria belonging to normal flora may digest polysaccharides • Bacteria belonging to normal flora may turn on and off host’s genes • Bacteria belonging to normal flora may created environment hostile

for development of pathogen

Disturbances in normal GI flora are linked to immune dysfunction Cancers are an exclusive results of gene mutations Omega 3 fatty acids have a triple unsaturated bond in the fatty acid chain Cholesterol is an important molecule for brain function Cholesterol is and important molecule for vitamin D production Cholesterol is a precursor for sex hormones Cholesterol is a precursor for mineralocorticoids Protista is a kingdom composed of …. This is the correct sequence of classification levels: Kingdom, Phylum, Class, Order, Family, Genus, Species An electron microscope has magnification up to …. An electron microscope allows to see viral particles A light microscope allows to see viral particles In fluorescence microscopy the secondary antibodies bind to bacterial antigens In fluorescence microscopy the primary antibodies bind to bacterial antigen In fluorescence microscopy the fluorophore is coupled with primary antibodies

yes

• In the simple stain, crystal violet is used as a dye and alcohol is used as a rinse fluid • Peptidoglycan is present only in Gram + bacteria • E. coli is an example of Gram - bacteria • Differentiation between Gram + and – bacteria has clinical implications - choice of

antibiotic treatment • The acid fast stain is typically used for Mycobacteria species, because of their

waxy cell wall • Some bacteria have glycocalyx instead of peptidoglycan • A capsule is a morphological type of glycocalyx • Pseudomonas aeruginosa is an opportunistic bacteria with a slime layer • Techoic acid is present in Gram – bacteria • Techoic acid function is to link peptidoglycan to cell membrane • Peptidoglycan is composed of two type of sugars and lipids • The LPS (lipopolysaccharide) is a component of cell membrane in Gram + bacteria • The outer membrane is present only in Gram + bacteria • The LPS is composed of Lipid A and polysaccharides • Lipopolysaccharides act as an endotoxin and may cause septic shock • Some of the Gram – bacteria are: Salmonella, Shigella, Pseudomonas, Helicobacter • Plasmids are small circular pieces of RNA • In bacteria, the antibiotic resistance genes are always encoded in nucleoids

No; glycocalyx –envelope, capsule or slime layer

• Endospores are dormant stages of Protozoa • Bacterial endospores can be a form of reproduction • Bacterial endospores contain only plasmids (the

nucleoid disintegrates during the spore forming process)

• Bacterial endospores are created when conditions are not optimal

• Flagella allow for attachment of viruses to surfaces • A flagellum is an appendage used for conjugation and

exchange of genetic material • Pilli allow for attachment of bacteria to each other • The minimum Generation time for bacteria is typically

48 hrs and more • The reproduction of bacteria could be described by

geometric progression

• Bacterial reproduction in a laboratory test tube undergoes the following phases: – Stationary phase – Exponential growth – Lag phase – Death phase

• Most of the bacterial pathogens are psychrophiles • Anaerobes breath oxygen • Aerobs breath oxygen • Mucosal pathogen are often microaerophiles • Parasites belong to heterotrophs • Saprobes belong to heterotrophs • Protozoa are heterotrophs • Bacteria are heterotrophs and autotrophs

• Bacteriophages can be grown in Petri dishes • Mycobactertium tuberculosis is an obligate aerobe and

therefore “likes to” infect lungs • Helicobacter pylori causes stomach ulcers • Differential Nutrient Agar allows to differentiate

between groups of bacteria • An agar is a basic bacterial nutrient when culturing any

type of bacteria • A streak plate method is used for isolating single

colonies of bacteria • Evaluating turbidity is a method for counting the

number of bacteria • A “counting chamber” is used for counting the number

of viruses • The first isolated virus by Dimitri Ivanowsky was the

tobacco mosaic virus

• Viruses have ribosomes, which normally produce viral capsids

• Viruses do not have a machinery to produce own energy

• In viruses, the nucleic acid is always RNA, while in bacteria is always DNA

• Viruses infect bacteria, animals and fungi but not plants

• Each pathogenic virus can infect only one specific species of host

• Viruses are difficult to treat because they are intracellular parasites

• Viruses are always build out of 3 components: nucleic acid, capsid and envelope

• Capsomers are building units of capsids

• Capsomers are build of protein and polysaccharides

• One of the capsid’s function is attachment

• Bacterial and viral envelopes are very similar in composition

• Non-enveloped viruses are not infectious • The viral envelope is a modified capsid • Spikes are morphological features present on the viral

envelopes • The first polio vaccine was a “killed” vaccine • Viruses in killed vaccine sporadically can revert to virulence • An attenuated polio vaccine can be given orally, as it is a

natural transmission pathway for polio virus • In Canada, children vaccination series against polio starts with

killed vaccine and is followed by 2 live vaccines • Polio virus is very simple virus and was fully synthesized in

2002 • Polio virus may undergo spontaneous reversion to virulence • Bacteriophages are viruses which infect protozoa • Bacteriophages are currently in use in US for sanitation of food

products

• Bacteriophages are used clinically for treatment of bacterial infections

• Neurotropic viruses infect nervous tissue

• Viscerotropic viruses infect respiratory system

• Herpes simplex viruses belongs to Herpesviridae family

• Polio viruses belongs to Picornaviridae family

• Hepatitis A viruses belongs to Picornaviridae family

• Influenza viruses belongs to Orthomyxoviridae

• Aflatoxins are produced by bacteria from Genus Bacillus

• Aflatoxin has been shown to have carcinogenic properties

• Viruses typically reproduce in hosts but reproduction outside of the hosts is also possible

• In bacterial cells, viruses undergo uncoating in the cytoplasm

• Is budding a process related to proliferation of fungi or a process of viral exit from animal cells?

• During viral reproduction of RNA viruses, the viral RNA may act as a messenger RNA

• The time from the attachment of a virus to the host cell to the release of new viruses is called doubling time

• A lytic cycle of a virus happens when viruses lyse cells

• Bacteriophages incorporated in to bacterial DNA are called prophages

yes

• A provirus is a virus which is incorporated in the host DNA

• Change from lysogenic to lytic cycle could be caused by stress

• Viruses can cause viral infections but not cancers • Papilloma virus can cause liver cancer • Viruses could be identified in the laboratory

setting by observing so called “cytopathic effect” • Prions can cause BSE • PrPc stands for “protease-resistant protein” • PrPsc stands for “cellular protein” • vCJD is a disease caused by mutation of a gene • Infectious prions are most often localized in

neuronal tissues

• Prions are build of proteins and polysaccharides

• Scrapie is a prion-induced disease in deer and elks

• TSE stands for Transmissible Spongiform Encephalitis

• Yeast are obligate aerobs

• A chain of fungal cells is called hyphae

• Fungi reproduce only sexually

• Sporangium contains blastospores

• Anaerobic processes by yeast are used in fermentation of wines

• Cyclosporine is a bacterial product used against transplant rejection

• Cryptococcosis is typically treated with amphotericin B

• Tinea corporis means fungal infection of the head

• Most of the protozoas are autotrophic and anaerobic

• Trophozoite is a dormant form of malaria • Entamoeba histolytica causes toxoplasmosis • Trophozites of Entamoeba histolytica can perforate

intestine • Blood infection with Entamoeba histolytica can result in

death • Toxoplasma gondii infection, in pregnant women, can

spread to fetus • Malaria is caused by one species, Plasmodium malariae

• Malaria is a disease which was mostly eradicated in sub-

Saharan Africa • Merozoites develop in RBCs

• Cerebral hemorrhage is one of the causes of death due to malaria

• Clinical picture of toxoplasmosis includes cycles of fever and exhaustion (every 48-72hrs)

Exam questions - examples

Which of the following infections is best identified using the acid-fast stain? 1. Staphylococcal wound infection 2. Toxoplasmosis 3. E. coli infection 4. Plasmodium falciparum 5. Mycobacterium bovis

Which of the following is associated with repeated bouts of red blood cell lysis? 1) malaria 2) toxoplasmosis 3) amoebiasis 4) cryptococcosis 5) none of the above

Bacteria are part of which Kingdom? 1) Plantae 2) Protista 3) Archaea 4) Monera 5) Animalia

Which of the following is a difference between an animal virus and bacterial virus life cycle?

a) fusion

b) uncoating

c) budding

d) biosynthesis

1) a

2) b and c

3) b and d

4) a, b, and c

5) a, b, c, and d