Exam 1

Question 1

Which statement does NOT correctly describe the current problems related to medical microbiology?

Answer 1

1. Emerging or re-emergin diseases continue to pose new microbiological problems
2. Globally, infectious diseases cause more than 20% of all deaths.
3. Examples of re-emerging infectios diseases include TB, malaria, and hepatitis
4. Modern lifestyles and technical developments facilitate transmission of disease
5. All of the above correctly dscribe current status of infectius disease

Question 2

_____, as a macroparasite, can grow in one host but cannot complete its full life cycle and thus must reproduce outside of the host

Answer 2

1. Influenza virus
2. Pathogenic E. coli
3. Candida albicans
4. Schistosoma haematobium (a fluke)
5. All of the above are microparasites

Question 3

Vibrio cholera is a(n) _____ because it causes disease by living on the surface of the intesting without invading

Answer 3

1. Extracellular pathogen
2. Obligate intracellular pathogen
3. Facultative intracellular pathogen
4. Macroparasite
5. Facultative microparasite

Question 4

Antibodies bind extraceulluar pathogens and facilitate their uptake and destruction by phagocytes. This action of the antibody is called _______.

Answer 4

1. Neutralization
2. Opsonization
3. Complement activation
4. Cell-mediated immunity
5. Antibody-mediated immunity

Question 5

Bacteria can be classified by the following EXCEPT

Answer 5

1. Morphology
2. Gram Reaction
3. Serological properties
4. Slime layer formation
5. DNA sequence

Question 6

One of the most important pathogens in Gram-negative cocci is

Answer 6

1. Staphylococcus aureus
2. Neisseria meningitidis
3. Haemophilus influenzae
4. Salmonella typhimurium
5. Escherichia coli

Question 7

Which pair is INCORRECT

Answer 7

1. Flagella–H antigen
2. LPS–Endotoxin
3. Pili–Attachment
4. Endospore–Survival under harsh conditions
5. Slime layer–Strengthens the pathogen’s cell wall

Question 8

Hepatitis B virus sometimes causes ____ where the host cell remains alive and continues to release virus particles by budding

Answer 8

1. A lytic infection
2. A persistent infection
3. A latent infection
4. A transformation
5. A cell lysis

Question 9

Which statement is NOT true about fungal pathogens?

Answer 9

1. Many grow as a mass of hyphae
2. They are multinucleate or multicellular organisms with a thick peptidoglycan cell wall
3. Some fungi form part of our body’s normal flora
4. Many fungal pathogens form hyphae at environmental temperatures, but occur as yeast cells in the host
5. Hyphae form of Candida albicans is the pathogenic form found inside the human hose

Question 10

Plasmodium falciparum is a(n) _______ pathogen

Answer 10

1. Fungal
2. Bacterial
3. Protozoan
4. Viral
5. Helminthic

Question 11

Which does NOT correctly describe prions?

Answer 11

1. Prions are small proteins
2. Prions are extremely resistant to heat, disinfectants, and irradiation
3. Prions do not elicit immune response
4. Prions are sensitive to Proteinase K digestion
5. Disease caused by prions typically have a long incubation period

Question 12

Influenza virus attaches by its ____ to sialic acid and portion of glycoproteins found on the mucous membranes

Answer 12

1. Hemagglutinin
2. Neuroaminidase
3. CD4
4. P antigen
5. Reverse transcriptase

Question 13

Which statement is NOT true about the normal flora on our body

Answer 13

1. In terms of number, approximately ten times more normal flora cells are present than our own body cells
2. Viruses, fungi, and protozoa are also regularly found as normal flora
3. The normal flora is acquired shortly after birth and the members of the normal flora are usually kept constant throughout life
4. Members of the normal flora can cause hospital-acquired infection when patients are exposed to invasive treatments
5. ALl of the above are correct

Question 14

_____ is an anti-microbial peptide secreted by human eccrine sweat glands onto the skin as a part of the innate host defense system

Answer 14

1. Dermcidin
2. Lysozyme
3. Pepsin
4. Bacteriocin
5. Bile salt

Question 15

Which is NOT found as a member of normal flora in the upper respiratory tract?

Answer 15

1. Streptococcus pyogenes
2. Staphylococcus aureus
3. Corynebacterium diphtheriae
4. Streptococcus pneumoniae
5. E. coli

Question 16

______ is present in the stomach and can cause gastric ulcers

Answer 16

1. Streptococcus pyogenes
2. Helicobacter pylori
3. Enterococcus faecalis
4. Streptococcus pneumoniae
5. None of the above

Question 17

The bacteria present in the large intestines carry out the following EXCEPT

Answer 17

1. Gas production
2. Odor production
3. Production of some essential vitamins
4. Production of some steroids
5. All of the above are carried out by gut microorganisms

Question 18

Which microbe is responsible for producing the acidic conditions int he vagina?

Answer 18

1. Lactobacillus areophilus
2. Candida alibicans
3. E. coli
4. Streptococcus acidophilus
5. Gardnerella vaginalis

Question 19

In general, the _____ ratio is regarded to be of significant relevance in human gut microbiota composition

Answer 19

1. Firmicutes to Bacteroidetes
2. Actinomyces to Bacteroidetes
3. Bacteroidetes to Clostridia
4. Actinobacteria to Firmicutes
5. None of the above

Question 20

In the lower respiratory tract, the bacterial cells settled onto the epithelia are beaten and pushed upward by ________

Answer 20

1. Pili
2. Flagellated cells
3. Ciliated cells
4. Mucus layer
5. Macrophages

Question 21

Briefly describe how our immune system defend against “intracellular pathogens”. For full credit, you have to include two types of intracellular pathogens

Answer 21

• Intracellular pathogen in the cytoplast: helped by TH1
• Intracellular pathogen inside the endosome: killed by cytotoxic T cells

Question 22

Briefly explain why only capsulated Streptococcus pneumoniae can cause a fata infection, but unencapsulated mutations cause no disease

Answer 22

Capsules inhibit phagocytosis

Question 23

Many transforming viruses carry ____ that cause transformation when their genome is incorporated into the host genome

Answer 23

Oncogenes

Question 24

Fungal infections are broadly termed ______

Answer 24

Mycoses

Question 25

Infectious disease transmitted from animals to humans are called \_\_\_\_\_\_\_\_\_\_

Answer 25

Zoonosis

Question 26

\_\_\_\_\_\_\_\_ is a prion disease that was identified with cannibalistic behavior in Papua New Guinea

Answer 26

Kuru

Question 27

Briefly describe how prions may damage our body

Answer 27

Interaction of abnormal priorns changes normal prion into abnormal prion, which then causes damage such as aggregation

Question 28

Saliva produces two enzymes ____ and \_\_\_\_\_\_, that are toxic to bacteria

Answer 28

Lysozyme and lactoperoxidase

Question 29

Briefly describe the develpment of dental plaque and cavity. Also describe how dextran contributes to the formation of dental cavities

Answer 29

* Formation of plaques by *L. sabrinus, etc. * * Deprivation of oxygen * Secondary bacteria such as Fusobacterium grow * Microbes produce lactic acid * L. mutans and others produce dextran from sucrose by dextransucrase * Dental caries develop

Question 30

Briefly explain why the skin is not a good place for most microbes to grow

Answer 30

* Low pH * High salt * Chaning physical conditions * Anti-microbial substances produced by skin cells

Question 31

When an organism infects the body, the defense system alread in place called _____ may prpevent replication and spread of the infections agent

Answer 31

Innate immunity

Question 32

Enhancement of phagocytosis by the binding of C3b or antibody on the bacterial surface is called \_\_\_\_

Answer 32

Opsonization

Question 33

Phagocytes recognize _____ such as LPS on the bacterial surface via their cell surface via their cell surface pattern recognition receptors

Answer 33

Pathogen Associated Molecular Patterns (PAMPs)

Question 34

Briefly explain anti-bodydependent cellular cytotoxicity

Answer 34

Parasites bigger than antibodies are killed by antibodies (IgG) mediated killing