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Case study #4 Plasmodium falciparum is the most virulent causative agent of malaria. This parasite has a trophozoite form that must undergo a life cycle within the gut of the female Anopheles mosquito to be naturally transmitted to the next host. The parasite also has separate trophozoite forms in the liver and blood of humans. If the malaria parasite is introduced into a pregnant woman, it can cross the placental barrier and infect the developing fetus. People at increased risk for malaria infection are children under 5 years old, pregnant women, and people with AIDS (active HIV infection).   For most cases of P. faciparum (not mother to fetus), the portal of entry is:

Case study #2 Human Immunodeficiency Virus (HIV) is an enveloped retrovirus that has humans as its only reservoir. The spikes on HIV specifically bind to CD4 molecules of specific leukocytes and lymphocytes. After the viral genetic material is reverse transcribed by an enzyme known for its high error rate and poor proofreading, it is integrated into the host cell’s chromosome. The virus then enters a period of latency. When activated, viral proteins are made using the same machinery and mechanisms as typical host cell proteins. Rapid viral replication results in the death of the host cell. A person with HIV has progressed to clinical AIDS when CD4 cells fall below 200 cells per cubic millimeter of blood. (The CD4 count of a healthy adult/adolescent ranges from 500 cells/mm3 to 1,200 cells/mm3.)   Which of the following is true regarding HIV?

Case study #2 Human Immunodeficiency Virus (HIV) is an enveloped retrovirus that has humans as its only reservoir. The spikes on HIV specifically bind to CD4 molecules of specific leukocytes and lymphocytes. After the viral genetic material is reverse transcribed by an enzyme known for its high error rate and poor proofreading, it is integrated into the host cell’s chromosome. The virus then enters a period of latency. When activated, viral proteins are made using the same machinery and mechanisms as typical host cell proteins. Rapid viral replication results in the death of the host cell. A person with HIV has progressed to clinical AIDS when CD4 cells fall below 200 cells per cubic millimeter of blood. (The CD4 count of a healthy adult/adolescent ranges from 500 cells/mm3 to 1,200 cells/mm3.)

Which of the following is not a characteristic of B cells?

Case study #5 Listeria monocytogenes is a chemoheterotrophic facultative anaerobic Gram-positive bacterium that can act as a human pathogen or as a saprobe, depending on its environment. This bacillus-shaped cell is motile, moving with peritrichous flagella. This bacterium has a high salt tolerance and can multiply readily at 4 oC (refrigerator temperatures). L. monocytogenes is part of the normal gut microbiota of many farm animals, including cows. Deli meats, hot dogs, and unpasteurized cheese and milk are likely sources of this pathogen. Many antibiotics can be used to treat infection with L. monocytogenes, including drugs that target peptidoglycan biosynthesis, the small ribosomal subunit of bacteria, and folic acid biosynthesis.   Choose all that apply: L. monocytogenes can evade the immune system by surviving inside of phagocytic leukocytes involved in innate immunity. Which of the following is/are phagocytic leukocytes?

Case study #5 Listeria monocytogenes is a chemoheterotrophic facultative anaerobic Gram-positive bacterium that can act as a human pathogen or as a saprobe, depending on its environment. This bacillus-shaped cell is motile, moving with peritrichous flagella. This bacterium has a high salt tolerance and can multiply readily at 4 oC (refrigerator temperatures). L. monocytogenes is part of the normal gut microbiota of many farm animals, including cows. Deli meats, hot dogs, and unpasteurized cheese and milk are likely sources of this pathogen. Many antibiotics can be used to treat infection with L. monocytogenes, including drugs that target peptidoglycan biosynthesis, the small ribosomal subunit of bacteria, and folic acid biosynthesis.   Choose all that apply: L. monocytogenes can evade the immune system by surviving inside of phagocytic leukocytes involved in innate immunity. Which of the following is/are phagocytic leukocytes?

Case study #1 NDM-1 is an enzyme that hydrolyzes and inactivates nearly all known β-lactam-class antibiotics. This enzyme requires a metallic ion, usually zinc, to catalyze the hydrolysis reaction. The gene encoding NDM-1 is found on a conjugative plasmid and is efficiently transferred to many Gram negative bacteria.   Which best describes where the ndm-1 gene is found in bacteria?

Case study #5 Listeria monocytogenes is a chemoheterotrophic facultative anaerobic Gram-positive bacterium that can act as a human pathogen or as a saprobe, depending on its environment. This bacillus-shaped cell is motile, moving with peritrichous flagella. This bacterium has a high salt tolerance and can multiply readily at 4 oC (refrigerator temperatures). L. monocytogenes is part of the normal gut microbiota of many farm animals, including cows. Deli meats, hot dogs, and unpasteurized cheese and milk are likely sources of this pathogen. Many antibiotics can be used to treat infection with L. monocytogenes, including drugs that target peptidoglycan biosynthesis, the small ribosomal subunit of bacteria, and folic acid biosynthesis.   Choose all that apply: The cell envelope of L. monocytogenes contains

Take a deep breath, you’re halfway there! This break indicates the start of the cumulative portion.  The cumulative portion consists of a series of questions about 6 case studies. For each case study, the reading will be introduced first, then the questions associated with the reading follow. The reading is repeated at the beginning of each question. The question that you need to answer will be displayed in bold type.

Case study #5 Listeria monocytogenes is a chemoheterotrophic facultative anaerobic Gram-positive bacterium that can act as a human pathogen or as a saprobe, depending on its environment. This bacillus-shaped cell is motile, moving with peritrichous flagella. This bacterium has a high salt tolerance and can multiply readily at 4 oC (refrigerator temperatures). L. monocytogenes is part of the normal gut microbiota of many farm animals, including cows. Deli meats, hot dogs, and unpasteurized cheese and milk are likely sources of this pathogen. Many antibiotics can be used to treat infection with L. monocytogenes, including drugs that target peptidoglycan biosynthesis, the small ribosomal subunit of bacteria, and folic acid biosynthesis.   What term(s) in the case study description supports your answer for what L. monocytogenes uses as a source of carbon and energy (what term(s) supports your answer to the previous question)?