PEQ Week 7

Which statement is true regarding the bacteria present in the stomachs or intestines of humans? Intestinal bacteria can produce important vitamins. All of these choices are correct. Many intestinal bacteria aid in digestion. Some stomach bacteria have been associated with cancers. Intestinal bacteria may play a role in immune system function.

All of these choices are correct.

Consider the graph. Which letter under the graph shown corresponds to increased mitotic division in memory B cells? D A C E B

D

For your summer internship you decide to help farmers characterize the microbiotas of their pigs. Below is a graphical representation of the diversity observed after sampling and sequencing the microbiotas present in the small intestine (jejunum and ileum) and large intestine (cecum) of their fattest pigs. Reference the data presented below to address the following statement. T/F: Each point on the graph above represents one microbial species present in the either the small intestine or the large intestine. True or False

False

Phylogenetic analysis of 16S rRNA-encoding gene sequences from fecal microbiota of control or patients with C. difficile associated diarrhea (both initial and recurrent episodes) are shown below. T/F: People with recurrent CDI have more resilient microbiomes. True or False

False

A host cell infected by a virus will activate the adaptive immune response involving (Select all that apply) Helper T cell Dendritic cell MHC I Cytotoxic T cell Macrophages MHC II

MHC I Cytotoxic T cell

Innate immunity activation depends on: memory B cells. diversity of antibodies in the blood stream. previous exposure to a foreign antigen. None of the other answer options is correct. major histocompatibility complex (MHC) class II proteins.

None of the other answer options is correct.

You are a doctor and have a patient who has been injured by a rusty nail. As a precaution, you vaccinate her against tetanus. In response to the vaccine, how does her body produce antibodies against C. tetani and prevent future illness due to tetanus? Every cell in her immune system produces antibodies against C. tetani. The B cell that produces the appropriate antibody undergoes genomic rearrangement in order to produce other cells that produce the same antibody. Every B cell in her body produces antibodies against C. tetani. The B cell with the appropriate antibody is stimulated to divide, producing plasma cells that make antibodies to C. tetani, and memory cells that "remember" C. tetani.

The B cell with the appropriate antibody is stimulated to divide, producing plasma cells that make antibodies to C. tetani, and memory cells that "remember" C. tetani.

For your summer internship you decide to help farmers characterize the microbiotas of their pigs. Below is a graphical representation of the diversity observed after sampling and sequencing the microbiotas present in the small intestine (jejunum and ileum) and large intestine (cecum) of their fattest pigs. Reference the data presented below to address the following statement. T/F: Points that cluster together have greater 16s rRNA gene sequence similarity than points that are farther apart. True or False

True

Phylogenetic analysis of 16S rRNA-encoding gene sequences from fecal microbiota of control or patients with C. difficile associated diarrhea (both initial and recurrent episodes) are shown below. T/F: Bacteroides are reduced in patients with recurrent CDI. True or False

True

The human body has about 10 bacterial cells for every eukaryotic cell. Bacteria coat our skin, gut, and mouth. Also present are protists, archaeans, and viruses. Collectively, these organisms are our microbiota. For most members of our microbiota, our body provides their environment, or space to live. They, in turn, have no effect on us. This is an example of: commensalism. an antagonistic relationship. predation. mutualism.

commensalism.

The complement system refers to: proteins circulating in the blood that are activated by antibodies or molecules on pathogens. proteins that are activated when histamine levels increase. proteins circulating in the blood that are activated by opsonization. proteins present on macrophages that recognize foreign proteins.

proteins circulating in the blood that are activated by antibodies or molecules on pathogens.

The reasoning behind the use of fecal transplants from healthy individuals is that: C. difficile feeds on other bacteria that are introduced with the fecal transplant. antibiotics are administered with the fecal transplant, thus controlling populations of C. difficile. the fecal matter from healthy patients does not have C. difficile. the competition from the introduction of other bacteria into the gastrointestinal tract keeps C. difficile numbers down.

the competition from the introduction of other bacteria into the gastrointestinal tract keeps C. difficile numbers down.