Please answer the following questions: Question #1: Which of the following gene transfer method does not require DNA recombination following the gene transfer event? A. transformation B. conjugation C. transduction Question #2: What is a R factor? A. A protein that can digest invasive DNA B. A section on a pathogen's chromosomal DNA that contains many virulent genes C. A plasmid that carries several genes contributes to the host bacteria's resistance to antibiotics, heavy metals, and/or cellular toxins. D. A genetic element that's found on DNA that can enhance the expression of a bacterium's resistance genes. Question #3: A nine-month-old infant had 12 clinic visits over a seven-month period due to recurring runny nose and/or ear infections. During each episode, nasopharyngeal swabs were obtained for bacterial culture, and Streptococcus pneumoniae was obtained. Although all the infections were resolved with antibiotics , scientists gained insight into pathogen evolution by seeing how the isolates compared. Each isolate was first analyzed for seven genes that can indicate strain variability, a process called multilocus sequence typing (MLST). The lab found two MLST types, indicating that the patient was infected with two divergent strains of S. pneumoniae . However, when the complete genomes of several of the isolates were sequenced and compared, four different genotypic strains were identified, all of which evolved as a result of 16 distinct recombination events between strains. Curiously, the technicians noticed that some recombined sequences did not seem to come from either of the two primary coinfecting strains. It appeared that this new DNA came from uncultured and undetected strains of S. pneumoniae that had colonized the patient's throat at one time or another. Horizontal gene transfers (transformation) between the undetected and detected isolates appear to have produced the new recombined strains of S. pneumoniae . The genome sequence data clearly support the idea that S. pneumoniae evolution is characterized by high rates of horizontal gene transfer and recombination. The scientists concluded that this and other related bacterial species use horizontal gene transfer to defeat the adaptive immunity of individual hosts by constantly changing their surface antigens, possibly explaining the patient's recurring infections. These types of bioinformatic comparisons suggest that horizontal gene transfers that produce most of the genetic variation (e.g., different surface antigens) pathogens develop while persisting within a host. Based on the case description above, which of the following best explains the patient's recurring Streptococcus pneumoniae ear infections? A. The strains with which she was infected were antibiotic-resistant due to horizontal gene transfer. B. Because she is a baby, she has low immunity. C. The strains with which she was infected varied in antigen production due to horizontal gene transfer. D. The strains with which .

1. Please answer the following questions:
Question #1: Which of the following gene transfer method does not require DNA
recombination following the gene transfer event?
A. transformation
B. conjugation
C. transduction
Question #2: What is a R factor?
A. A protein that can digest invasive DNA
B. A section on a pathogen's chromosomal DNA that contains many virulent genes
C. A plasmid that carries several genes contributes to the host bacteria's resistance to antibiotics,
heavy metals, and/or cellular toxins.
D. A genetic element that's found on DNA that can enhance the expression of a bacterium's
resistance genes.
Question #3:
A nine-month-old infant had 12 clinic visits over a seven-month period due to recurring runny
nose and/or ear infections. During each episode, nasopharyngeal swabs were obtained for
bacterial culture, and Streptococcus pneumoniae was obtained.
Although all the infections were resolved with antibiotics , scientists gained insight into
pathogen evolution by seeing how the isolates compared.
Each isolate was first analyzed for seven genes that can indicate strain variability, a process
called multilocus sequence typing (MLST). The lab found two MLST types, indicating that the
patient was infected with two divergent strains of S. pneumoniae . However, when the complete
genomes of several of the isolates were sequenced and compared, four different genotypic strains
were identified, all of which evolved as a result of 16 distinct recombination events between
strains.
Curiously, the technicians noticed that some recombined sequences did not seem to come from
either of the two primary coinfecting strains. It appeared that this new DNA came from
uncultured and undetected strains of S. pneumoniae that had colonized the patient's throat at one
time or another.
Horizontal gene transfers (transformation) between the undetected and detected isolates appear
to have produced the new recombined strains of S. pneumoniae . The genome sequence data

2. clearly support the idea that S. pneumoniae evolution is characterized by high rates of horizontal
gene transfer and recombination.
The scientists concluded that this and other related bacterial species use horizontal gene transfer
to defeat the adaptive immunity of individual hosts by constantly changing their surface antigens,
possibly explaining the patient's recurring infections.
These types of bioinformatic comparisons suggest that horizontal gene transfers that produce
most of the genetic variation (e.g., different surface antigens) pathogens develop while persisting
within a host.
Based on the case description above, which of the following best explains the patient's
recurring Streptococcus pneumoniae ear infections?
A. The strains with which she was infected were antibiotic-resistant due to horizontal gene
transfer.
B. Because she is a baby, she has low immunity.
C. The strains with which she was infected varied in antigen production due to horizontal gene
transfer.
D. The strains with which she was infected were highly virulent due to horizontal gene transfer.
Question #4:
Although none of the strains with which the above case patient was infected with appear to be
resistant (she was treated successfully with antibiotics for each infection), drug-resistant S.
penumoniae (pneumococcus) infection has been a serious public health threat in the United
States.
According to the CDC Streptococcus pneumonia report , there are more than 2 million
pneumococcal infections yearly. In more than 30% of infections, the bacteria are resistant to one
or more clinically relevant antibiotics.
Fortunately, drug-resistant S. penumoniae is one of the only germs listed in the CDC's
"Antibiotic Resistance Threats in the United States, 2019" report with an effective vaccine to
prevent infection. The vaccine is called the pneumococcal conjugate vaccine (PCV). PCV-7
(protects against seven pneumococcal strains) was introduced in 2000, while PC-13 (protects
against thirteen pneumococcal strains) was introduced in 2010 for children and 2014 for adults.
Below is a chart showing the rates of antibiotic-resistant invasive pneumococcal infections
among different age groups in the U.S. from 2005 to 2017. The two red arrows indicate the time
points when PCV 13 was introduced to children and adults.

3. Continue from the above chart. The infection rate for children under 4 drastically dropped
from 2010. What is the most likely explanation for this reduction?
A. A new antibiotic has been introduced to treat this infection
B. The introduction of the PCV13 vaccine has prevented many potential pneumococcal
infections
C. A new public health campaign was launched to promote hand washing awareness to parents
with young children
D. the chart did not explain the drastic drop of cases among this age group
Rates of antibiotic-resistant invasive pneumococcal infections have decreased across age groups
in the United States from 2005 to 2017