unit 4 questy Flashcards
Which of the following is a much more potent greenhouse gas than carbon dioxide and is found in sediments on the ocean floor?
a. ethane
b. methane
c. propane
d. butane
b. methane
Choose the factors that influence the rate of degradation of carbon compounds in the environment.
a. Redox potential
b. Composition of the microbial community
c. Availability of competing nutrients
d. All of these
d. All of these
Normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms. This is called microbial
a. mutualism.
b. symbiosis.
c. antagonism.
d. commensalism.
c. antagonism.
hich of the following is NOT TRUE about normal microbiota?
They begin to be established at birth.
Physical and chemical factors affect their growth.
They are localized in specific body regions.
They are present only for a relatively short time.
They are present only for a relatively short time.
The spread of pathogens via contaminated water is an example of ________ transmission.
indirect contact
direct contact
vehicle
vector
vehicle
During 2007, there were 3.6 new cases of pertussis per 100,000 susceptible individuals in the United States, part of a steady increase that has been occurring since the 1980s. (https://www.cdc.gov/pertussis/clinical/index.html). This statistic illustrates the term _________blank.
outbreak
disease
incidence
attack rate
pandemic rate
incidence
The first outbreaks of E. coli O157:H7 in the United States were traced to eating ______.
undercooked hamburger
soft cheeses like feta or Brie
contaminated dairy products
peanut butter
undercooked hamburger
Most microorganisms do not usually cause disease when they enter a human host due to _________.
an unsuccessful mode of transmission that results in a weakened ability to cause disease
competition between resident microbiota and the potential pathogen, as well as successful attack by innate and adaptive immune cells
weakened pathogenicity by antibiotics
predisposing factors in the host, such as age, gender, lifestyle, and access to adequate health care
competition between resident microbiota and the potential pathogen, as well as successful attack by innate and adaptive immune cells
Spinach-associated outbreaks of food-borne disease have been traced to the spinach in the field, where the likely source of the E. coli is ______.
run-off from melting glaciers
migratory birds
irrigation water contaminated by wild animal feces
improper installation of irrigation equipment
irrigation water contaminated by wild animal feces
Pathogens produce virulence factors primarily to _________.
change its environment
cause disease
outcompete host cells for resources
maintain temperature and pH values
outcompete host cells for resources
One strategy for exploiting host cells that is used by certain bacteria such as Listeria, Shigella, and Rickettsia is to _________.
degrade biofilms to make the cells in the interior more susceptible to antibiotics
decrease cellular pH so the acidic environment prevents protein synthesis and therefore enzyme function
stimulate innate host defenses to turn the mechanisms of destruction onto the host’s own cells
use the actin filaments of the host cytoskeleton to facilitate motility through the host cell thereby enhancing infection of neighboring cell
use the actin filaments of the host cytoskeleton to facilitate motility through the host cell thereby enhancing infection of neighboring cell
The ID50 refers to the _________.
number of organisms in the initial inoculum required to infect 50 host cells
number of organisms in the initial inoculum required to cause infection in 50% of hosts
inoculum of organisms required to kill 50% of host cells
replication rate required for the pathogens to grow by 50% in the host
number of organisms in the initial inoculum required to cause infection in 50% of hosts
This type of pathogen cannot grow outside a host cell.
Multiple Choice
Obligate extracellular pathogen
Facultative intracellular pathogen
Obligate intracellular pathogen
Extracellular pathogen
Obligate intracellular pathogen
