Lifson Quizes 4 a, b, c
How do normal flora protect us?
a. they produce acid that discourages growth of pathogens b. they kill other microbes including pathogens with poisonous compounds c. they prevent pathogens from adhering d. diminish available nutrients making it difficult for pathogens to survive
siderophores
allow absorption of an essential
kinases and hyaluronidase
allow the microbes to spread through the host
Opportunistic pathogens
are microbes that in their normal habitat in contact with a normal host do not cause disease
mutalism
both benefit
Which of the following is true? a. viruses do not divide b. viruses do not have a cell membrane c. mature viral particles have only one type of nucleic acid viruses are small d. all of the above are true
d. all of the above are true
Which of the following is not true of viruses? a. viruses contain DNA or RNA but never both b. viruses contain a protein coat c. viruses use the anabolic machinery of the cell d. viruses use their own catabolic pathways for ATP production
d. viruses use their own catabolic pathways for ATP production
IgA proteases
detroy an important host resistant factor
What is the mechanism of transmission for a Chlamydia (sexually transmitted) infection?
direct contact
Lipid A from lipopolysaccharide from the outer membrane of Gram - bacteria is called
endotoxin
The chromosome of a virus can be
for some viruses DNA for others RNA
Referring to the previous question, the reservoir is
humans
The reservoir for the hepatitis C virus is?
humans
Order the appearance of viral nucleic acid from a retrovirus following uncoating from the following list. 1. DNA 2. DNA/RNA hybrid 3. single stranded RNA
3, 2, 1
Put the following in the correct order for virus replication: 1 - Maturation (assembly), 2 Biosynthesis, 3 - Attachment, 4 - Penetration, 5- Release, 6- Uncoating
3,4,6,2,1,5
In recent years there has been significant attention turned to the amount of gastrointestinal illness that is contracted on cruise ships. The most common type of virus linked to gastrointestinal illness is the Norwalk-like Virus (NLV) or norovirus, which gained notoriety from a 1968 outbreak in Norwalk, Ohio. Noroviruses are the leading cause of gastrointestinal illness with an estimated 23 million cases a year, according to the U.S. Centers for Disease Control & Prevention (CDC). After an outbreak a cruise ship will undergo extensive sanitization, yet there is often more outbreaks on subsequent cruises. It is suspected that infected crew members are the sources of continued outbreaks. Although a few cases of the virus have been due to contaminated seafood, most of the problem has been due to ill people vomiting in public places, having diarrhea in the public lavatories and handling all the railings and elevator buttons with unwashed hands. What is the method of transmission?
indirect contact
Probiotics are
microbes that are ingested to antagonize pathogens
parasitism
one benefits, one is harmed
commensalism
one benefits, one is unaffected
The envelope of a virus is made up of
partly the membrane of the host and partly viral proteins
Exotoxins which can be found in Gram + or Gram - (!) bacteria is easily denatured by heat because it is
protein
The capsid coat of a virus is made up of what material?
protein
An envelope is acquired during which of the following steps?
release
Endotoxin has low toxicity, however, when their is a septicemia (infection of the blood) there is so much bacteria that are being lysed either by the action of your immune system or due to the action of antibiotics that the toxin can kill. The action that causes death is by
release of immune factors that can cause lethal shock
capsules, M proteins of Steptococcus pyogenes and A protein of Staphylococcus aureus
resist phagocytosis
What type of chromosome does a +RNA virus have?
single stranded mRNA
What is the first biosynthetic event after un-coating for a +RNA virus?
translation
Borrelia burgdorferi causes Lyme disease in humans, an accidental host. The normal host is deer and deer mice. Ticks carry the microbe from one host to another including the accidental host. What is the mode of transmission for this disease?
vector
Salmonella Saint Paul is an unusual strain that has sickened many people in the US in the Spring of 2008. It is believed that a common source of transmission has been tomatoes from Mexico or Florida. What is the likely mechanism of transmission?
vehicle