Use the concepts of antigenic drift and antigenic shift to describe why influenza causes both "routine" seasonal outbreaks as well as to periodically cause more serious global outbreaks, or pandemics
What will be an ideal response?
Influenza has two spikes, HA and NA, which allow the virus to attach to and escape cells. During infection, the immune system generates antibodies which will neutralize that influenza pathogen during a current or subsequent infection. Because influenza is an RNA virus, it undergoes frequent mutations which result in minor changes in the spikes. These spikes may be different enough to evade quick detection by the previously-generated antibodies. This is antigenic drift, and is why a new influenza vaccine must be formulated each year and why a portion of the population is unprotected, leading to seasonal outbreaks. Antigenic shift occurs when the virus undergoes a major genetic reassortment that dramatically changes the spikes. These "new" viruses may have increased infectivity or expanded host range, and are also unlikely to be recognized by current vaccines. Most of the population will have no residual immunity to this new strain, so the virus spreads rapidly and causes serious illness.
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Somatic system fibers in nerves carry
information a. to and from receptors. b. to and from effectors. c. from receptors in skin, tendons, and skeletal muscles. d. to skeletal muscles. e. from receptors in skin, tendons, and skeletal muscle and to skeletal muscles.
The gene encoding coat color is X-linked, and male cats have a single copy of the X chromosome. They can therefore express either the O or o allele, resulting in orange or black coat, respectively
Female cats, on the other hand, have two copies of the X chromosome. Thus, they can be heterozygous and express either orange or black. Using this information, list the possible genotypes for these individuals: • orange male • orange female • black male • black female • tortoiseshell
A medical researcher is trying to develop a diagnostic technique for a disease that is characterized by replication of a particular chromosomal region. What would be the most appropriate technique?
A. white blood cell count B. FISH C. gene chip D. genome sequencing
True or false? Isotopes differ in the number of electrons
True False