Bio Exam 1
How does the body recognize "self" cells compared to "nonself" cells?
"Self" cells are marked by glycoproteins called major-histocompatibility complexes (MHCs).
For naming purposes, which form of influenza would be characterized by the types of H and N spikes found on its surface?
A
Which of the following statements explains the relationship between mutations and natural selection?
A mutation in the genetic material may or may not have an effect on the protein. A mutation may result in the death of an organism or cell. A mutation may result in a variation of a trait that may be more advantageous.
Which of these best describes a virus?
A nonliving complex of RNA or DNA protected by a protein coat
Which of the following characteristics of life are present in viruses?
Ability to evolve over time
What is the correct sequence of events in viral reproduction?
Attachment, penetration, biosynthesis, maturation and release
Which of the following best describes the action of B cells?
B cells develop and mature in the bone marrow. B cells carry receptor molecules on their cell surfaces. B cells change into plasma cells after encountering an antigen and then produce antibodies.
In most organisms, the flow of information is from
DNA, RNA, then protein.
A certain species of butterfly varies in color from white to dark blue. The birds found in the same area feed on the white or lightly colored butterflies, leaving butterflies that are darkly colored. This is an example of what type of selection?
Directional selection
Which of the following is a challenge in developing an annual influenza vaccine?
Influenza evolves rapidly. It takes six months to develop the vaccine. There are many strains of influenza.
Cells of the body are marked as "self" by
MHC-I markers
Which protein structures on the SARS-CoV2 virus identify host cells?
S (spike proteins)
All viruses are made up of two components. These components are:
a protein capsid and genetic material, in the form of either RNA or DNA.
The immune system's role is to
actively seek and destroy pathogens.
When pathogens are ingested by the macrophages and dendritic cells of the immune system, they are digested and a small portion of the pathogen, __________, is attached to the surface of the macrophage.
an antigen
Once specfic B cells are activated they begin producing antibodiesthat are released into the body fluid and mark free-floating pathogens for death .this is known as
antibodie-mediated immunity
TWhen pathogens are ingested by the macrophages and dendritic cells of the immune system,they are digested and a small portion of the pathogen, called an ___, is attached to the surface of the macrophage
antigen
When two different forms of a virus infect the same cell, the host cell may manufacture viral particles from both viruses to reassemble them into a new form of virus. This process is called __________.
antigenic shift
The activities of macrophages
are part of the nonspecific response against disease and stimulate phagocytic neutrophils.
All of the following are antigen-presenting cells (APC) except
cytotoxic T cells
The nonspecfic immune response is also known as
innate immunity
The most common flu vaccine is called a trivalent vaccine because
it contains three different strains of inactivated viruses.
The adaptive immune response can remember past exposures to pathogens by holding ______ in reserve.
memory B cells
In the influenza strain name A/Singapore/INFIMH-16-0019/2016 A(H3N2)-like virus, this was the ______ strain isolated in 2016 in this region.
nineteeth
Evolution is described as the change in heritable traits of a(n) __________ over a period of time.
population
In the history of life on earth, which organisms evolved first?
prokaryotic organisms
In the early 1800s, prior to Darwin and Wallace, the common beliefs of the time were
that species did not change over time. that the earth was young. that all species were created when the earth was young
Wallace shared his ideas with Darwin, which led to the book, On the Origin of Species. Wallace contributed his biogeographical studies of the __________.
South Pacific Islands
Structures that are passed on from a common ancestor, such as the bone structure of a limb, are called ______ structures. Structures that have the same function but evolved independently, such as wings of bats and birds, are called ______ structures.
homologous; analogous
The cycle of viral infection that will rapidly result in the death of a bacterial cell is called the ______ cycle.
lytic
Why are new flu vaccinations required for each new flu season instead of developing a universal flu vaccine?
The flu virus mutates frequently enough that last year's vaccination will no longer target currently circulating flu strains.
One of the four categories of the innate immune system is the inflammatory system. Its role is to
increase blood flow to the infected area. isolate the infection to a limited area. allow fluid, containing cells from the immune system, to reach the infected area.
The SARS-CoV 2 virus enters host cells by
attaching to ACE2 receptors.
When the influenza virus enters into an epithelial cell within the respiratory tract, the infected cell responds by
posting antigens on its cell surface, acting as a flag for the cytotoxic T cells to destroy it.