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.