A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (i.e., halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap. If these fly species lost the ability to fly independently of each other as a result of separate mutation events in each lineage, then the flightless condition in these species could be an example of

TLS Online TPP Program

#Question id: 16145

#Unit 4. Cell Communication and Cell Signaling

 Which line is not true for follicular dendritic cells?

TLS Online TPP Program

#Question id: 16144

#Unit 4. Cell Communication and Cell Signaling

  _______are motile phagocytic cells they play their most important role in the defense against multicellular parasitic organisms, including worms. They can be found clustering around invading worms, whose membranes are damaged by the activity of proteins released from its granules. it may also secrete cytokines that regulate B and T lymphocytes, thereby influencing the adaptive immune response.

TLS Online TPP Program

#Question id: 16143

#Unit 4. Cell Communication and Cell Signaling

undifferentiated hematopoietic stem cells would not express surface markers specific for mature cells from the multiple blood lineages (“Lin” markers). They used several approaches to eliminate cells in the bone marrow that did express these markers (Lin+ cells) and then examined the remaining (Lin+) population for its potential to continually give rise to all blood cells over the long term. Lin- cells were, indeed, enriched for this potential. what marker is   express If cells inter in lymphoid lineages?

TLS Online TPP Program

#Question id: 16142

#Unit 4. Cell Communication and Cell Signaling

Stem cells are defined by two capacities:

(1) the ability to regenerate or “self-renew” and

(2) the ability to differentiate into all diverse cell types. Embryonic stem cells have the capacity to generate every specialized cell type in an organism, in other words,

TLS Online TPP Program

#Question id: 16141

#Unit 4. Cell Communication and Cell Signaling

Indicate to which branch of the immune system the following statements apply, using H for the humoral branch and CM for the cell-mediated branch. Which cells involve in both response?

TLS Online TPP Program

#Question id: 15850

#Unit 4. Cell Communication and Cell Signaling

For innate and adaptive immunity to work together, these two systems must be able to communicate with one another. This communication is achieved by both cell-cell contact and by soluble messengers. Most of these soluble proteins are growth factor–like molecules known by the general name cytokines. Which of these molecule can work as communicator between innate and adaptive immunity?