M25. Cell communication

Question 1

What is cell signalling?

Answer 1

the communication between cells that allows effective coordination of a response.

Question 2

How is cell signalling achieved?

Answer 2

through cell surface molecules and the release of hormone like chemicals called cytokines

Question 3

What do B lymphocytes and T lymphocytes have that allow them to detect foreign invaders?

Answer 3

receptor sites that are complementary to the foreign antigens (whether that is an isolated protein, attached to a pathogen, or on the surface of a host cell.)

Question 4

What sort of information is communicated?

Answer 4

identification
distress signals
antigen presentation
instructions

Question 5

How are cells identified?

Answer 5

As pathogens carries antigens that act as markers

Question 6

How do cells send distress signals?

Answer 6

If part of a pathogen ends up attached ti the hosts plasma membrane, then they either:

1. act as distress signals and can be detected by cells from the immune systems
2. act as markers to indicate that the cell has been infected, which t killer cells can recognise.

Question 7

How is antigen presentation communicated?

Answer 7

As macrophages act like phagocytes and engulf and digest the pathogen, but they dont fully digest it, instead they separate out the antigens and incorporate them into a cell surface molecule which is then exposed on the surface of the macrophage which becomes known as the antigen-presenting cell.

Question 8

What is the role of an antigen-presenting cell?

Answer 8

to find the lymphocytes that can neutralise that particular antigen.

Question 9

How is information communicated between cells?

Answer 9

As there are a range of cytokines released by cells that act as instructions to their target cells by binding to specific membrane-bound receptors on the target cell which causes a second set of messengers to be released inside the cell which then takes an effect on the cell.

Question 10

Give 4 examples of communication using cytokines

Answer 10

• macrophages release monokines that attract neutrophils (by chemotaxis, the movement of cells towards a particular chemical)
• macrophages released monokines that can stimulate B cells to differentiate and release antibodies.
• T cells, B cells and macrophages release interleukins, which can stimulate proliferation and differentiation of B and T cells.
• Many cells can release interferon, which can inhibit virus replication and stimulate the activity of T killer cells.

Question 11

What is chemotaxis?

Answer 11

that attract neutrophils (by chemotaxis, the movement of cells towards a particular chemical

Question 12

Describe the communication between cells in the specific immune response.

Answer 12

-Pathogen is engulfed by cells from the immune system
- Removal of antigens from pathogen
- Antigen presentation
-Reproduction of T killer and helper cells
T KILLER:
-t killer cells search for infected cells.
-T killer cells attach to infected cells
- T killer cells secrete toxic substances into infected cells to kill the cell and the pathogens it contains
T HELPER:
-release of interleukins
-activation of B cells
- Reproduction of B cells
- Some B cell clones differentiate to make plasma cells, which manufacture antibodies
- Some B cell clones differentiate to make B memory cells which circulate in the body to provide immunilogical memory.

Question 13

Describe how T killer cells destroy pathogens

Answer 13

• Pathogen is engulfed by cells from the immune system
• Removal of antigens from pathogen
• Antigen presentation
• t killer cells search for infected cells.
• T killer cells attach to infected cells
• T killer cells secrete toxic substances into infected cells to kill the cell and the pathogens it contains