Cell recognition and Immune system

Question 1

Antigen?

Answer 1

Part of organism/substance that is recognised as non-self

Question 2

B-lympocyte?

Answer 2

matures in bone marrow
Humoral immunity
Produce antibodies
Responds to Foreign material outside the cell
Responds to bacteria and viruses

Question 3

T-Lympocyte?

Answer 3

Matures in Thymus Gland
Cell Mediated Immunity
Responds to Foreign material inside Body Cells
Responds to own cells altered by viruses/ cancer. transported tissue

Question 4

Describe how the following prevents infection of microorganisms

Answer 4

Skin - barrier to microorganisms/bacteria/pathogen/layer of toxins
Tears - Contains enzymes capable digesting
Cilla- Transports mucus up back up oesophagus into stomach. Mucus Traps bacteria
Phagocytic cells- engulfs microorganisms digested by dead by enzymes.

Question 5

Inflammation?

Answer 5

Caused by phagocytosis
The swollen area contains dead pathogens and phagocytes
Inflammations results in release of histamines which causes dilation of the blood vessels - speedup delivery phagocytes

Question 6

What does a cloned T-cell do

Answer 6

• Develops into B-cells into memory cells to enable a rapid response.
• Stimulates phagocytes to engulf pathogens by phagocytosis.
• Stimulates B-cells to divide.
• Kills infected cells by activating cytotoxic t-cells.

Question 7

Cytotoxic t-cells

Answer 7

• It kills cell by producing a protein called perforin
• makes a whole in the cell surface membrane
• cell membrane becomes freely permeable
• T-cells most effective against viruses because they replicate inside cells.

Question 8

How does immune system respond to a pathogen that has a high antigenic variability

Answer 8

Antibody of the previous strain does not correspond to the antigen of the new strain
Returns to primary response
You get ill

Question 9

Scientists believe that it may be possible to develop vaccines that make use of micro-fold cells (lines 9 -10). Explain how this sort of vaccine would lead to a person developing immunity to a pathogen. (5)

Answer 9

1. (Vaccine contains) antigen/attenuated/dead pathogen;
2. Micro-fold cells take up/bind and present/transport antigen (to immune system/lymphocytes/T- cells);
3. T-cells activate B-cells;
4. B-cells divide/form clone/undergo mitosis;
5. B-cells produce antibodies;
6. Memory cells produced;
7. More antibodies/antibodies produced faster in secondary response/on reinfection;