Specific cellular defences against pathogens

Question 1

Lymphocytes

Answer 1

WBC involved in specific immune response.

Recognise specific antigens on invading pathogens.

Question 2

Antigen

Answer 2

Molecules, often proteins, located on surface of cell that trigger a specific immune repsonse.

Question 3

Lymphocytes detect and produce what

Answer 3

Foreign proteins and pathogens - produce antibodies

Question 4

Antibody

Answer 4

Created by lymphocytes cause pathogens to stick together and make it easier for phagocytes to engulf.

Question 5

Each lymphocyte produces its own

Answer 5

Receptor that corresponds to a specific antigen. When a lymphocyte encounters that antigen it multiples creating larger number of identical lymphocytes bearing that particular receptor.

Question 6

Pathogens that produce toxins

Answer 6

Make you feel ill

Lymphocytes can produce antitoxins to neutralise these toxins. This means toxins cannot bind to body cells and cause damage.

Question 7

What makes lymphocytes specific?

Answer 7

Antibodies or antitoxins are highly specific to antigen or toxin made by pathogen.

Question 8

2 types of lymphocyte?

Answer 8

1. B - lymphocyte
2. T - Lymphocyte

Question 9

B- Lymphocyte

Answer 9

Produce antibodies against antigens which leads to destruction of pathogens.

Question 10

Antibody shape

Answer 10

Y shaped protein molecules which have binding sites specific to particular antigens. When antibody binds to antigen, pathogen is inactivated.

Question 11

Allergic reaction

Answer 11

B lymphocytes trigger immune response against substances that are harmless to body such as pollen.. This triggers conditions such as hay fever or asthma. Hypersensitive responses to harmless antigen is an allergic reaction.

Question 12

T- lymphocyte

Answer 12

Destroy cells that have been infected by pathogen. Recognise antigens of pathogen on surface of cell and induce apoptosis (programmed cell death).

Question 13

Apoptosis

Answer 13

T-lymphocytes attach onto infected cells and release proteins. these proteins diffuse into infected cell. This causes production of self-destructive enzymes, which cause cell death. the remains of cell are removed by phagocytosis.

Question 14

T-lymphocytes can determine what difference?

Answer 14

Antigens found on body’s own cells (self-antigen) and antigens belonging to pathogen (non-self-antigen)

Question 15

Immune system fails to recognise difference

Answer 15

T-lymphocytes attacking body’s own cells - leads to autoimmune disease

Question 16

Examples of autoimmune disease

Answer 16

Rheumatoid arthritis and type 1 diabetes

Question 17

Memory cells

Answer 17

Lymphocytes are produced in response to specific antigens on a pathogen. After pathogen is removed some of lymphocytes continue to remain in immune system - called memory cells

if pathogen enters for 2nd time - rapid response

Question 18

HIV

Answer 18

Human immunodeficiency Virus

Virus that attacks and destroys body’s T-lyphocytes. reduction in T-lymphocytes leads to development of AIDS (acquired immune deficiency syndrome)

So weaker immune system and more vulnerable to infection - tuberculosis and pneumonia are more common and fatal

Question 19

HIV/AIDS treatment

Answer 19

No cure

Given antiretroviral drugs - these stop virus replicating in body - allows immune system to repair itself and prevent development of AIDS. Gives those with HIV longer life.