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Flashcards in Cells And The Immune System Deck (63):
1

Why do some antigens generate an immune response?

The immune system identifies them as foreign

2

What do antigens allow the immune system to do?

To tell the difference between self cells and foreign invaders

3

Where are antigens usually found

On the surface of cells

4

Antigens that aren't normally found in the body are referred to as what?

Foreign antigens

5

What do antigens allow the immune system to identify?

Pathogens
Abnormal body cells
Toxins
Cells from other individuals of the same species

6

What are pathogens??

Organisms that cause disease

7

Give examples of pathogens

Bacteria
Viruses
Fungi

8

How does the immune system know to destroy a pathogen

Because it has antigens on its surface which are identified as foreign by the immune system

9

What is the problem with organ transplants and blood transfusions within the immune system?

The cells are from another person therefore they have different antigens on their surface, therefore an immune response is triggered by the foreign antigens. This leads to the rejection of transplanted organs if drugs aren't taken

10

What is a phagocyte?

Type of white blood cell that carries out phagocytosis

11

What is phagocytosis

Engulfment of pathogens

12

Where are phagocytes found?

In the blood and in tissues

13

What are antigens?

Molecules that are usually proteins that trigger an immune response when detected by the body

14

Name the 4 main stages of the immune response

-phagocytosis
- T-cells
-B-cells
-antibody production

15

Outline the basic stages in phagocytosis

- phagocyte recognises the foreign antigens on the pathogen
- phagocyte engulfs the pathogen into its cytoplasm
- the pathogen is contained into a phagocystic vacuole
- lysosome fuses with the vacuole
- lysozymes in the lysosomes hydrolyise the pathogen
- the pathogen is destroyed and the phagocyte presents the pathogens antigens on its surface

16

Why does a phagocyte present the pathogens antigens on its surface when it's destroyed it and what does this mean it's acting as?

To activate other immune system cells
Acting as an antigen-presenting cell

17

What is another name for a T-cell

A T-lymphocyte

18

Phagocytes, T-Cells and B-cells are all types of what?

White blood cells

19

What do T-cells have on its surface?

Receptor proteins

20

What do the receptor proteins on T-cells bind to?

Complementary antigens presented to it by phagocytes

21

What do Helper T-cells do?

-Release chemical signals that activate and stimulate phagocytes and cytotoxic cells which kill abnormal and foreign cells
- also, they activate B-cells which secrete antibodies

22

What are B-cells covered in?

Antibodies

23

What are antibodies and what do they form?

They are proteins that bind to antigens to form an antigen-antibody complex

24

What are the differences between antibodies on different B-cells?

Their shape

25

When are B-cells activated?

When an antibody on the surface of a B-cel binds to an antigen
When the substances from helper T-cells are released

26

What do the activated B-cells divide into

Plasma cells

27

What do plasma cells secrete

Antibodies specific to the antigen

28

How many binding sites does an antibody have

2

29

An antibody having 2 binding sites means what?

It can bind to two pathogens at the same time, meaning pathogens become clumped together

30

What is the term for when pathogens are clumped together by antibodies

Agglutination

31

What kind of biological molecule are antibodies

Proteins

32

What are the monomers of antibodies

Amino acids

33

The specificity of an antibody depends on what?

It's variable regions

34

What do the variable regions form on an antibody

Their binding sites

35

Each antibody has a variable region with a unique what??

Tertiary structure

36

What is the unique tertiary structure due to?

Different amino acid sequences

37

What do all antibodies have that is the same?

Constant regions

38

What is the function of helper T-cells?

Release chemical signals to activate phagocytes, cytotoxic T-cells and B-cells

39

What is the function of plasma cells?

Produce antibodies

40

What is the difference between the cellular and humoral immune response

Cellular immune response- involves T-cells and other immune cells that they interact with eg phagocytes
Humoral immune response- involves B cells, clinal selection and production of monoclonal antibodies

41

Give 4 differences between primary and secondary immune response

Primary is slow (speed)
Primary happens first time a pathogen invades
Primary involves B cells/ secondary also involves memory cells
There are symptoms with primary but not secondary

42

Why is the primary response slow

Because there aren't many b-cells that can make the antibody to bind to it

43

What do memory T-cells remember?

The specific antigen

44

What do memory B-cells remember

Record the specific antibodies needed to bind to the antigen

45

What is active immunity?

When your immune system makes its own antibodies after being stimulated by an antigen

46

What is natural active immunity

This is when you become immune after catching a disease

47

What is artificial active immunity

This is when you become immune after being given a vaccination containing a harmless dose of antigen

48

What is passive immunity?

When you are given antibodies made by a different organism

49

What is natural passive immunity

When a baby becomes immune due to antibodies it receives from its mother, through the placenta and boobie milk

50

What is artificial passive immunity

When you become immune after being injected antibodies from someone else

51

Name 4 differences between active immunity and passive immunity

Active: Passive:
Requires exposure to antigen Don't require exposure
Memory cells are produced Memory cells aren't produced
Takes a while for protection to Protection is immediate
develop
Protection is long term Protection is short term because
antibodies are broken down

52

What do vaccines contain

Antigens that are free or attached to the dead/ attenuated (weakened) pathogen

53

What are the two ways that vaccines can be given

Orally or injected

54

Give 2 disadvantages of taking a vaccine orally

-They may be broken down my enzymes in the gut
-The molecules of the vaccine may be too large to be absorbed into the blood

55

Why are booster vaccines sometimes given later on

To make sure more memory cells are produced

56

What is antigenic variation

When the antigens on the surface of a pathogen change

57

Explain why you can become ill with the flu even if you've been infected with the influenza virus before

Because if the pathogen undergoes antigenic variation, memory cells produced from the first infection won't recognise the antigens from the new strain. The immune system has to carry out a primary response to the new antigens and as this takes time to get rid of the infection, you get ill again

58

In antigenic variation how are different antigens formed on a pathogen?

Due to changes in the gene of a pathogen

59

How often does the influenza vaccine change?

Every year

60

What is the influenza virus otherwise known as

The flu

61

What are monoclonal antibodies

Antibodies produced from plasma cells

62

What are plasma cells

Genetically identical B cells

63

Why are antibodies very specific

Because their binding sites have a unique tertiary structure