Antibodies

Question 1

what are plasma cells and what do they do

Answer 1

they are clones of B- lymphocytes

they release antibody specific to the antigen into the blood

which bind to antigens on the pathogen forming LOTS of antigen antibody complexes

Question 2

how many polypeptide chains make up an antibody

Answer 2

4 polypeptide chains
2 heavy ( bottom)
2 light (top)

each heavy and light chain has a:

• variable region ( AT THE TOP)
• constant region ( at the bottom)

Question 3

what is special about the variable region of an antibody

Answer 3

It is complementary in shape to the antigen

variable regions differ between different antibodies

Question 4

why is the hinge region good

Answer 4

Allows flexibility

when the antibody and antigen bind

Question 5

constant regions

Answer 5

allow binding to receptors on immune system cells

constant region is the SAME in ALL antibodies

Question 6

what bond holds the polypeptide chains of the antibody together

Answer 6

Disulfide bridge

S=S

Question 7

3 ways Antibodies get rid of pathogens

Answer 7

1) Agglutinating pathogens
2) neutralising toxins
3) Preventing pathogens from binding to human cells

Question 8

Agglutinating pathogens

Answer 8

• antibodies have 2 binding sites, so 2 pathogens can bind to an antibody at the same time.
• pathogens BECOME CLUMPED TOGETHER
• Phagocytes then bind to antibodies, phagocytosing a lot of pathogens at once

Question 9

Neutralising toxins

Answer 9

antitoxins can bind to toxins

preventing the toxins from affecting human cells, so toxins are neutralised

Question 10

Preventing pathogens from binding to human cells

Answer 10

• When antibodies bind to pathogens, hey may BLOCK the cell receptors that pathogens need to bind to the host cell from working
• Which means that the pathogen can not attach to host cells

Question 11

What is the Primary immune response? ( simple def)

Answer 11

when pathogens enter the body and the antigens on its surface activate the immune system

Question 12

why is primary response slow

Answer 12

Arent many antibodies that can make the B- lymphocytes needed to bind it

Question 13

can the primary immune response make the person experience symptoms of illness

Answer 13

YES

as it is so slow that by the time the body will produce enough of the right antibody, symptoms start to develop

Question 14

After being exposed to the antigens what happens (primary immune response) ?

Answer 14

T and B lymphocytes produce memory cells, which remain in the body for a long time

T lymphocytes: remember the specific antigen and recognises it

B lymphocyte: works out the specific ANTIBODIES needed to bind to the antigen

and the person is now IMMUNE
and can now respond to quickly to a second infection that could happen in the future

Question 15

Secondary immune response

Answer 15

• If the same Pathogen enters the body the immune system produces a much quicker and stronger response to deal with it
• CLONAL SELECTION happens a lot faster, memory B lymphocytes divide into plasma cells to produce the right antibody for the antigen
• Memory t lymphocytes divide into T killer cells that kill the cell carrying the antigen
• Secondary response gets rid of pathogens so quick that no symptoms show up