Specific immune system - antibodies

Question 1

What are antibodies?

Answer 1

Y-shaped glycoproteins called immunoglobulins

there are millions and there is a specific antibody for each pathogen

Question 2

What is the function of antibodies?

Answer 2

bind to specific antigen on the pathogen or toxin that has triggered the immune response

Question 3

What is the structure of an antibody?

Answer 3

two identical long polypeptide chain called the heavy chain and two much shorter identail chains called the ligh chains

held together by disulfide bridges, also have them within the polypeptide, holding them in shape

Question 4

How do antibodies bind to antigens?

Answer 4

‘lock and key’ mechanism similar to the active site and its substrate

where the antigen binds is the variable region

the rest of the antibody molecule is the samne so it is called the constant region

forms a antigen-antibody complex

the hinge region of the antibody provide the molecule with flexibility, allowing it to bind to two seperate antigens

Question 5

How do antibodies defend the body?

Answer 5

antigen-antibody complex acts as an opsonin, so the complex is easily engulfed and digested

makes the pathogen ineffective once the complex has formed

act as agglutins, causing pathogens part of the antigen-antibody complex to clump together, this slows the spread and makes in easy for phagocytes to engulf at number of pathogens at the same time