Antibodies

Question 1

How many proteins make up an antibody?

Answer 1

4

Question 2

What is the variable region on an antibody?

Answer 2

the area on an antibody that contains the antigen binding site. They are different on each antibody, this is caused by the difference in the primary structure of the protein.

Question 3

What is the constant region of an antibody?

Answer 3

an area of the antibody that stays the same on every antibody

Question 4

What is agglutination?

Answer 4

When antibodies bond to more than one pathogen causing them to clump together

Question 5

Why does agglutination aid the immune response to a pathogen?

Answer 5

It leads to an increased rate in phagocytosis, as more than one pathogen can be engulfed and destroyed at the same time. (also increases the concentration of chemicals, attracting more phagocytes)

Question 6

Why are antibodies specific to one antigen?

Answer 6

• the variable region of an antibody contains the antigen binding site
• the 3° structure of this protein is specific and is complementary to one antigen
• this is caused by the different 1° structures that result in the variable region having a varied, specific shape
• as the shape of the antigen binding site is specific is can only form antibody-antigen complexes with the antigens on a specific pathogen

Question 7

What is an antibody?

Answer 7

a protein specific to an antigen
that is produced by B cells/plasma cells

Question 8

What is a Monoclonal antibodies?

Answer 8

a single type of anti-body that can be isolated and cloned

Question 9

How does an ELISA test test for the presence of antigens?

Answer 9

• sample is attached to slide, excess is washed off
• complementary antibody to the antigen being tested for is added, unbound antibodies are washed off
• a 2nd complementary antibody is added, it is complementary to the first. Unbound antibodies are washed off
• substrate is added, it will produce a coloured product in the presence of an enzyme
  colour change = antigen
  no colour change = no antigen

Question 10

Describe the process of direct monoclonal antibody therapy to treat cancer

Answer 10

• MAB designed with a binding site complementary to the antigen on the cancer
• once bound, antibodies stop chemicals binding to the cell that cause division
• cancer cells stop growing

Question 11

What bond occurs between 2 cysteine amino acids?

Answer 11

disulfide bridges

Question 12

Why do antibodies bind to a specific substrate?

Answer 12

antibodies have a specific tertiary structure which is complementary to a specific substrate

Question 13

How do antibodies increase the rate of phagocytosis?

Answer 13

• bind to antigens on pathogens
• agglutination(increases [toxins]

Question 14

How could you test whether memory cells had formed?

Answer 14

• inject vaccine
• fastER response means memory cells present
  OR
• add enzyme attached to antibody for memory cell
• colour change shows memory cell is present

Question 15

why are antibodies only effective against a specific pathogen?

Answer 15

• Antibodies have specific tertiary structure
• antigens (on pathogen) are complementary to antibody so
  antibody-antigen complex can form;

Question 16

What is an antibody?

Answer 16

-a protein specific to an antigen;
- Produced by B cells

Question 17

Explain how the treatment with an antivenom works and why it is essential to use passive immunity, rather than active immunity

Answer 17

• antibodies bind to the toxin/venom/antigen and
  causes its destruction;
• active immunity would be too slow/slower

Question 18

What does ELISA stand for?

Answer 18

ELISA stands for enzyme-linked immunosorbent assay