Immune System

Question 1

Non-specific response types

Answer 1

1. Phagocytosis

2. Inflammation

Question 2

Phagocytosis

Answer 2

Macrophages decide if the incoming substance foreign using detector proteins
Phagocytosis starts cytoplasm surrounds the virus
Virus engulfed in a phagosome
Lysosomes are attracted to it and join to form a phagolysosome
Digestive enzymes break down the virus during lysis and any waste material is thrown out of the cell by exocytosis

Question 3

Inflammation

Answer 3

Calls become damaged
Area is red and swollen and painful
Becomes hot due to inc blood flow
Histamines stimulate small arteries towards it to become dilated
If the skin is cut a yellow puss may form full of phagocytes that may have attacked the possible pathogens

Question 4

Antigens

Answer 4

A substance ( usually a protein ) not normally found in host 
Triggers immune response enabling the immune system to identify it as foreign and causes production of specific antibodies

Question 5

Antibodies

Answer 5

Specific proteins made by b lymphocyte in response to the presence of a specific antigen
Each antibody is aY shaped molecule with 4 poly peptide chains

Each antibody has 2 binding sites where it can bind to an antigen forming an antigen-antibody complex

Question 6

Antigen antibody complex

Answer 6

Complementary tertiary structure
Precisely fit to each other to form a lattice like structure
Antibody collides w/ non self cell and binds to antigens
Stops the virus attaching to host cells

Question 7

Lobed nucleus WBC with granules in cytoplasm

Answer 7

Phagocyte

Question 8

Large or kidney shaped nucleus WBC w/ no lysosomes in cytoplasm,

Answer 8

B or T lymphocyte

Question 9

B lymphocytes

Answer 9

Mature in bone marrow 
Cause humoral response 
Secrete antibodies 
Production stimulated by T helper cell 
Memory or plasma

Question 10

T cells

Answer 10

Mature in thymus gland
Cause cell mediated response
Do not secrete antibodies
Specific T helper cell activated in response to the antigen presenting cell

Question 11

Memory cell

Answer 11

Survive for years

Will rapidly multiply to memory and plasma cells when exposed to the corresponding same antigen

Question 12

Plasma cells

Answer 12

Short lived

Antibody factories

Question 13

Cell mediated response

Answer 13

1. Pathogens invade body cells.
2. The phagocyte places antigens from the pathogen on its cell surface membrane.
3. Receptors on a specific T helper cell fit exactly to the antigens
4. T cells then begin to divide by mitosis and form a large clone of identical cells. ( memory T cells, T cells and mainly T helper cells and
5. T helper cells raise the alarm to stimulate other phagocytes to carry out phagocytosis
6. T cells stimulate cytotoxic T cells that kill infected cells

Question 14

Vaccines

Answer 14

• Artificial Passive immunity is the introduction into the body of antibodies elsewhere that are already made . Such as anti venom for a snake bite that lasts for weeks- direct antibodies are collected.
• Active passive immunity is where the antibodies are already made and last for a few weeks. Eg from the mother through the placenta or breast milk.
• Active natural immunity is making antigens when exposed to antigens as memory cells are made however this decades over time
• Active artificial immunity decades over time eg. Vaccines. Which are a preparation of antigens that stimulate antibody production

Question 15

How vaccines are made harmless

Answer 15

• Killing the pathogen in a way that doesn’t effect the antigens
• Weakening the pathogen so that it cannot reproduce
• Removing the antigens from the pathogen and using the purified antigen to make a vaccine

Question 16

Monoclonal antibodies

Answer 16

• Antigen is inserted into a mouse who creates plasma cells which create more of the same antibodies but don’t live long out of the body
• The plasma B cells are then fused with tumour cells to make hybridoma cells which keep dividing and making anti bodies
  o Tumour cells are used as they divide rapidly and are long lived
• Like a B cell the hybridoma cell creates an antibody Called a monoclonal antibody which are exact clones of the original antibodies

Question 17

How monoclonal antibodies are used

Answer 17

o Separating chemicals from mixtures
o Ingesting Into someone in the initial stages of infection so that they have the antibodies to overcome the disease
o To knock out specific T cells that attack healthy cells after a transplant surgery
o Immunotherapy which sends medication to specific cell types by attaching a therapeutic drug to an antibody. Eg a type of cancer treatment
o Medical diagnosis

Question 18

ELISA TEST ( testing for mumps)

Answer 18

1. Mumps antigens are isolated and attached to the base of the well in a test dish.
2. A sample fo the blood plasma being tested is added to the well. If mumps antibodies are present in the blood they will attach to the mumps antigens. The well is then washed to remove any blood plasma. If any antibodies were present in the blood they will remain in the well attached to the antigen
3. An indicator solution is added
4. A second antibody with an enzyme attached is put into the well. This antibody is specific to the mumps antibody. The well is thoroughly washed again to remove any unmatched (2nd) antibodies.
5. If the unattached antibodies are not removed there will be a false positive
6. A solution is one added which will change colour is the enzyme is present. Of toy does not change couloir the solution is not present as there was no original antigen for them attach to and therefore they were washed away

Question 19

Virus’s made of

Answer 19

Capsid
Inside the centre of the HIV virus is a protein called the capsid.
The capsid contains the genetic material and enzymes.

RNA
The genetic material for HIV consists of two strands of single-stranded RNA.
The RNA is inside the capsid.

Enzymes
The enzymes inside the capsid include reverse transcriptase.
Reverse transcriptase is important to the role of HIV in infection.

Viral envelope
The capsid is enclosed by a viral envelope.
The viral envelope has glycoproteins on its surface.
The glycoproteins bind to the cell surface membrane of TH cells to infect the cells

Question 20

Fighting viral disease (HIV)

Answer 20

• HIV enters the bloodstream via bodily fluids. If mum has HIV child has a high chance of having it.
• A protein on the HIV readily binds to a protein called CD4 ( which most commonly attaches to T. Helper cells.)
• The protein capsid fuses with the cell surface membrane. The viral RNA and enzymes enter the T helper cell.
• The viral reverse transcriptase enzyme makes a DNA copy of the viral RNA
• The DNA copy is inserted into the nucleus of the T helper cell and into the DNA
• The HIV DNA in the t helper cells nucleus creates mRNA usuing the cells enzymes. Which contains the instructions for making the viral proteins and the RNA to go into the new HIV
• The mRNA passes out of the nucleus through a nuclear pore and uses the cells protein synthesis to made HIV particles.
• The HIV breaks away from the T helper cell with a piece of its cell surface membrane surrounding them which forms the lipid envelope.
• This can carry on for years as the virus slowly kills more and more T helper cells
• Shortage of T helper cells cause B cells to not be activated and therefore no antibodies can be produces which causes AIDS