defence against disease

Question 1

specific defence systems

Answer 1

defence against a specific type type of pathogen due to its unique antigens

Question 2

non-specific defence systems

Answer 2

generalised defence against any pathogen

Question 3

how does skin protect the body

Answer 3

covers the whole body and provides a physical barrier that is difficult for microbes top penetrate

Question 4

how does the stomach protect the body

Answer 4

contains hydrochloric acid which kills microbes that are swallowed

Question 5

how does the nose protect the body

Answer 5

• nasal hairs act as a physical barrier against dust and larger microorganisms
• sticky mucus traps dust and microbes, these are expelled or swallowed and destroyed by stomach acid

Question 6

how does trachea and bronchi protect the body

Answer 6

• goblet cells produce further mucus which traps microbes
• cilated cells contain cilia which beat rhythmically to propel mucus back up the airway to the back of the throat

Question 7

how do tears protect the body

Answer 7

contain enzymes known as lysozymes which destroy microbes, preventing them from entering their eyes

Question 8

phagocyte function

Answer 8

engulfs the pathogens and kills it

Question 9

lymphocytes function

Answer 9

• third line of defence 1 ~ produce antibodies
• third line of defence 2 ~ produce antitoxins

Question 10

antibodies function

Answer 10

bind to antigems on pathogen

Question 11

antitoxins function

Answer 11

bind to toxins which bacteria produced

Question 12

where can white blood cells be found?

Answer 12

• circulating around the body in the plasma travelling through the blood vessels
• static in some organs e.g. liver and brain

Question 13

what are anitbiotics

Answer 13

medicines e.g. that help to cure bacterial disease

Question 14

how to antibiotics work

Answer 14

by killing infective bacteria inside the body

Question 15

why do antibiotics not work against viruses?

Answer 15

viruses live inside host cells and hence are out of reach of the antibiotics

Question 16

how are painkillers and other medicines used?

Answer 16

used to treat the symptoms of disease but do not kill pathogens

Question 17

where is the drug digitalis extracted from and how is it used for treatment

Answer 17

extracted from foxglove plants
- used to treat heart conditions

Question 18

where is the drug aspirin extracted from and how is it used for treatment

Answer 18

• extracted from willow bark plants
• used to reduce fevers

Question 19

where is the drug penicillin extracted from and how is it used for treatment

Answer 19

• extracted from the microorganism mould
• used to kill bacteria

Question 20

what are placebos

Answer 20

tablets that look identical to the new drug but contain no active ingredient i.e. they are a dummy tablet with no actual drug in them

Question 21

what are monoclonal antibodies?

Answer 21

• identical copies of antibodies that have been made in laboratories
• they have a number of different uses and need to be made in large numbers to work properly

Question 22

how are monoclonal antibodies produced? (9 points)

Answer 22

1. mouse is injected with the specific antigen that the scientist wants to produce antibodies to
2. B-lymphocytes in the mouse respond by producing antibodies to the antigen
3. B-lymphocytes in the mouse are extracted
4. B-lymphocytes are combined with a tumour cell. done by adding a detergent to the cells to make both othe cell surface membranes cell fuse together
5. the combining of the B-lymphocyte and the tumour cell forms a hybridoma cell
6. The hybridoma cell has 2 important characteristics:
   - it can divide repeatedly to produce genetically identical cells
   - it can produce the desired specific antibody
7. the hybridoma cell is then cloned i.e. divides repeatedly making genetically identical copies of itself
8. each of the cloned hybridoma cells produces the specific antibodies to the antigen
9. the antibodies can be collected and purified

Question 23

advantages of mAb’s

Answer 23

• can target any molecule including human ones
• they don’t kill adjacent cells
• can be produced in high quantities quickly
• can be used:
• in diagnostic tests
• measure hormone levels
• detect pathogens in blood
• locate or identify specific molecules in a cell or tissue by binding them with a fluorescent dye
• treat diseases e.g. cancer
• help prevent transplant rejection
• attack cells that are causing arm in auto-immune system
• attack viruses

Question 24

disadvantages of mAb’s

Answer 24

• can create more side effects than expected
• not as widely used as everyone first hoped when the theory was first discovered

Question 25

how does our body stop pathogens from getting in?

Answer 25

• immune system defends humans from pathogens as it can recognise different types of pathogens
• physical barriers which stop pathogens from entering our body
• inflammatory responses ~ when a pathogen enters our body the inflammatory response is triggered meaning you start to start, warmth redness and pain

Question 26

why are people vaccinated?

Answer 26

so they can become immune from the specific disease

Question 27

name 3 diseases that we can be vaccinated against

Answer 27

• measles
• mumps
• rubella