Immunity

Question 1

Bacterial Structural features

Answer 1

Cell Wall
No membrane bounding organelles
Rings of DNA

Question 2

Virus structural features

Answer 2

Flagellum
Protein spikes
Protein sheath
Contains RNA

Question 3

Difference between bacteria and a Virus

Answer 3

Virus can infect widespread whereas bacteria is localised

Virus is non-living whereas bacteria is a unicellular living organism

Bacteria can be beneficial whereas viruses cannot be beneficial

Question 4

Contact transmission of pathogens

Answer 4

Indirect contact - touching something an infected person has touched

Direct contact - touching an infected person

EXAMPLE - STIs

Question 5

Transfer of bodily fluids of pathogens

Answer 5

Bodily fluids come into contact with mucous membranes of an uninfected person so the pathogen can enter the body

EXAMPLE - HIV

Question 6

Transfer of pathogens via droplets

Answer 6

Droplets of moisture containing pathogen emitted when sneezing or coughing can be breathed in by another or settle on food

EXAMPLE - Measles

Question 7

Transmission of pathogens via ingestion

Answer 7

Consumption of food or drink contaminated with pathogen allowing it to enter via the digestive tract

EXAMPLE - Salmonella

Question 8

Transmission of pathogen via airborne transmission

Answer 8

When moisture in exhaled droplets evaporates, some bacteria and viruses remain viable which cause infection when inhaled

Question 9

Transmission of pathogens by vectors

Answer 9

Transfer of pathogen via an animal

EXAMPLE - Malaria

Question 10

Skin as external defence

Answer 10

Impervious barrier prevents entry

Secrete sebum containing antibacterial substances

Sweat glands produce lysozyme

Question 11

Cilia as an external defence

Answer 11

Beating motion moves mucous upwards where it can be expelled

Question 12

Hair as an external defence

Answer 12

Traps particles

Question 13

Mucous as an external defence

Answer 13

Traps microogranisms

Question 14

Acids as an external defence

Answer 14

In stomach, kill pathogens which have been ingested

In vagina which reduce growth of microorganisms

Question 15

Lysozyme as an external defence

Answer 15

Enzymes that kill bacteria

Question 16

Flushing action as an external defence

Answer 16

Urine flowing prevents bacterial growth

Question 17

Cerumen as an external defence

Answer 17

Earwax, protects outer ear against infections

Question 18

Sneezing as a protective reflex

Answer 18

Forceful expulsion of air from lungs

Carries foreign particles out nose and mouth

Question 19

Coughing as a protective reflex

Answer 19

Forces mucous upwards and out

Question 20

Vomiting as a protective reflex

Answer 20

Expels contents of stomach

Question 21

Diarrhoea as a protective reflex

Answer 21

Contractions of large intestine muscles allow pathogen to be removed quickly

Question 22

Steps of the inflammatory response as a non-specific defence

Answer 22

1. Damage tissues stimulate mast cells to release histamine and heparin into the tissue fluid
2. Histamine causes vasodilation of blood vessels to increase blood flow to damaged area, it also causes the increase of permeability of the capillaries which allows fluid to be filtered from the blood, this causes redness and heat
3. Heparin prevents clotting in the area
4. Other chemicals attract macrophages and leukocytes to consumed microorganisms and debri via phagocytosis
5. Pain receptors are stimulated to feel pain
6. Phagocytes collect all bacteria and debri to form pus as dead cells begin to die
7. New cells are formed by mitosis and repair of damaged tissue takes place in formation of a scab

Question 23

Fever as a non-specific defence

Answer 23

1. Set point rises
   - WBC release pyrogens, this causes the hypothalamus to change its set point at a higher than normal temperature this causes the body to seem coler than it is, this causes vasoconstriction and shivering to try and warm the body up
2. Fever break
   Once the pyrogens stop being released by the WBCs, the hypothalamus resets its set points to 36 degrees which causes the body to vasodilate and profuse sweating to cool the body temp

Question 24

Why is high temperatures beneficial for pathogens?

Answer 24

1. Increases production of killer T-cells = speeds up cell-mediated response
2. Increases metabolic to allows an increase in tissue repair
3. Creates non-optimum environment for pathogens so it inhibits them
4. Inhibits bacterial growth

Question 25

How to maintain good hygiene, prevent pathogens from entering the body

Answer 25

Washing hands Covering mouth Wiping surfaces

Question 26

Steps of the antibody mediates immune response / humoral response

Answer 26

1. Macrophages detect a microorganism with a foreign antigen 2. They engult it and display the antigen on the surface of its cell membrane 3. The macrophage then presents the antigen to a b-cell 4. The antigen then binds to the surface of the B-cell membrane at antigen receptor site, causing the b-cell to become sensitised 5. The macrophage also presents the antigen to a t-cell 6. The helper t-cell than matures and is induced to release substances = cytokines 7. These activate B-cells to enlarge and divide into a group of cells = clones 8. These clones further develop into plasma cells which secrete the complimentary antibody which is capable of attaching to the antigen active site 9. These circulate in blood, lymph and extracellular fluid to reach the microorganism of foreign material and inactivate it

Question 27

What is the secondary response of the humoral response

Answer 27

B-cells clones which don't develop into plasma cells become memory cells which allow the immune response to occur more rapidly if the same froegn material enter the body again

Question 28

Why are memory cells beneficial

Answer 28

1. Allows more antibodies to be produced at a faster rate 2. Antibody concentration remains higher for longer 3. Symptoms of foreign antigen are minor to none at all

Question 29

How do antibodies inactive the pathogen

Answer 29

1. Binds to surface of viruses to prevent entering cell 2. Coat bacteria so more easily consumed by phagocytes 3. Inhibit reactions with other cells which causes cell breakdown 4. React with soluble substances to make insoluble to be consumed by phagocytes

Question 30

Steps of the cell-mediated immune response

Answer 30

1. Foreign antigen enters the body 2 Macrophage detects it and present the antigen to a helper t-cell 3. The helper t-cell binds to the antigen and secretes cytokines which activate and sensitise the T-cell 4. Sensitised T-cells that don't become memory cells develop further into specialised T-cells known as helper t-cells, suppressor t-cells or killer t-cells 5. Intracellular pathogen infection will stimulate the T-cells to become inactivated by non-self antigen

Question 31

Types of immunity

Answer 31

1. Natural, mothers antibodies across the placenta 2. Artificial, someone else's antibodies injected 3. Passive, only lasts as long as the antibodies are in the body 4. Antibodies can be produced quickly, results in no/slight symptoms

Question 32

Live attenuated vaccine

Answer 32

contains live microorganism with reduced virulence EXAMPLE - Measles

Question 33

Inactivated vaccine

Answer 33

Contains dead microorganisms EXAMPLE - Influenza

Question 34

Toxoid vaccine

Answer 34

Inactivated toxins produced by bacteria EXAMPLE - Tetanus

Question 35

Biosynthetic Vaccine

Answer 35

Contain synthetic substances EXAMPLE - HIB

Question 36

Social Factors for Vaccinations

Answer 36

FOR Following health advice of health professionals Helps to create herd immunity Negative side effects are rare ``` AGAINST Lack of availability of the vaccine Perceived health concerns Parents don't see the importance Can encourage sexual activity Ethical concerns ```

Question 37

Cultural factors for vaccinations

Answer 37

FOR Historically always done in families AGAINST Ethical objection to medical interventions with religious beliefs

Question 38

Economic factors for Vaccinations

Answer 38

FOR Immunisation bonus paid to participants Reduced health care costs for treating the sick No loss of family tax benefits AGAINST Cost of visiting a doctor to abstain Cost prohibitive for some governments Interests of commercial enterprise that manufacture the vaccine can affect its use

Question 39

Vaccine Delivery

Answer 39

Via a syringe Sprays, skin patches and ingestion are continuously being tested

Question 40

Types of antibiotics

Answer 40

1. Bacterial antibiotics: Kill bacteria by changing structure of cell wall or membrane 2. Bacteriostatic: Stop bacteria from reproducing, usually by disrupting protein synthesis 3. Broad-spectrum: Affects many types of bacteria 4. Narrow-spectrum: Affects only a particular type of bacteria

Question 41

Two types of antibiotic resistance

Answer 41

1. Multiple drug resistance: Resistance of some strains of bacteria to most of the available antibiotics 2. Total drug resistance: Resistance of some strains to bacteria to all antibiotics

Question 42

How do antivirals help viruses

Answer 42

It inhibits the development of the virus by interfering with reproduction EXAMPLE - HIV, Herpes

Question 43

Whats the difference between antibiotics and antivirals

Answer 43

Antivirals are harder to make because viruses replicate which makes it difficult to find drugs that will treat viral infections Antivirals are often toxic to the host Antibiotics are used to treat bacterial infections whereas antivirals treat viral infections