Module 4

Question 1

Bacterial disease

Answer 1

Tuberculosis
Humans, deer, cow
Transmitted by airborne droplets
Damages lungs and suppresses immune system
Treated using antibiotics

Question 2

Bacterial disease (plant)

Answer 2

Ring rot
Potatoes tomato’s
Bacteria damage leaves tubers and fruit
Transmitted through micropropagation
Reduce crop yield

Question 3

Viruses

Answer 3

Non living, acellular
Smaller than bacteria, only genetic material, capsid and attachment proteins
Replication occurs inside host cells
Bacteriophage

Question 4

HIV

Answer 4

Virus
Transport in blood, attach to helper T cell,
AIDS is where the replicating virus interferes with normal functioning of the immune system

Question 5

Influenza

Answer 5

Effect ciliated cells in the lining if the gas exchange surfaces
Airborne droplets

Question 6

Tobacco mosaic

Answer 6

Viral
Damage leaves and fruit
Transmitted through touch, eg gardeners and contaminated tools
No cure

Question 7

Protosctista

Answer 7

Eukaryotes that exist as single celled organisms
Very few that are pathogenic
Parasites, usually transmitted through a vector eg malaria

Question 8

Malaria

Answer 8

Protostista
Spread to humans via mosquitoes
Produce sexually and a sexually
Plasmodium affects red blood cells, liver and brain
Some preventative methods

Question 9

Potato blight

Answer 9

Protocista
Fungus like
Potato Bligh or tomato late blight
Transmitted by spores
No cure but can develop resistant strains

Question 10

Fungi

Answer 10

Eukaryotic, multi or singular cells
Parasitic, release enzymes which digest host tissues (animals or plants)

Question 11

Black Sigatoka

Answer 11

Infect banana
Damage to the leaves, turn black, prevent growth
Spread by spores on the wind
Fungicides can kill the fungus

Question 12

Althletes foot

Answer 12

Fungal disease
Only humans, type of ring worm
Crack skins, direct contract
Cured with anti-fungal creams

Question 13

Living conditions which can make transmission more likely

Answer 13

Hot climate, more kinetic energy for chemical reactions
Social factors , for example poverty, lack medicine, overcrowded

Question 14

Direct transmission

Answer 14

Direct contact, touch, kissing
Inoculation, animal bites, needles
Ingestions, drinking or eating contaminated food or drink

Question 15

Indirect

Answer 15

Vectors, animal pass along the pathogen to humans
Droplets, droplets in water, saliva
Fomites, dirty bedding, socks, innate object which can carry

Question 16

Plants transmission, direct

Answer 16

Direct contact between plants , e.g ring rot

Question 17

Plant transmission, indirect

Answer 17

Contaminated soil, pathogens and their spores remain in soil, and infect roots of plants
Vectors, wind water, animals, spores carry pathogen from one plant to the next

Question 18

Plant responses

Answer 18

Barriers to prevent entry
Antibacterial chemicals and proteins
Physical defences, produce callose, prevent spread after infections

Question 19

Primary in humans (non specific)

Answer 19

-Skin, physical barrier
-Blood clots, temporary barrier
-Muscus membrane, trap pathogen, ciliated cells remove it from the body
-Lysozymes, hydrolysis enzymes which digest pathogens
-Explosive reflexes, sneezing to force pathogen out of the body Lysozymes
-Inflammation, localised to areas which are infected, red hot and sore, triggers mast cell release histamines and cytokines
-Histamines cause increased blood flow, increase temp to kill pathogen, becom3 more permeable allows white blood£ -cells to ravel through tissue and kill pathogens

Question 21

Phagocytosis (macrophages and neutrophils

Answer 21

Travel into blood and out of capillaries, enfold and digest pathogens, this is non specific.

Question 22

Second line of defence- lymphocytes

Answer 22

Specific response
B lymphocytes (mature in bone marrow)
T lymphocytes (mature in the thymus)

Question 23

Specific response (T cell)

Answer 23

Receptors on the T cell will bind to the antigen presenting cells causes the T cell to divide rapidly by mitosis

Antigen presenting cells are cells which presents a non self antigen on their surface:
Including infected cells and macrophages which have engolfed the pathogen
Cells of a transported organ
Cancer cells

Question 24

Cell mediated response

Answer 24

Pathogen engulfed and destroyed by a phagocytes, antigens positioned on the surface, now called an antigen presenting cells.

T helper cells have recpotors on the surface, attach to the surface of the antigens on the APC

Once attached interleukins are produced which stimulate the t helper cells to divide by mitosis and make a large number of clones

Cloned t helper then differentiate into different cells which are needed, some remain as t helper to produce interleukins, for more clones to be made, other turn into T memory cells, which remain in the same shape and provide long lasting immunity, T killer cells, t regulator, suppress the response

Question 25

T killer cells

Answer 25

Destroy abnormal or infected cells Releases the protein perforin, embeds in the surface of the membrane, makes a pore, substances can enter or leave the cell, causing cell death, most common in viral infections as they infect the body cells meaning that the cells have to be destroyed to prevent the virus from replicating

Question 26

B lymphocytes Humoral response

Answer 26

T helper cells- stimulate B cells by producing interleukins Initiates the humoral response, involves antibodies.

Question 27

Antibody

Answer 27

Is a globular, quaternary structure with four polypeptide chains, two heavy two light, contains a variable region, which has a unique 3D shape which is complementary to the antigen, the rest is the constant region, When the antigen and antibody bind if forms a antigen, antibody complex Hinge region=flexible, when binding to multiple pathogens

Question 28

Antibodies work in three ways

Answer 28

Agglutination, marking pathogens, acting as anti-toxins

Question 29

Passive immunity

Answer 29

Natural- passed along to feotus through the placenta or beast milk Artificial- transfusion of injection of antibodies as a part of medical treatment

Question 30

Active immunity

Answer 30

Natural- following infection of the pathogen Artificial- introduction of weakened version of the pathogen or antigen by a vaccine

Question 31

Autoimmune system

Answer 31

Identifies your own cells as non self and therefore potentially harmful Makes antigens against your cells

Question 32

Antigen variability

Answer 32

Pathogen mutated, no longer got the same shape antigen, your no longer immune This is why you have booster vaccine

Question 33

Epidemic

Answer 33

Spread rapidly on a national level

Question 34

Pandemic

Answer 34

Spread rapidly on a global level

Question 35

Herd immunity

Answer 35

Large enough proportion of the population is vaccinated, then it’s unlikely that if someone is susceptible that they will become infected