4.1.1 Communicable diseases

Question 1

What is health?

Answer 1

free from illness/disease;
physical and social and mental well being;
good nutrition;
suitably housed;

Question 2

What is disease?

Answer 2

impairment of normal functioning of organism;
malfunction of body or mind;
symptoms may be physical, mental or social;

Question 3

What is a parasite?

Answer 3

organism that lives in or on and harms host;
they take their nutrients/feeds on the host;
provides warmth/protections;
allows transmission to new host;

Question 4

What is a pathogen?

Answer 4

microorganisms that cause disease;
they take nutrients from the host and damage it in the process;

Question 5

How does bacteria cause disease?

Answer 5

reproduce fast;
damaging cells;
releasing toxins;

Question 6

What are 3 bacterial diseases on the spec?

Answer 6

tuberculosis(TB)
bacterial meningitis
ring rot (patatoes, tomatoes)

Question 6

How do fungi cause disease?

Answer 6

sends out reproductive hyphae;
they grow on the surface of the skin and release spores;

Question 7

What are the 3 fungal diseases from the spec?

Answer 7

black sigatoka(bannanas)
ringworm (cattle)
athletes foot

Question 8

How do viruses cause disease?

Answer 8

viruses invade cells;
insert their DNA into ours;
cell makes more copies of the cell;
host eventually bursts releasing new viruses;

Question 9

What are the 3 viruses from the spec?

Answer 9

HIV/AIDS
influenza
TMV

Question 10

How does protocista cause disease?

Answer 10

eukaryotic cells that have membrane bound organelles;
cause harm by entering host cells and feeding on contents as they grow;

Question 11

What are the 3 protoctistas on the spec?

Answer 11

malaria
tomato blight
patato blight

Question 11

What is the differences between direct and indirect transmission?

Answer 11

direct - directly from one individual to another

indirect - indirectly from one individual to another e.g airbone

Question 12

What is vertical transmission?

Answer 12

mother to baby through placenta

Question 13

What is horizontal transmission?

Answer 13

peer transmission; person to person

Question 14

What are the 3 types of direct transmission?

Answer 14

direct contact
inoculation
ingestion

Question 15

What are the 3 types of indirect transmission?

Answer 15

droplet infection
fomites
vectors

Question 16

What are other factors that can affect transmission of disease?

Answer 16

poor waste disposal
poor nutrition
culture and infrastructure
climate change
international travel

Question 17

How can we try and reduce direct transmission?

Answer 17

handwashing
reduce overcrowding
disposal of both bodily and household waste effectively

Question 18

How is TB spread?

Answer 18

through droplets of water in the air release through sneezing/coughing
inhaled by the unaffected individual
indirect contact

commonly spread:
overcrowded
poor ventilation
malnutrition

Question 19

How is bacterial meningitis spread?

Answer 19

through direct contact
e.g kissing, touch

Question 20

How is ring rot spread?

Answer 20

indirect transmission

Question 21

What does HIV stand for?

Answer 21

Human
immunodeficiency virus

Question 22

What does AIDS stand for?

Answer 22

Autoimmune deficiency

Question 23

How is influenza spread?

Answer 23

direct and indirect

Question 24

How is TMV spread?

Answer 24

direct

Question 25

How is patato blight spread?

Answer 25

though water e.g rain indirect

Question 26

How is ring worm spread?

Answer 26

direct contact

Question 27

How is athletes foot spread?

Answer 27

direct and indirect

Question 28

Describe how a mosquito transmits the malarial parasite to a human?

Answer 28

mosquito is a vector; plasmodium present in mosquito; in the salivary gland; mosquito feeds on human; passes parasite plasmodium from saliva to blood;

Question 29

What is direct transmission in plants?

Answer 29

contact with leaves

Question 30

What is indirect transmission in plants?

Answer 30

soil contamination (infected plants leave pathogens for next plant) wind water animals humans

Question 31

What are factors that affect transmission of disease in plants?

Answer 31

choice of plant species overcrowding monoculture poor availability of minerals

Question 32

How can transmission of communicable disease be prevented in plants?

Answer 32

leave plenty of room between plants clear fields as thoroughly as possible rotate crops follow strict hygiene practices

Question 33

What is a plant physical response to pathogens?

Answer 33

callose is deposited into the cell walls and reinforced with lignin it blocks the sieve tubes end plates in the phloem = sealing off infected area blocks the plasmodesmata between infected cells and their neighbours

Question 34

What are chemical defences of plants?

Answer 34

tannins insect repellants antifungal compounds anti oomycetes general toxins - cynanide

Question 35

What are some primary defences in humans?

Answer 35

eyes - lysozymes skin - barrier, sebum, low pH, flora (healthy microbes) stomach - HCl mucous membranes expulsive reflexes - coughing and sneezing

Question 36

What is the process of blood clotting?

Answer 36

tissue is damaged platelets activated by damaged tissue platelets release thromboplastin which catalyses prothrombin into thrombin with calcium ions and thrombin catalyses soluble fibrinogen into insoluble fibrin which forms a blood clot

Question 37

Why does blood clotting occur?

Answer 37

prevent excessive blood loss form a barrier (scab) to prevent entry of pathogens

Question 38

What is inflammation?

Answer 38

swelling of the immediately around the rupture = pain, heat, redness

Question 39

Describe the process of inflammation?

Answer 39

mast cells are activated when the skin is rupture which release histamines and cytokines histamines causes the capillaries to dilate = causing heat and redness = high temp = prevent pathogens reproducing histamines cause leaky capillaries = allows tissue fluid to release = swelling cytokines attract phagocytes to cause phagocytosis

Question 40

What is a structure of a neutrophil?

Answer 40

formed in the bone marrow multi lobed nucleus

Question 41

What is the structure of macrophages?

Answer 41

formed in the bone marrow longer life than neutrophils monocytes in blood lobed nucleus

Question 42

What is a non-specific resposne and what are the two types of processes?

Answer 42

response is immediate and same for all pathogens physical barrier phagocytosis

Question 43

What is a specific response and what are the 2 types of processes?

Answer 43

response is slower and is specific to each pathogen cell- mediated - T lymphocytes humoral response - B lymphocytes

Question 44

Describe the process of phagocytosis?

Answer 44

pathogens produce chemicals and other toxins that attract phagocytes phagocytes recognise foreign antigens on pathogens not to be of the organisms phagocyte engulfs pathogen via endocytosis = phagosome binds to lysosome = phagolysosome enzymes in phagolysosome break down pathogen harmless products e.g amino acids absorbed into cytoplasm antigen presenting cell formed

Question 45

What is an opsonin?

Answer 45

any molecule that enhances phagocytosis marking antigen of pathogen e.g antibodies

Question 46

What is the structure of a lymphocyte?

Answer 46

spherical nucleus

Question 47

What are cytokines?

Answer 47

act as cell signalling molecules and stimulate phagocytes to move to the site of infection/inflammation

Question 48

What is an immune reponse?

Answer 48

response to antigen; involves lymphocytes; production of antibodies;

Question 49

What is the difference between T-Cells and B-Cells?

Answer 49

T cells mature in the thymus B cells mature in the bone marrow