4.1.1 Communicable diseases, disease prevention and the immune system

Question 1

4 pathogens you need to know

Answer 1

-viruses
-bacteria
fungi
protoctists

Question 2

What do bacteria do?

Answer 2

produce toxins that damage body cells

Question 3

What do viruses do?

Answer 3

Use host cells to replicate before bursting out and destroying cells

Question 4

What do protoctists do?

Answer 4

Take over the cells and break them open

Question 5

What do fungi do?

Answer 5

Digest living cells to destroy them- some also produce toxins

Question 6

How does climate increase the risk of communicable diseases?

Answer 6

-Warmer conditions allow mosquitoes to breed
- increased heat so more KE for chemical reactions + reproduction

Question 7

How do social factors increase the risk of disease?

Answer 7

lack of healthcare etc

Question 8

bacterial diseases to remember

Answer 8

meningitis, ring rot,, TB

Question 9

Viral diseases to remember

Answer 9

HIV/AIDS, influenza, tobacco mosaic virus

Question 10

Which protoctist diseases to remember

Answer 10

late tomato blight, malaria

Question 11

which fungal diseases to remember

Answer 11

black sigatoka, athlete’s foot, ringworm

Question 12

How is ring rot spread

Answer 12

direct contact

Question 13

How is TB transmitted

Answer 13

airborne, contaminated food + drink

Question 14

The effect of TB on the body

Answer 14

damage lungs + suppress the immune system

Question 15

The effect of bacterial meningitis on the body

Answer 15

Damage the membranes of the brain and cause blood poisoning

Question 16

The effect of HIV/AIDS on the body

Answer 16

gradually destroys the immune system

Question 17

The effect of influenza on the body

Answer 17

Kills ciliated epithelial cells in the gas exchange system

Question 18

The effect of athlete’s foot on the body

Answer 18

Causes cracking and scaling of skin between the toes

Question 19

The effect of ringworm on the body

Answer 19

Causes a circular red rash

Question 20

The effect of malaria on the body

Answer 20

Damages the red blood cells, liver, and brain

Question 21

Give 4 examples of vectors

Answer 21

wind, water, animals, humans

Question 22

Four factors that increase the risk of communicable disease in plants

Answer 22

Crop variety, Overcrowding, mineral nutrition, and Climate change

Question 23

Effect of ring rot on the plant

Answer 23

damages leaves, tuber and fruit

Question 24

The effect of TMV on plants

Answer 24

Damages the leaves, flowers and fruits

Question 25

The effect of black sigatoka on plants

Answer 25

Attacks and destroys leaves, turning them black

Question 26

Effect of late tomato blight on plants

Answer 26

Destroys leaves, fruit and tuber

Question 27

3 physical plant defences

Answer 27

waxy cuticle, cell wall, production of callose

Question 28

What are pathogens?

Answer 28

microbes that cause infections and disease

Question 29

What is a bacteriophage?

Answer 29

Viruses that attack bacteria

Question 30

What are parasites?

Answer 30

Organisms that benefit at the harm of the host

Question 31

Explain waxy cuticles as a plant defense

Answer 31

Waxy cuticles - Leaves and stems are covered in a waxy cuticle which provides a physical barrier against pathogens.

Question 32

Explain the cell wall as a plant defence

Answer 32

Cell walls - Plant cells are surrounded by cell walls that form a physical barrier against pathogens

Question 33

Explain callose deposition as a plant defence

Answer 33

Production of callose - When pathogens attack plants, they produce a polysaccharide called callose. This is deposited between the cell wall and the cell-surface membrane, making it harder for pathogens to enter cells.

Question 34

3 methods of direct transmission (animals)

Answer 34

- direct contact - innoculation (animal bites, sharing needles, cuts in skin) - ingestion (contaminated food/water)

Question 35

2 mechanical responses to infection in plants

Question 36

method of direct transmission (plants)

Answer 36

- direct contact

Question 37

2 methods of indirect transmission

Answer 37

- contaminated soil - vectors

Question 38

skin as a physical animal defence

Answer 38

contains skin flora which outcompete pathogens for space on skin

Question 39

explain blood clotting as a skin defence in animals

Answer 39

form if the skin is cut

Question 40

explain lysozymes as an animal defence

Answer 40

lysozymes are found in tears and saliva and contain hydrolytic enzymes which digest pathogens

Question 41

explain inflammation as an animal defence (3)

Answer 41

- damaged cells trigger mast cells to release histamines and cytokines - histamines cause vasodilation and make capillaries more permeable - so more wbc's can be delivered to the site of damage

Question 42

explain cytokines as an animal defence

Answer 42

attract phagocytes which can engulf and destroy pathogens

Question 43

2 types of phagocytes

Answer 43

macrophages or neutrophils

Question 44

phagocytosis (7)

Answer 44

- damaged cells/pathogens release cytokines which attract phagocytes to the site of infection - opsonin protein attaches to pathogens to mark them and make it easier for macrophages and neutrophils to engulf them - phagocytes have receptors which can attach onto chemicals on the surface of pathogens - pathogen engulfs the pathogen into a vesicle to create a phagosome - phagocytes have lysosomes in them with hydrolytic enzymes - lysosome fuses with phagosome 2 expose pathogen to lysozyme, lysozyme hydrolyses the pathogen+ and any soluble useful molecules are absorbed into cytoplasm of phagocyte - phagocytes present antigen of digested pathogen on their surface =apc's

Question 45

where are the two types of lymphocytes produced and where do they mature

Answer 45

- bone marrow (produced) - b cells mature in bone marrow, T cells mature in thymus

Question 46

cell mediated response (t-cells)

Answer 46

- receptors on t-cells bind 2 antigens on apc's - causes t-cells 2 divide rapidly by mitosis (clonal expansion) - examples of apc's = infected body cells, macrophage

Question 47

4 physical plant defences

Answer 47

- cellulose cell walls - lignified layer - waxy upper cuticle - old vascular tissue blocked to prevent spread of pathogen

Question 48

2 mechanical