Disease

Question 1

Health

Answer 1

Health

Free from disease
Physically and mentally capable
Balanced diet
Happy
Sanitation
social

Question 2

Disease

Answer 2

Disease

Absence of good health
Malfunction of body or mind
Symptoms
Physical
Mental
Social

Question 3

Pathogens

Answer 3

Bacteria: tuberculosis, bacterial meningitis, ring rot (plants)
Viruses: hiv/aids, influenza, tobacco mosaic virus,
Fungi: black sigatona(bananas) s ring worm, athletes foot
Protoctista: blight (potatoes + tomatoes), malaria

Question 4

Pathogens

Answer 4

• Are organisms that cause disease
• take nutrition from another organism out also cause harm

Question 5

Parasites

Answer 5

“organisms that live in or on another living thing (the host)”
Parasites always harm their host by taking nutrition
They can cause damage, leading to secondary infections

Question 6

bacteria

Answer 6

Prokaryotes
Reproduce very rapidly
They damage cells and release toxic waste products
E.g. Cholera (Vibrio cholerae)
E.g. Tuberculosis (Mycobacterium tuberculosis and bovis).

Question 7

Fungi

Answer 7

Fungi live in the skin, sending out reproductive hyphae
They release spores at the surface of the skin
E.g. ringworm (tinea)
E.g. athlete’s foot (tinea)

Question 8

Viruses

Answer 8

E.g. flu, common cold
E.g. HIV/AIDS
E.g. Tobacco Mosaic Virus
Viruses take over the genetic material within cells
They make the cell make more copies of the virus
The host cell bursts releasing viruses

Question 9

Protoctista

Answer 9

E.g. dysentery
E.g. malaria (Plasmodium)
They cause harm by entering host cells and feeding on contents while they grow

Question 10

Global impact

Answer 10

Good health is a “human right”
Ill health has economic impacts
Medical services – NHS
Pharmaceuticals
Ill people cannot work, function in society

Question 11

LEDCs

Answer 11

In LEDCs, why might there be more ill health?

Poverty, war
Lack of shelter
Water contamination
Poor hygiene
Poor nutrition
No health service
No education about disease
Transport facilities

Question 12

Malaria

Answer 12

Kills 3 million per year, 3-500 million affected
Mosquito as a vector for the disease (Anopheles)
Therefore in tropical regions
Most in Saharan Africa

Question 13

Transmission of Malaria

Answer 13

Caused by the eukaryotic plasmodium
The Anopheles mosquito carries the plasmodium from an infected to uninfected person
Females feed on blood
The plasmodium gametes will be taken into the mosquito’s stomach, move to the saliva and when the mosquito bites, will be transferred into the host’s blood
In the human host, the gametes of plasmodium will reproduce in the liver, before being transported through the blood.

Question 14

Transmission of pathogens

Answer 14

Direct transmission
Direct physical contact
Washing hands
Using disinfectants
Using antiseptics
Sterilising surgical instruments
Using barriers in sex (e.g. condoms)

Question 15

Direct transmission

Answer 15

Faecal-oral transmission
Cooking foods properly
Clean water – sewage treatment
Washing foods with clean water

Droplet infection
Covering mouth when coughing / sneezing
Using tissues
Washing hands

Spore transmission
Masks
Washing hands

Question 16

Social factors that affect transmission of pathogens

Answer 16

Overcrowding
Poor diet
Poor health
Lack of education
Poor ventilation
Poor sanitation

Question 17

Indirect transmission

Answer 17

Some pathogens can be transmitted indirectly using a vector
E.g. Plasmodium (which causes malaria) is carried by a mosquito, which acts as a vector for its transmission to the host

Question 18

Plant defences - passive

Answer 18

Passive Plant Defences

Plants are adapted to prevent entry of pathogens
These are known as passive defences
They include physical and chemical defences

Question 19

Plant defences - physical

Answer 19

Explain how the listed physical defences stop the entry and spread of pathogens

Question 20

passive chemical defences

Answer 20

Some chemicals are present in plant structures and are therefore passive (e.g. tannins in bark)
Most are produced when plants actively defend themselves against pathogens

Question 21

Active plant defences

Answer 21

Pathogens are detected by plant cells by molecules in their cell wall
What type of molecules are these?
Plant tissues will then fortify their current physical defences and produce chemicals to attack the pathogens

Question 22

Chemicals

Answer 22

Terpenoids – oils that have antibacterial and antifungal properties
Phenols (e.g. tannins) – also have antibacterial and antifungal properties. Tannins reduce attack by insects by binding to salivary proteins and digestive enzymes
Alkaloids – N containing compounds (e.g. caffeine, nicotine, cocaine, morphine). These give a bitter taste and inhibit enzyme action and protein synthesis
Defensins – cysteine-rich proteins that inhibit the action of ion transport channels
Hydrolytic enzymes – found in the spaces between cells – e.g. chitinases, glucanases, lysozymes

Question 23

Other active defences

Answer 23

Necrosis – cells are killed in order to prevent the spread of infection further. This is carried out by intracellular enzymes which are activated when cells are injured
Canker – a canker is produced by the death of the cambium. It creates a sunken lesion in the stem