Topic 3- Infection And Response

Question 1

What is a pathogen?

Answer 1

A disease-causing microorganism e.g. bacteria

Question 2

How do bacteria cause disease?

Answer 2

Divide rapidly by binary fission. Kill cells and produce harmful toxins

Question 3

How do viruses cause disease?

Answer 3

Invade + reproduce inside body cells leading to cell damage

Question 4

Which 3 ways do pathogens spread?

Answer 4

1. Air- droplet infection (cold, flu)
2. Water- plant diseases (fungal spores)
3. Direct contact- (plant diseases + STIs)

Question 5

Give 4 ways in which the spread of pathogens can be reduced

Answer 5

1. Hygiene- hand washing
2. Isolation
3. Removing vectors- pesticides
4. Vaccination

Question 6

Why is it important to prevent the spread of viral diseases?

Answer 6

Scientist haven’t developed cures yet

Question 7

What is measles?

Answer 7

Viral disease causing blindness and brain damage.

Symptoms; fever, red skin rash

Question 8

How is measles spread?

Answer 8

Through air- inhalation of droplets

Question 9

What is HIV/AIDS

Answer 9

HIV- virus that damages immune system

AIDS- condition resulting from long term HIV

Question 10

How is HIV spread?

Answer 10

Direct sexual contact and exchange of bodily fluids

Question 11

How can spread of HIV be prevented?

Answer 11

Use of condoms

Not sharing needles

Question 12

What is tobacco mosaic virus?

Answer 12

Plant pathogen causes leaf discolouration. Affected areas cant photosynthesise

Question 13

How is tobacco mosaic virus spread?

Answer 13

Contact between infected and healthy plants. Insects may act as vectors which transfer virus

Question 14

What is salmonella?

Answer 14

Type of bacteria in raw meat. Affect natural gut bacteria

Question 15

What are the symptoms of salmonella?

Answer 15

Fever
Abdominal cramping
Vomiting
diarrhoea

Question 16

How can spread of salmonella be limited?

Answer 16

Vaccinating animals
Keep raw meat away from cooked meat
Cook meat

Question 17

What is gonorrhoea and its symptoms?

Answer 17

STI
Yellow discharge from genitals
Painful urination

Question 18

What is rose back spot?

Answer 18

Fungal disease- black spots develop on leaves. Reduces area of leave available for photosynthesis

Question 19

How is the rose black spot spread?

Answer 19

Fungal spores are spread in water

Question 20

What is malaria?

Answer 20

Disease caused by protists pathogens- carried by mosquitoes. Protists enter bloodstream when they feed.

Question 21

How can spread of malaria be reduced?

Answer 21

Using insecticides

Using insect nets

Question 22

How does skin prevent pathogens from entering body?

Answer 22

Acts as physical barrier

Scab formation

Question 23

How does the respitory system prevent pathogens from entering body?

Answer 23

Nose- hairs and mucus trap pathogens

Trachea + bronchi- mucus traps pathogens

Question 24

How does stomach prevent pathogens infecting body?

Answer 24

Secretes hydrochloric acid- kills any pathogens

Question 25

How does phagocytosis protect against disease?

Answer 25

White blood cells (phagocytes) ingest and destroy pathogens so they cant infect more cells

Question 26

How does antibody production protect us against disease?

Answer 26

WBCs produce antibodies. | Binding of antibodies to antigens causes pathogens to clump together- easier to destroy

Question 27

How does antitoxin production protect us against disease?

Answer 27

Bind to toxins released by pathogens and neutralise them

Question 28

What is a vaccination?

Answer 28

Contains dead form of pathogen which stimulates WBCs to produce antibodies. In case of second infection memory cells quickly produce correct antibodies

Question 29

What is herd immunity?

Answer 29

If a high proportion of a population are immune to disease the spread will be limited

Question 30

What are the advantages of vaccinations?

Answer 30

Eradicated many diseases Many epidemics can be prevented Herd immunity protects those who cannot have vaccinations

Question 31

What are the disadvantages of vaccinations?

Answer 31

Not guaranteed to work | May be side effects

Question 32

What is the role of antibiotics?

Answer 32

Kill bacterial pathogens inside body

Question 33

How do antibiotics work?

Answer 33

Kill pathogens inside body bot not human cells.

Question 34

Why cant antibiotics be used to treat viral diseases?

Answer 34

Have no effect on viral pathogens as they live inside human cells. Hard to design drugs that would kill virus and not the cell

Question 35

What effect to painkillers have on infectious disease?

Answer 35

Only treat the symptoms but don’t kill pathogens

Question 36

What plant is the heart drug digitalis extracted from?

Answer 36

Foxgloves

Question 37

What painkiller originates from a compound in willow bark?

Answer 37

Aspirin

Question 38

What antibiotic was discovered by Alexander Fleming from a type of mould?

Answer 38

Penicillin

Question 39

What are 4 qualities of a good medicine?

Answer 39

Effective Stable Safe Able to be taken in and removed easily

Question 40

What 3 factors are tested for when developing new drugs?

Answer 40

Toxicity Efficacy Dose

Question 41

How is clinical testing carried out?

Answer 41

Healthy volunteers and patients. Low doses on healthy people, then on a larger to scale to find optimum dose.

Question 42

What is the difference between a single-blind and a double-blind trial?

Answer 42

Single blind- only doctor knows whether patient is receiving drug or placebo Double blind- neither know- helps remove bias

Question 43

What is a peer review?

Answer 43

Results are checked over by scientists knowledgeable in the field

Question 44

How do aphids cause plant damage?

Answer 44

Sharp teeth extract sap from phloem-weakens plant. | Vectors- transfer pathogens

Question 45

How can we reduce number of aphids?

Answer 45

Chemical pesticides | Biological pest control

Question 46

Why do plants need nitrate ions?

Answer 46

Convert sugar into proteins required for plant growth.

Question 47

Why do plants need magnesium ions?

Answer 47

Required to synthesise chlorophyll. Leaves cant photosynthesise properly without it.

Question 48

What are the symptoms of disease in plants (3)?

Answer 48

Stunted growth Spotted leaves Discolouration

Question 49

What 2 ways can a plant be identified?

Answer 49

Reference to website or manual | Lab testing

Question 50

What are 3 physical defence responses used by plants?

Answer 50

Cellulose cell walls Tough waxy cuticle on leaves Outside layer on stems