B3

Question 1

What are pathogens?

Answer 1

Microorganisms that enter the body and cause communicable disease.

Question 2

What is bacteria?

Answer 2

Small cells that can reproduce very quickly in the body. They produce toxins that make you ill and damage your cells and tissue

Question 3

What are viruses?

Answer 3

• Much smaller than bacteria
• Reproduce quickly in the body
• Live in cells and replicate
• Then they burst releasing new viruses

Question 4

What are protists?

Answer 4

Eukaryotes (multicellular). Some are parasites which live in or inside other organisms.

Question 5

How can pathogens be spread?

Answer 5

• water, by drinking dirty water
• air, carried by air and breathed in
• direct contact, touching contaminated surfaces

Question 6

How is measles spread?

Answer 6

By droplets of liquid from sneezes and coughs

Question 7

What are the symptoms of measles?

Answer 7

Red rash on the skin and fever

Question 8

How is HIV spread?

Answer 8

Spread by sexual contact or exchanging of bodily fluids

Question 9

How does tobacco mosaic virus affect plant growth?

Answer 9

Infects the chloroplasts, changes the leaves and changes their colour from green to yellow or white. This reduces the amount of sunlight being able to be absorbed for photosynthesis and therefore less of it occurring. Refusing the rate of plant growth

Question 10

Give an example of a plant that TMV effects

Answer 10

Tomatoes

Question 11

What does tmv cause in plants?

Answer 11

Cause the leaves to discolour in a mosaic pattern

Question 12

Malaria is caused by what?

Answer 12

The protist - mosquito

Question 13

The protist for malaria is inserted into what?

Answer 13

The blood vessel

Question 14

What type of disease is gonorrhoea and salmonella?

Answer 14

Bacterial

Question 15

What are the symptoms of salmonella?

Answer 15

Fever, stomach cramps, vomiting and diarrhoea

Question 16

What causes salmonella?

Answer 16

Food contaminated with salmonella

Question 17

How is gonorrhoea spread?

Answer 17

Passed on by sexual contact

Question 18

How to prevent the spread of bacterial diseases?

Answer 18

• being hygienic, washing hands thoroughly
• destroying vectors, using insecticide or destroying their habitats
• isolating the infected
• vaccinating people

Question 19

What barriers do the body have when defending itself from disease?

Answer 19

• the skin acts as a barrier to pathogens
• hairs and mucus in the nose trap particles
• the trachea and bronchi secrete mucus to trap pathogens.
• the stomach contains hydrochloric acid to kill pathogens that enter the body via the mouth

Question 20

What is phagocytosis?

Answer 20

When white blood cells engulf pathogens and digest them

Question 21

What do white blood cells produce?

Answer 21

• Antitoxins to neutralise the toxins
• antibodies. They lock onto the antigen on the outside of the pathogen the white blood cells can then destroy the pathogens

Question 22

What is a vaccination?

Answer 22

And infection of a dead or weakened version of the pathogen

Question 23

How do vaccinations work?

Answer 23

They carry antigens which cause your body to produce complimentary antibodies which will attack the pathogen, if you get infected again the white blood cells can produce antibodies quickly

Question 24

What are pros of vaccines?

Answer 24

• helps to control communicable diseases
• epidemics can be prevented

Question 25

Cons of vaccines

Answer 25

- don’t always work - some people have a bad reaction (which is very rare)

Question 26

What are the three main stages of drug testing?

Answer 26

Pre - clinical 1. Drugs are tested on human cells and tissues 2. Testing carried out on living animals Clinical testing 3. Tested in healthy human volunteers in clinical trials, started with low dose then tested on people with the disease to determine dosage

Question 27

What is a placebo?

Answer 27

A substance that looks like the drug but does not do anything

Question 28

What is the placebo effect?

Answer 28

When the patient thinks the treatment will work even tho their treatment isn’t doing anything

Question 29

What is a blind trial?

Answer 29

When the patient doesn’t know if they are getting the drug or placebo

Question 30

What is a double- blind trial?

Answer 30

When both the doctor and the patient do not know whether they are getting the drug or the placebo

Question 31

What plant / microorganism did aspirin come from?

Answer 31

Willow

Question 32

What plant / organism did digitalis come from?

Answer 32

Foxglove

Question 33

What plant / organism did penicillin come from?

Answer 33

Mould

Question 34

If the pathogens enter the immune system tries to destroy the pathogens Describe how the immune system defends the body against disease

Answer 34

- White blood cells detect foreign antigens - phagocytosis engulfing the antigens - Releases antibodies which attached to the antigen and destroy it - Produce antitoxins which destroys toxins causing less damage to the cells and tissue - also produces memory cells which means next time you’re infected there is a fast response