Infection and Response

Question 1

What are Pathogens?

Answer 1

> They are micro-organism that enter the body and cause diseases

Question 2

What can pathogens be?

Answer 2

> Fungi, Protist, Viruses and Bacteria

Question 3

What is Bacteria and what can it do?

Answer 3

> They are very small cells, which can reproduce rapidly inside your body.
They can make you feel ill by producing toxins that damage your cell/tissues

Question 4

What are Viruses and what can they do?

Answer 4

> Viruses are tinier than cells
The reproduce rapidly and live inside your cells.
.They replicate themselves, the cell will usually burst releasing all new viruses
Cell damages makes you ill.

Question 5

What are Protist and what can they do?

Answer 5

> They are single celled eukaryotes
Some are parasites
Parasites live on or inside other organism to cause them damage.

Question 6

What are Fungi and what can they do?

Answer 6

> They come in different shapes
Some are single celled, these hyphae can grow and penetrate human skin.

Question 7

How are pathogens spread?

Answer 7

> Some are picked up by drinking/bathing in dirty water.
Carries in air and be breathed in.
Picked up by touching contaminated surfaces.

Question 8

Measles: Spread, Effects, Treatment

Answer 8

> Spread by droplets from an infected person’s cough
People will develop a red skin rash
Most people are vaccinated against it
(can be fatal)

Question 9

HIV: Spread, Effects, Treatment

Answer 9

> Spread through sexual contact
Causes flu like symptoms for a few weeks, these symptoms can be controlled with antiretroviral drugs
The virus attacks the immune system, damaging it until a stage where it can’t cope.
This stage is known as AIDS.

Question 10

TMV (Tobacco Mosaic Virus) :

Answer 10

> Affects Species of Plants
.Causes mosaic pattern on the leaves
The discolouration means plant’s cant carry out photosynthesis.

Question 11

Rose Black Spot: (Fungi)

Answer 11

.Fungus causes purple/black spots on leaves.
>Leaves turn yellow and drop off
>Meaning less photosynthesis
>Spread by water/wind
>Can be treated by fungicides/stripping the plant

Question 12

Malaria:(Protist)

Answer 12

> Mosquitoes are vectors-they pick up the protist when they feed.
Causes repeated episode of fever
Can be fatal, prevent by using insecticides or nets.

Question 13

Salmonella:(Bacteria)

Answer 13

> Causes food poisoning
.Suffer from fever, vomiting , diarrhoea
Caused by toxins
Infected through contaminated food,prevented by vaccinating poultry.

Question 14

Gonorrhoea (STD):

Answer 14

> Spread by sexual contact
Pain when urination, thick yellow discharge from the penis
Was originally treated with antibiotics, but bacteria have become resistant
Treated by antibiotics, barrier methods.

Question 15

How to prevent diseases?

Answer 15

> Being Hygienic: Using simple hygiene measures
Destroying vectors: Getting rid of organisms that spread the disease
Isolating individuals that are infected
Vaccination

Question 16

Fighting Diseases:

Answer 16

> The skin attacks as a barrier to pathogens, also secreted substances to kill pathogens
Hairs and mucus trap particles
Trachea and Bronchi secrete mucus
Stomach produce HCL which kills pathogens

Question 17

Explain Phagocytosis?

Answer 17

> White blood cells, engulf foreign cells and digest them

Question 18

Explain how immune system protects against pathogens?

Answer 18

immune system / white blood cells (WBCs)
* WBCs engulf pathogens
* antitoxins are produced
* (antitoxins) neutralise toxins / poisons (produced by pathogen)
* antibodies are produced
* (antibodies) help destroy pathogens
* memory cells (are formed)
* (memory cells give a) more rapid response if pathogen

Question 19

Explain what testing must be done before this new drug can be used to
treat people. (6)

Answer 19

• pre-clinical trials of the new drug on cells / tissues / live animals
• to test toxicity, dosage and efficacy
• clinical trials / test on healthy volunteers and Ebola patients at very
  low doses
• so that you can monitor for safety / side effects
• and only then do trials to find the optimum dosage and test for
  efficacy
• double blind trial / use of placebo
• which does not contain the new drug
• random allocation of Ebola patients to groups
• so no one knows who has placebo / the new drug
• peer review of data
• to help prevent false claims

Question 20

Explain how a vaccination can prevent an illness.

Answer 20

dead / inactive pathogen
* introduced to the body
* white blood cells respond
* produce antibodies
* antibodies are specific to pathogen
* antibodies produced quickly (on reinfection) / rapid response
* in larger quantities
* killing the pathogen

Question 21

What are the Pros of Vaccines?

Answer 21

> They have helped control of many communicable diseases
Big outbreaks called epidemics can be prevented.

Question 22

What are the cons of Vaccines?

Answer 22

> Vaccines don’t always work, sometime they don’t give you immunity
Sometime have a bad reaction e.g. swelling but its very rare.

Question 23

What are painkillers?

Answer 23

> Drugs that relieve pain

Question 24

What are antibiotics?

Answer 24

> They kill the bacteria causing the problem without killing your own body cells

Question 25

Explain how bacteria can become antibiotic resistant?

Answer 25

> When you’re infected some of the bacteria may be resistant to antibiotics.
When treated, only non-resistant strains will be killed
The individual resistant bacteria will survive and reproduce, increasing the population.
Which can cause a serious infection