Topic 3 - Infection and response

Question 1

What are pathogens?

Answer 1

Pathogens are microorganisms which cause communicable diseases

Question 2

What are the 4 types of pathogens?

Answer 2

Bacteria
Fungi
Virus
Protist

Question 3

How do bacteria make you ill?

Answer 3

They produce toxins that damage your cells and tissues

Question 4

Are viruses cells?

Answer 4

No

Question 5

How do viruses make you feel ill?

Answer 5

They live inside your cells and replicate using that cell’s machinery, the cell will then burst and release new viruses. The cells being damaged is what causes you to feel ill

Question 6

What type of cell are protists?

Answer 6

Eukaryotic (single-celled) some can be parasites and act as vectors which spread diseases

Question 7

How do fungi make you ill?

Answer 7

Some fungi are single-celled and others have a body made up of hyphae. These hyphae can grow and penetrate the skin and the surfaces f plants which could produce spores and give other things diseases

Question 8

What are the 3 ways a pathogen can be spread?

Answer 8

Water - cholera is caused by drinking dirty water
Air - influenza virus is airborne and can be spread when people who have it cough or sneeze via droplets
Direct contact - athlete’s foot is a fungus mostly caused when someone else with it touches the same things with their foot as you do

Question 9

What is measles?

Answer 9

measles is a viral disease spread by droplets from infected persons sneeze/cough. people who have it have a red skin rash and fever. Measles can sometimes be fatal. Most people are vaccinated

Question 10

What is HIV?

Answer 10

HIV is a virus spread by sexual contact or the exchange of bodily fluids. The virus attacks the immune system and can’t fight off other infections. Can be controlled using antiretroviral drugs which stop the virus from replicating

Question 11

What is the Tobacco Mosaic Virus?

Answer 11

A virus which affects plants, leaving a mosaic pattern on the leaves and discoloured and means that they can’t carry out photosynthesis and doesn’t grow well

Question 12

What are rose black spots?

Answer 12

They are a fungus that causes purple or black spots to develop on leaves on roses, this means less photosynthesis and less growing. It spreads through the environment through water and wind but can be treated using fungicides or stripping the affected leaves

Question 13

What is malaria?

Answer 13

It’s caused by a protist and half its life cycle happens inside a mosquito. the mosquitos pick it up by eating from an infected animal and pass it on. malaria can be fatal and causes fever

Question 14

What are some of your body’s defences against pathogens?

Answer 14

The skin which acts as a barrier
Your stomach which has hydrochloric acid
Cilia which waft up mucus which has particles that contain pathogens

Question 15

What does your immune system produce to destroy pathogens?

Answer 15

White blood cells

Question 16

What is phagocytosis?

Answer 16

When a white blood cell engulfs foreign cells and digests them

Question 17

What is unique about every invading pathogen?

Answer 17

the antigen on its surface

Question 18

What do white blood cells produce to target specific antigens?

Answer 18

Proteins called antibodies which lock onto different antigens and destroy them

Question 19

How are the trachea and bronchi adapted to defend the body against pathogens?

Answer 19

They secrete mucus which traps particles containing pathogens

Question 20

What does it mean to get vaccinated?

Answer 20

You have a small amount of dead or inactive pathogens injected into you, these carry antigens which cause your body to produce antibodies and your memory cells remember how and when to make them for when you may get the disease for real and can produce these antibodies rapidly.

Question 21

What are some pros and cons of vaccinations?

Answer 21

PROS
- have helped control many communicable diseases in the past
- epidemics can be prevented if a large population is vaccinated
CONS
- they don’t always work
- you can sometimes have bad reactions to them

Question 22

What type of pathogens do antibiotics kill?

Answer 22

Bacteria

Question 23

Why is it difficult to develop drugs which get rid of viruses?

Answer 23

Because viruses live inside your body cells so it’s difficult to destroy them without destroying your healthy body cells

Question 24

Why isn’t it good to use antibiotics too much?

Answer 24

because the bacteria may become resistant and reproduce to make more antibiotic-resistant bacteria

Question 25

What are the stages of drug testing?

Answer 25

1) Preclinical trials - drug tested on human tissues and cells in a lab (which can’t be used to test drugs that affect whole-body systems)
2) Then you test the drug on animals to test for efficacy (if the drug works), its toxicity, and the correct dosage
3) Clinical trials - healthy human volunteers
4) then patients suffering from the illness if the drug hasn’t caused any harmful side effects to the healthy volunteers after finding the optimum dosage
5) Double-blind test where two groups are given a drug or a placebo and neither the patient nor the doctor know which group has which, to avoid biases