Infection and Response

Question 1

What are pathogens

Answer 1

Microorganisms that enter the body and cause disease

Question 2

Bacteria

Answer 2

Very small cells (1/100 of body cells)
Can reproduce rapidly inside your body
Make you ill by producing toxins that damage your cells and tissues

Question 3

Viruses

Answer 3

Not cells, 1/100 the size of a bacterium
They replicate themselves inside a cell until it bursts, releasing all the new viruses. The cell damage makes you ill

Question 4

Fungi

Answer 4

Some are single-celled and others are made up of hyphae which grow and penetrate human skin and the surface of plants, causing diseases. Hyphae can produce spores which can spread to other plants/animals

Question 5

What three ways can pathogens be spread

Answer 5

Water, Air, Direct contact

Question 6

Three viral diseases how they spread and what they do

Answer 6

Measles- droplets from an infected person’s sneeze or cough (red skin rash, fever can be fatal), can be vaccinated

HIV- sexual contact or exchange in bodily fluids (flu-like symptoms), it attacks the immune system, can be controlled with antiretroviral drugs

Tobacco mosaic virus- direct contact from flower to flower from a farmers gloves for example (discolouration)

Question 7

One fungal and one protist disease and what they do

Answer 7

Rose black spot (fungal)- spots develop on leaves of rose plants which prevents photosynthesis to stunt growth, spreads in environment through water or wind and can be stopped with fungicides

Malaria (protist)- repeated episodes of fever, can be fatal. Mosquitoes are vectors, picks it up by feeding on an infected animal and gives it to any other animal it feeds on. Can be stopped destroying the vector

Question 8

2 bacterial diseases and what they do

Answer 8

Salmonella- causes food poisoning, can suffer from fever, stomach cramps, vomitting, diarrhoea. Caused by toxins that bacteria produce. Obtained by eating contaminated food, can be stopped by vaccinating poultry

Gonorrhoea- pain when unrinating or thick yellow/green discharge from penis or vagina, transported by sexual contact, spread stopped with antibiotics or contraception. Was once treated with penicilin but now some bacteria have become resistant

Question 9

4 ways to prevent the spread of disease

Answer 9

Being hygenic, Destroying vectors, Isolating infected individuals, Vaccination

Question 10

What is phagocytus

Answer 10

When white blood cells engulf foreign cells and digest them

Question 11

Four things that act as a body’s defence system to pathogens entering the body

Answer 11

The skin acts as a barrier to pathogens and it also secretes antimicrobial substances
Hair and mucus in your nose trap particles that could contain pathogens
Stomach produces hydrochloric acidwhich kills pathogens
Trachea and bronchi secrete mucus and are lined with cilia which wafts the mucus to the back of the throat where it can be swallowed

Question 12

What are antibodies

Answer 12

Proteins produced by white blood cells to lock onto invading cells so that they can be found and destroyed by other white blood cells

Question 13

Protists

Answer 13

Single-celled Eukaryotes, some are parasites. Parasites live inside other organisms and can cause them damage, often transferred by a vector

Question 14

3 ways immune system attacks pathogens

Answer 14

Phagocytosis, producing antibodies, producting antitoxins

Question 15

Antitoxins

Answer 15

Counteract toxins produced by invading bacteria

Question 16

Vaccinations

Answer 16

Injecting small amounts of dead or inactive pathogens. This allows yiur body to produce antibodies to attack them even though its harmless. If live versions of the pathogen appear then white blood cells can rapidly mass produce antibodies to kill off the pathogen

Question 17

Pros and Cons of vaccines

Answer 17

Pros:
- helped control lots of communicable diseases that were once common like smallpox
- big outbreaks of diseases can be prevented since fewer people can pass it on
Cons:
- don’t always work
- can have a bad reaction to a vaccine, very bad ones are rare

Question 18

3 examples of drugs

Answer 18

Penicilin- kills bacteria, discovered by Alexander Fleming
Aspirin- painkiller, found in the plant willow
Digitalis- treat heart conditions, found in plant foxgloves

Question 19

3 stages of developing drugs and drug testing

Answer 19

1. Tested on human cells and tissues in the lab but can’t use cells and tissues to test drugs that affect whole or multiple organ systems
2. Test the drug on live animals to test efficacy (if it works) and toxicity (harm) and to find the best dosage. Law in Britain states that it must be tested on two different live mammals, some think its cruel while others think it’s the safest way to test a drug before giving it to humans
3. Tested on human volunteers in a clinical trial if it passes the animal test. Tested on healthy volunteers to check for side effects. It is then tested on people suffering from the illness and the optimum dosage is found. Patients are randomly put into two groups and one is given a placebo and the other the new drug to get thr placebo effect. It is a blind test so neither the pateint or the doctor know until results are provided. Results go through peer review to prevent false claims

Question 20

How to slow down the rate of resistant bacteria

Answer 20

To slow down the rate of development of resistant strains it is important that doctors avoid over-prescribing antibiotics, so you won’t get them for sore throats only something more serious. It is also important that you finish the whole course of antibiotics to kill all bacteria, don’t just stop once you are feeling better

Question 21

MRSA

Answer 21

Causes serious wound infections and is resistant to the powerful antibiotic, meticillin.