B3 - Infection and Response

Question 1

What is a PATHOGEN ?

Answer 1

A Micro-Organism that causes diseases

eg. Bacteria, Virus, Fungi and Protist

Question 2

How do VIRUSES REPRODUCE ?

Answer 2

By Inserting Genes into Cells which Causes them to Produce more Copies

Question 3

Give 2 VIRUSES EXAMPLES and their SYMPTOMS and what they do ?

Answer 3

Measles : Rash, Spread by Droplets
HIV : An STD that Causes AIDS - Compromises Immune System, Spreads by Sexual Contact or Needles

Question 4

BACTERIA

Answer 4

Release Toxins into your Body that Damage Cells

Question 5

BACTERIA EXAMPLES

Answer 5

Salmonella : Undercooked Food - Food Poisoning
Gonorrhoea : STD, Causes Yellow Discharge

Question 6

What do FUNGI do ?

Answer 6

Damage Cells

Question 7

What are PROTISTS and give an EXAMPLE of one ?

Answer 7

Single-Celled Organisms
eg. Malaria - Caused by a Protist that infects Red Blood Cells ( Mosquitoes are the Vector )

Question 8

PLANT DISEASES

Answer 8

Rose Black Spot ( Fungus ) - Causes Leaves to Fall Off
Tobacco Mosaic Virus - Discolours Leaves, Less Chlorophyll - Stunned Growth

Question 9

4 EXAMPLES of PLANT DEFENCES

Answer 9

Cell Wall
Waxy Cuticle and Bark ( Barriers )
Antibacterial Chemicals
Poison/Thorns ( Deter Other Organisms )

Question 10

SKIN DEFENCES

Answer 10

Skin Stops Pathogens Entering

Mucus in Nose/Trachea Traps Pathogens

Acid and Enzymes kill Pathogens

Question 11

Describe how LYMPHOCYTES ( WHITE BLOOD CELL ) work

Answer 11

Lymphocytes Produce Antitoxins to Neutralize Toxins made by Pathogens

Then they Produce Antibodies that Bind to the Antigen of a Pathogen ( Only if they Fit )

These Antibodies stop Viruses from Infecting Cells and Cause them to Clump Together

Once the Correct Antibody is found, T Cells store it in your Lymph Nodes, Ready for Next Time ( Immunity )

Question 12

PHAGOCYTES ( WHITE BLOOD CELL )

Answer 12

Will Ingest these Pathogens and Destroy them

Question 13

What does a VACCINE do ?

Answer 13

Introduces a Dead/Inert version of a Virus into your Body, so you gain Immunity without you becoming ill

Question 14

ANTIBIOTICS ONLY

Answer 14

Kill Bacteria, NOT Viruses

Question 15

ANTIBIOTICS

Answer 15

Difficult to Make them Target Specific Bacteria, and not Damage our Cells or other ‘Good’ Bacteria

Whole Course must be Taken to Kill All Bacteria, or More Resistant Bacteria will Survive and Multiply

Question 16

NATURAL DRUGS

Answer 16

Aspirin ( A Painkiller ) - Came from Trees
Penicillin ( First Antibiotic ) - Came from a Mould

Question 17

SYNTHETIC DRUGS

Answer 17

Cost a lot of Money to Develop

They are put through Trials to asses for Efficacy, Toxicity and Dosage

Firstly, Tested on Cell Tissue, then Animals, then Humans

Question 18

What is a BLIND TRIAL ?

Answer 18

• Test Group are given Drug
• Control Group are given Placebo ( Without being made Aware )

Question 19

What is a DOUBLE BLIND TRIAL ?

Answer 19

Doctors do not know which is which

To Eliminate Bias