B3- Infection And Response Flashcards
What is a PATHOGEN?
A micro-organism that causes disease.
Name 4 examples of a PATHOGEN
Bacteria, Virus, Fungi, Protists.
How do VIRUSES reproduce?
VIRUSES reproduce by inserting genes into cells which causes them to produce more copies.
Name 2 examples of a VIRUS
- Measles - (SYMPTOM OF A RED RASH) Spread by droplets from sneezing/coughing.
- HIV (STD/STI) Causes aids and compromises the immune system.
How do BACTERIA damage cells?
BACTERIA release toxins into your body that damage cells.
Name 2 examples of BACTERIA
- Salmonella - (undercooked food - food poisoning)
- Gonorrhoea - (STD) Causes yellow discharge from genitalia.
What do FUNGI do?
FUNGI damage cells (e.g, athlete’s foot)
What are PROTISTS?
PROTISTS are single-celled organisms.
Name an example of a PROTIST
Malaria is caused by a protist that infects red blood cells.
MOSQUITOS are the vector - ‘Vector’ meaning spread.
What is ROSE BLACK SPOT?
ROSE BLACK SPOT is a FUNGAL plant disease that causes leaves to fall off.
What is TOBACCO MOSAIC VIRUS?
TOBACCO MOSAIC VIRUS is a VIRAL plant disease that discolours leaves - LESS chlorophyll = LESS photosynthesis = STUNTED GROWTH.
What are the DEFENCES/BARRIERS in the human body?
1st barrier; skin
2nd barrier; mucus in nose/trachea
3rd barrier; enzymes/acid in digestive system
ALL KILL/DESTROY PATHOGENS
What are the DEFENCES/BARRIERS in plants?
Cell wall, waxy cuticle; antibacterial chemicals; poison/thorns to deter other organisms.
What do LYMPHOCYTES do?
Lymphocytes are a type of WHITE BLOOD CELL that produce antitoxins to neutralise toxins made/released by pathogens, and they produce antibodies that bind to the antigen of a pathogen.
What do ANTIBODIES and ANTIGENS do?
Antigens stop viruses from infecting cells, causing the pathogens to clump together.
ANTIGENS have a SPECIFIC shape, only certain antibodies can fit each one.
What do PHAGOCYTES do?
PHAGOCYTES are a type of white blood cell that ingest pathogens when they antibody has bonded to the antigen.
What is PHAGOCYTOSIS?
1) Phagocytes recognise the foreign pathogen
2) Macrophage extends its cell membrane to engulf the pathogen
3) Engulfs the pathogen into the macrophage.
How is IMMUNITY built?
If an UNKNOWN pathogen enters the body, lymphocytes will keep making antibodies until one fits the antigen of the pathogen; once the correct antibody is found, T-Cells store it in your lymph nodes for next time’s exposure to the pathogen - this is known as IMMUNITY.
What is a VACCINE?
A vaccine introduces an inert version of a virus into your body, so you can gain immunity without becoming ill.
What do ANTIBIOTICS kill?
ANTIBIOTICS kill BACTERIA not viruses.
However, it is difficult to make them target specific bacteria and not damage body (‘good’) cells.
What has to happen to ensure all BACTERIA are killed by antibiotics?
Whole course of antibiotics must be taken to kill all BACTERIA or else more resistant bacteria will survive and multiply.
What is ANTIBIOTIC-RESISTANT BACTERIA?
When antibiotics are taken, the bacteria that isn’t killed may mutate and become resistant to antibiotics - comes about via NATURAL SELCETION (becomes harder to treat as it’s better adapted).
Where did ASPIRIN and PENICILLIN come from?
ASPIRIN derived from trees.
PENICILLIN derived from mould.
Describe the process of DRUG DEVELOPMENT
Every new medical treatment is extensively tested and put through many trials to ensure it works and is safe.
1) Tested on cells/tissues in a laboratory
2) Tested on live animals to assess effectiveness/toxicity and dosage.
3) Tested on healthy human volunteers in a clinical trial before being used to treat those who are ill.
What is a BLIND TRIAL?
A BLIND TRIAL is where the volunteers receive a placebo drug without being told.
What is a DOUBLE-BLIND TRIAL?
A DOUBLE BLIND TRIAL is where both the volunteers and the doctors aren’t aware of who has the placebo drug or the study drug.
This is used to minimise bias - also known as a DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL.
