Defence Mechanisms Flashcards
Antibody
2 marks
Chemical produced by a lymphocyte in response to an antigen.
Antigen
(2 marks)
A marker on a microorganism that causes the body to produce antibodies.
Antimicrobial
2 marks
Substance that kills or inhibits the growth of microorganisms.
Aseptic Techniques
3 marks
Name given to the laboratory procedures carried out to prevent the contamination of pure cultures of microorganisms.
Communicable
2 marks
A disease that can be passed from one organism to another.
Immobilise
(1 mark)
Prevent something from moving.
Incubate
2 marks
To keep a sample of microbes warm so that the cells reproduce quickly.
Lymphocytes
(3 marks)
WBC’s which attack pathogens by producing antibodies.
Microorganism
2 marks
Microscopic (too small to see) organisms, such as bacteria + viruses.
Phagocytosis; Simplified
2 marks
Process of the ingestion of bacteria or other material by phagocytes.
Respiratory System
2 marks
Organ system where air is taken into + out of the body + gas exchange happens.
Vaccine
3 marks
Substance which stimulates the body to produce antibodies to provide immunity against a disease.
Defence mechanisms
2 marks
Help the body protect itself against the entry of microorganisms + resulting communicable diseases.
If a microorganism does enter the body
1 mark
Mechanisms in place to destroy it quickly.
Preventing Entry of Microorganisms in Body
3 marks
- Skin
- Mucous membranes
- Blood clotting
Prevention of microorganisms into body;
Skin
(1 mark)
Barrier to microorganisms.
Prevention of Microorganisms into body;
Mucous Membranes
(2 marks)
Present in the respiratory system to trap microorganisms.
Prevention of Microorganisms into Body;
Blood clotting
(3 marks)
Stops blood escaping + prevents entry of microorganisms where the skin has been damaged.
Entry of a microorganism into the Body
2 marks
May cause us to be sick while our body fights the infection.
Invading microorganisms
2 marks
Have antigens on their surface that the human body can recognise as being foreign.
Foreign Body
1 mark
Not belonging to the Body.
When the body recognises a foreign antigen
5 marks
Lymphocytes (WBC’s) produce antibodies
- complementary in shape to the antigen
- Antibodies immobilise microorganisms before being destroyed by phagocytosis.
Antibodies - complementary in shape to the _______.
1 mark
Antigen
An antibody will only work on ______________.
2 marks
1 type of microorganism
- because of this complementary nature.
How do Antibodies immobilise microorganisms?
1 mark
By clumping them together.
What does Immobilisation of the microorganism do?
2 marks
Reduces symptoms + prevents the spread of infection.
After immobilisation of Microorganisms; the clump of microorganisms
(1 mark)
Is then destroyed by phagocytosis.
Phagocytosis
4 marks
When a phagocyte (WBC) engulfs + digests the microorganisms.
During Phagocytosis
3 marks
Enzymes within the phagocyte digest the microorganism.
Primary Response To Microorganisms entering the Body
4 marks
Infected individual will be sick
- while lymphocytes work to produce enough antibodies to provide immunity.
During Primary Response (to Microorganisms entering the Body);
the body will make
(2 marks)
Memory lymphocytes that remain in the body for years.
Secondary Response to Microorganisms entering the Body
5 marks
If the same microorganism is encountered as found in the Primary Response
- Memory lymphocytes produce high numbers of the correct antibody quickly preventing the person getting sick again.
Immunity
3 marks
If you have a high enough antibody level to protect you against a particular infection, you are immune.
Active immunity
3 marks
When the body is activated + produces the antibodies needed to fight an infection.
Active immunity is:
2 marks
- Slow acting
- Provides long-lasting protection.
Natural Active Immunity
2 marks
Primary response when a microorganism enters the body.
Vaccines provide
1 mark
Artificial active immunity
Passive immunity
3 marks
When ready-made antibodies, from another source, are introduced to the body.
Passive immunity is:
2 marks
- Fast acting
- Only lasts a short period of time.
Source of Natural Passive Immunity
1 mark
Breastfeeding
Anti-venom
2 marks
Provides artificial passive immunity after a poisonous bite.
Active Immunity - Vaccinations
2 marks
The injection of dead or modified microorganisms.
Body’s response to Vaccines
5 marks
Body’s lymphocytes produce antibodies in response to the antigens present in the vaccine.
Memory lymphocytes produced (primary response).
If the microorganism is encountered after the vaccine
4 marks
Memory lymphocytes will produce large numbers of the antibody very quickly.
Individual does not get sick (Secondary Response).
Booster vaccination
2 marks
Sometimes needed to maintain the high levels of antibodies needed to provide immunity.
Antibiotics
3 marks
Chemicals produced by fungi that kill or prevent the growth of bacteria.
First antibiotic discovered
1 mark
Penicillin
Era Penicillin was discovered
1 mark
1920s
Discovered Penicillin
1 mark
Alexander Fleming
How Alexander Fleming discovered Penicillin
5 marks
Investigating Bacteria - fungus (a mould) had contaminated one of his bacterial cultures.
- it did not grow near fungus.
Conclusion of Alexander Flemings discovery of Antibiotics
3 marks
Antibacterial substance was diffusing out of the fungus, preventing the growth of the bacteria.
Era a pure form of Penicillin was first produced
1 mark
1940s
2 scientists who produced a pure form of Penicillin
2 marks
Florey and Chain
Alexander Fleming was unable to
1 mark
Produce a Pure Form of Penicillin
Began a large-scale production of penicillin.
2 marks
Florey and Chain
Used to produce Penicillin + other antibiotics commercially.
1 mark
Carefully controlled conditions
The Fungi that make Penicillin are
7 marks
grown in large biodigesters or fermenters that create the perfect conditions for fungal growth.
penicillin is then extracted, purified + packaged in a process known as downstreaming.
From Biodigesters or Fermenters Penicillin is
4 marks
Extracted, purified + packaged in a process known as downstreaming.
Create the perfect conditions for fungal growth
2 marks
Biodigesters or fermenters
What is Penicillin extracted from?
2 marks
Fungus (mould)
Downstreaming in Penicillin
3 marks
Packaging of Penicillin after Extraction + Purification.
Preclinical Trials
2 marks
- In-vitro testing
- Animal testing
First Preclinical Trial
1 mark
In-vitro testing
Second Preclinical Trial
1 mark
Animal Testing
In-vitro testing
4 marks
First Preclinical trial
- involves testing a drug in a lab on cells + tissues.
Animal Testing
4 marks
Second Preclinical Trial
- allows scientists to check how well the drug works on an entire living organism.
- Computer modelling is also carried out at this stage.
Computer modelling
3 marks
Carried out during Preclinical Trials during Animal Testing (Second Trial)
Preclinical trials are necessary to:
2 marks
- Check if the drug is poisonous or harmful.
- Check how effective the drug is.
Clinical trials will occur if
2 marks
The preclinical trials prove that the drug works + has no harmful side effects.
Who is involved in Clinical Trials?
2 marks
Small groups of healthy, human volunteers with the groups eventually becoming larger.
What do participants get in return for taking part in Clinical Trials?
(3 marks)
Sometimes paid - some are willing to help medical research for free
- Some potentially benefit from the drug.
Clinical trials are necessary to
2 marks
Determine the correct dosage required
- If successful the drug can be licensed for use.
Peer Review
6 marks
Where scientific research (including drug development)
- new research + discoveries are scrutinised by other experts in the same field
- is tested + validated to ensure any conclusions from the research are correct.
After Peer Reviews;
After reviewers provide feedback
(1 mark)
Results of the research can be published.
Antibiotics are
1 mark
- used to treat bacterial infections.
Antibiotics aren’t
3 marks
As specific as antibodies
- meaning an antibiotic can be used to treat more than 1 type of bacterial infection.
Antibiotic-resistant bacteria
2 marks
Bacteria resistant to antibiotics - making them ineffective.
Overuse of Antibiotics
3 marks
Responsible for antibiotic resistance
- as it has allowed bacteria to mutate + become resistant.
Superbugs
2 marks
Bacteria resistant to many antibiotics (e.g. MRSA).
Why are ‘superbugs’ such a serious problem in hospitals?
4 marks
- Patients have weak immune systems.
- Possible open wounds that allow the entry of microorganisms.
- Environment is antibiotic-rich.
The Problem with Antibiotic-Rich Environments
2 marks
Microorganisms come into contact with many different antibiotics promoting resistance.
Preventing the spread of superbugs in hospital
3 marks
- Increased hygiene
- Greater care when administering antibiotics.
- Isolate ‘superbug’ patients from other patients.
Examples of Hygiene in Hospitals
5 marks
- Wear gloves
- Clean up bodily fluids immediately
- Wash hands
- Disinfect surfaces
- Disposable equipment
Plant Defence Mechanisms
2 marks
Plants defences developed to fight against infectious microorganisms.
Plants Defence Mechanisms;
Structural defences
(4 marks)
- Waxy cuticle; prevent microorganisms entering the leaf.
- Thick cell walls; prevent microorganisms entering the cells.
Plants Defence Mechanisms;
Chemical Defences
(3 marks)
Plants can produce chemicals that kill infectious microorganisms (bacteria/viruses/fungi).
Examples of Plants Chemical Defences
7 marks
- Antimicrobial chemicals produced by mint can kill or reduce the growth of bacteria.
- A chemical (digitalis) made by foxgloves is poisonous to slugs + other animals that feed on it.
Types of Plants Defence Mechanisms
2 marks
Structural + Chemical
