B3 Infection And Response Flashcards
How is the stomach adapted to prevent infection?
Contains hydrochloric acid to destroy microorganisms in mucus or food/drink
How is the skin adapted to prevent infection?
Forms an outer protective layer. Produces secretions of mucus - traps pathogens
How are the trachea/bronchi adapted to prevent infection?
Cilia in the trachea trap and waft mucus back up to be swallowed
What are cilia?
Tiny hairs in the trachea
What is phagocytosis?
The process where white blood cells ingest pathogens and destroy them
What are white blood cells?
Lymphocytes
What are antigens?
Antigens are unique proteins found on the surface of bacteria cells
Why do white blood cells produce antibodies?
To neutralise the antigens produced by bacterium inside the body
Why do white blood cells produce antitoxins?
To neutralise the toxins produced by bacterium inside the body
Give 2 examples of diseases caused by fungal pathogens:
Athlete’s foot, rose black spot
What is a fungal pathogen?
Fungi that can cause disease in humans or other organisms
What is a bacterial pathogen?
Bacteria that can cause disease
Give 2 examples of diseases caused by bacterial pathogens:
Any 2 from:
Salmonella, gonorrhoea, cholera
What is a viral pathogen?
Particles which invade your body’s cells to reproduce inside body cells to damage/destroy them
Give 2 examples of diseases caused by viral pathogens:
Any 2 from:
Influenza (flu), HIV, measles, COVID-19, TMV (Tobacco Mosaic Virus)
What is a protist pathogen?
A single-celled organism of the kingdom protista, such as protoroan or simple alga
Name an example of a disease caused by protist pathogens:
Malaria
Give the 3 ways in which pathogens can spread:
- Direct contact of the skin or bodily fluids
- Tiny droplets in air
- Food and water
What are pathogens?
Micro-organisms that cause disease
Why do we have drug trials?
To prevent unexpected side-effects -> THALIDOMIDE
Which medication is sourced from foxglove?
Source of the heart drug ‘digitalis’
Which medication is sourced from willow?
Source of the painkiller ‘aspirin’
Which medication is sourced from mould?
Source of ‘penicillin’
Who discovered penicillin?
Alexander Fleming discovered penicillin by studying mould which had been left unattended
What are painkillers?
Drugs which relieve the symptoms
Give 2 examples of painkillers:
Aspirin and paracetamol
What are antibiotics?
Medicines which work inside the body to kill bacterial pathogens
Give an example of an antibiotic:
Penicillin
What do vaccines contain?
A small amount of dead or weakened pathogen particles, which will simulate the production of antibodies and train the immune system on what to do if these pathogens infect it later on.
What is herd immmunity?
When a large percentage of the population are immune to a disease
What are the 4 affecting factors when growing micro-organisms?
- Temperature
- Nutrients
- Oxygen
- pH
What does it mean to ‘culture’ bacteria?
To grow large bacteria numbers in order to observe colonies
What is agar jelly?
Medium containing carbohydrate (glucose) minerals and nitrogen source (proteins)
Why do we incubate at 25 degrees Celsius when growing micro-organisms?
To reduce the chance of growing harmful pathogens
What temperature is most ideal for growing harmful pathogens ?
37.5 degrees Celsius
What type of pathogen is malaria a result of?
A single-celled parasite called a protist. These reproduce sexually in mosquitoes and asexually in humans
What is the equation for calculating bacteria at the end of a growth period?
Bacteria at end of growth period = Bacteria at start of growth period x 2 ^Number of divisions
What type of pathogen causes measles?
Viral
Give 2 symptoms of measles:
Any 2 from:
Fever, red skin rash, can lead to death/blindness/damage
How is measles spread?
Inhalation of drops from coughs or sneezes
How can the risk of developing measles be reduced?
No treatment, only vaccination - patient must be isolated
What type of pathogen causes HIV?
Viral
Give 2 symptoms of HIV:
Starts like flu, damages immune system
How is HIV spread?
Sexual contact or exchanging of bodily fluids
How can the risk of developing HIV be reduced? Give 2:
Any 2 from:
Cleaning needles, using condoms, taking drugs to prevent AIDS
What type of pathogen causes TMV (Tobacco Mosaic Virus)
Viral
Give 2 examples of the symptoms of TMV:
Mosaic pattern on leaves, no photosynthesis in affected areas
How is TMV spread?
Contact between plants
How can the risk of developing TMV be reduced?
Farmers grow TMV resistant plant strains
What type of pathogen causes salmonella?
Bacterial
Give 2 symptoms of salmonella:
Any 2 from:
Fever, cramps, vomiting, diarrhoea, dehydration
How is salmonella spread?
Caused by eating raw food (chicken)
Give 2 examples of ways to reduce your risk of developing salmonella:
Cook food properly, vaccinate poultry
What type of pathogen causes gonorrhoea?
Bacterial
Give 2 symptoms of gonorrhoea:
Pain when urinating, green/yellow discharge from the penis/vagina
How is gonorrhoea spread?
Contact with infected skin particles
Give one example of how to reduce the risk of developing gonorrhoea:
Antiferal drugs
What is a placebo?
A fake drug which doesn’t actually contain the medicine (ie. filled with sugar)
What is a double-blind trial?
A drug trial where neither the doctor nor the patient knows who received the drug and who received the placebo. This is to demonstrate the actual effectiveness of the drug - no bias
What would happen during the pre-clinical stages of a drug trial?
- Tissue samples
- Computer simulation
- Animal testing (mainly rodents)
- Testing on MIRA and ethical bodies
What would happen during the human testing stage of a drug trial?
Test:
1. Healthy volunteers
2. Selected people with relevant illness
3. Large number of people with relevant illness
4. DRUG LICENSED - wider testing against other drugs for further side-effects and long-term risks or benefits
What are stem cells?
Unspecialised cells that can differentiate into many different cell types
What are embryonic stem cells and where are they found?
Stem cells which can still develop into all the different cell types in the body. Found in the embryo
Name an advantage of embryonic stem cells over adult stem cells:
No risk of rejection
Name a disadvantage of embryonic stem cells over adult stem cells:
Any from;
Arguably less ethical (embryo will die), rapid division could cause cancer
What are adult stem cells and where are they found?
Stem cells which can differentiate into a limited number of cells. Found in the body after birth - BONE MARROW
Name a disadvantage of using adult stem cells:
Potential risk of immune rejection
How long does cell division take?
Approximately 24 hours
Name the three reasons why cell division takes place: (HINT - GRR..)
Growth, repair, replacement of worn-out cells
What happens during cell division?
Cytoplasm and cell membrane divide to form 2 identical cells
What is mitosis?
The process which produces 2 identical cells in which the number of chromosomes is the same as the original cell
In mammals, the cells’ chromosome numbers are diploid. What does this mean?
Chromosomes need to be copied exactly so that new cells can be produced for (GRR) growth, repair and replacement of worn-out cells
What is the chromosome number for mitosis?
Diploid
What is the chromosome number for meiosis?
Haploid
What does meiosis produce?
4 genetically different haploid cells. As meiosis is reduction division, the chromosome number is halved.
What does meiosis produce?
4 genetically different haploid cells. As meiosis is reduction division, the chromosome number is halved.
What is meiosis used for?
Production of gametes for sexual reproduction
What is cancer caused by?
A tumour
How are tumours formed?
Tumours are formed when the body loses control of cell division and cells grow in an unusual or abnormal way.
What are the 2 types of tumours?
Benign and malignant
What is a benign tumour?
A tumour which grows slowly within a membrane. It is easily removed as it does not invade other body parts
What is a malignant tumour?
A tumour which grows quickly and invades other neighbouring tissues, forming secondary tumours
What are carcinogens?
Chemicals or other agents which can cause cancer
What is chemotherapy?
Cancer treatment using drugs
What is radiotherapy?
Cancer treatment involving using gamma rays to stop mitosis
What is the first stage of the cell cycle?
DNA is replicated to form 2 copies of each chromosome and the number of sub-cellular structures increases
What is the second stage of the cell cycle?
Mitosis - one set of chromosomes is pulled to each end of the cell and the nucleus divides
What is the third stage of the cell cycle?
Cell divides to form 2 identical cells
What is a totipotent stem cell?
A stem cell which is capable of becoming any type of cell
What is a pluripotent stem cell?
A stem cell which is capable of becoming most types of cell
What is a multipotent stem cell?
A stem cell which is capable of becoming some types of cell
What is a unipotent stem cell?
A stem cell which is capable of becoming only one type of cell
