SB5 - Health, disease and the development of Medicines Flashcards
What is the definition of Health?
A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
As defined by WHO
What are the 3 sub categories of Well-being?
- Physical
- Social
- Mental
What does having a good Physical wellbeing include?
- Being free from disease
- Eating & sleeping well
- Limiting the intake of harmful substances (e.g. alcohol & drugs)
- Getting regular activity
What does having a good Social wellbeing include?
- How well you get on with other people
- How your surroundings affect you
What does having a good mental wellbeing include?
How you feel about yourself
What is a disease?
A disorder of the body or mind that negatively affects an individual’s health
What are the 2 categories of disease?
- Communicable
- Non communicable
What is a communicable disease?
A disease that is caused by a pathogen which can be spread
between individuals (either directly or indirectly)
Give some examples of communicable diseases
- Common cold
- Flu
- Parasitic infections
What is a non-communicable disease?
A disease that cannot be spread between individuals.
–> Caused by the interaction of a number of risk factors (also usually genetic)
Give some examples of Non communicable diseases
- Asthma
- Diabetes
- Cardiovascular disease
How does the presence of one disease lead to a higher susceptibility to other diseases?
- One disease damages the immune system
- Damages the body’s natural barriers & defences
- Stops an organ from working effectively
If a ‘disease damages the immune system’ how does it make a person more likely to have another disease?
Makes it easier for other pathogens to cause disease. Opportunistic viruses
—> Immune system protects the body from communicable diseases
If ‘diseases damages the body’s natural barriers & defences’ how does it make a person more likely to have another disease?
Allows pathogens to get inside the body more easily
If ‘diseases stops an organ from working effectively’ how does it make a person more likely to have another disease?
Makes more diseases likely to occur
What is a pathogen?
A disease-causing organism, including:
viruses, bacteria, fungi and protists
Describe the characteristics of Viruses?
● Very small
● Move into cells and makes many copies of itself
● Cell bursts and releases all of the copies into the bloodstream
● The damage and the destruction of the cells makes the individual feel ill
Describe the characteristics of Bacteria?
● Small
● They multiply very quickly through dividing by a process called binary fission
● They produce toxins that can damage cells
Describe the characteristics of Fungi?
● They can either be single celled or have a body made of hyphae
● They can produce spores which can be spread to other organisms
Describe the characteristics of Protists?
Some are parasitic
What does parasitic mean?
They use humans and animals as their hosts (live on and inside, causing damage)
What is Hyphae?
Thread-like structures
What is malnutrition?
A condition resulting from a diet lacking in, or too rich in nutrients.
What category of pathogen is Cholera?
Bacteria
What are the symptoms of Cholera?
- Diarrhoea
- Stomach cramps
- Vomiting
How is Cholera spread?
Water
What category of pathogen is Tuberculosis?
Bacteria
What are the symptoms of Tuberculosis?
- Lung damage
- Coughing
- Tiredness
How is Tuberculosis spread?
Airborne
What category of pathogen is Chalara ash dieback?
Fungi
What are the symptoms of Chalara ash dieback?
- Leaf loss
- Bark lesions
How is Chalara ash dieback spread?
Airborne
What category of pathogen is Malaria?
Protist
What are the symptoms of Malaria?
Damage to blood & liver
How is Malaria spread?
Animal vectors
What category of pathogen is HIV?
Virus
What are the symptoms of HIV?
- Destroys white blood cells
- Leads to onset of AIDS
How is HIV spread?
Body fluids
What category of pathogen is Helicobacter?
Bacteria
What are the symptoms of Helicobacter?
Can lead to stomach ulcers
How is Helicobacter spread?
Oral transmission
What category of pathogen is Ebola?
Virus
What are the symptoms of Ebola?
- Can haemorrhagic fever
- Muscle weakness
- Muscle pain
How is Ebola spread?
Body fluids
What is haemorrhagic fever?
Fever accompanied with severe bleeding
What are the ways pathogens can spread?
- Direct contact
- Water
- Air
How can the damage that disease causes to populations be reduced?
By limiting the spread of the pathogens
What are some ways to limit the spread of pathogens?
- Improving hygiene
- Reducing contact
- Removing vectors
- Vaccination
How does being vaccinated help to reduce the spread of pathogens?
By injecting a small amount of a harmless pathogen into an individuals body
—> They can become immune so it won’t affect them
—> Means they can’t pass it onto individuals
How can you remove vectors?
Using pesticides or insecticides and removing their habitat
Name some ways to improve hygiene
- Hand washing
- Disinfectants
- Isolating raw meat
What are the ways viruses can reproduce?
- Lytic
- Lysogenic
Describe the lytic pathway
- Using host cell machinery, the virus replicates its DNA.
- Next, these are assembled to form new virus particles.
- Once the host cell is full of virus particles, it bursts in a process called lysis
- The process is then repeated with nearby cells.
Describe the lysogenic pathway
- The virus uses restriction enzymes to insert its DNA into the host cell DNA - or it can insert plasmids into the host cell cytoplasm.
- The host cell replicates, and the viral DNA is also copied in this process
- The lytic cycle begins at this point, starting with the assembly of new viral particles
Give some example of some STIs
- Chlamydia
- HIV
What type of pathogen is Chlamydia?
Bacteria
What are the symptoms of Chlamydia?
- Often symptomless
- Painful urination
- Pelvic pain
- Can lead to infertility
How are STIs spread?
- Sexual contact
- Oral/ vaginal sex
How can the spread of STIs be reduced?
Give an example
- Barrier methods of contraception (e.g. condoms)
- Abstaining from sexual activity
What are the types of plant barriers?
- Physical
- Chemical
Name some physical barriers that plants have to protect themselves from disease
- Thick cellulose cell wall
- Thick waxy cuticle
- Having the ability to close their stomata
- Covered in a layer of bark
How does a cellulose cell wall help protect plants from disease?
Impermeable to many pathogens
How does a waxy cuticle help protect plants from disease?
Acts as a barrier to most pathogens
How does a layer of bark help protect plants from disease?
Prevents pathogens from reaching the cells and tissues inside
How does the ability to close stomata help protect plants from disease?
Stops pathogens entering the plant
Name some chemical barriers that plants have to protect themselves from disease
- Some plants produce antimicrobial chemicals
- Some plants can release compounds that attract larger insects than the pests
Some plants can release compounds that attract larger insects than the pests, how does this protect plants against disease?
The larger insects feeds on the pests and stop them eating the plant
How can we benefit from antimicrobial compounds?
We can extract antimicrobial compounds from these plants for use in drugs (such as antibiotics)
How can we identify diseases on the field?
By using visible clues
What disease is this plant suffering from?
Chalara ash dieback
What disease is this plant suffering from?
Tobacco mosaic virus
What are the symptoms of the Tobacco mosaic virus?
Causes discolouration of leaves
What disease is this plant suffering from?
Bacterial canker on fruit trees
What are the symptoms of the Bacterial canker?
- Causes loss of leaves
- Stunted growth
- Pus-filled lesions on trunk
What disease is this plant suffering from?
Aphids
What are the symptoms of the Aphids?
Causes serious structural damage to plants
How can we identify diseases on the laboratory?
- Cuttings are taken from the diseased plant.
- The virus/bacterium causing the disease is grown on a culture medium/agar plate
- The pathogen is tested and identified using a monoclonal antibody testing kit
What is the name of the kit that is used to identify & test a pathogen?
ELISA kit
Name some physical barriers that humans have to protect themselves from disease
- Mucus
- Cilia
- Skin
What produces Mucus?
Goblet cells
How does Mucus help protect humans from disease?
Mucus traps bacteria and other pathogens before they reach the lungs and cause infection
How does Cilia help protect humans from disease?
Wafts away mucus that has trapped pathogens, to be killed by stomach acid
How does the skin help protect humans from disease?
Provides a physical barrier against pathogens, protecting the tissues and cells beneath it from infection
Name some chemical barriers that humans have to protect themselves from disease
- Lysozymes
- Hydrochloric acid
Where are Lysozymes found in the body?
White blood cells
How does Lysozymes help protect humans from disease?
Used by white blood cells to kill and digest bacteria
Where is Hydrochloric acid found in the body?
Stomach
How does Hydrochloric acid help protect humans from disease?
Used to kill bacteria in food reaching the stomach
—> Prevents infection
Give some examples of specific immune responses in the human body
- Producing antibodies
- Producing antitoxins
- Phagocytosis
What is Phagocytosis?
White blood cells engulfing and consuming pathogens
How do Phagocytes protect the human body?
This destroys the pathogens, meaning they can no longer make you feel ill
What are Phagocytes an example of?
White blood cells
How does producing antitoxins protect the human body?
They neutralise the toxins released by the pathogen by binding to them
How does producing antibodies protect the human body?
- Each pathogen has a complementary antibody which it can bind to. Antibodies make the pathogens clump together
- Memory Lymphocytes are also produced. If you become infected again - complementary antibodies will be produced at a faster rate
What is herd immunity?
When the vaccination of a large proportion of the population provides some protection to unvaccinated individuals who are less likely to catch the disease
Explain the body’s response to immunisation (using an inactive pathogen)
Vaccine contains a dead/ inactivated form of pathogen
—> This stimulates white blood cells to produce antibodies complementary to the antigens on the pathogen
What are the advantages of vaccinations?
- Epidemics can be prevented through herd immunity
- They have eradicated many diseases so far and reduced the occurrence of many
What are the disadvantages of vaccinations?
- They are not always effective in providing immunity
- Bad reactions can occur in response to vaccines (although very rare)
Why can antibiotics only be used to treat bacterial infections?
- Antibiotics inhibit cell processes in the bacterium
—> So bacteria are only susceptible to antibiotics - Viruses and other pathogens often use cell machinery in host cells to reproduce
—> Unaffected by antibiotics
What is aseptic technique?
Name given to the laboratory procedures carried out to prevent the contamination of pure cultures of microorganisms
What are the ways that we can grow microorganisms in the lab?
- Nutrient broth solution
- Agar gel plate
What is a nutrient broth solution also known as?
Culture medium
Explain how a culture medium works
Uses a liquid/ gel to provide all the nutrients needed for bacteria to grow successfully
What does a culture medium need to contain?
- Carbohydrates - energy
- Nitrogen - protein synthesis
- Other minerals
Explain how an agar gel plate works
- Sterilised agar jelly is poured into a sterilised Petri dish , which is left to cool and set
- Inoculating loops are dipped in a solution of the microorganism and spread over the agar evenly
- A lid is taped on and the plate is incubated for a few days so the microorganisms can grow (stored upside down)
Core practical: Investigating the effects of antiseptics and antibiotics
Why must ‘Petri dishes and culture media be sterilised before use’?
It may be contaminated with other microorganisms:
* Could be harmless but will compete with desired bacteria for nutrients & space
* If they are harmful, it could produce a new pathogen
Core practical: Investigating the effects of antiseptics and antibiotics
Why must ‘Inoculating loops must be sterilised’?
Kills unwanted microorganisms
Core practical: Investigating the effects of antiseptics and antibiotics
How are Inoculating loops sterilised?
By passing them through a flame
Core practical: Investigating the effects of antiseptics and antibiotics
Why must ‘The lid of the Petri dish should be sealed (but not completely) with tape’?
- Sealing stops airborne microorganisms from contaminating the culture
- It should not be sealed all the way around as this would result in
harmful anaerobic bacteria growing
Core practical: Investigating the effects of antiseptics and antibiotics
Why must ‘The Petri dish should be be stored upside down’?
Prevents condensation from the lid landing on the agar surface and disrupting growth
Core practical: Investigating the effects of antiseptics and antibiotics
Why must ‘The culture should be incubated at 25 degrees’?
If it were incubated @ a higher temp (near human body temp) it would be more likely that bacteria could be harmful to humans
@ A Lower temp, colonies of such bacteria won’t be able to grow
Core practical: Investigating the effects of antiseptics and antibiotics
How do we calculate the cross sectional area of a bacteria culture?
Using the area of a circle
Core practical: Investigating the effects of antiseptics and antibiotics
How do we determine the effectiveness of an antibiotic in an agar plate?
By calculating the cross sectional area of a bacterial culture
Core practical: Investigating the effects of antiseptics and antibiotics
How do we grow a bacterial culture?
1) Take a petri dish that has been pre-poured with agar gel, and sterilise it in an autoclave before use
2) Use an inoculating loop to sterilise
3) Seal the top of the plate using tape (but not completely)
4) Incubate the culture at 35 degrees
5) Apply a filter paper soaked in antibiotic solution to the centre of the agar plate & wait 24 hours (or until there is no further change)
Core practical: Investigating the effects of antiseptics and antibiotics
How do we calculate the effectiveness of the antibiotic?
1) Use a ruler to measure the diameter of the circle taken yo by the bacterial culture & record
2) Repeat for the diameter of the clear agar jelly in the centre (where the antibiotic has killed the bacteria)
3) Get the radius by dividing the diameters by 2. Calculate area of the circle
4) Divide the smaller circle by the larger and multiply by 100. This gives the percentage of the bacterial culture that has been destroyed by the antibiotic
What do new drugs need to be tested for?
- Safety
- Effectiveness
- Dosage
Why do new drugs need to be tested for safety?
Important as some drugs are toxic, and have other side effects that might be harmful to people
Why do new drugs need to be tested for effectiveness?
Checks how well the drug cures the disease, or improves symptoms
Why do new drugs need to be tested for dosage?
Dosage varies, and has to closely controlled, as too high a concentration might be toxic
What are the main stages of testing new drugs?
- Preclinical drug trials
- Animal trials
- Human clinical trials
Describe what are the preclinical trials
Drugs are tested using computer models and human cells grown in the laboratory
What is the purpose of the preclinical trials
Allows the efficacy and possible side effects to be tested
Describe what are the animal trials
Drugs are tested on animals
Typical tests:
Giving a known amount of the substance to the animals, then monitoring them carefully for any side-effects
Describe what are the human clinical trials
They are tested on healthy volunteers to check that they are safe
THEN tested on people with the illness to ensure that they are safe and that they work
What is a disadvantage of human clinical trials?
Could be dangerous
What are monoclonal antibodies?
Identical antibodies, that have been produced from the same immune cell
What are antibodies?
Proteins produced by lymphocytes
How are monoclonal antibodies produced?
- Scientists obtain mice lymphocytes, which have been stimulated to produce a specific antibody
- They are combined with tumour cells (do not make antibodies but divide rapidly), to form a cell called a hybridoma
- The hybridoma can divide to produce clones of itself, which all produce the same antibody
- The antibodies are collected and purified
Name some uses of monoclonal antibodies?
- Pregnancy tests
- Identifies blood clots
- In research to find/ identify certain molecules on a cell/tissue
- Treatment of disease (e.g. Cancer)
What hormone is present in women who are pregnant?
hCG
Describe the structure of a pregnancy test?
1st section contains mobile antibodies complementary to the hCG hormone (antibodies are also attached to the coloured beads)
2nd section has stationary antibodies complementary to the
hCG hormone which are stuck down to the stick
Describe how a pregnancy test works
If hCG is present it binds to the mobile antibodies attached to blue beads to form hCG/antibody complexes
Carried in the flow of liquid to the second section
Stationary antibodies then bind to the HCG/antibody complexes
they are each bound to a blue bead, results in a blue line
What are the advantages of using monoclonal antibodies?
1) They only bind to specific cells, meaning healthy cells are not affected
2) Can be engineered to treat many different conditions
3) Making monoclonal antibodies for the first time can be time consuming
What are the disadvantages of using monoclonal antibodies?
- It is difficult to attach monoclonal antibodies to drugs
- Expensive to develop
- As they were produced from mice lymphocytes, they often triggered an immune response when used in humans
Describe how monoclonal antibodies can be used to identify blood clots?
The monoclonal antibodies can be attached to dyes that will glow
fluorescently under UV light or attached to radioactive elements which can be detected with special camera
How are monoclonal antibodies targeted to cancer cells?
Cancer cells have antigens on their cell membranes (tumour markers) which can be targeted
Describe what ways monoclonal antibodies can be used to treat cancer?
- Encourage immune system to attack cancer cells directly
- Using monoclonal antibodies to transport toxic drugs, chemicals or radioactive substances as they can only bind to cancer cells
- Injecting someone so the monoclonal antibodies will bind with these cancer cells and clump them together.
—> Easier to remove
What are non-communicable diseases caused by?
Interaction of a number of different factors
What factors increase the likelihood of having cardiovascular diseases?
Can be caused by high dietary intake of saturated fat w/ a sedentary lifestyle
What factors increase the likelihood of having certain forms of cancer?
Can be contributed to by various factors:
* Smoking
* Age
* Genetics
What factors increase the likelihood of having lung & liver diseases?
- Smoking
- High alcohol intake
- Age & genetics
What factors increase the likelihood of having vitamin & nutritional deficiencies?
- Being anorexic
- Those who can’t absorb or use nutrients properly
- Obesity
- Genetics
Describe how obesity can contribute to increasing a persons likelihood of having non-communicable diseases?
- Cardiovascular disease and high blood pressure: Lipid deposits form inside blood vessels
- Type 2 diabetes: As Insulin as won’t be as effective when there is a high proportion of body fat
*
Describe how malnutrition can contribute to increasing a persons likelihood of having non-communicable diseases?
Not having enough vitamins/ nutrients will cause problems
—> Symptoms can be different depending on the vitamin or nutrient that is deficient
What are some ways to determine if a person is obese, underweight or healthy?
- BMI
- Waist: Hip ratio
What is the equation for BMI?
Describe how liver disease can contribute to increasing a persons likelihood of having non-communicable diseases?
Usually caused by high alcohol intake:
* Liver disease can lead to liver
cancer & impaired liver function
- Can also lead to vitamin deficiencies
Describe how lung disease can contribute to increasing a persons likelihood of having non-communicable diseases?
Usually caused by/ related to smoking
Cigarettes have lots of different chemicals & can cause different problems
Name the different treatment methods to treat cardiovascular diseases
- Life-long medication
- Lifestyle changes
- Surgical procedures
Explain how life-long medication can be used to treat cardiovascular diseases
Several medications that will either reduce cholesterol or reduce blood pressure
Explain how lifestyle changes can be used to treat cardiovascular diseases
Lifestyle changes are important in preventing and treating cardiovascular disease:
- Reducing the amount of saturated fat we eat can reduce the risk of developing fat deposits in the arteries & high cholesterol
- Maintaining a healthy BMI can reduce strain on the heart
—> Regular exercise - Reducing salt & stress levels for High bp
Explain how surgical procedures can be used to treat cardiovascular diseases
- Coronary artery bypass - Blocked sections of arteries are bypassed
- Stents - Widens arteries