Health, disease and the development of medicines

Describe health as defined by WHO

a state of complete physical, social and mental well-being

non-communicable disease

not transferred between people, animals or plants

communicable disease

transferred from one person to another, or one organism to another e.g malaria

made up of pathogens

why can the presence of one disease lead to higher susceptability of other diseases?

Because disease weakens the immune system, so you are more likely to catch another disease as your body isn't able to protect you

define a pathogen

Disease causing organism

Can spread from infected organisms; spores in the air; in water or in food

what are the four main forms of a pathogen?

virus, bacteria, fungi, protist

cause of cholera

bacterial infection caused by dirty water

cholera symptoms

diarrhoea

stomach cramps

cholera treatment

vaccine

prevent dehydration

tuberculosis cause

bacterial infection spread by droplets in the air when a person coughs or sneezes (airborne)

tuberculosis symptoms

cough up blood

causes lung damage

tuberculosis treatment

BCG vaccine

antibiotics

Chalara ash dieback cause

fungal infection that affects ash trees

airborne

chalara ash dieback symptoms

leaf loss

bark lesions

chalara ash dieback treatment

scientists are developing

malaria cause

protist infection

spread by animal vectors of mosquitoes

malaria symptoms

Fever

causes damage to the blood and liver

malaria treatment

vaccine

HIV cause

virus transmitted through bodily fluids

HIV symptoms

destroys white blood cells

leading to AIDS

helicobacter cause

bacterial disease causing stomach ulcers

transmitted orally

helicobacter symptoms

many show no symptoms

heartburn

stomach ulcers

helicobacter treatment

antibiotics

ebola cause

viral infection

transmitted through bodily fluids, unsterilised needles

ebola symptoms

haemorrhagic fever

ebola treatment

none

Describe the stages of the lytic cycle

1. Virus attaches to another cell and injects it's genetic material into it

2. New viral genetic material and proteins are produced and assembled

3. Cell lyses (bursts) releasing viruses

4. Virus attaches itself to another cell etc. (cycle repeats)

Describe the lysogenic cycle

1. The virus injects its DNA into the host cell and the DNA becomes incorporated into the host DNA

2. As the host cell replicates, the viral DNA replicates also. No new virus particles are made during this time (the virus is dormant)

3. Changes in the environment cause the viral DNA to move to the lytic pathway to make new virus particles

How is chlamydia and HIV spread, and how this spread can be reduced or prevented

Chlamydia= bacterial infection

HIV= Viral infection

Both STDs

Reduced by:

- Wearing condoms

- Screening to detect cases

- Medications

- Drug users with HIV should also avoid sharing needles

- Limiting the number of sexual partners

- Raising awareness by education programmes

What are some plant physical defences against pests and pathogens?

1. The cellulose cell wall not only provides support for the plant but also protection from microorganisms

2. The waxy cuticle of the leaf and stems acts as a barrier to microbes from entering the plant. The only place that they can enter in the leaf is through the stomata

3. Thorns or hairy stems also make it more difficult for pests to access the plant tissue to feed

What are some plant chemical defences against pests and pathogens?

1. Antiseptics or antimicrobial enzymes

2. Chemical poisons to deter pests that might eat them

Which plant chemical defences can be used to treat human diseases?

1. Chemicals with antimicrobial properties can be extracted for human use such as in antibiotics

2. The pain relief drug, aspirin, originated from the bark of willow trees

How to detect and identify plant diseases in the lab and in the field

1. Eliminate possible environmental causes to make sure it is definitely a disease and not an issue from the plant

2. Complete distribution analysis of affected plants to find out where it is coming from

3. Observation of visible symptoms to identify the disease (in the field)

4. Diagnostic testing to identify the disease (in the lab)

Define physical barriers

Structures that make it hard for pathogens to get past them and into the body

Describe the human physical barriers

Skin:

Provides a physical barrier against pathogens, protecting the cells beneath it from infection

Mucus:

Traps bacteria and other pathogens before they reach the lungs and cause infection

Cilia:

Wafts away mucs that has trapped pathogens, to be killed by stomach acid

Describe the human chemical barriers

Lysozyme:

Used by white blood cells, used to kill and digest bacteria

Hydrochloric acid:

Found in stomach acid, used to kill pathogens in food or mucus that has made it's way to the stomach

2 main white blood cells

lymphocyte, phagocyte

What are antibodies and antigens?

Antibodies- found on lymphocytes. complimentary to antigens on specific pathogens

Antigens- markers on pathogens, complimentary to specific antibodies

What happens when an antibody attaches to an antigen of a pathogen?

Pathogen dies

Explain the specific immune response

1. Lymphocytes come into contact with a pathogen in the blood

2. Once a complimentary antibody attaches to an antigen, the lymphocyte of the antibody becomes activated

3. Activated lymphocytes clone themselves rapidly, producing more complimentary antibodies which attach to the pathogens, causing them to die

3. Antigens trigger the production of memory lymphocytes

What is a memory lymphocyte?

Lymphocytes that remain in the blood after the primary immune response.

They can produce much larger quantities of required antibodies in a much shorter time to fight of the diesease before the patient suffers symptoms in a secondary immune response

What is a secondary immune response?

Triggered if the memory lymphocyte encounters another pathogen of the same kind.

Memory lymphocyte issues a response by releasing antibodies, killing the pathogen quicker and more effectively this time

What is the body's response to immunisation using an inactive pathogen?

1. Triggers an immune response, therefore also the production of memory lymphocytes. Patient will be symptomless because pathogen is inactive.

2. Upon a secondary infection, due to the memory cells, more antibodies will be produced more quickly so the infection will be killed before the patient feels any symptoms

Advantages of immunisation

herd immunity, prevents epidemics, wipe out disease (e.g. smallpox)

Disadvantages of immunisation

Vaccine doesn't always work

Can cause negative side effects

Define herd immunity

By immunising a large proportion of people, the spread of the pathogen is reduced as there are less people to catch the disease

What are antibiotics and how do they work?

Antibiotics are medicines to help cure bacterial infections by inhibiting cell processes in the bacterium, but not the host organism

E.g. penicillin

Aseptic techniques used in culturing microorganisms in the lab

1. Innoculating loop is passed through a flame before it is used to transfer the bacteria to the agar plate

--> Any microorganisms on the loop are killed to prevent contamination

2. Petri dishes opened as little as possible

--> decreases risk of any microorganisms contaminating dish

3. Petri dish is sterilised using an autoclave (oven)

--> to kill any microorganisms contaminating the dish that could corrupt the experiment

Calculate zone of inhibition (where bacteria is NOT present)

πr²

Describe the stages of developing new medicines

Discovery, development, all drugs needed to be tested for toxicity, efficacy and dose using:

Preclinical testing- using cells, tissues, live animals

Clinical testing- using volunteers and patients

Describe the production of monoclonal antibodies

1. Antigen injected into a mouse to make it's lymphocytes produce the desired antibody

2. These lymphocytes are combined with tumour cell to produce a hybridoma cell- tumour cells are used because they can divide rapidly

3. Single hybridoma cells are cloned, resulting in high numbers of the same cell producing the same antibody--> hence monoclonal antibodies

Explain the use of monoclonal antibodies in pregnancy tests

The monoclonal antibodies are specific to HCG hormone, produced in pregnancy, found in urine

The HCG-specific antibodies are mobile and contain blue dye

If the HCG hormone is present in the urine, it will bind to the mobile monoclonal antibodies, rise up the test and produce a colour change

Explain the use of monoclonal antibodies in the diagnosis of disease

The monoclonal antibodies can be specific to pathogens, blood clots or cancer cells

They can have markers which allow doctors to find the location of them

Explain the use of monoclonal antibodies in the treatment of disease e.g. cancer

Monoclonal antibodies can be used 3 ways to treat cancer:

1. Use of monoclonal antibodies to trigger immune system to destroy cancer cells

2. to block receptors to stop cancer cells growing or dividing

3. to carry toxic drugs or radiactive substances to the site of the tumour to destroy it

Advantages of monoclonal antibodies

1. Bind to only what needs treatment so healthy cells are not affected

2. Can treat a wide range of conditions

Non communicable diseases include...

Cardiovascular diseases

Cancer

Lung and liver diseases

Diabetes

Explain the effect of bad exercise and diet

If you eat more calories (particularly saturated fat) than you burn during exercise, this can lead to obesity.

Malnutrition is when you don't eat enough calories or vitamins/nutrients

BMI calculation

weight (kg) / height (m)²

What BMI score means you're obese?

Over 30

waist:hip ratio formula

waist circumference/hip circumference

Explain the effect of alcohol

A high alcohol intake leads to liver diseases

Explain the effect of smoking

Smoking dramatically increases the risk of developing several lung diseases

Evaluate life-long medication for CV disease

PROS:

Lowers the risk of CVD

Lowers cholesterol

CONS:

Have to take the medication for the rest of your life

Undesirable side effects

Evaluate surgical procedures for CV disease

Metal stent widens arteries that have been narrowed by fat deposits.

PROS:

Very effective- lowers blood pressure lowering risk of heart attack

CONS:

Surgery is risky

Evaluate lifestyle changes for CVD

Doing regular exercise, maintaining a healthy BMI, reducing salt levels and quitting smoking can all help to reduce CVD