Development of Medicines (Edexcel GCSE Biology)

An autoclave is used to prepare sterile growth medium and Petri dishes.

False.

The development of new drugs has many stages including discovery, development, preclinical and clinical testing.

Preclinical drug testing is done in a laboratory using cells, tissues, and live animals.

The purpose of testing new drugs on animals is to see the effect of medicines on a whole organism.

Clinical drug trials are conducted to test the safety, efficacy, and optimal dosage of new drugs.

Clinical trials are conducted as follows:

1. very low doses of the drug are given to healthy volunteers to test safety

2. patients with relevant medical conditions take part in the trial, often using a double-blind study, to test efficacy and find the lowest effective dose

In a double-blind trial some patients are given a placebo, and neither the doctor nor the patient knows whether each patient is receiving the placebo or the active drug.

A placebo is an inert substance given to some participants in clinical trials instead of a true drug. Its role is to eliminate the effects of the brain and expectations on any results.

Monoclonal antibodies are antibodies that all come from clones of a single lymphocyte. They are specific to one antigen.

A lymphocyte is a type of white blood cell involved in the specific immune response.

The process of producing monoclonal antibodies is as follows:

1. a mouse is injected with antigens to stimulate mouse lymphocytes to produce the required antibodies

2. the lymphocytes are combined with a tumour cell to make a hybridoma cell

3. the hybridoma cell is then cloned to produce many identical cells producing the same antibody

A hybridoma cell is a cell produced by combining a lymphocyte with a type of tumour cell.

True.

Monoclonal antibodies can bind to specific proteins because of their specific shape.

Monoclonal antibodies may be used as follows:

• pregnancy testing

• locating the position of blood clots and cancer cells

• in the treatment of certain diseases by targeting specific cell types, e.g. cancer cells

Monoclonal antibodies can be used to indicate pregnancy by using them in pregnancy tests. The antibodies bind to a hormone released during pregnancy, known as hCG.

False.

Labelling monoclonal antibodies with fluorescent dyes allows them to be used to locate certain cell types or molecules.

The use of dyes is not related to the delivery of cancer drugs.

Monoclonal antibodies can be used to identify and destroy cancer cells without harming healthy cells because the antibodies bind to specific proteins that are displayed by cancer cells but not by healthy body cells.

The advantage of using monoclonal antibodies over traditional treatments is that only the cancer cells are targeted, which leaves healthy cells unaffected. This can reduce the side effects of the cancer treatment.

Examples of non-communicable diseases include:

• lung disease

• lung cancer

• cardiovascular disease

• type 2 diabetes

• liver disease

• cancer

A risk factor is a factor that increases the likelihood of developing a disease. Exposure to a risk factor does not mean that disease will definitely occur.

Lifestyle factors that can affect the incidence of non-communicable disease include:

• diet

• alcohol consumption

• smoking

Correlation is an association between two factors while causation is when a change in one factor causes a change in another. A correlation between two factors not not guarantee that there is a causal link.

Examples of risk factors that have been causally linked to a disease include:

• diet / smoking / exercise and CVD

• alcohol and liver disease

• obesity and type 2 diabetes

• smoking and lung disease / lung cancer

• smoking / alcohol and fetal development

• ionising radiation and cancer

Obesity and malnutrition can be assessed using:

• BMI

• waist:hip ratio calculations

BMI can be calculated using the following equation:

Mass is measured in kg and height in m.

Problems that can be caused by an increase in cases of liver disease at a local level include:

• it can put a strain on the local medical resources

• absence from work can impact local businesses and employment rates

Problems that can be caused by an increase in cases of cardiovascular disease at a national level include:

• increased economic costs due to premature deaths and fewer people in work

• longer waiting lists for hospital treatment due to increased demand

• money be be put into hospital funding rather than other national projects, e.g. housing or education

CVD is any long-term condition of the heart or blood vessels, e.g. narrowing of the arteries or a heart attack.

Medication can be used in the treatment of CVD to:

• lower blood pressure

• reduce blood cholesterol

• reduce blood clot formation

Advantages of treating cardiovascular disease using medication include:

• medications can be effective ways of aiding management of some risk factors, e.g. blood pressure and cholesterol

Disadvantages of treating cardiovascular disease using medications include:

• need to be taken continuously

• can take time to be effective

• can cause side effects

False.

The insertion of a stent can be carried out during minor surgery, though the process does bring some risk of blood vessel damage and infection.

Stents are used to widen the lumen of the coronary arteries; this keeps the arteries open and increases blood flow to the heart muscle.

Lifestyle changes that can reduce the likelihood of cardiovascular disease include:

• stopping cigarette smoking

• eating a balanced diet

• increase physical activity levels