Cancer, Lifestyle Risk Factors & Non-Communicable Disease
Non-communicable diseases cannot be spread between organisms because they are not caused by pathogens; instead, they arise from interactions between genetic predisposition, environmental exposures, and lifestyle risk factors. Cancer occurs when mutations in a cell's DNA disrupt the normal regulation of the cell cycle and mitosis, leading to uncontrolled cell division and the formation of benign or malignant tumours. Examiners frequently test the distinction between benign and malignant tumours, the difference between correlation and causal mechanisms, and epidemiological data analysis.
- Non-Communicable Diseases & Risk Factors
- Diseases that are not infectious and cannot be passed from one person to another (e.g., coronary heart disease, cancer, Type 2 diabetes). A risk factor is any aspect of a person's lifestyle, environment, or genetics that is linked to an increased likelihood of developing a disease.
- Correlation vs Causal Mechanism
- A correlation is a statistical link between a risk factor and a disease in epidemiological studies. However, correlation does not prove causation unless a scientific causal mechanism can be demonstrated (e.g., tar carcinogens mutating proto-oncogenes/tumour suppressor genes in lung cells).
- Cancer & Uncontrolled Mitosis
- Changes (mutations) in the DNA of a cell lead to uncontrolled growth and division by mitosis. Instead of responding to normal signals to stop dividing or undergo programmed cell death, the abnormal cells continue dividing rapidly to form a mass of cells called a tumour.
Cancer, Lifestyle Risk Factors & Non-Communicable Disease: Enzyme Collision, Active Site & Rate Curve Lab
Drag the temperature, pH, and substrate sliders to watch how kinetic collisions, active-site binding, and denaturation change the reaction rate in real time.
Key Concepts & Exam Definitions (6)
- Non-Communicable Diseases & Risk Factors
- Diseases that are not infectious and cannot be passed from one person to another (e.g., coronary heart disease, cancer, Type 2 diabetes). A risk factor is any aspect of a person's lifestyle, environment, or genetics that is linked to an increased likelihood of developing a disease.
- Correlation vs Causal Mechanism
- A correlation is a statistical link between a risk factor and a disease in epidemiological studies. However, correlation does not prove causation unless a scientific causal mechanism can be demonstrated (e.g., tar carcinogens mutating proto-oncogenes/tumour suppressor genes in lung cells).
- Cancer & Uncontrolled Mitosis
- Changes (mutations) in the DNA of a cell lead to uncontrolled growth and division by mitosis. Instead of responding to normal signals to stop dividing or undergo programmed cell death, the abnormal cells continue dividing rapidly to form a mass of cells called a tumour.
- Benign vs Malignant Tumours
- Benign tumours are growths of abnormal cells contained in one area, usually within a membrane; they do not invade other parts of the body. Malignant tumours are cancers: they invade neighbouring tissues and spread to distant organs via the blood or lymphatic system to form secondary tumours (metastasis).
- Carcinogens & Ionising Radiation
- Carcinogens are chemical agents that cause DNA mutations and increase cancer risk, such as tar in tobacco smoke and asbestos fibres. Ionising radiation (UV rays from the sun, X-rays, and gamma rays from radioactive materials) also damages DNA, increasing the risk of skin and tissue cancers.
- Lifestyle Impacts on Health (Smoking, Alcohol, Obesity)
- Smoking damages artery linings, raises blood pressure (via nicotine), reduces oxygen transport (via carbon monoxide), and causes lung cancer, bronchitis, and low birth mass in babies. Alcohol breaks down into toxins in the liver, causing cirrhosis and brain damage, and causes Fetal Alcohol Syndrome in unborn babies. Obesity causes Type 2 diabetes by making body cells less responsive to insulin.
Quick-Fire Flashcards (6)
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Compare benign and malignant tumours (3 key differences).
What is metastasis?
State two effects of smoking or drinking alcohol during pregnancy on an unborn baby.
Give two examples of how different types of disease can interact.
Why does cancer have both genetic and lifestyle risk factors?
Explain the human and financial costs of non-communicable diseases.
Exam-Style Questions & Mark Schemes (4)
Write or think through your answer first, then click Check Mark Scheme to see the exact points examiners award marks for.
- Q1
Explain what cancer is and describe how a malignant tumour in the lung can lead to secondary tumours in the liver. [4 marks]
Click “Check Mark Scheme” to compare your answer, 1. Cancer is the result of changes (mutations) in a cell's DNA that lead to uncontrolled growth and cell division by mitosis [1 mark]. 2. This uncontrolled division forms a mass of abnormal cells called a malignant tumour that invades surrounding lung tissue [1 mark]. 3. Cancer cells can break away from the primary lung tumour and enter the bloodstream or lymphatic system [1 mark]. 4. These cells are carried in the blood to other organs like the liver, where they lodge and divide again to form secondary tumours (metastasis) [1 mark].
- Q2
A study of 50,000 adults found that people who drank more than 4 cups of coffee per day had a higher incidence of heart disease. Explain why scientists cannot immediately conclude from this study that coffee causes heart disease. [3 marks]
Click “Check Mark Scheme” to compare your answer, 1. The study only shows a correlation (statistical link) between coffee consumption and heart disease, and correlation does not prove causation [1 mark]. 2. Other confounding lifestyle risk factors may be responsible (for example, heavy coffee drinkers in the study might also smoke more, exercise less, or have higher stress/poorer diets) [1 mark]. 3. To prove causation, scientists would need to identify a biological causal mechanism showing how a chemical in coffee directly damages the heart or arteries [1 mark].
- Q3
Explain how smoking cigarettes increases the risk of both lung cancer and coronary heart disease. [4 marks]
Click “Check Mark Scheme” to compare your answer, 1. Cigarette smoke contains chemical carcinogens (such as tar) that damage the DNA of cells lining the bronchi and alveoli, causing mutations and uncontrolled mitosis (lung cancer) [1 mark]. 2. Nicotine in cigarette smoke increases heart rate and constricts blood vessels, increasing blood pressure [1 mark]. 3. High blood pressure and chemicals in smoke damage the inner endothelial lining of the coronary arteries, accelerating the build-up of fatty cholesterol deposits (atheroma) [1 mark]. 4. Carbon monoxide binds irreversibly to haemoglobin in red blood cells, reducing the oxygen supplied to heart muscle [1 mark].
- Q4
Describe two ways in which having one health condition can make a person more susceptible to developing a different disease. [4 marks]
Click “Check Mark Scheme” to compare your answer, 1. A viral pathogen can damage the immune system, such as HIV destroying white blood cells [1 mark], which leaves the patient unable to defend against other communicable pathogens like tuberculosis or pneumonia [1 mark]. 2. A viral infection can trigger a non-communicable cancer, such as the Human Papillomavirus (HPV) infecting cervical cells [1 mark] and causing DNA mutations that lead to cervical cancer (or severe physical illness causing mental health conditions such as depression) [1 mark].
Common Exam Questions (4)
What is the difference between a benign tumour and a malignant tumour?
A benign tumour grows in one place (usually contained within a fibrous membrane) and does not invade other tissues in the body. A malignant tumour is cancerous: its cells invade neighbouring healthy tissues and can break off into the bloodstream or lymphatic system to form secondary tumours elsewhere (metastasis).
Does a correlation between a lifestyle factor and a disease prove that the factor causes the disease?
No, correlation alone does not prove causation. To prove that a risk factor causes a disease, scientists must identify and demonstrate a biological causal mechanism explaining exactly how the factor leads to the disease (for example, showing how chemicals in cigarette smoke mutate DNA to cause lung cancer).
How can a viral infection act as a risk factor for a non-communicable disease like cancer?
Different types of disease can interact. For example, infection with the Human Papillomavirus (HPV), a communicable viral infection spread sexually, can damage the DNA of cervical cells and trigger uncontrolled cell division, acting as a major risk factor for cervical cancer.
What are the proven causal risk factors for cardiovascular disease, Type 2 diabetes, and liver cirrhosis?
Smoking, high-fat diet, and lack of exercise are causal risk factors for cardiovascular disease. Obesity is a major causal risk factor for Type 2 diabetes. Excessive long-term alcohol consumption is a causal risk factor for liver cirrhosis and brain damage.
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Related study guides
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Mitosis vs Meiosis
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