bio disease

Define health.

A: Health is a state of physical and mental well-being, not simply the absence of disease.

Q: Define disease.

A: A disease is a condition that negatively affects the structure or function of the body.

Q: Define a communicable disease.

A: A communicable disease is a disease caused by pathogens that can spread between organisms.

Q: Define a non-communicable disease.

A: A non-communicable disease is a disease that is not caused by pathogens and cannot spread between organisms.

Q: Define a pathogen.

A: A pathogen is a microorganism that causes disease, such as bacteria, fungi, protists, or viruses.

Q: Define a host.

A: A host is the organism in which a pathogen lives.

Q: Define a multifactorial disease.

A: A multifactorial disease is a disease caused by a combination of genetic, lifestyle, and environmental factors.

Explain how different factors interact in the development of disease.

A: Disease is more likely to occur when three factors are present together: a pathogen, a susceptible host, and a stressful environment. Stressful environments include poor diet, overcrowding, poor sanitation, lack of healthcare, poverty, war, and poor living conditions. Improving the environment, removing pathogens, and improving the health of the host all reduce the chance of disease developing.

Q: Describe ways to reduce the spread of diseases such as cholera after natural disasters.

A: The spread of disease can be reduced by improving sanitation and sewage disposal, providing clean drinking water, reducing overcrowding, improving hygiene, isolating infected individuals, and providing healthcare and medical treatment. These actions reduce pathogens and improve the environment and health of the host.

Q: What is a multifactorial disease and what factors increase cancer risk?

A: A multifactorial disease is caused by a combination of genetic, environmental, and lifestyle factors. Cancer is an example. Risk factors for cancer include smoking, obesity, alcohol abuse, poor diet, inherited genetic mutations, family history, UV radiation, ionising radiation, and some viral infections such as HPV.

Q: Explain why people with AIDS or protein deficiency are more likely to suffer from infectious disease.

A: AIDS is caused by HIV, which damages the immune system and reduces the body’s ability to fight pathogens. Protein deficiency and starvation weaken the immune system because proteins are needed to make antibodies and immune cells. This makes infections more likely.

Q: Explain how severe physical illness may lead to mental illness.

A: Severe physical illness can cause stress, chronic pain, tiredness, reduced independence, isolation, and inability to take part in normal activities or hobbies. These factors may lead to depression and other mental illnesses.

Q: Describe asthma, its causes, and its treatment.

A: Asthma is a disease where the airways become narrowed and inflamed, making breathing difficult. Asthma attacks may be triggered by dust, smoke, pollution, exercise, stress, allergies, pets, pollen, cold air, infections, or immune reactions caused by pathogens. Asthma is usually treated using inhalers. Reliever inhalers quickly open the airways, while preventer inhalers reduce inflammation over time. Avoiding triggers can help prevent attacks.

Q: Define correlation and distinguish between positive and negative correlation.

A: Correlation is an apparent relationship between two variables. Positive correlation means that as one variable increases, the other also increases. Negative correlation means that as one variable increases, the other decreases. Correlation does not always prove causation because other factors may also affect the results.

Q: Explain the difference between correlation and causation.

A: Correlation means two variables appear linked, but it does not prove that one causes the other. Causation means there is evidence and a biological mechanism showing that one factor directly causes another. For example, smoking and lung cancer are positively correlated, and scientists know smoking causes lung cancer because carcinogens in tobacco smoke damage cells and cause mutations.

Q: What is a risk factor and how can it increase disease risk?

A: A risk factor is something linked to an increased chance of developing a disease. Risk factors may be lifestyle factors, environmental factors, substances in the body, or inherited genes. Examples include smoking, obesity, alcohol, poor diet, lack of exercise, UV exposure, and ionising radiation.

Q: Explain how obesity increases the risk of disease.

A: Obesity is a risk factor for type 2 diabetes because body cells become less responsive to insulin, causing blood glucose levels to rise. Obesity also increases the risk of coronary heart disease, stroke, some cancers, joint problems, high blood pressure, and breathing problems. Fat around the abdomen is particularly dangerous because it affects the cardiovascular and metabolic systems.

Q: Describe cancer, tumours, benign tumours, malignant tumours, and metastasis.

A: Cancer is caused by uncontrolled cell division due to mutations in genes controlling the cell cycle. A tumour is a mass of abnormal cells. Benign tumours are contained in one area and do not spread. Malignant tumours are cancerous and invade nearby tissues. Cancer cells may spread in the blood to other parts of the body, forming secondary tumours. This spreading process is called metastasis.

Q: Describe HPV and explain its link to cervical cancer.

A: HPV (human papillomavirus) is a very common group of viruses. Most infections cause no symptoms, but some types can cause genital warts and cervical cancer. HPV can cause abnormal changes in cervical cells which may become cancerous. The HPV vaccine protects against the types most likely to cause cervical cancer and some other cancers.

Q: Describe the effects of alcohol on the body.

A: Small amounts of alcohol may reduce inhibitions and make people feel relaxed. Larger amounts slow reaction time, impair judgement and coordination, and affect decision making. Very high levels can cause unconsciousness, coma, or death. Alcohol damages the liver and may cause cirrhosis, where scar tissue replaces healthy liver tissue. Alcohol is also linked to liver cancer and stomach ulcers. Drinking during pregnancy may cause miscarriage, premature birth, stillbirth, low birth weight, and fetal alcohol syndrome, which affects brain and body development.

Q: Describe the harmful effects of smoking.

A: Smoking damages many organs in the body. Tar damages the lungs and causes bronchitis and emphysema by destroying alveoli and cilia. Carbon monoxide binds to haemoglobin more strongly than oxygen, reducing oxygen transport in the blood. Nicotine is addictive and increases heart rate and blood pressure. Smoking increases the risk of lung cancer, coronary heart disease, stroke, chronic lung disease, and many other cancers.

Q: Describe the harmful effects of nicotine, tar, and carbon monoxide in cigarette smoke.

A: Nicotine is addictive and increases heart rate and blood pressure. Tar is a carcinogen, meaning it can cause cancer. Tar also damages cilia and alveoli, causing bronchitis and emphysema. Carbon monoxide binds strongly to haemoglobin, reducing the amount of oxygen carried by the blood. In pregnant women this reduces oxygen reaching the fetus.

Q: Explain how smoking affects unborn babies.

A: Smoking during pregnancy increases the risk of miscarriage, premature birth, low birth weight, stillbirth, and respiratory problems in babies. Carbon monoxide reduces oxygen delivery to the fetus because it binds to haemoglobin. Nicotine narrows blood vessels, reducing blood flow to the placenta.

Q: Describe adaptations of the respiratory system.

A: Alveoli provide a very large surface area for gas exchange. The walls of alveoli and capillaries are thin, giving a short diffusion distance. The trachea contains cartilage rings to keep it open. Goblet cells produce mucus to trap dust, dirt, and bacteria. Cilia move the mucus up the trachea to be swallowed.

Q: Describe how red blood cells transport oxygen and explain the effect of carbon monoxide.

A: Red blood cells contain haemoglobin which binds to oxygen and transports it around the body. Their biconcave shape increases surface area for diffusion. Red blood cells do not contain a nucleus, leaving more space for haemoglobin. Carbon monoxide binds to haemoglobin more strongly than oxygen, preventing oxygen transport.

Q: Describe how scatter graphs are used in biology.

A: Scatter graphs are used to identify possible relationships or correlations between two variables. Each point represents one result. A line of best fit may show positive correlation, negative correlation, or no correlation. Scatter graphs help scientists identify trends but do not prove causation.

Q: Explain what graphs show about smoking and lung cancer.

A: Graphs show a positive correlation between smoking rates and lung cancer rates. As smoking increases, lung cancer cases also increase. Lung cancer rates rise after smoking rates because cancer takes time to develop. Scientists concluded smoking causes lung cancer because evidence from large population studies supports the link and there is a known biological mechanism involving carcinogens damaging cells.

Q: Why are disease rates often shown per 100,000 people?

A: Showing disease rates per 100,000 people allows fair comparison between populations of different sizes. Without standardising the population size, results from large and small populations could not be compared accurately

🧬 Define health and explain the relationship between health and disease.

A: Health is a state of physical and mental well-being, not simply the absence of disease. Diseases are major causes of ill health and may be communicable or non-communicable. Other factors such as diet, stress, and life situations can also affect physical and mental health. Different types of disease may interact with each other. Defects in the immune system increase the risk of infectious diseases. Viruses may trigger cancers, and immune reactions caused by pathogens can trigger allergies such as asthma and skin rashes. Severe physical illness may also lead to depression and other mental illnesses.