AQA Biology B1, Unit 1. 1-keeping Healthy

Explanation
A balanced diet refers to consuming the right balance of food types that provide the necessary nutrients for the body. This means including a variety of foods from different food groups such as fruits, vegetables, grains, protein sources, and dairy products. Each food group offers unique vitamins, minerals, and macronutrients that are essential for overall health and well-being. By maintaining a balanced diet, individuals can ensure that they are meeting their nutritional needs and promoting optimal physical and mental health.

Explanation
Carbohydrate, fat, and protein are used by the body to release energy. Carbohydrates are the body's primary source of energy, as they are broken down into glucose, which is then used by cells for fuel. Fats are also a source of energy, providing a concentrated form of fuel that can be stored for later use. Proteins, although not the body's preferred source of energy, can be broken down into amino acids and used for energy when carbohydrates and fats are not available. Therefore, all three macronutrients play a role in providing the body with the energy it needs for various functions.

Explanation
Mineral ions and vitamins are essential for maintaining a healthy body. Mineral ions such as calcium, potassium, and iron are necessary for various bodily functions, including nerve transmission, muscle contraction, and maintaining proper fluid balance. Vitamins, on the other hand, are organic compounds that play a crucial role in metabolism, immunity, and overall health. They help in converting food into energy, supporting the immune system, and promoting cell growth and repair. Therefore, a combination of mineral ions and vitamins is needed to ensure the body functions optimally and stays healthy.

Explanation
If a person's diet is unbalanced, it means that they are not getting all the necessary nutrients and vitamins that their body needs to function properly. This can lead to malnourishment, which is a condition where the body does not receive enough essential nutrients to maintain good health. Malnourishment can result in various health problems, such as weakened immune system, stunted growth, fatigue, and impaired cognitive function. Therefore, the correct answer is malnourished.

Explanation
Exercise increases your metabolic rate by stimulating your muscles and increasing the demand for energy. When you exercise, your body burns more calories to fuel your muscles and meet the increased energy needs. This increased calorie burn continues even after you finish exercising, as your body works to repair and recover from the workout. Regular exercise can help boost your metabolism in the long term, leading to increased calorie burn and potentially weight loss or weight maintenance.

Explanation
The metabolic rate refers to the speed at which chemical reactions occur within cells. It is a measure of how quickly the body converts food into energy and performs various physiological processes. A higher metabolic rate indicates a faster rate of energy expenditure, while a lower metabolic rate indicates a slower rate of energy expenditure. Understanding the metabolic rate is crucial for understanding an individual's energy needs, weight management, and overall health.

Explanation
The proportion of muscle to fat and inherited factors are two key factors that affect an individual's metabolic rate. Muscle is more metabolically active than fat, meaning that the more muscle a person has, the higher their metabolic rate will be. Inherited factors, such as genetics and family history, can also play a role in determining metabolic rate. Certain genetic variations can affect how efficiently the body processes and burns calories, which can impact metabolic rate. Therefore, both the proportion of muscle to fat and inherited factors are important considerations when assessing an individual's metabolic rate.

Explanation
If the energy intake is equal to the energy expenditure, it means that the body is in an energy balance. In this state, the body is neither gaining nor losing energy, which means that there is no excess energy available for storage as fat or for utilization in building new tissues. As a result, the body weight or mass remains constant. This principle is based on the law of conservation of energy, which states that energy cannot be created or destroyed, only transferred or converted from one form to another.

Explanation
Eating too much food can lead to an excessive intake of calories, which the body stores as fat. This can result in weight gain and eventually lead to being overweight or obese. Overweight refers to having a higher body weight than what is considered healthy for a given height, while obesity is a more severe condition characterized by excessive body fat. Both conditions are associated with various health risks, including heart disease, diabetes, and certain types of cancer.

Explanation
Long-term obesity can lead to type 2 diabetes because excessive body fat can cause insulin resistance, where the body's cells do not respond properly to insulin. Insulin is a hormone that helps regulate blood sugar levels, and when the cells become resistant to insulin, it leads to high blood sugar levels. Over time, this can lead to the development of type 2 diabetes, a chronic condition characterized by high blood sugar levels and impaired insulin function. Therefore, it is important to manage and prevent obesity to reduce the risk of developing type 2 diabetes.

Explanation
Reducing the intake of carbohydrates helps in managing blood sugar levels and preventing insulin resistance, which are key factors in reducing the risk of developing diabetes. Additionally, engaging in regular exercise helps in maintaining a healthy weight, improving insulin sensitivity, and reducing the likelihood of developing diabetes. By combining these two lifestyle changes, individuals can effectively lower their chances of developing diabetes.

Explanation
If you have a lack of vitamins or minerals, you may develop deficiency diseases. These diseases occur when the body does not receive enough essential nutrients, leading to various health problems. Common deficiency diseases include scurvy (vitamin C deficiency), rickets (vitamin D deficiency), and anemia (iron deficiency). These conditions can cause symptoms such as fatigue, weakness, impaired immune function, and abnormalities in growth and development. It is important to maintain a balanced diet to prevent deficiency diseases and ensure optimal health.

Explanation
Good cholesterol, also known as high-density lipoprotein (HDL), is needed for the formation and maintenance of cell membranes. It helps transport cholesterol from different parts of the body back to the liver, where it can be broken down and eliminated. Additionally, HDL plays a crucial role in the production of certain hormones, such as cortisol, estrogen, and testosterone. These vital substances are necessary for various bodily functions, including metabolism, immune response, and reproductive health. Therefore, having sufficient levels of good cholesterol is essential for overall health and well-being.

Explanation
Small members of the population inheriting 'bad' cholesterol can lead to heart disease. This is because high levels of bad cholesterol, also known as LDL cholesterol, can build up in the arteries, forming plaques. These plaques can restrict blood flow to the heart, leading to various heart conditions such as coronary artery disease, heart attack, or stroke. Therefore, the presence of inherited bad cholesterol increases the risk of developing heart disease.

Explanation
Foods rich in saturated fats can increase cholesterol levels. Saturated fats are typically found in animal-based products such as fatty meats, full-fat dairy products, and tropical oils like coconut oil. When consumed in excess, these fats can raise LDL (bad) cholesterol levels in the blood, increasing the risk of heart disease and other health issues. It is important to limit the intake of saturated fats and opt for healthier fats like monounsaturated and polyunsaturated fats found in foods like nuts, seeds, avocados, and olive oil.

Explanation
Regular exercise has been proven to increase metabolic rate, which means that the body is able to burn calories more efficiently. This can lead to weight loss and help maintain a healthy weight. Additionally, exercise has a positive effect on cholesterol levels. It increases the levels of HDL (good) cholesterol and lowers the levels of LDL (bad) cholesterol. This can reduce the risk of heart disease and improve overall cardiovascular health. Therefore, by exercising regularly, people can indeed increase their metabolic rate and lower high cholesterol levels.

Explanation
Pathogens are microorganisms such as bacteria, viruses, fungi, or parasites that can cause infectious diseases. These pathogens can enter the body through various means such as inhalation, ingestion, or direct contact with infected individuals. Once inside the body, they can multiply and disrupt normal bodily functions, leading to the development of symptoms and the spread of the disease. Pathogens can be transmitted through various routes, including respiratory droplets, contaminated food or water, sexual contact, or insect bites. Understanding the role of pathogens is crucial in preventing and treating infectious diseases.

Explanation
Pathogens are tiny microorganisms that can cause diseases or infections in living organisms. These microorganisms can include bacteria, viruses, fungi, or parasites. They can enter the body through various means such as inhalation, ingestion, or direct contact with the skin. Once inside the body, pathogens can multiply and disrupt normal bodily functions, leading to illness. It is important to understand pathogens and how they spread in order to prevent and control the spread of diseases.

Explanation
Bacteria or viruses can make you feel ill by producing toxins. These toxins can cause various symptoms and reactions in the body, such as inflammation, fever, nausea, and tissue damage. When bacteria or viruses enter the body, they release toxins as part of their survival and replication process. These toxins can disrupt normal bodily functions and trigger an immune response, leading to the symptoms of illness.

Explanation
Ignaz Semmelweiss discovered that infection could be transferred. He was a Hungarian physician in the 19th century who observed that the mortality rate of women giving birth was significantly higher in hospitals than at home births. After conducting various experiments and observations, he concluded that the high mortality rate was caused by the transfer of infection from doctors and medical students who were not properly washing their hands. Semmelweiss introduced handwashing with chlorinated lime solution, which led to a significant decrease in mortality rates. His discoveries laid the foundation for the importance of hand hygiene in preventing the spread of infections.

Explanation
Pathogens are stopped from entering the body through the skin, which acts as a physical barrier. The outer layer of the skin, known as the epidermis, is tough and impermeable, preventing most pathogens from penetrating it. Mucus also plays a role in preventing pathogens from entering the body. Mucus is produced by the respiratory and digestive systems and acts as a sticky trap for pathogens, preventing them from reaching the body's cells. Additionally, mucus contains antimicrobial substances that can kill or neutralize pathogens, further protecting the body from infection.