Lifestyle & Health (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Flashcards

False.

Exposure to a risk factor increases the chance of developing a disease but does not guarantee it. For example, a smoker has a much higher risk of lung cancer but is not certain to develop it.

A correlation shows a relationship between a risk factor and a disease. A causal mechanism goes further — it provides a proven biological explanation for how the risk factor actually causes the disease.

Obesity is a risk factor for Type 2 diabetes, while alcohol is a risk factor for liver and brain damage.

Smoking is a risk factor for:

1. Lung disease and lung cancer

2. Cardiovascular disease

3. Harm to unborn babies

True.

Carcinogens and ionising radiation are both risk factors that can increase the likelihood of developing cancer.

Scientists use scatter diagrams to identify correlations between two variables — for example, to determine whether a factor such as obesity is associated with an increased risk of developing a disease such as Type 2 diabetes.

Scientists sample populations to determine risk factors for different diseases without having to investigate every individual.

True.

Many diseases result from the interaction of multiple risk factors. A poor diet high in cholesterol, lack of exercise and smoking all independently increase the likelihood of cardiovascular disease.

Coronary heart disease is a condition in which layers of fatty material (plaque) build up inside the coronary arteries, reducing blood flow to the heart muscle.

Angina results from a partial blockage of the coronary arteries, restricting blood flow and causing severe chest pain. A heart attack results from a complete blockage, preventing aerobic respiration in heart muscle cells.

False.

Statins reduce the levels of cholesterol in the blood by blocking an enzyme in the liver, slowing the rate of fatty deposit build-up. It is stents that physically widen the lumen of the arteries.

Stents are used to keep the coronary arteries open by increasing the width of the lumen of the artery.

Advantage: Stents are effective at widening the lumen, increasing blood flow, and the procedure is relatively simple surgery.

Disadvantage: There is a risk of blood clots (thrombosis) forming after insertion.

True.

Biological valves from animals such as cows or pigs are effective but typically need to be replaced after 12–15 years. They also carry a risk of immune rejection.

An artificial heart can be used to:

1. Keep patients alive while waiting for a heart transplant

2. Allow the heart to rest as an aid to recovery

Patients with mechanical heart valves have a lifelong need to take anticoagulant medication to prevent blood clots.

True.

Artificial hearts are made of plastic and metal, so they are less likely to trigger an immune rejection response compared to a donor heart.

Statins block an enzyme in the liver that produces cholesterol. If they are not taken consistently, the liver resumes normal cholesterol production, allowing fatty deposits to continue building up in the blood.

Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.

Homeostasis regulates:

1. Blood glucose concentration

2. Body temperature

3. Water levels

False.

Homeostasis is under involuntary (automatic) control. The brain stem and spinal cord maintain internal conditions without conscious effort.

In a homeostatic control system, receptors detect changes in the environment, coordination centres process this information, and effectors bring about a corrective response.

The normal core body temperature is 37 °C. It must be kept within a narrow range because a change of more than 2 °C can be fatal — enzymes would not function optimally.

True.

Homeostasis maintains body temperature at about 37 °C because enzymes have an optimum temperature. A large change in temperature would cause enzymes to denature, stopping cell functions.

When blood water content is too high, the kidneys reabsorb less water, producing a large amount of dilute urine. When blood water content is too low, the kidneys reabsorb more water, producing a small amount of concentrated urine.

Three internal conditions regulated by homeostasis are blood glucose concentration, body temperature and water levels.

True.

Effectors are the components that bring about the corrective response in a homeostatic control system. They can be muscles or glands.

Insulin is a hormone produced by the pancreas that causes cells, particularly in the liver and muscles, to take in glucose from the bloodstream and convert excess glucose into glycogen for storage.

True.

Excessively low blood glucose levels mean the brain receives insufficient glucose for respiration, which can potentially lead to a coma or even death.

In liver and muscle cells, excess glucose is converted into glycogen for storage by the action of insulin.

Glucagon is a hormone produced by the pancreas when blood glucose is too low. It causes glycogen stored in the liver to be converted back into glucose and released into the blood.

False.\n\nInsulin and glucagon are both produced by the pancreas, not the liver. The liver is the organ that stores and releases glycogen in response to these hormones.

Type 1 diabetes is caused by the pancreas failing to produce sufficient insulin, thought to result from the immune system destroying the insulin-producing cells. It is treated with insulin injections.

In Type 2 diabetes, body cells no longer respond to insulin — the person still produces insulin but their cells are resistant to it. Unlike Type 1, it is not caused by a failure to produce insulin.

Common treatments for Type 2 diabetes include a carbohydrate-controlled diet and an exercise regime.

True.

Obesity is a significant risk factor for Type 2 diabetes, partly because a diet high in carbohydrates can lead to over-production of insulin and the development of insulin resistance.

Testosterone is the main male reproductive hormone, produced by the testes. It stimulates sperm production and causes secondary sex characteristics to develop during puberty.

Ovulation is the release of a mature egg from the ovary. It occurs approximately every 28 days as part of the menstrual cycle.

False.

Oestrogen is the main female reproductive hormone and is produced by the ovaries, not the testes.

FSH is a hormone produced by the pituitary gland that causes an egg to mature inside a follicle in the ovary. It also stimulates the ovaries to produce oestrogen.

When oestrogen levels peak, they stimulate the release of LH from the pituitary gland, which causes ovulation.

Progesterone maintains the uterus lining. If the egg is not fertilised, progesterone levels fall, causing the lining to break down (menstruation). If fertilisation occurs, progesterone continues to be produced to maintain the lining.

True.\n\nOestrogen causes the growth and repair of the uterus lining and also inhibits the production of FSH, preventing further egg maturation once levels are high enough.

After ovulation, the follicle becomes the corpus luteum and begins producing progesterone.

The placenta takes over progesterone production once it has developed, and continues to secrete progesterone throughout the pregnancy to maintain the uterus lining.

Contraception refers to methods used to prevent fertilisation and pregnancy, allowing humans to control their fertility. Methods can be hormonal or non-hormonal.

High levels of oestrogen inhibit FSH production, preventing the maturation and release of eggs from the ovaries.

False.

The combined pill contains both oestrogen and progesterone. There is also a progesterone-only pill, which has fewer side effects.

Progesterone stimulates the production of a thick mucus that prevents sperm from reaching any eggs, and also inhibits the maturation and release of mature eggs.

Barrier methods physically prevent sperm from reaching an egg. Examples include condoms and diaphragms.

True.

Condoms are the only contraceptive method that also provides protection against sexually transmitted infections (STIs). Other barrier methods, hormonal methods, and surgical methods do not offer this protection.

The sperm ducts — the tubes connecting the testes to the penis — are cut and tied, preventing sperm from being released during ejaculation. It is a highly effective method of surgical sterilisation.

Spermicidal agents kill or disable sperm cells, but are only 70 to 80% effective at preventing pregnancy.

True.

Complete abstinence is the only method guaranteed to prevent pregnancy. Natural methods that involve avoiding intercourse during fertile periods are not as reliable because fertility cannot be accurately predicted.

IVF (In Vitro Fertilisation) is a fertility treatment in which eggs are collected from the mother and fertilised by sperm in a laboratory. One or two embryos are then inserted into the mother's uterus.

FSH and LH are given to stimulate the maturation and release of eggs in women whose pituitary gland does not produce sufficient FSH naturally. This helps them produce eggs for potential fertilisation.

False.

In IVF, eggs are collected from the mother and fertilised by sperm in a laboratory (outside the body). The resulting embryos are then inserted into the mother's uterus.

During IVF, a mother is given FSH and LH to stimulate the maturation of several eggs, which are then collected and fertilised by sperm in the laboratory.

1. The mother is given FSH and LH to stimulate the maturation of several eggs.

2. Eggs are collected from the mother and fertilised by sperm from the father in the laboratory.

3. Fertilised eggs develop into embryos.

4. One or two embryos are inserted into the mother's uterus.

False.

The success rate of IVF is relatively low, at approximately 30%, though advancements in medical technology are helping to increase this figure over time.

Any two from:

1. More embryos may be produced than are used, raising questions about ownership and their use in research.

2. Genetic testing of embryos is controversial as it could potentially be misused to select offspring characteristics.

3. IVF can allow women to conceive at a later age than would be naturally possible, which some find ethically questionable.

True.

Because several embryos may be implanted during treatments such as IVF, the risk of multiple births (e.g. twins or triplets) is increased. This raises the risk of miscarriage, stillbirth and complications for the mother.

Fertility treatments increase the risk of multiple births, which raises the risk of miscarriage or stillbirths and poses a greater risk to the mother.