Diet & Health (Edexcel International A Level (IAL) Biology): Flashcards

Vitamin A is found in orange vegetables such as carrots and sweet potato.

Vitamins A, C and E are antioxidants found in the diet.

Vitamin C is found in citrus fruits.

False.

Recent data analysis has suggested that there is not enough evidence to conclude antioxidants reduce the risk of heart disease.

Vitamin C helps the formation of connective tissues, which could reduce damage to the artery endothelial layer and help prevent atherosclerosis.

A study that analyses the results of many existing studies is called a meta-analysis.

A study that analyses the results of many existing studies is called a meta-analysis.

Ascorbic acid is the chemical name for vitamin C.

Vitamin C is mainly found in green vegetables, fruits, and potatoes.

A reducing agent is a substance that donates electrons to another substance and is easily oxidised. Ascorbic acid acts as a reducing agent.

DCPIP is a blue dye that turns colourless in the presence of vitamin C, allowing detection and measurement of vitamin C.

The chemical method used to determine the concentration of vitamin C by adding a solution to DCPIP is called titration.

Keeping the shaking time the same is important because it acts as a control variable, ensuring a fair test and reliable results.

DCPIP is a blue dye that turns colourless in the presence of vitamin C.

A calibration curve is a graph plotting the volume of vitamin C needed to decolourise DCPIP against the concentration of vitamin C, used to estimate vitamin C concentration in unknown samples.

False.

As the vitamin C concentration increases, less volume is needed to decolourise DCPIP.

The concentration of vitamin C in an unknown fruit juice can be estimated by comparing its results to the calibration curve produced from known concentrations.

Vitamin C is essential for a healthy diet, helping to prevent deficiency diseases such as scurvy.

Two pieces of apparatus used are a measuring cylinder and a pipette.

Wear eye protection and avoid skin contact as DCPIP is an irritant.

A correlation is when a change in one variable occurs at the same time as a change in another variable.

A causal relationship is when a change in one variable causes a change in another variable.

False.

Correlation does not always mean causation; many other factors could influence the relationship.

It is important to consider other factors that might influence the results and not assume causation from correlation.

When describing data, you should identify trends and use numbers to back up your descriptions.

Drawing a conclusion from data means working out what the data show about the relationships between variables.

Conclusions should always be limited to what the data show.

False.

A causal relationship cannot be concluded from just one data set; more evidence is needed.

A control group allows researchers to compare results and see if the effect is due to the variable being tested and not other factors.

Larger sample sizes are more likely to give valid results as they are more representative of the population.

The study should be repeated or there should be many studies showing the same result to confirm the findings.

Conflicting evidence suggests that other variables are involved and more research is needed.

A representative sample is a group of participants that accurately reflects the characteristics of the population being studied, often achieved by using a large, randomly selected sample.

An experimental control provides a point of comparison and ensures that the results are due to the variable of interest by keeping all conditions the same except for the independent variable.

Reliable data can be reproduced by repeating an experiment, while valid data has only tested one independent variable.

True.

Bias can result from human sources such as non-random sampling or changing data to emphasise a particular outcome.

A placebo is a dummy treatment, such as a sugar pill, that has no therapeutic effect. It is given to the control group so they are treated identically to the group receiving the real treatment, except for the independent variable.

Larger samples are more likely to be representative of the population being studied. This reduces the effect of anomalies and makes the results more reliable.

Randomly selecting participants removes bias and increases the likelihood of a representative sample.

True.

In a double-blind trial, neither the participants nor the researchers know who is in the treatment or control group. This helps to reduce bias in the collection and analysis of data.

Risk is the chance or probability that a harmful event will occur.

Perceived risk is an individual's personal judgement about the likelihood of harm, while actual risk is the scientifically calculated probability that a harmful event will occur.

False.

An individual's perception of risk can be different from the actual risk, and is often influenced by factors unrelated to statistical evidence.

The statistical chance of a harmful event occurring should be supported by scientific evidence gained from research.

Risk can be overestimated because of factors such as misleading information in the media, overexposure to information, personal experience, unfamiliarity, severe harm, or lack of enjoyment.

Risk can be underestimated because of lack of information, misunderstanding, lack of experience, unfamiliarity, non-immediate harm, or enjoyment of an activity.

Enjoyment of an activity can lead people to underestimate the actual risk, making them believe it is safer than it really is.

True.

People often overestimate the risk of flying compared to driving, even though flying is statistically much safer.

A risk factor is any factor that increases the chance of developing a particular condition or disease.

False.

An increase in a risk factor only increases the risk of developing the disease but does not guarantee it.

An example of a risk factor for the incidence of CVD is increased blood cholesterol.

The incidence of disease describes the number of cases of a disease that occur within a particular group of people within a given time.

Cholesterol is a type of lipid produced in the body, required for cell membrane functioning, sex hormone structure, and bile synthesis.

A lipoprotein is a molecule composed of lipid and protein, used to transport cholesterol around the body.

HDLs (high density lipoproteins) reduce blood cholesterol levels by transporting cholesterol from tissues to the liver, while LDLs (low density lipoproteins) increase blood cholesterol levels by transporting cholesterol from the liver to the blood and cells.

High density lipoproteins contain unsaturated fat, cholesterol, and protein.

LDLs are often thought of as bad cholesterol, while HDLs are thought of as good.

The ratio of LDLs to HDLs is important because a higher ratio (more LDLs than HDLs) is associated with an increased risk of heart disease; a healthy ratio is about 3:1, and ratios above 5:1 increase risk.

A study with a large sample size is more likely to give results representative of the target population.

If the standard deviations overlap, the difference between the data sets is not statistically significant. This means the observed difference may be due to random chance rather than a real effect.

Two factors that should be controlled are genetics and diet. Other factors include exercise and secondary exposure to smoking.

Body Mass Index (BMI) is a value calculated by dividing an individual's mass in kilograms by the square of their height in metres.

True.

A BMI of 30 or above is classified as obese.

The waist-to-hip ratio is calculated by dividing the circumference of the waist by the circumference of the hips.

Traffic light food labels use red, orange, and green colours to indicate whether a food contains high, medium, or low levels of sugar, saturated fat, and salt.

Food labels allow people to make informed choices about their diet, helping them avoid high levels of saturated fat, sugar, and salt, which are linked to CVD risk.

The waist-to-hip ratio should be less than 0.9 for men and less than 0.86 for women.

Many scientific studies have linked a diet high in saturated fats to an increased risk of CVD.

Smoking has been targeted by health warnings on packets, restrictions on advertising, and free support materials to help people stop, all of which aim to reduce CVD risk.

Regular exercise helps to lower blood pressure, reduce LDL cholesterol and maintain a healthy body mass, all of which reduce the risk of coronary heart disease.

Cardiovascular disease (CVD) refers to any condition affecting the heart or blood vessels, such as coronary artery disease or stroke.

The main aim of treatments for CVD is to reduce risk factors and lower the risk of developing or worsening cardiovascular disease.

Types of medication for treating cardiovascular disease include antihypertensives, statins, anticoagulants, and platelet inhibitors.

An antihypertensive is a drug that lowers blood pressure to reduce the risk of arterial damage and cardiovascular disease.

Beta blockers prevent increases in heart rate, thus lowering blood pressure as antihypertensive drugs.

ACE inhibitors block the production of angiotensin, a hormone causing constriction of blood vessels.

Diuretics reduce blood volume by decreasing sodium and water reabsorption in the kidneys, which lowers blood pressure.

Statins are drugs that lower blood cholesterol by blocking an enzyme in the liver, reducing LDL concentration and the risk of atheroma formation.

Statins not only lower LDL but also reduce inflammation in the arterial lining.

False.

Warfarin is an anticoagulant that decreases prothrombin levels in the bloodstream, reducing blood clot formation.

A platelet inhibitor is a substance that prevents platelets from clumping together, reducing blood clot formation.

Aspirin and clopidogrel are examples of platelet inhibitors used to reduce blood clotting.