Biology Flashcards 8 (CIE IGCSE specific)

Describe the effects of coronary heart disease

Coronary heart disease (CHD) is when cholesterol sticks to the walls of your arteries. Sometimes, this even forms blood clots. This cuts off or limits the supply of blood that your heart muscles receive, leading to a heart attack. This arises from consuming too many saturated fats.

Principle source of calcium?

Dairy foods such as milk, cheese and yoghurt contain it; greens like kale are good vegetable sources; fish with bones soft enough to eat, such as sardines and salmon; most grainy food, like bread or rice; etc.

Dietary importance of water?

Every cell in our body is made of and surrounded by water, we are approximately 70% water. Every reaction in our body occurs in water. Hormones and other substances are dissolved in water; most of your blood is made of plasma (which is 92% water), gas exchange is possible because the gas exchange surface area moistened using water, etc.

Dietary importance of fibre?

Insoluble fibres can not be digested. They basically adds bulk and 'roughage' to your food so that your intestines can push it along your alimentary canal. Insoluble fibre keeps your bowels healthy and helps prevent digestive problems.

Principle source of iron?

Iron can be found in liver, meat, beans, nuts, dried fruit, whole grains, fortified breakfast cereals, clams, oysters, shrimps and dark green leafy vegetables.

Explain the causes iron deficiencies

Iron deficiency could be due to a poor diet - you're not eating enough iron-rich foods. Pregnant women need more iron than the rest of us, so are at a higher risk of iron deficiency. Inflammatory bowel disease can cause iron deficiency, and high blood loss through heavy periods or bleeding can also cause iron deficiency.

Explain the effects of an iron deficiency

Iron deficiency is the leading cause of anaemia (a condition where there is a deficiency in RBCs or haemoglobin in the blood). As a result of the anaemia, and the iron deficiency itself, you may experience fatigue, decreased work and school performance, slow cognitive and social development in childhood, difficulty in regulating body temperature, decreased immune function and glossitis (an inflamed tongue).

Dietary importance of iron?

Iron is primarily needed to form the haemoglobin in RBCs. It also plays an essential role in the process of respiration.

Principle source of Vitamins C?

Vitamin C is found in many fresh fruits, especially citrus fruits, e.g. oranges, lemons, peppers, etc. It is also found in dark leafy greens.

Dietary importance of Vitamin C?

Vitamin C is required for the development and maintenance of scar tissue, blood vessels and cartilage. It's needed to make ATP (your source of energy), too. Vitamin C contributes to healthy teeth and gums as well.

Effects of a vitamin D deficiency

Vitamin D deficiency symptoms include bone pain and muscle weakness and rickets (a disease where the bone tissue doesn't properly mineralize, leading to soft bones and skeletal deformities).

Dietary importance of Vitamin D?

Vitamin D is equally important to the maintenance of bone health as calcium because it regulates the flow of calcium into the bloodstream. This is done by promoting the absorption of calcium from food.

Principle source of water?

Water is usually present in varying amounts in food, but that's not nearly enough for our body. Water can be drawn from wells, taken from springs, rivers, and other freshwater sources, or just a running tap.

Principle source of fats?

Oil, butter and margarine.

Explain the causes of a vitamin D deficiency

One cause of vitamin D deficiency is a poor diet. If you don't have enough vitamin D in your diet, you won't ingest enough vitamin D. Lack of exposure to sunlight could also result in a vitamin D deficiency.

How does activity level affect the dietary needs of humans?

People who lead a more active lifestyle or work manual labour jobs will require more energy - so they will have higher carbohydrate and fat requirements.

How does pregnancy affect the dietary needs of humans?

Pregnant females require a lot of protein, iron, vitamin D, calcium, too, because they are growing a foetus. However, women who are already eating a healthy diet do not need to increase their food intake when pregnant.

Principle source of proteins?

Proteins are found in meats, such as chicken, beef, fish, etc. It is also found in vegetables such as lentils and beans.

Dietary importance of protein?

Proteins form our muscles, enzymes, skin, hair, etc.

State what is meant by the term balanced diet for humans

A balanced diet is a diet consisting of the right proportions of every type of nutrient (carbohydrates, proteins, fats, vitamins, minerals, etc.) in suitably sized portions.

Dietary importance of calcium?

Almost all calcium is stored in bones and teeth, where it supports their structure and hardness. Calcium is required for muscles to move and for nerves to carry messages between the brain and every body part.

How does breastfeeding affect the dietary needs of humans?

Breastfeeding women need a lot of water. Note: breastfeeding women may also be referred to as lactating women. Lactating means producing milk.

Describe the effects of constipation

Constipation is when you are unable to defecate. This is caused by a lack of fibre - your intestines won't have anything to push on to move the food along the alimentary canal if there's no fibre.

What is the dietary importance of fats?

Fats insulate the body, helping reduce fluctuations in our body temperature. They are also a good store of energy

Explain how gender affects the dietary needs of humans

Generally, males use up more energy than females.

Explain how age affects the dietary needs of humans

In general, our energy demand increases until we stop growing (the bigger we are, the more of us there is to fuel). While children are growing, they need more protein per kilogram of body weight than adults do. This means teenagers need more proteins and energy altogether than adults.

Principle source of vitamin D

Most of the vitamin D in our body is formed under our skin as a reaction to sunlight. Food sources include oily fish, eggs, fortified fat spreads, fortified breakfast cereals, and some powdered milks.

Describe the effects of obesity

Obesity arises from consuming too much food. This can lead to several diseases such as diabetes, strokes, difficulty breathing, etc.

Describe the effects of scurvy

Scurvy is a disease resulting from a lack of vitamin C. It is very rare because it is pretty difficult to get scurvy - your diet has to be that bad. Early symptoms include weakness, feeling tired and sore arms and legs. Without treatment, you may have less red blood cells, gum disease, thinning hair, and bleeding from the skin. Since vitamin C is found in most fresh fruit and vegetables, especially citrus fruit like oranges and lemons, simply eat these fruit and vegetables to treat scurvy.

Describe the effects of starvation

Starvation is caused by consuming too little food (maybe due to lack of food supply or a mental disorder causing an intense fear of gaining weight). This leads to acute weight loss, organ damage and in severe cases, death.

What is the dietary importance of carbohydrates?

They are our primary source of energy - they are broken down to release energy in respiration.

What are the principle sources of carbohydrate?

They are present in almost any food, but are present in large quantities in staple foods such as rice, potatoes, wheat, cereal, bread, etc.

Principle sources of (insoluble) fibre?

Wholemeal bread, bran, cereals, nuts and seeds (other than golden linseeds).

What should a balanced diet consist of?

carbohydrate, fat, protein, fibre, vitamins, minerals and water