Back to AI Flashcard MakerBiology /Biology IB HL - D1 Human Nutrition Part 1
What is a nutrient?
A nutrient is a chemical substance found in foods that is used in the human body
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Key Terms
Term
Definition
What is a nutrient?
A nutrient is a chemical substance found in foods that is used in the human body
What are the 6 classes of nutrient?
There are six classes of nutrients – carbohydrates, proteins, lipids, vitamins, minerals and water
What are essential nutrients?
Essential nutrients are those that cannot be synthesised by the body and must be ingested as part of the diet
What are non-essential nutrients?
Non-essential nutrients can be made by the body or have a replacement nutrient which serves the same dietary purpose
Are carbohydrates essential nutrients?
NO
Carbohydrates are not considered essential nutrients as human diets can obtain energy from other sources without ill effect
What is malnutrition?
Malnutrition is a health condition caused by a deficiency, imbalance or excess of nutrients in the diet
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| Term | Definition |
|---|---|
What is a nutrient? | A nutrient is a chemical substance found in foods that is used in the human body |
What are the 6 classes of nutrient? | There are six classes of nutrients – carbohydrates, proteins, lipids, vitamins, minerals and water |
What are essential nutrients? | Essential nutrients are those that cannot be synthesised by the body and must be ingested as part of the diet |
What are non-essential nutrients? | Non-essential nutrients can be made by the body or have a replacement nutrient which serves the same dietary purpose |
Are carbohydrates essential nutrients? | NO
Carbohydrates are not considered essential nutrients as human diets can obtain energy from other sources without ill effect |
What is malnutrition? | Malnutrition is a health condition caused by a deficiency, imbalance or excess of nutrients in the diet |
What can cause malnutrition? 2 | It can be caused by an improper dietary intake of nutrients – e.g. overnutrition (too much) or undernutrition (not enough)
It can be caused by the inadequate utilisation of nutrients by the body – e.g. due to illness or disease |
Are symptoms of malnutrition the same for each imbalance? | NO
The symptoms of malnutrition will vary according to the specific nutrient and the type of imbalance involved |
What are common signs of malnutrition? | Common signs of malnutrition included stunted growth and wasting (undernutrition), as well as obesity (over nutrition) |
How can the energy content of food be estimated? (experimentally) | The energy content of food can be estimated by burning a sample of known mass and measuring the energy released via calorimetry |
What does combustion of food release? | Combustion of the food source causes the stored energy to be released as heat, which raises the temperature of water |
What is the equation used to calculate the energy content of food via calorimetry? | Energy (joules) = Mass of water (g) × 4.2 (J/gºC) × Temperature increase (ºC) |
What is the biggest source of error in calorimetry? | The biggest source of error in calorimetry is usually caused by the unwanted loss of heat to the surrounding environment |
What should be kept constant in calorimetry? | The food sources should be burnt at a constant distance from the water to ensure reliability of results
The initial temperature and volume of water should also be kept constant (1 g of water = 1 cm3 or 1 ml) |
Which nutrient is most commonly used an energy source and why? | Carbohydrates are preferentially used as an energy source because they are easier to digest and transport |
What type of energy are lipids used for and why? | Lipids can store more energy per gram but are harder to digest and transport (hence are used for long-term storage) |
What happens when proteins are used for energy? | Protein metabolism produces nitrogenous waste products which must be removed from cells |
What are amino acids? | Amino acids are the monomeric building blocks from which proteins are constructed |
How many amino acids are there? | There are 20 different amino acids which are universal to all living organisms |
What categories do amino acids fit into? | Amino acids can be either essential, non-essential or conditionally non-essential according to dietary requirements |
What are essential amino acids? | Essential amino acids cannot be produced by the body and must be present in the diet |
What are non-essential amino acids? | Non-essential amino acids can be produced by the body and are therefore not required as part of the diet |
What are conditionally non-essential amino acids? | Conditionally non-essential amino acids can be produced by the body, but at rates lower than certain conditional requirements (e.g. during pregnancy or infancy) – they are essential at certain times only |
What happens if there is a shortage of one or more of the essential amino acids? | A shortage of one or more essential amino acids in the diet will prevent the production of specific proteins |
What is a lack of amino acids called? | This is known as protein deficiency malnutrition and the health effects will vary depending on the amino acid shortage |