Nutrition
Overview
Food keeps every cell in your body running, but the molecules on your plate are far too large to cross a cell membrane. Your digestive system breaks them down into absorbable units, while plants build their own food from scratch using light energy. This topic connects the chemistry of nutrients to the biology of how organisms obtain and process them.
In this lesson you will learn what makes a diet balanced, how each nutrient contributes to health, how the alimentary canal digests food mechanically and chemically, and how photosynthesis supplies the organic molecules that underpin almost every food chain. These ideas appear in both Paper 1 and Paper 2, often as data-response or extended-writing questions.
Objectives
- Understand the process of photosynthesis and its importance in the conversion of light energy to chemical energy
- Know the word equation and the balanced chemical symbol equation for photosynthesis
- Understand how varying carbon dioxide concentration, light intensity and temperature affect the rate of photosynthesis
- Describe the structure of the leaf and explain how it is adapted for photosynthesis
- Understand that plants require mineral ions for growth, and that magnesium ions are needed for chlorophyll and nitrate ions are needed for amino acids
- Investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll
- Understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre
- Identify the sources and describe the functions of carbohydrate, protein, lipid, vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of the diet
- Understand how energy requirements vary with activity levels, age and pregnancy
- Describe the structure and function of the human alimentary canal, including the mouth, oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum) and pancreas
- Understand how food is moved through the gut by peristalsis
- Understand the role of digestive enzymes, including the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases
- Understand that bile is produced by the liver and stored in the gall bladder
- Understand the role of bile in neutralising stomach acid and emulsifying lipids
- Understand how the small intestine is adapted for absorption, including the structure of a villus
- Investigate the energy content in a food sample
Mind map
This topic is mapped out so you can see how the ideas connect.
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Flashcards
Quick recall practice on the facts this topic is tested on.
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Nutrition. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which mineral ion is needed for the production of chlorophyll? A) Iron B) Calcium C) Magnesium D) Nitrate Answer: C
- What is the correct order of organs through which food passes? A) Mouth, stomach, oesophagus, small intestine, large intestine B) Mouth, oesophagus, stomach, small intestine, large intestine C) Mouth, oesophagus, small intestine, stomach, large intestine D) Mouth, stomach, small intestine, oesophagus, large intestine Answer: B
- Which enzyme breaks down maltose into glucose? A) Amylase B) Maltase C) Lipase D) Protease Answer: B
- What is the role of bile in digestion? A) It chemically digests proteins B) It neutralises stomach acid and emulsifies lipids C) It breaks down starch into maltose D) It absorbs nutrients into the blood Answer: B
- Which adaptation of a villus provides a short diffusion distance? A) Large surface area B) Rich blood supply C) Walls one cell thick D) Presence of a lacteal Answer: C
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Recommended Books
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