IB MYP 4-5 Biology-Nutrition- Study Notes - New Syllabus
IB MYP 4-5 Biology-Nutrition- Study Notes – New syllabus
IB MYP 4-5 Biology-Nutrition- Study Notes – IB MYP 4-5 Biology – per latest IB MYP Biology Syllabus.
Key Concepts:
- Macronutrients (carbohydrates, proteins, lipids)
- Micronutrients (vitamins, minerals)
- Balanced diet and dietary requirements
Macronutrients (carbohydrates, proteins, lipids)
Understanding Metabolism
Metabolism refers to all the chemical reactions that take place inside living organisms to maintain life. These reactions are responsible for:
- Breaking down food to release energy (catabolism)
- Building new molecules and repairing tissues (anabolism)
Energy from metabolism powers every cell activity – from breathing and thinking to growing and healing.
What Is Nutrition?
Nutrition is the process through which organisms take in food and convert it into usable substances. It includes both the intake of food (feeding) and its processing within the body.
Humans are heterotrophs, meaning we depend on external sources of organic molecules. These molecules give us:
- Energy for biological work
- Raw materials for tissue growth and repair
- Compounds to regulate and support bodily functions
Poor nutrition can lead to malnutrition, deficiency diseases (like anaemia), or metabolic disorders (like obesity and diabetes).
Types of Nutrients
| Category | Examples | Main Role |
|---|---|---|
| Macronutrients | Carbohydrates, Proteins, Fats | Provide energy and building material |
| Micronutrients | Vitamins, Minerals | Support metabolic reactions |
| Water | – | Solvent, temperature regulator, transport medium |
Macronutrients in Detail
1. Carbohydrates
- Primary source of energy for the body
- Simple sugars (e.g., glucose, fructose) provide quick energy
- Complex carbs (e.g., starch, cellulose) offer long-term energy and fiber
- Excess carbohydrates are stored as glycogen or converted into fat
2. Proteins
- Built from amino acids (20 total, 8 essentials in the diet)
- Support repair, growth, structure (muscles, enzymes, hormones)
- Can be used for energy in extreme cases
- Examples: hemoglobin (transport), antibodies (defence), enzymes (catalysis)
3. Lipids (Fats and Oils)
- Most energy-dense macronutrient (9 kcal/g)
- Formed from glycerol and fatty acids
- Used for long-term energy storage, insulation, and membrane formation
- Includes saturated (solid) and unsaturated (liquid) fats
- Cholesterol is a lipid involved in hormone production and cell structure
Macronutrients are required in large quantities, unlike micronutrients, and must be balanced to support optimal health and prevent disease.
Quick Summary
- Metabolism is the sum of all life-sustaining chemical reactions.
- Nutrition provides the raw materials and energy needed by cells.
- Carbohydrates offer quick energy, proteins support growth and repair, and lipids provide long-term energy storage.
- A balanced intake of macronutrients is essential for health, energy, and function.
Micronutrients: Vitamins and Minerals
What Are Micronutrients?
1. Vitamins
Vitamins are organic compounds that assist in regulating chemical reactions. They help release energy from food, support immune function, and aid tissue growth and repair.
- Water-soluble vitamins (Vitamin C, B-complex): Not stored in the body – need daily intake.
- Fat-soluble vitamins (Vitamins A, D, E, K): Stored in body fat and liver – excess intake can be harmful.
Key Vitamins
| Vitamin | Sources | Deficiency Disease | Functions |
|---|---|---|---|
| A (Fat-soluble) | Green vegetables, liver | Night blindness | Vision, skin health |
| B-Complex (Water-soluble) | Whole grains, peas, meat | Fatigue, nerve issues | Brain function, energy release |
| C (Water-soluble) | Citrus fruits, kiwi | Scurvy | Wound healing, immune defense |
| D (Fat-soluble) | Egg yolk, salmon | Rickets | Calcium absorption, bone health |
| E (Fat-soluble) | Nuts, vegetable oils | Muscle weakness | Antioxidant, protects cells |
| K (Fat-soluble) | Kale, spinach | Blood clotting issues | Helps blood clot after injury |
2. Minerals
Minerals are inorganic elements essential for health. They help in bone formation, nerve function, enzyme activity, and maintaining fluid balance. Though needed in small amounts, they are crucial for survival.
Key Minerals and Their Roles
| Mineral | Sources | Deficiency | Functions |
|---|---|---|---|
| Calcium | Milk, cheese | Osteoporosis | Bone and heart health |
| Iron | Liver, fish | Anaemia | Oxygen transport via hemoglobin |
| Potassium | Potatoes, squash | Hypokalemia | Nerve signals, fluid balance |
| Sodium | Salt, beetroot | Hyponatremia | Nerve impulse, water balance |
| Magnesium | Almonds, spinach | Cramps, fatigue | Heartbeat, enzyme activity |
| Phosphorus | Milk, beans | Rickets | Bone structure, energy storage |
| Iodine | Seaweed, iodised salt | Goitre | Thyroid hormone production |
| Zinc | Meat, legumes | Poor immunity | Healing, taste and smell |
| Fluoride | Tea, cocoa | Tooth decay | Strengthens teeth and bones |
| Selenium | Sardines, eggs | Hypothyroidism | Antioxidant, immune support |
Important Notes
- A balanced diet must include both vitamins and minerals in appropriate amounts.
- Deficiencies can cause serious health issues, both mental and physical.
- Water-soluble vitamins are easily destroyed by heat or light eat fresh fruits and vegetables.
- Whole foods are better sources than processed ones – minerals are often lost during processing.
Quick Tip
Balanced Diet and Dietary Requirements
What Is a Balanced Diet?
A balanced diet provides all the essential nutrients carbohydrates, proteins, fats, vitamins, minerals, fiber, and water – in correct proportions to support energy, growth, and repair. It protects against deficiency diseases and supports daily performance.
Key Components of a Balanced Diet
| Nutrient Group | Main Role | Examples |
|---|---|---|
| Carbohydrates | Main source of energy | Rice, bread, fruits |
| Proteins | Tissue building and repair | Eggs, meat, pulses |
| Fats | Energy storage, insulation | Butter, oils, nuts |
| Vitamins | Regulate metabolism | Fruits, vegetables, dairy |
| Minerals | Bone and nerve support | Milk, leafy greens |
| Fiber | Aids digestion | Whole grains, fruits |
| Water | Hydration and transport | Water, juice, watermelon |
Importance of a Balanced Diet
- Prevents malnutrition and chronic diseases
- Boosts immunity and energy levels
- Essential for physical and mental growth
- Supports quicker recovery from illness
- Improves cognitive function and focus
Factors Affecting Dietary Needs
- Age: Infants, children, adults, and the elderly have different needs.
- Gender: Males may require more calories.
- Physical activity: Athletes need more protein and energy.
- Health: Illness, pregnancy, and recovery increase nutritional demand.
- Lifestyle: Stress, sleep, and habits impact metabolism and nutrient use.
Tips for Healthy Eating Habits
- Eat a variety from all food groups daily
- Focus on whole foods and fresh produce
- Use healthy oils and limit trans fats
- Stay hydrated (1.5–2 L/day)
- Minimize sugar, salt, and processed snacks
- Eat smaller, frequent meals
- Always have a nutritious breakfast
Dietary Imbalance Can Lead To:
- Deficiency diseases: anaemia, scurvy, rickets
- Metabolic disorders: diabetes, obesity
- Mental health issues: eating disorders
- Weakened immunity and frequent illness
Quick Tip