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Human Body Systems - Nutrition and Healthy Growth

Grade 3IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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A balanced diet provides the body with necessary nutrients for growth and repair. It includes five main groups: Carbohydrates, Proteins, Fats, Vitamins, and Minerals.

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Energy is required for all bodily functions and is measured in kilocalories (kcalkcal) or kilojoules (kJkJ).

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Carbohydrates like glucose (C6H12O6C_6H_{12}O_6) are the primary source of immediate energy for the body.

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Proteins are made of chains of amino acids and are essential for building and repairing muscle and tissues.

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Minerals such as Calcium (CaCa) are vital for strong bones, while Iron (FeFe) is necessary for healthy blood to carry oxygen (O2O_2).

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Water (H2OH_2O) makes up about 60%−70%60\% - 70\% of the human body and is essential for transporting nutrients and removing waste.

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Healthy growth requires a combination of a balanced diet, regular physical activity, and sufficient sleep.

📐Formulae

EnergyBalance=EnergyIntake−EnergyOutputEnergy_{Balance} = Energy_{Intake} - Energy_{Output}

H2O (Water)H_2O \text{ (Water)}

C6H12O6 (Glucose/Sugar)C_6H_{12}O_6 \text{ (Glucose/Sugar)}

Ca+Vitamin D→Strong BonesCa + Vitamin\ D \rightarrow Strong\ Bones

💡Examples

Problem 1:

If a child consumes 1800 kcal1800\ kcal of food in a day and uses 1800 kcal1800\ kcal through exercise and body functions, what is their energy balance?

Solution:

1800 kcal−1800 kcal=0 kcal1800\ kcal - 1800\ kcal = 0\ kcal

Explanation:

The child is in a state of energy balance. Their weight will likely remain stable because the energy consumed equals the energy expended.

Problem 2:

Why is it important to include Calcium (CaCa) in a Grade 3 student's diet?

Solution:

Calcium is used to build Ca10(PO4)6(OH)2Ca_{10}(PO_4)_6(OH)_2 (Hydroxyapatite) in bones.

Explanation:

During childhood, the body is growing rapidly. Minerals like Calcium (CaCa) are essential to ensure that the skeletal system becomes strong and dense.

Problem 3:

Identify the primary molecule the body uses for quick energy during a physical education class.

Solution:

Glucose, which has the chemical formula C6H12O6C_6H_{12}O_6.

Explanation:

Carbohydrates are broken down into simple sugars like glucose to provide the muscles with the energy needed for movement.