ICSE Class 7 Biology Chapter 04 Nutrition in Animals and Plants

Nutrition In Animals And Plants

The Primary Need For Life

Syllabus

1. Classes of foods (carbohydrates, fats, proteins) and examples of these - why the body needs them.

Vitamins - A, B group, C, D, E - sources, need, deficiency symptoms (in brief).

Minerals - iron, calcium, phosphorus, iodine - sources, need, deficiency symptoms (in brief).

Water and roughage.

Energy obtained from food is measured in calories. (Definition of calorie not required) - link with nutritional information often available on food packets. The daily requirement of calories is dependent on age and occupation.

Note: Most foods contain more than one class of foodstuff - however they may be rich in the particular group. Students need to have a clear concept about this.

2. A balanced diet - analysis of daily diet to find ways of improving the same, if needed.

3. Food fads - fast foods, additives, obesity, developing good food habits.

4. What animals eat - herbivores, carnivores, omnivores (revision).

Games involving classification of everyday foods into the groups, developing good food habits etc. These may even be developed by students with guidance from the teacher (E).

Testing raw and cooked foods for starch with a dilute aqueous solution of iodine. (Note: include dals and discuss why they test positively for starch) (E).

Testing foods for fats by rubbing them on paper (E).

Test for protein (D only).

Analysing their own food, checking if the daily diet is balanced (E).

5. Plants are the only living things that make their own food. Photosynthesis and factors that affect it - macro and micronutrients for plants - some examples - deficiency diseases in plants (e.g. nitrogen, iron).

How plants obtain their requirements for photosynthesis.

The working of the stomata.

Experiments to show the need for light and chlorophyll during photosynthesis - to be demonstrated only.

Transport of food to different parts of the plant.

Plants also use the food they make for their own growth/repair.

6. Autotrophic and heterotrophic nutrition - parasitism and symbiosis with examples.

7. Food chains, food webs - revision.

Location of vascular bundles in the stem (D).

Observing root hair in germinating seeds (E).

Food For Life

Food is a kind of "fuel" as well as a kind of building material for all living organisms. Food contains nutrients - the raw materials our body needs to build everything from muscles and bones to the brain and the heart.

We drink milk and eat different types of food like bread, chapati, rice, butter, ghee, vegetables, fruits, meat, eggs, pulses, etc. The food provides us nutritive substances for growth and energy. Good choice of foods gives the body what it needs to grow and do its daily tasks. Choosing the wrong foods deprives the body of some of the nutrients it needs to function properly.

The food provides our body:

Energy to do work.

Nutrients for the growth, repair of damaged cells and tissues.

Materials for keeping us healthy and disease-free.

Food that provides us all the above substances is a nutritive food. Such food contains various nutrients like carbohydrates, proteins, fats, minerals and vitamins. A nutrient can be defined as "a constituent of food that helps one way or the other in the body functions".

The food constituents are categorised into carbohydrates, fats and proteins as macronutrients (bulk requirement) and minerals and vitamins as micronutrients (minute requirement).

Nutrition

It is a process by which living things receive food and utilise it to grow and become healthy. Animals eat food for getting energy and nutrients, but the green plants obtain nutrients by synthesising food through photosynthesis. For an infant, food is just the mother's milk, which provides everything for growth and good health. But, as the child grows, he or she requires a variety of other items in the food so that the needs of the growing body are fulfilled.

Types Of Nutrients

Nutrients are classified into five major groups:

Carbohydrates (like rice and potato provide starch and sugar cane provides sucrose) provide energy.

Proteins (like pulses, milk, egg, etc.) to provide body building material.

Fats (like ghee, oil and butter) to provide energy.

Minerals, such as iron, sodium, calcium, phosphorus, etc., for their specific role in the body.

Vitamins are needed for the normal functioning of various body processes.

Classification Of Food

We have a variety of foods that provide us energy. A group of some foods help us in body building, while some foods are protective foods. As such, foods can be classified into three groups

Teacher's Note

Every meal we eat demonstrates these nutrient categories - a balanced lunch might include rice (carbohydrates), dal (proteins), vegetables (minerals and vitamins), and oil (fats), showing how food groups work together in daily nutrition.

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