lesson-food (POST 1)

Good morning boys! Welcome to the first class of science in class 7. 
The lesson we going to study is -Food. We all eat food everyday. Can you  recollect ,why do we need food?
You have learnt in your earlier classes that food contains useful substance that our body needs, which are called nutrients. The five nutrients are carbohydrates, proteins, fats,vitamins and minerals.
Each food is rich in one nutrient even though it may contain more than one nutrient.
TRY THIS !
Recollect the names of  5 foods that are rich in one nutrient each.
For example, rice is rich in carbohydrate, egg is rich in protein.

LEARNING OUTCOMES OF THIS CLASS
By the end of this class you will be able to -
.name the two modes of nutrition in organisms
.name the raw materials required for photosynthesis 
.write the word equation of photosynthesis
.list the factors that effect the rate of photosynthesis

We eat food to get energy,which is stored in food materials as chemical energy. The process of taking food and its utilization by the body is called nutrition.

MODES OF NUTRITION IN LIVING ORGANISMS
The  two main modes of nutrition in living organisms are- Autotrophic and heterotrophic nutrition.
- Autotrophic nutrition -   It is the  mode of nutrition in which organisms make their own food. These  organisms are called autotrophs or producers. All green plants are autotrophs.


STUDY THE PICTURE GIVEN ABOVE THAT EXPLAINS THE PROCESS OF PHOTOSYNTHESIS AND ANSWER THE QUESTIONS GIVEN BELOW

1. Name the three things a pant needs for the process of  photosynthesis.
2. What are the two things produced as a result of photosynthesis ?

So ,photosynthesis is process by which green plants prepare their own food.

Carbondioxide + water ...sunlight ,chlorphyll..............>  Glucose + oxygen
(from the air)                         (from the soil)

Plants take in carbon dioxide from the air and give out oxygen from the leaves through tiny pores present on the under surface of the leaves called stomata.
HOTS!!
1.Can a non green leaf produce food ?
2. Can a plant kept in a dark room photosynthesize ?

The following factors affect the process of photosynthesis -
1. As the light intensity is increased ,the rate of photosynthesis increases. But at higher intensity of light , the rate of photosynthesis becomes limiting.
2. Blue and red regions of the visible light are most effective for photosynthesis.
3.Poor availability of carbon dioxide and water lowers the rate of photosynthesis.
4. Temperature does not effect photosynthesis.

HOMEWORK-
1. Learn  the terms - (i) nutrition  (ii) photosynthesis (iii) stomata (iv) autotrophs
2. Learn the word equation of photosynthesis.

SDG - ZERO HUNGER
Reflect... there is enough for everyones need but not for everyones greed. What measures can we take to ensure no one is hungry (starves )?