Level – STD 10 Science
Topic Tree
- Life process – Introduction
- Nutrition
- Respiration
- Transportation
- Excretion
INTRODUCTION
- All living things peform certain life processes.
- What is life process? – the processes that keep the living organisms alive and perform the job of body maintenance.
- Examples of life processes – growth, digestion, respiration, circulation, excretion.
NUTRITION
- Definition – The whole process by which an organism obtain its food.
- Can be broadly classified as nutrition in plants and animals.
- Nutrition in plants
- Plants are autotrophs
- can make their own food
- Nutrition in animals
- animals are heterotrophs
- depend on plants or other animals for their food
What are the modes of nutrition?
- They are autotrophic and heterotrophic
- Autotrophic
- Kind of nutrition in which carbon dioxide, water are utilized to prepare organic food by the process of photosynthesis..e.g. green plants.
- Heterotrophic
- Kind of nutrition in which organisms do not possess the ability to synthesize their own food.
- They depend on autotrophs for their food supply directly or indirectly.
- e.g. animals, fungi
Explain Autotrophic nutrition.
- The organism which carry out autotrophic nutrition are called autotrophs.
- Autotrophic nutrition is fulfilled by the process by which autotrophs absorb carbon dioxide and water.
- They are converted into carbohydrates in the presence of chlorophyll and sunlight.
- This process is called photosynthesis.
- Photon = light
- Synthesis = preparation
- Photosynthesis = synthesis of plant food in presence of light.
- Photosynthesis is represented by the following equation.
- A – Light energy
- B – Carbon dioxide
- C – Water
- D – Minerals
- E – Starch
- F – oxygen
Site of Photosynthesis
- Photosynthesis takes place in the chloroplast.
- Choroplast is present in the leaf.
- Chloroplast contains chlorophyll.
- Chlorophyll is a green pigment.
Main Events of Photosynthesis
- Absorption of light energy by chlorophyll.
- Conversion of light energy into chemical energy to split the bond of water into hydrogen and oxygen.
- On combining with carbon dioxide it is converted into carbohydrates.
- Stomata – tiny pores present on the surface of the leaves.
Functions of Stomata
- Exchange of gases – oxygen / carbon dioxide
- Looses large amount of water vapour during transpiration