An organism uses outside raw materials mostly in the form of food and oxygen. The raw materials required by an organism can be quite varied depending on the complexity of the organism and its environment.
When water enters the guard cells, they become turgid. This results in opening of stomatal pore. When water exits from the guard cells, they become flaccid. This results in closing of stomata
Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be shown by following equation:
The whole process of Photosynthesis is composed of following steps:
(a) Absorption of light energy by chlorophyll
(b) Conversion of light energy into chemical energy
(c) Splitting of water molecules into hydrogen and oxygen.
(d) Reduction of carbon dioxide to form carbohydrate
These steps need not take place one after another immediately. For example;
desert plants take up carbon dioxide at night to make an intermediate. During daytime, they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.
The availability of oxygen is much less in aquatic environment than in terrestrial environment. Due to this, aquatic organisms need to work harder to obtain oxygen. Hence, rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
Fats are present in the form of large globules in the small intestine. The small intestine receives the secretions from the liver and the pancreas. The bile salts (from the liver) break down the large fat globules into smaller globules so that the pancreatic enzyme lipase can easily act on them. This is referred to as emulsification of fats. This process takes place in the small intestine.
Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reasons for your answer.
If leaves of a healthy potted plant are coated with Vaseline, it will clog the stomatal pores on leaves. Blockage of stomata will stop transpiration and exchange of gases from leaves. Transpiration plays an important role in ascent of sap in plants. Hence, lack of transpiration will stop ascent of sap. Moreover, stoppage of exchange of gases would also stop respiration and photosynthesis in leaves. This will result in death of leaves and finally the plant would die due to lack of food.