A1. Nutrients are various organic and inorganic substances required by the organism to carry out their functions.
A2. The process by which the organisms synthesis their own food using carbon dioxide and water is called autotrophic nutrition. For example, green plants, sulphur bacteria, etc.
A3. The process of nutrition where the organisms obtain their food from other organisms. For example, most of the bacteria, fungi and all animals. They are all dependent on autotrophs directly or indirectly.
A4. Photosynthesis requires the radiant energy of the sun, chlorophyll, carbon dioxide, water and minerals.
A5. Many processes like respiration, combustion, volcanic activity, etc. release carbon dioxide into the atmosphere. This carbon dioxide of the atmosphere is used by the terrestrial plants and the hydrophytes use the carbon dioxide dissolved in the water.
A6. Minerals like magnesium form essential compounds such as chlorophyll. Hence, they are important for photosynthesis.
A7. The nutrition that involves the taking in of solid or liquid (in case of fluid feeders) particles of food which have to be further broken down into simpler particles inside the organism. These particles may be big or small.
A8. Saprotrophs are organisms that feed on dead and decaying matter. They secrete substances that decompose the dead matter and then take in the food. For example: Rhizopus, musroom, etc.
A9. Heterotrophic nutrition is broadly classified as holozoic, saprotrophic and parasitic.
A10. Haemoglobin is the respiratory pigment that transports oxygen to the body cells for cellular respiration. Therefore, deficiency of haemoglobin in blood can affect the oxygen supplying capacity of blood. This can lead to deficiency of oxygen in the body cells. It can also lead to a disease called anaemia. The average haemoglobin content of blood, irrespective of sex, is 14.5 gm per 100 mL.
A2. Photosynthetic reaction centers are the core area of a plant responsible for capturing photons of light and transforming that into energy needed for growth. These centers are a combination of pigments, proteins, and other co-factors.
All green plants have two photosynthetic reaction centers. One is called photosystem Iand the other is called photosystem II. These centers are very complex, and are as yet not well understood by science. Algae has only a single reaction center, and because it contains fewer proteins and is much less complex, it is better understand.
