LIFE PROCESSES -1.pptx

Life Processes Class X Science

1. BIOLOGY SECTION CLASS X CHAPTER 6 - LIFE PROCESSES PART -1

2. Is invisible movements of molecules (molecular movement) necessary for life?  Molecular movement is definitely essential or necessary for life. For example movement of oxygen, carbon dioxide, water, glucose, nitrogenous substances, proteins, vitamins, minerals etc. in the body of organisms. Viruses don't show any molecular movement out of the host cells.  They are nonliving entity out of the host. They can be crystallized. They only behave as a living being when they infect a cell. That is why, viruses are also known as a connective link between living and nonliving things.

3. Why are molecular movement needed for life? Living organisms are well organised structures. They can have organs. Organs are made up of tissues. Tissues are made up of cells. And cells have smaller components called organelles etc. Living creatures must keep repairing and maintaining their structures. Since, all the structures are made up of molecules like proteins, lipids, nucleic acid etc., the organisms must move molecules around all the time.

4. What are the maintenance processes in living organisms? All the processes that work together for the proper functioning of body by providing required substances for the growth and repair of the tissues, organs etc and for the energy, preventing damage and breakdown. What are life processes? The processes which together perform the maintenance job and that provide energy for these processes to prevent damage and breakdown are together called life processes. Such as nutrition, respiration, excretion, transportation etc.

5. Nutrition : The energy comes from outside the body of the individual organisms. The source of energy is transferred from outside of  the body of the organisms to the inside through the process called nutrition. Nutrition is the mode of taking food. The mode of Nutrition is divided  into two main categories such as autotrophic mode of nutrition e.g. plants) and heterotrophic mode of nutrition (e.g. animals).   Since life on the earth depends on carbon based molecules most of these food sources are also carbon based.

6. Oxidising - reducing reactions are some of the most common chemical means to break down molecules . For the breakdown of food sources, oxygen is required from the outside of body. Respiration : The process of the breakdown of  source of energy (food) (in presence or absence of oxygen) is known as respiration. If the breakdown of source of energy takes place in absence of oxygen it is known as anaerobic respiration. Less energy is released in this process. (In yeast). If the breakdown of source of energy takes place in presence of oxygen,  it is known as aerobic respiration. More energy is released in this process.(In most of the organisms)

7. In case of single celled organisms no specific organs for taking in food, exchange of gases or removal of wastes may be needed because the entire surface of the organism is in direct contact with the environment. But in case of multicellular organisms all the cells may not be in direct contact with the surrounding environment. Thus, simple diffusion will not meet the requirement of all the cells. Hence, the multicellular organisms need special organ system to perform these life processes. Such as transportation system, excretory system, digestive system etc. Note: All the basic materials already present in the environment that can be used by organism as such are termed as raw materials such as oxygen, carbon dioxide, water, some salt etc.

8. Excretion : When chemical reactions use the carbon  source and the oxygen for energy generation, they create by-products that are not only useless for the cells of the body but could even be harmful. These waste byproducts are therefore needed to be removed from the body and discarded outside by a process called excretion. Thus, excretion is the process of discarding and removal of useless and harmful byproducts from the body. Note: Oxidising reaction: Addition of oxygen or removal of hydrogen takes place. Reducing reaction: Removal of oxygen or addition of hydrogen takes place.

9. All the biochemical processes taking place in the body of organisms can be categorised as metabolic processes ( metabolism ). The metabolic processes can be further categorised into two types: Anabolic process ( anabolism ) and catabolic process ( catabolism ). Anabolism creates molecules the body needs for functionality and it uses energy in the process. e.g. photosynthesis. Catabolism , on the other hand, breaks down complex molecules and releases energy which is available for the body to use. e.g. respiration .

10. QUESTIONS Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans? What criteria do we use to decide whether something is alive? What are outside raw materials used for by an organisms? What processes would you consider essential for maintaining life? Define the term aerobic and anaerobic respiration. What do you mean by nutrition and excretion?