Tiêu đề Chapter - 1 Life_Processes.pdf ✅

SCIENCE (Biology)
BIOLOGY LIFE PROCESSES Life Processes The basic functions performed by organisms to maintain their life on Earth are called life processes. All living things perform certain life processes like growth, excretion, respiration, circulation etc. All the processes like respiration, digestion, which together keep the living organisms live and perform the job of body maintenance are called life processes. Nutrition 1. Autotrophic Nutrition ● It is the mode of nutrition in which organisms synthesise their own food from simple inorganic substances such as water and carbon dioxide. ● Green plants are autotrophs. They synthesise food by the process of photosynthesis. ● Photosynthesis is a physiological process by which plant cells containing chlorophyll produce food in the form of carbohydrates using carbon dioxide, water and light energy. Oxygen is released as a by- product of this process. ● Chlorophyll is the green pigment found in green plants. ● Chlorophyll is present in chloroplasts. ● Chloroplast is a membrane-bound oval cell organelle. ● It is enclosed by a double membrane. Its interior contains closely packed flattened sacs called thylakoids. Chlorophyll is present in the thylakoids. ● Thylakoids are arranged in piles called grana lying in a colourless ground substance called stroma. ● Cells present in the spongy mesophyll layer and the palisade layer contain chloroplasts; Life Processes Nutrition Respiration Transportation Excretion
BIOLOGY LIFE PROCESSES therefore, they are the site of photosynthesis. Chloroplast Stomata ● Stomata are minute openings present in the epidermal layers of leaves. ● They are responsible for gas exchange during photosynthesis. Process of Photosynthesis ● The palisade layer is the centre for photosynthesis. Light energy is trapped in the chlorophyll of the mesophyll cells in the palisade layer of leaves. ● The chemical equation for photosynthesis is