Life Process

• Life Processes:

  • Living organisms need energy to perform various life processes
  • Energy is obtained from food, which acts as fuel for living organisms
  • Nutrition is the process of intake and utilization of nutrients by an organism
  • Nutrients include carbohydrates, fats, proteins, minerals, vitamins, and water
• • Holozoic nutrition: Ingesting complex organic food materials, digesting, and absorbing them (e.g., human beings)
• Modes of Nutrition:

  • Autotrophic mode of nutrition: Organisms make their own food from inorganic materials like carbon dioxide and water using sunlight energy (autotrophs)
  • Heterotrophic mode of nutrition: Organisms cannot make their own food and depend on other organisms for food (heterotrophs)
  • Types of Heterotrophic Nutrition:
  • Saprotrophic nutrition: Obtaining food from decaying organic matter (saprophytes)
  • Parasitic nutrition: Deriving food from another living organism without killing it (parasites)
• Photosynthesis in Plants:

  • Green plants are autotrophic and synthesize their own food through photosynthesis
  • Photosynthesis involves making food from carbon dioxide and water using sunlight energy and chlorophyll
  • Oxygen is released during photosynthesis
  • Raw materials for photosynthesis: Carbon dioxide and water
  • Plants obtain carbon dioxide through stomata on leaves and water through roots via osmosis
• Conditions for Photosynthesis:

  • Sunlight, chlorophyll, carbon dioxide, and water are necessary for photosynthesis
  • Green leaves make starch as food, which gives a blue-black color with iodine solution
  • Nitrogen, phosphorus, iron, and magnesium are also essential for plant growth and obtained from the soil
• Site of Photosynthesis:

  • Chloroplasts in the mesophyll cells of green plants contain chlorophyll for photosynthesis
  • Experiments show that green leaves make starch as food, which confirms the occurrence of photosynthesis
  • Chloroplasts convert sunlight energy into chemical energy by making carbohydrates
• Nutrition in Animals:

  • Animals are heterotrophs and depend on other organisms for food
  • Animals can be divided into three groups based on their
• Animals are heterotrophs and depend on other organisms (plants and other animals) for their food
• All animals can be classified into three groups based on their food habits: Herbivores, Carnivores, Omnivores
• The process of obtaining food by Amoeba is called phagocytosis
• The process of taking food into the body is called ingestion, while the process in which the undigested food is removed from the body is called egestion
• All the processes of nutrition are performed by the single cell in unicellular animals, and Paramecium is one such animal which lives in water
• The process in which the absorbed food is taken in by the body cells and used for energy, growth and repair is called assimilation
• The various organs of the human digestive system in sequence are: Mouth, Oesophagus, Stomach, Small intestine, and Large intestine
• The stomach is a J-shaped organ present on the left side of the abdomen
• The gastric juice contains three substances: Hydrochloric acid, the enzyme pepsin, and mucus
• The small intestine in human beings is the site of complete digestion of food (like carbohydrates, proteins, and fats) and it receives the secretion of two glands: Liver and Pancreas
• The process in which the food containing large, insoluble molecules is broken down into small, water-soluble molecules is called digestion, while the process in which the digested food passes through the intestinal wall into the bloodstream is called absorption
• The small intestine is the main region for the absorption of digested food
• In water-logged conditions, soil air becomes deficient
• In the absence of oxygen, metabolic activity of the root declines and the plant may wither
• Stems of herbaceous plants have stomata for gas exchange
• Oxygen from air diffuses into the stem of a herbaceous plant through stomata for respiration
• Carbon dioxide gas produced during respiration diffuses out into the air through stomata
• In woody stems, the bark has lenticels for gaseous exchange
• Leaves of a plant have tiny pores called stomata for gas exchange
• During the day, oxygen diffuses out and carbon dioxide diffuses in the leaves
• At night, oxygen diffuses in and carbon dioxide diffuses out in the leaves
• Amoeba exchanges gases through its cell membrane via simple diffusion
• Amoeba uses oxygen for respiration and produces carbon dioxide gas
• Earthworm exchanges gases through its skin
• Fish breathes through gills, extracting oxygen from water
• Human respiratory system includes: Nose, Nasal passage, Trachea, Bronchi, Lungs, and Diaphragm
• Mechanism of respiration involves oxygen diffusing into blood from alveoli and carbon dioxide diffusing out
• Rate of breathing is controlled by the respiratory system of the brain
• Average breathing rate in an adult man at rest is about 15 to 18 times per minute
• Normal range of haemoglobin in the blood of a healthy adult person is from 12 to 18 grams per deciliter of blood
• Deficiency of haemoglobin in the blood reduces oxygen carrying capacity, resulting in breathing problems, tiredness, and lack of energy
• Carbon monoxide poisoning occurs when carbon monoxide binds strongly with haemoglobin, preventing oxygen transport in the body