Life Processes in Biology

Life Processes

• Living organisms require energy for various processes, such as growth, movement, and repair.
• This energy comes from food, which is obtained from the environment.
• The process of obtaining and breaking down food is called nutrition.
• Depending on the type of food source, organisms use distinct nutritional processes.
• Autotrophs can synthesize their own food from inorganic sources like carbon dioxide and water.
• Ex: Green plants & certain bacteria.
• Heterotrophs depend on autotrophs for their energy requirements.
• Ex: Animals and fungi.
• Photosynthesis is the process used by autotrophs to convert light energy into chemical energy in the form of carbohydrates.
• The key components of photosynthesis are chlorophyll, sunlight, carbon dioxide, and water.
• Chlorophyll is a green pigment present in chloroplasts, which are organelles found in plant cells.
• Sunlight provides the energy for the conversion of carbon dioxide and water into carbohydrates.
• Carbon dioxide is absorbed from the atmosphere through tiny pores called stomata present on leaves.
• Water is absorbed from the soil through roots.
• Carnivores have a shorter small intestine compared to herbivores.
• Herbivores have a longer small intestine to digest cellulose.
• Bile juice from the liver emulsifies fats, breaking them down into smaller globules that can be acted upon by enzymes.
• The pancreas secretes pancreatic juice containing enzymes like trypsin (for protein digestion) and lipase (for fat digestion).

Respiration

• Respiration is the process of breaking down food molecules to release energy, which is used for various life processes.
• Oxygen is typically used in this process, although some organisms use other substances.
• The energy released during the breakdown of food molecules is stored in the form of ATP (adenosine triphosphate).
• ATP is the primary energy currency for living organisms.

Human Digestive System

• The human digestive system is a complex system that breaks down food into smaller molecules which can be absorbed and used by the body..
• It is composed of several organs, including the mouth, esophagus, stomach, small intestine, large intestine, and rectum.
• Mouth: Where food enters the digestive system and initial breakdown occurs through chewing and saliva.
• Esophagus: A muscular tube that transports food from the mouth to the stomach.
• Stomach: An organ that churns food, mixes it with gastric juices, and begins the digestion of proteins.
• Small intestine: Site of the majority of nutrient absorption.
• Large intestine: Absorbs water and forms wastes.
• Rectum: Stores waste until it is eliminated from the body.
• Liver: Produces bile, which helps to emulsify fats.
• Pancreas: Produces pancreatic juices that aid in the digestion of carbohydrates, proteins, and fats.
• Digestive enzymes: These catalysts help break down complex food molecules into smaller, simpler ones that can be absorbed by the body.
• The digestive system is tightly regulated by hormones like gastrin and secretin, which coordinate digestion and ensure the appropriate release of enzymes and other digestive fluids.