Life Processes and Nutrition in Organisms

Life Processes

• Life processes are crucial for all living organisms to survive and maintain themselves.
• These processes support the upkeep and repair of an organism's body at a cellular level.
• Living organisms are made of cells, which are composed of molecules.
• Cells need a continuous supply of new materials and removal of waste to function.
• Life processes ensure the necessary supply and removal of these substances, a vital aspect of life itself.

Nutrition

• Definition: The process of obtaining food and converting it into nutrients for growth, repair, and maintenance.
• In plants: Plants create their own food through photosynthesis.
• Photosynthesis: The process where plants utilize sunlight, water, and carbon dioxide to produce glucose and oxygen.
  • Chloroplasts: Specialized structures within plant cells where photosynthesis takes place.
  • Chlorophyll: Green pigment in chloroplasts that absorbs light energy, enabling the process.
  • Process: Light activates chlorophyll, splitting water into hydrogen and oxygen. Hydrogen combines with carbon dioxide to create glucose.
• Nitrogen: Plants require nitrogen to produce proteins.
  • Source: Soil nitrogen-fixing bacteria convert atmospheric nitrogen to nitrites and nitrates.
• In humans: Food is ingested, passing through the digestive system.
  • Digestive System:
    • Mouth: Food is mechanically broken down and mixed with saliva, initiating starch digestion by salivary amylase.
    • Esophagus: Food is transported to the stomach through peristaltic contractions.
    • Stomach: Food is mechanically further broken down, and mixed with gastric juice containing pepsin (protein digestion), hydrochloric acid (creating acidic conditions for pepsin), and mucus (protecting stomach lining).
    • Small Intestine: The major site of digestion and nutrient absorption.
      • Pancreatic Juice: Contains enzymes for digesting carbohydrates, fats, and proteins.
      • Intestinal Juice: Further breaks down food through specialized enzymes.
      • Bile: Produced by the liver, emulsifies fats to enhance digestion and absorption.
      • Villi: Small finger-like projections lining the small intestine that increase the surface area for absorption.
    • Large Intestine: Absorbs water from undigested material.
    • Anus: Eliminates waste.

Respiration

• Definition: The process of obtaining oxygen and releasing carbon dioxide from the body.
• Purpose: Respiration releases energy from food, mainly glucose.
• Types:
  • Aerobic Respiration: Requires oxygen, breaking down glucose into water, carbon dioxide, and energy.
  • Anaerobic Respiration: Occurs without oxygen, yielding less energy. Lactic acid is produced in animals and ethanol/carbon dioxide is a product in yeast fermentation.
• Breathing: The process of inhaling and exhaling air.
  • In Plants: Gas exchange through stomata.
  • In Humans: The respiratory system is involved:
    • Air enters through nostrils, moving through the nasal cavity for filtering, warming, and moistening.
    • Passes into the windpipe (trachea), two bronchi leading to the lungs.
    • Bronchioles are smaller branches within the lungs.
    • Gas exchange occurs in alveoli (tiny air sacs), where oxygen diffuses into the blood, and carbon dioxide out.
    • Hemoglobin (present in red blood cells) carries oxygen.

Transportation

• Definition: The movement of materials throughout an organism.
• In Humans:
  • Circulatory System: The heart pumps blood through blood vessels.
    • Right Side: Receives deoxygenated blood and pumps it to the lungs.
    • Left Side: Receives oxygenated blood and pumps it to the body.
    • Double Circulation: Blood passes through the heart twice for a complete circuit.
    • Arteries: Carry oxygen-rich blood away from the heart.
    • Veins: Carry oxygen-poor blood towards the heart.
    • Capillaries: Tiny vessels connecting arteries and veins, facilitating exchange of materials.
  • Lymphatic System: A system of vessels carrying lymph (colorless fluid).
    • Absorbs digested fats from the intestines.
    • Collects fluid from tissues to return to the bloodstream.
• In Plants:
  • Xylem: Transports water and minerals from roots to other parts.
  • Phloem: Transports food (glucose) from leaves to other parts.
  • Translocation: Movement of materials through phloem.
  • Water Movement in Xylem:
    • Root Pressure: Water pushed up the xylem due to root cell pressure.
    • Transpiration: Water evaporation from leaves pulls water upwards.
    • Active Transport: Ions pumped in root cells to drive water uptake, supporting upward pressure flow.

Excretion

• Definition: Removal of waste products from the body.
• In Humans: The excretory system carries waste through the body.
  • Kidneys: Filter waste from the blood, producing urine.
    • Contain nephrons which have a glomerulus (capillary cluster) and Bowman's capsule.
  • Ureters: Carry urine from the kidneys to the bladder.
  • Bladder: Stores urine until excretion.
  • Urethra: Transports urine out of the body.
  • Urine: Contains waste products (urea, uric acid, creatinine), dissolved salts, and water.

Explore the essential life processes that enable living organisms to survive, including nutrition, photosynthesis, and cellular maintenance. This quiz covers key concepts of how organisms obtain and utilize food, with a focus on plant processes. Understand the role of chloroplasts and chlorophyll in these vital functions.