Science:1

• Topics


  • The Digestive System
  • Cellular Reproduction
  • Biodiversity
• Digestive system


  Where the body breaks down food and absorbs nutrients
• Food movement through digestive tract


  Wavelike muscle contraction (peristalsis)
• Organs of the digestive system


  • Mouth
  • Salivary glands
  • Tongue
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestine
  • Pancreas
  • Liver
  • Gallbladder
  • Large intestine
  • Rectum
  • Anus

  
• Mouth


  Where food is ingested
• Salivary glands


  Soften and wet food in the mouth
• Tongue


  Manipulates food during chewing and swallowing
• Pharynx


  Serves as a passage for food and air
• Esophagus


  Receives food from the mouth when swallowing
• Stomach


  Further breaks down food through muscular contractions and gastric juices, converting it into chyme
• Small intestine


  Breaks down food using enzymes released by the pancreas and bile from the liver
• Pancreas


  Secretes digestive enzymes into the duodenum that break down protein, fats and carbohydrates
• Enzymes


  • Serve as catalysts, facilitating the chemical processes that convert food into nutrients
• Liver


  Makes a digestive juice called bile that helps break down fats
• Gallbladder


  Stores and releases bile into the small intestine
• Gallbladder removal


  Reduction of bile production that leads to poor digestion of fats
• Large intestine


  Responsible for absorption of water from the indigestible residue of food, and forms feces
• Rectum


  Stores feces until elimination through the anus
• Anus


  Where feces are expelled from the body
• Digestive processes


  1. Ingestion

  2. Mechanical digestion

  3. Chemical digestion

  4. Absorption

  5. Assimilation

  6. Excretion

  
• Ingestion


  Food is taken into the mouth where it is physically broken down by the teeth into smaller pieces
• Mechanical digestion


  Food is physically broken down into smaller pieces through actions such as chewing in the mouth and churning in the stomach
• Chemical digestion


  Involves enzymes breaking down complex molecules of carbohydrates, proteins, and fats into simpler forms for absorption
• Absorption


  Nutrients are absorbed through the walls of the small intestine into the bloodstream for distribution to cells
• Assimilation


  Absorbed nutrients are taken up and utilized by cells to support growth, repair, and maintenance of tissues and organs
• Excretion


  Undigested or unabsorbed materials, along with waste products produced during digestion, are eliminated from the body as feces
• Cell cycle

  The process by which cells grow, replicate their DNA, and divide into two daughter cells
• Stages of the cell cycle

  • Interphase
  • Mitotic phase
• Substages of interphase


  • Gap 1 (G1)
  • Synthesis (S)
  • Gap 2 (G2)
• Mitosis


  A type of cell division that produces two identical cells with the same number of chromosomes
• Stages of mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Importance of mitosis


  • Growth
  • Cell replacement
  • Repair and regeneration
• Meiosis


  A type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes
• Biodiversity


  The variety of life on Earth, encompassing all living organisms and the complex ecosystems they inhabit
• Levels of biodiversity


  • Species diversity
  • Genetic diversity
  • Ecosystem diversity
• Taxonomic levels


  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species