BIO Q4

• Carbohydrates


  Serve as a major energy source for the cells in the body, usually obtained from grains, cereals, breads, fruits and vegetables, contain 4 Calories per gram
• Proteins


  Can be used as an energy source but the body mainly uses these as building materials for cell structures and as enzymes, hormones, parts of muscles, and bones, come from dairy products, poultry, fish, meat, and grains, contain 4 Calories per gram
• Fats


  Used to build cell membranes, steroid hormones, and other cellular structures, used to insulate nervous tissue, serve as an energy source, contain certain fat-soluble vitamins, obtained from oils, margarine, butter, fried foods, meat, and processed snack foods, contain 9 Calories per gram
• Essential Nutrients

  • Essential amino acids
  • Essential fatty acids
  • Vitamins
  • Trace elements or minerals
• Food Uptake in Cells via the Three Types of Endocytosis

  1. Phagocytosis

  2. Pinocytosis

  3. Receptor-mediated endocytosis
• Types of animals based on feeding mechanisms

  • Substrate-feeders
  • Filter-feeders
  • Fluid-feeders
  • Bulk-feeders
• Different kinds of digestive compartments in animals

  • Food vacuoles in unicellular organisms
  • Gastrovascular cavity or incomplete digestive system
  • Complete digestive system
• Accessory organs for digestion in a complete digestive system

  • Liver
  • Gallbladder
  • Pancreas
• 1.      liver – secretes bile for emulsifying fats.
• 2.  gallbladder – stores bile produced by the liver.
• 3.  pancreas – secretes enzymes that break down all major food molecules; secretes buffers against HCl from the stomach; secretes the hormone insulin for control of glucose metabolism.
• 1.      substrate-feeders – animals that live in or on their food source. Examples: earthworms that feed through the soil where they live in; caterpillars that eat through the leaves where they live on
• 2. filter-feeders – include many aquatic animals which draw in water and strain small organisms and food particles present in the medium. Examples: whales and coelenterates
• 3. fluid-feeders – suck fluids containing nutrients from a living host. Examples: mosquitoes, leeches, head lice, aphids
• 4. bulk-feeders – eat relatively large chunks of food and have adaptations like jaws, teeth, tentacles, claws, pincers, etc. that help in securing the food and tearing it to pieces.
• 1. Food vacuoles in unicellular organisms – these fuse with lysosomes that contain hydrolytic enzymes. Example: food vacuole in a protozoa like Paramecium.
• 2. Gastrovascular cavity or incomplete digestive system – composed of a single opening through which the food is taken in and where wastes are disposed of. It is a sac-like body cavity. Examples: cnidarian Hydra and flatworm Planaria
• 3. Complete digestive system – essentially like a tube with an opening at one end for taking in food (mouth) and an opening at the outer end where unabsorbed waste materials are eliminated (anus). In between the mouth and anus, are specialized organs that carry out transport, processing, and absorption of digested nutrients.