NUTRIENT AND GAS EXCHANGE

• Nurient required for the growth and maintenance of an organism

  Nutrientrequired for the growth and maintenance of an organismfor the growth and maintenance of an organism
• Types of organisms based on mode of nutrition

  • Autotrophs
  • Heterotrophs
• Autotrophs


  obtain energy from sunlight and chemicals to produce their own food
• Autotrophs


  • Plants
  • Chemosynthetic bacteria
• Heterotrophs


  Organisms that cannot make their own food
• Heterotrophs


  • Animals
  • Fungi
• Nutritional requirements of plants

  • Water
  • Carbon dioxide
  • Essential nutrients or elements
• Macronutrients


  Nutrients normally required in amounts above 0.5% of the plant's dry weight
• Micronutrients


  Nutrients required in minute or trace amounts
• Routes for absorption of water and minerals across plant roots

  • Symplast route
  • Apoplast route
• Symplast route


  Through plasmodesmata
• Apoplast route


  Along cell walls
• Specialized absorptive structures in plants

  • Root hairs
  • Root nodules
  • Mycorrhizae
• Root hairs


  Slender extensions of specialized epidermal cells
• Root nodules


  where bacterial cells exist symbiotically with the plant
• Mycorrhizae


  A symbiotic interaction
• Calorie


  A unit of energy that indicates the amount of energy contained in food
• Calorie specifically refers to the amount of heat energy required to raise the temperature of 1 kg (2.2 lb.) of water by 10C (1.80F)
• The greater the number of Calories in a quantity of food, the greater energy it contains
• Nutritional requirements of animals

  • Carbohydrates
  • Proteins
  • Fats
• 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, obtained from oils, margarine, butter, fried foods, meat, and processed snack foods, contain 9 Calories per gram
• Essential nutrients for animals

  • Essential amino acids
  • Essential fatty acids
  • Vitamins
  • Trace elements or minerals
• Essential amino acids


  Needed for synthesis of proteins and enzymes, 8 that could not be synthesized by humans: lysine, tryptophan, threonine, methionine, phenylalanine, leucine, isoleucine and valine
• Essential fatty acids


  Used for making special membrane lipids, an example is linoleic acid in humans
• Vitamins


  Organic molecules required in small amounts for normal metabolism, include fat-soluble Vitamins A, D, E, K, and water-soluble Vitamins B, B2, B3, B12, C
• Trace elements or minerals

  Inorganic nutrients needed by the body in minute amounts, form part of enzymes, body tissues, and body fluids, examples include iodine, cobalt, zinc, molybdenum, manganese, selenium
• Different types of animals based on feeding mechanisms

  • Substrate-feeders
  • Filter-feeders
  • Fluid-feeders
  • Bulk-feeders
• Substrate-feeders


  Animals that live in or on their food source
• Substrate-feeders


  • Earthworms that feed through the soil where they live in
  • Caterpillars that eat through the leaves where they live on
• Filter-feeders


  Aquatic animals which draw in water and strain small organisms and food particles present in the medium
• Filter-feeders


  • Whales
  • Coelenterates
• Fluid-feeders


  Animals that suck fluids containing nutrients from a living host
• Fluid-feeders


  • Mosquitoes
  • Leeches
  • Head lice
  • Aphids
• Bulk-feeders


  Animals that 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
• Bulk-feeders


  • Snakes
  • Cats
  • Humans
• Different kinds of digestive compartments in animals

  • Food vacuoles in unicellular organisms
  • Gastrovascular cavity or incomplete digestive system
  • Complete digestive system
• Food vacuoles in unicellular organisms

  These fuse with lysosomes that contain hydrolytic enzymes
• Food vacuoles in unicellular organisms

  • Food vacuole in a protozoa like Paramecium