Nutrition

• Nutrient


  Any substance required for the growth and maintenance of an organism
• Types of organisms based on mode of nutrition

  • Autotrophs
  • Heterotrophs
• Autotrophs


  Organisms that obtain energy from sunlight and chemicals to produce their own food.
• Heterotrophs


  Organisms that cannot make their own food and obtain their energy from other organisms. Examples: animals, fungi
• Nutritional requirements of plants

  • Water
  • Carbon dioxide
  • Essential nutrients or elements (macronutrients and micronutrients)
• Plant's fresh mass


  • 80-90% is water
• Plant's dry mass


  • 4% is inorganic substances from soil
  • 96% is from CO2 assimilated during photosynthesis

  
• Macronutrients


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


  Nutrients required in minute or trace amounts
• Common mineral deficiencies in maize leaves

  • Phosphate-deficient
  • Potassium-deficient
  • Nitrogen-deficient
• Apoplast


  Everything external to the plasma membrane
• Symplast


  The cytosol of the living cells in a plant, as well as the plasmodesmata
• Root hairs


  • Slender extensions of specialized epidermal cells that greatly increase the surface area available for absorption

  
• Root nodules


  • Localized swellings in roots of certain plants where bacterial cells exist symbiotically with the plant. The bacteria help the plant fix nitrogen and the bacteria utilize organic compounds provided by the plant

  
• Nutritional adaptations by plants

  • Mycorrhizae
  • Plant parasites
  • Saprophytes
  • Symbionts
  • Epiphytes
  • Insectivorous plants
• Mycorrhizae


  Symbiotic relationship between fungi and plant roots where the plant obtains phosphate and other minerals, and the fungus obtains nutrients like sugars from the plant root
• Plant parasites


  Parasitic plants that depend on their host for survival, obtaining water and nutrients through connections
• Saprophytes


  Plants that do not have chlorophyll and get their food from dead matter, using enzymes to convert organic food materials into simpler forms
• Symbionts


  Plants in a symbiotic relationship, with special adaptations like mycorrhizae or nodule formation
• Epiphytes


  Plants that grow on other plants, but are not dependent on the other plant for nutrition
• Insectivorous plants


  Plants with specialized leaves to attract and digest insects, like the Venus flytrap

  
• Types of animals based on feeding

  • Herbivores
  • Carnivores
  • Omnivores
• Most animals are also opportunistic feeders
• Calorie


  A unit of energy that indicates the amount of energy contained in food, specifically the amount of heat energy required to raise the temperature of 1 kg of water by 1°C
• 2 specialized absorptive structures of plants

  • Root hairs
  • Root nodules
• What is this deficient?

  Phosphate-deficient

  
• What is this deficient?

  Potassium-deficient

  
• What is this deficient?

  Nitrogen-deficient

  
• The greater the number of calories in a quantity of food, the greater the energy it contains. (Johnson and Raven, 1996)
• Nutritional requirements of animals

  • Carbohydrates
  • Proteins
  • Fats
  • Essential Nutrients (includes essential amino acids, essential fatty acids, vitamins, trace elements or minerals)
• Three types of endocytosis

  • phagocytosis
  • pinocytosis
  • receptor-mediated endocytosis
• Types of animals based on feeding mechanisms

  • Substrate-feeders (animals that live in or on their food source)
  • Filter-feeders (include many aquatic animals which draw in water and strain small organisms and food particles present in the medium)
  • Fluid-feeders (suck fluids containing nutrients from a living host)
  • 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)
• Different kinds of digestive compartments in animals

  • Food vacuole in unicellular organisms (these fuse with lysosomes that contain hydrolytic enzymes)
  • Gastrovacsular cavity or incomplete digestive system (composed of a single opening through which food is taken in and where wastes are disposed of; it is a saclike body cavity)
  • Complete digestive system (essentially like a tube with an opening at one end for taking in food (mouth) and an opening at the other end where unabsorbed waste materials are eliminated (anus))
• Accessory organs for digestion in a complete digestive system

  • liver (secretes bile for emulsifying fats)
  • gallbladder (stores bile produced by the liver)
  • pancreas (secretes enzymes that break down all major food molecules)
• What type of digestive compartment?

  Gastrovascular cavity or incomplete digestive system

  
• What type of digestive compartment?

  Food vacuoles in unicellular organisms

  
• Proteins can also 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. Like carbohydrates, proteins also contain 4 Calories per gram.
• Carbohydrates serve as a major energy source for the cells in the body. On average, carbohydrates contain 4 Calories per gram.
• Fats are used to build cell membranes, steroid hormones, and other cellular structures; also used to insulate nervous tissue, and also serve as an energy source. They contain a higher amount of energy per gram than carbohydrates or proteins, about 9 Calories per gram.
• What nutritional adaptation?

  Saprophytes