plants and animals

• Nutrient Procurement and Processing

  Nutrient procurement and processing in plants and animals
• 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 can produce their own food. They obtain energy from sunlight or inorganic chemicals and convert it into organic compounds through photosynthesis or chemosynthesis.
• Autotrophs


  • Plants
  • Chemosynthetic bacteria
• Heterotrophs


  Organisms that cannot synthesize their own food and rely on other organisms for their energy and nutrient requirements.
• Heterotrophs


  • Animals
  • Fungi
• Nutritional requirements of plants

  • Water
  • Carbon dioxide (CO2)
  • Essential nutrients or elements
• Macronutrients


  Nutrients required in relatively large amounts, typically present in plant tissues above 0.5% of the plant's dry weight. Examples: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), and sulfur (S).
• Micronutrients


  Essential nutrients required in minute or trace amounts by plants. Examples: chlorine (Cl), iron (Fe), boron (B), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), and cobalt (Co).
• Absorption of water and minerals across plant roots

  1. Symplast route

  2. Apoplast route
• Symplast route


  • Movement of water and minerals through the symplast (interconnected cytoplasmic continuum of plant cells)
  • Utilizes plasmodesmata (cytoplasmic channels connecting adjacent cells)
  • Reaches the endodermis and passes through the Casparian strip
  • Enters the xylem
• Apoplast route


  • Movement of water and minerals through the cell walls and intercellular spaces
  • Bypasses the endodermis
  • Enters the xylem
• Root hairs


  • Slender extensions of specialized epidermal cells that increase the surface area for nutrient absorption
• Root nodules


  • Localized swellings on the roots of legumes, formed due to a symbiotic relationship with nitrogen-fixing bacteria
  • Bacteria convert atmospheric nitrogen into a form usable by the plant
  • Plant provides carbohydrates and other organic compounds to the bacteria
• Mycorrhizae


  • Mutually beneficial association between plant roots and certain types of fungi
  • Ectomycorrhizae: Fungal hyphae form a sheath-like structure around the root tips
  • Endomycorrhizae (Arbuscular mycorrhizae): Fungal hyphae penetrate the root cells, forming arbuscules
• Nutritional adaptations by plants

  • Symbiosis with soil microbes (nitrogen fixation, phosphorus and nutrient acquisition)
  • Symbiosis with fungi (mycorrhizal associations)
  • Parasitism (obtaining nutrients from host plants)
  • Predation (capturing and digesting small animals)
• Mutualism


  • Fungal hyphae extend into the soil, accessing nutrients that may be otherwise inaccessible to the plant
  • Plant supplies the fungi with carbohydrates
• Parasitism


  Plants obtain nutrients from other living organisms through parasitic relationships
• Parasitic plants


  • Have specialized structures, such as haustoria, which penetrate the host's tissues to extract water, minerals, and carbohydrates
  • Examples include mistletoe and dodder
• Predation


  • Plants have evolved to capture and digest small animals to acquire nutrients
  • Carnivorous plants have specialized structures to attract, trap, and digest insects and other small organisms
• Calorie


  Unit of energy that indicates the amount of energy contained in food
• A Calorie is the amount of heat energy required to raise the temperature of 1 kg (2.2lb.) of water by 1oC (1.8oF)
• The greater the number of Calories in a quantity of food, the greater energy it contains
• Macronutrients


  Carbohydrates, proteins, and fats
• Carbohydrates


  Provide approximately 4 calories per gram
• Proteins


  Provide approximately 4 calories per gram
• Fats


  Provide approximately 9 calories per gram
• Alcohol


  Provides approximately 7 calories per gram
• Carbohydrates


  • Serve as a major energy source for the cells in the body
  • Usually obtained from grains, cereals, breads, fruits, and vegetables
• 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
• Fats


  • Used to build cell membranes, steroid hormones, and other cellular structures
  • Used to insulate nervous tissue, and also serve as an energy source
  • Obtained from oils, margarine, butter, fried foods, meat, and processed snack foods
• Essential Nutrients


  • Essential amino acids
  • Essential fatty acids
  • Vitamins
  • Trace Elements or Minerals
• Essential amino acids


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


  • Used for making special membrane lipids
  • Example is linoleic acid in humans
• Vitamins


  • Organic molecules required in small amounts for normal metabolism
  • Examples 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
• Phagocytosis


  Engulfment of organic fragments or big particles, e.g. Pseudopod formation in Amoeba
• Pinocytosis


  Uptake of extracellular fluid by a cell using small vesicles derived from the plasma membrane
• Receptor-mediated endocytosis


  Relies on membrane receptor recognition of specific solutes which are then taken up by the cell via receptor-coated pits