plants and animals/digestive system

• 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
• Water


  An essential nutrient for plants. It serves as a medium for various biochemical reactions, transports nutrients within the plant, and helps maintain turgidity and structural integrity.
• Carbon Dioxide (CO2)


  Another vital nutrient for plants. During photosynthesis, plants use carbon dioxide from the atmosphere as a raw material to produce glucose and other organic compounds.
• Essential nutrients or elements for plants

  • Macronutrients (carbon, hydrogen, oxygen, nitrogen, potassium, calcium, magnesium, phosphorus, sulfur)
  • Micronutrients (chlorine, iron, boron, manganese, zinc, copper, molybdenum, cobalt)
• Macronutrients


  Required in relatively large amounts and are typically present in plant tissues above 0.5% of the plant's dry weight. Involved in various physiological processes, such as energy transfer, structural support, and enzyme activity.
• Micronutrients


  Essential nutrients required in minute or trace amounts by plants. Although they are required in smaller quantities, they are equally important for plant growth and development. Function as cofactors for enzymes and play crucial roles in various metabolic processes.
• Absorption of water and minerals across plant roots

  1. Symplast route (through the cytoplasmic continuum of plant cells)

  2. Apoplast route (through the cell walls and intercellular spaces)
• Symplast route


  • Involves the movement of water and minerals through the symplast, utilizing specialized channels called plasmodesmata
  • Water and minerals enter the root hairs
  • Move through the symplast to the endodermis
  • Casparian strip blocks movement through cell walls, forcing passage through plasma membranes
  • Passage into the xylem
• Apoplast route


  • Involves the movement of water and minerals through the cell walls and intercellular spaces
  • Water and minerals enter the root hairs
  • Move through the apoplast, bypassing the endodermis
  • Entry into the xylem
• Root hairs


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


  • Localized swellings on the roots of certain plants, particularly legumes, due to a symbiotic relationship with nitrogen-fixing bacteria
  • Plant benefits: Bacteria convert atmospheric nitrogen into a form that can be used by the plant
  • Bacterial benefits: Receive a source of energy and nutrients from the plant
• 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 highly branched structures called arbuscules
• Symbiosis of plants and soil microbes


  1. Nitrogen fixation by bacteria in root nodules

  2. Phosphorus and nutrient acquisition by mycorrhizal fungi
• Symbiosis of plants and fungi


  • Mycorrhizal fungi enhance the plant's ability to absorb water and nutrients, especially phosphorus and other minerals, from the soil
• Parasitism


  • Some plants obtain nutrients from other living organisms through parasitic relationships, using specialized structures like haustoria to extract water, minerals, and carbohydrates
• Predation


  • Carnivorous plants capture and digest small animals to acquire additional nutrients, such as nitrogen
• 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


  • Mistletoe
  • Dodder
• Carnivorous plants


  • Have specialized structures to attract, trap, and digest insects and other small organisms
  • Obtain additional nutrients, such as nitrogen, from the prey they capture
• Calorie


  Unit of energy that indicates the amount of energy contained in food
• Calories refer to 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
• Nutritional requirements of animals

  • Carbohydrates
  • Proteins
  • Fats
  • Essential nutrients
• 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; an example is linoleic acid in humans
• Vitamins


  • Fat-soluble: A, D, E, K
  • Water-soluble: B, B2, B3, B12, C
• Trace elements or minerals


  • Iodine
  • Cobalt
  • Zinc
  • Molybdenum
  • Manganese
  • Selenium
• Phagocytosis


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