Genbio, nutrient

• This lesson will focus on: enumerate the structures or organs involved in nutrient procurement and processing in plants and animals; describe the functions of structures or organs involved in nutrient procurement and processing; and explain how food is processed in a mammalian digestive system
• Activity 2A. Venn Diagram

  1. Compare and contrast plant and animal nutrition

  2. Use the words provided
• 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
• Nutrition is a process by which organism obtain food for sustenance and source of energy
• In this lesson, you will compare and contrast the nutrient procurement and processing of plants and animals. After which you will study the human digestive system
• Nutrient


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

  • Autotrophs
  • Heterotrophs
• Examples of autotrophs


  • Plants
  • Chemosynthetic bacteria
• Examples of heterotrophs


  • Animals
  • Fungi
• Nutrient requirements of plants

  • Water
  • Carbon dioxide
• Water and carbon dioxide are the raw materials needed for photosynthesis, the process by which plants convert the energy from sunlight into chemical energy
• Essential nutrients or elements for plants

  • Macronutrients (normally required in amounts above 0.5% of the plant's dry weight)
  • Micronutrients (required in minute or trace amounts)
• Examples of macronutrients


  • C, H, O, N, K, Ca, Mg, P, S
• Examples of micronutrients


  • Cl, Fe, B, Mn, Zn, Co, Mo
• Routes for absorption of water and minerals across plant roots

  1. Symplast route (passing through plasmodesmata)

  2. Apoplast route (along cell walls)
• Specialized absorptive structures in plants

  • 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)
  • Mycorrhizae (symbiotic interaction between a young root and a fungus)
• Nutritional adaptation by plants

  • Symbiosis of plants and soil microbes
  • Symbiosis of plants and fungi
  • Parasitism
  • Predation
• Calorie


  A unit of energy that indicates the amount of energy contained in food
• Nutritional requirements of animals


  • Carbohydrates
  • Proteins
  • Fats
  • Essential nutrients (amino acids, fatty acids, vitamins, minerals)
• Essential amino acids


  Amino acids that cannot be synthesized by the human body and must be obtained through food
• Types of vitamins


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

  Inorganic nutrients needed by the body in minute amounts
• Endocytosis


  The process by which cells take up food
• Types of feeding mechanisms in animals


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


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


  The act of eating or feeding
• Digestion


  Breakdown of food into particles, then into nutrient molecules small enough to be absorbed
• Absorption


  Passage of digested nutrients and fluid across the tube wall and into the body fluids
• Elimination


  Expulsion of the undigested and unabsorbed materials from the end of the gut
• Organs involved in the food processing of the human digestive system

  • Oral Cavity
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine
  • Liver
  • Pancreas
  • Gallbladder
• Digestion


  1. Breakdown of food into particles

  2. Breakdown of particles into nutrient molecules small enough to be absorbed
• Chemical digestion


  Breaking of chemical bonds through the addition of water, i.e., enzymatic hydrolysis
• Absorption


  1. Passage of digested nutrients and fluid across the tube wall and into the body fluids

  2. Cells take up (absorb) small molecules such as amino acids and simple sugars
• Organs involved in the food processing of the human digestive system

  • Oral Cavity
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Accessory Digestive Organs (Liver, Gallbladder, Pancreas)
  • Large Intestine
  • Rectum
  • Anus
• Oral Cavity


  • Food is initially chewed into shreds by the teeth, and mixed with saliva by the tongue
  • Saliva is secreted into the mouth by three pairs of salivary glands
• Pharynx


  • Serves as the entrance to the esophagus and trachea
  • Flap-like valve (the epiglottis) and the vocal cords close off the trachea to block breathing as food leaves the pharynx
• Esophagus


  • Connects the pharynx with the stomach
  • No digestion takes place within the esophagus but the contractions within its muscular wall propel the food past a sphincter, into the stomach
  • Rhythmic waves of contraction of the smooth muscle wall are called peristaltic contractions or peristalsis
  • Esophagus is about 25 cm (10 in.) long
• Stomach


  • Muscular, stretchable sac located just below the diaphragm
  • Mixes and stores ingested food
  • Secretes gastric juice that helps dissolve and degrade the food, particularly proteins
  • Regulates the passage of food into the small intestine
• Gastric juice


  Combination of HCl and acid-stable proteases