Scie

• 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
• Autotrophs


  • Plants
  • Chemosynthetic bacteria
• Heterotrophs


  Organisms that cannot make their own food and obtain their energy from other organisms
• Heterotrophs


  • Animals
  • Fungi
• Nutritional requirements of plants

  • Water
  • Carbon dioxide
• Photosynthesis


  The process by which plants convert the energy from sunlight into chemical energy
• Essential nutrients or elements for plants

  • Macronutrients (C, H, O, N, K, Ca, Mg, P, S)
  • Micronutrients (Cl, Fe, B, Mn, Zn, Co, Mo)
• Routes for absorption of water and minerals across plant roots

  • Symplast route (through plasmodesmata)
  • Apoplast route (along cell walls)
• Calorie


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

  • Carbohydrates
  • Proteins
  • Fats
• Carbohydrates


  Serve as a major energy source for the cells in the body
• 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
• 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
• Essential nutrients for animals

  • Essential amino acids
  • Essential fatty acids
  • Vitamins
• Main stages of food processing

  • Ingestion
  • Digestion
  • Absorption
  • Elimination
• Organs involved in food processing in the human digestive system

  • Oral cavity
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestine
  • Accessory digestive organs (pancreas, liver, gallbladder)
  • Large intestine
  • Rectum and anus
• Oral cavity


  Where food is initially chewed into shreds by the teeth, and mixed with saliva by the tongue
• Pharynx


  The region in the back of the throat that serves as the entrance to the esophagus and trachea
• Esophagus


  Connects the pharynx with the stomach, no digestion takes place within it but the contractions within its muscular wall propel the food past a sphincter, into the stomach
• Stomach


  • 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


  A combination of HCl and acid-stable proteases
• Chyme


  The thick, liquid mixture that the churning action of the stomach together with the potent acidity of the gastric juice convert food into
• Small intestine


  • Where most enzymatic hydrolysis of the macromolecules from food occurs
  • The complete digestion of carbohydrates, fats, and proteins occurs in the duodenum, about the first 25 cm
  • The rest of the small intestine is devoted to absorbing water and the products of digestion into the bloodstream
• Villi and microvilli


  Increase the surface area for absorption in the ileum
• Large intestine


  • Concentrates and stores undigested matter by absorbing mineral ions and water
  • A small amount of fluid, sodium, and vitamin K are absorbed through its walls
  • Does not have villi and has only one thirtieth of the absorptive surface area of the small intestine
• Rectum


  The final segment of the digestive tract where the compacted undigested food from the colon are pushed via peristaltic contractions
• Anus


  The terminal opening of the digestive system through which feces are expelled
• Development


  The process by which a multicellular organism, beginning with a single cell, goes through a series of changes, taking on the successive forms that characterize its life cycle
• Types of Reproduction

  • Sexual
  • Asexual
• Sexual Reproduction


  The combination of reproductive cells from two individuals to form a third unique offspring
• Reproductive states


  • Haploid
  • Diploid
• Syngamy


  The fusion of haploid sex cells resulting in the formation of a diploid zygote
• Conjugation


  Two organisms come together in a fusion to exchange micronuclear material. It is different from syngamy.
• Hermaphroditism


  Occurs in animals where one individual has both male and female reproductive parts. May self-fertilize or may mate with another of their species, fertilizing each other and both producing offspring
• Types of Asexual Reproduction

  • Binary Fission
  • Budding
  • Fragmentation
  • Sporogenesis

  
• Human Reproductive System


  • Liberate an ovum at a specific time
  • Internal fertilization of the ovum by spermatozoa
  • Transport of the fertilized ovum to the uterus
  • Implantation of the blastocyst in the uterus wall
  • Formation and maintenance of a placenta
  • Birth of the child and expulsion of the placenta
  • Suckling and care of the child, with an eventual return of the maternal organs to virtually their original state
• The human female reproductive system
• The human male reproductive system