Review Sheet 2 for Test #2 - Biology 1108

     Macronutrients = needed in "parts per thousand: Micronutrients: needed in "parts per million"

Essential Nutrient (for life) means:

  1.  performs some vital function, i.e., needed for either growth & maintenance and/or reproduction
  2.  cannot be substituted for by other elements
  3.  function is a direct one (structural component/enzyme or cofactor)

Plants - Autotrophs
         Can basically live in an inorganic environment and make organic nutrients
    Nutrients Required = CO2 & H2O for PS
        Many other elements (besides C, H, O) also necessary; most dissolved as ions in H2O

Bacteria, Some Protists, Fungi, Animals 
            Herbivores, Omnivores, Carnivores

Essential Nutrients
    Organic Molecules

    Vitamins/Minerals (Table 45-3 and 45-4, pages 1005 and 1006)
        Vitamins - many (particularly water-soluble) function as coenzymes
               1.  water-soluble: C, B-complex
               2.  lipid-soluble (vertebrates only): A, D, E, K (not used as coenzymes)
             D, K and some B not essential in the diet for humans, for reasons discussed in class
        Minerals (elements) -- All essential 
                (C, H, O, N, S, some P from prots./carbos./lipids -- organic molecules)
                 Macronutrients: Na, Cl, K, P, Mg, Ca, Fe             Know function for each of macros
             Micronutrients: Cu, Mn, Zn, Mo, I, Se                     and for I and Zn 

            These are for humans; plants and other heterotrophs may require some different minerals


DIGESTION B two types:

  1. physical (mechanical: chewing/muscular mashing) 
  2. chemical (enzymatic, mainly hydrolytic)

Specializations in different groups:

        I.  Incomplete Digestive System B One-opening/two-way
                Cnidarians, Flatworms

        II.  Complete Digestive System B Two-opening/one-way; with specialized organs and 
                numerous digestive enzymes; roundworms and all higher animal groups. 
             1. Longer Transit Time B more complete digestion and absorption
                2. Specialization of organs for specific digestive functions
                3. Continuous feeding possible, though some organs used for storage

                Some organs in you should know from other animals: Crop, gizzard

Human Digestive System:


I. Oral Cavity B
        Teeth (incisors, canines, premolars, molars) -- functions of each?
        Tongue -- for physical digestion and taste
        Salivary glands -- Saliva has salivary amylase, which begins chemical digestion of carbohydrates, 
                as well as lysozyme
II. Pharynx (throat)/Esophagus B Swallowing -- Peristalsis
III. Stomach B storage (discontinuous feeding), many folds for expansion
        Chief (zymogenic) cells release pepsinogen (inactive --WHY?)
        Parietal cells release HCl and intrinsic factor (intrinsic factor vital as aid in absorbing vit. B-12)
                HCl activates the pepsinogen to form pepsin -- begins chemical digestion of protein
IV. Small intestine B most digestion, absorption takes place here through the surfaces of the 
; bile from liver/gall bladder and tremendous numbers of digestive enzymes are 
        dumped into small intestine from pancreas; [see handout on digestive enzymes]

            Note: bile does *not* contain enzymes -- only bile salts/phospholipids for emulsifying fats

V. Large intestine/rectum/anus

Know function of bile and function of the indicated (discussed in lecture) enzymes from the handout.

See also Table 45-1, page 998.