Test 2

A1.1 & D2.3: Water

B1.1 Carbs

Monosaccharides — Glucose:

• polar → many hydroxyl groups

• form a ring structure when in water

• most function as a source of energy for cells

  • oxidation (breaking down) of glucose produces large amounts of ATP in aerobic cellular respiration

  • Stable molecules: covalent bonds are string and cyclical structures are generally more energetically favorable than linear structures

  • easy to transport

Disaccharides:

• All have the formula: C₁₂H₂₂O₁₁

  • homopolymers of glucose

• All are connected by glycosidic bonds

  • Bonds form through condensation (water out, synthase catalyses)

  • Bonds break through hydrolysis (water in, hydrolase catalyses)

• Sucrose: glucose + fructose

• Lactose: galactose + glucose

  • lactose intolerance → cannot hydrolyze (break bond) lactose due to an enzyme deficiency

• Maltose: glucose + glucose

Polysaccharides:

• All are made of glucose monomers → homopolymers

• Cellulose:

  • beta-1,4-glycosidic bond

    • hydrolyzed by cellulase

  • direction of glucose molecules flips alternatively → maintains linear shape instead of curved

  • unbranched chains of glucose

  • hydrogen bonds link the chains (they are polar)

    • bundles formed are called cellulose microfibrils

    • very high tensile strength

    • cell walls are made of many sheets of cellulose microfibrils → strong and prevent cell from bursting under very high pressure (from water)

    • space between chains is very small, so cellulase cannot fit to hydrolyze, and neither can water molecules

      • insoluble in water

      • hard to digest

• Starch:

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