biological molecules

• Explain how the structure of cellulose means that it provides rigidity and strength to cell walls.

  Cellulose is made up of many long, straight, unbranched chains of beta glucose.The chains are joined with many weak hydrogen bonds.These grouped chains form micro- and macro-fibrils.
• Starch and glycogen are large, insoluble molecules.Explain how these properties make them good storage molecules.

  • Being large prevents starch and glycogen from crossing the cell membrane, so once they are in a cell they can be stored there easily.
  • Being insoluble means that starch and glycogen don’t dissolve into the cytoplasm of the cell they are stored in. This means that they do not affect the water potential of the cell, which would interrupt other processes and risk osmotic lysis.
• How would u obtain a quantitative measure to represent how much reducing sugar is resent in the test sample?

  Filter the solution for orange-brown precipitate, then dry the precipitate and measure its mass.
• name the 3 structures that phospholipids can form in water

  micelle, monolayer and bilayer
• Glycolipids are formed when sugars or carbohydrates bind to a phospholipid on the bilayer.

  Glycolipids are important for cell recognition as they allow cells to be recognized as the body’s own cells.
• An emulsion test is an example of what type of test?

  Qualitative test because it tells you if the lipid is present or not in a sample.