Lipids: Built by Condensation but Not Polymers · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The lipid that breaks the polymer rule

Science · Organisms & Life Processes · ages 16-17
Name ______________________   Date ____________

  1. Glycerol grabs three fatty acids by condensation, releasing one water per join. How many water molecules form one triglyceride?

    Answer: ______________

  2. Why is a triglyceride not called a polymer?

    • It is built without condensation
    • Its three fatty acids sit on one hub instead of chaining as repeating units
    • It holds too much energy

  3. Phospholipids and triglycerides behave exactly the same way in water.

    Circle one:   True   False

  4. Why do triglycerides clump into fat droplets instead of sheets?

    • All three of their tails avoid water
    • They carry a phosphate head
    • They dissolve too easily

  5. Why do phospholipids line up in a sheet when dropped into water?

    • Heads face the water while tails hide together
    • Tails face the water while heads hide together
    • They dissolve completely like salt

  6. Why does a gram of lipid store about twice the energy of a gram of carbohydrate?

    • Lipids hold extra water weight
    • Long carbon hydrogen tails release lots of energy with oxygen, while sugars are already part joined to oxygen
    • Carbohydrates cannot be broken apart

  7. A new lipid has two water hating tails and one water loving head. What will it do in water?

    • Clump into droplets like a triglyceride
    • Vanish like dissolved salt
    • Line up into sheets like a phospholipid

  8. A student calls a triglyceride a polymer because condensation built it. What is the flaw?

    • Condensation never builds polymers
    • The same glue can join different architectures, and a hub with three tails is not a chain
    • Polymers never involve water
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Answer key

For grown-ups. Fold this page away before handing over the rest.

The lipid that breaks the polymer rule W1-mt_8-JYrLwjCw-s1

  1. 3 · Three joins release three waters, one per fatty acid.
  2. Its three fatty acids sit on one hub instead of chaining as repeating units · Polymers need many similar units linked in a series, which the hub lacks.
  3. False · Phospholipids sheet into membranes while triglycerides clump into droplets.
  4. All three of their tails avoid water · With no water loving part, huddling into droplets is the only shelter.
  5. Heads face the water while tails hide together · Water loving heads turn outward and water hating tails huddle inward.
  6. Long carbon hydrogen tails release lots of energy with oxygen, while sugars are already part joined to oxygen · Unburned tails hold more releasable energy than already part burned sugars.
  7. Line up into sheets like a phospholipid · One loving head plus hating tails is the sheet building plan.
  8. The same glue can join different architectures, and a hub with three tails is not a chain · Joining chemistry never decides the name; repeating chain architecture does.
Worksheet · LightMySky