Video

Biological Molecules

Well, today was a little wacky, with no electricity or projector, class photographs in the middle of one class, and virtually no air circulating in my room to make for a hot hot hot day at school. Add in the noise and distraction of holding class in the courtyard, and we have….well, we have a bit of a mess.

Just so we’re all on the same page of the biology unit, I thought I’d summarize the key points from today’s lesson on biological molecules. Below are the finer points of the lesson.

The 3 major functions of all biological molecules

  1. Instructions
  2. Energy storage
  3. Source of energy

Screen Shot 2013-09-24 at 3.02.57 PMCarbohydrates

  • chains of C, H, and O
  • supply all energy in cells and food chains
  • energy tends to be short-term energy (glycogen)
  • simple sugars such as glucose may build more complex molecules
  • some long chains of sugars, such as cellulose, are used for cellular structure

Screen Shot 2013-09-24 at 3.03.49 PMLipids

  • do not dissolve in water
  • long chains of C, H, O, and P
  • have more bonds than carbs, so they’re used for energy storage
  • slow release of energy
  • saturated fats: all single C-H bonds, tend to be solids
  • unsaturated fats: some C-C double bonds, tend to be liquids (oils)
  • Image credit: http://www.uic.edu

    Image credit: http://www.uic.edu

    phospholipids make up cell membranes and have two main parts:

    • a phosphate group at one end, which is polar (charged), meaning it is hydrophilic
    • the hydrophobic hydrocarbon tails

Proteins

  • most important biological molecule
  • many functions in organisms:
    • enzymes
    • structural components (building blocks)
    • hormones
    • antibodies
  • made of chains of amino acids
  • only 20 amino acids make all the 1000’s of proteins in the world

Nucleotides

  • made of C, H, O, P, and N
  • 3 parts of each nucleotide:
    • nitrogen base
    • sugar
    • phosphate
  • Screen Shot 2013-09-24 at 3.03.33 PM

    4 different nitrogen bases to know: A-C-G-T (shown at right)

  • several functions in organisms:
    • chemical messengers
    • coenzymes
    • carry energy from one part of a cell to another
    • build nucleic acids
  • two kinds of nucleic acids:Screen Shot 2013-09-24 at 3.03.20 PM
    • DNA: sequence of nucleotides makes up the genetic code of an organism
    • RNA: translates the code into specific proteins

And finally, the slides from class…

 

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