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

Carbohydrates

• 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

Lipids

• 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)

• 

  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

• 

  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:
  • 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…