Chapter Three:The Molecules of Cells

Questions:

1.  Why are people lactose intolerant?

  A:  This is the wrong question.  The question should, in fact, be why are people lactose TOLERANT?  It is shown through research and surveys that most of the worlds population cannot easily digest dairy based products.  The ones that can are so able because of a mutation in an enzyme called "lactase," this enzyme helps to break down and easily digest dairy products.  Most people of Asian, African, and Native American descent do not have this handy mutation.  Nearly all lactose tolerant people are from european descent (a place that long depended on cattle and dairy products for survival.)

2.  What determines a proteins function?

  A:  The determining factor of a proteins function is it's molecular build.  20 amino acids can be combined in millions of different ways, providing the code for the function that certain protein is to perform.

3.  Is high-fructose corn syrup to blame for obesity?

  A: Maybe.  There are still ongoing studies trying to prove or disprove this theory, but the evidence is circumstantial.


Five Main Facts From The Reading:

1.  Proteins are essential to the structures and functions of life.
2.  A protein's specific shape determines its function.
3.  Mutations can harm or help us. (exp. sickle-cell, lactose tolerance.)
4.  A protein has four levels of structure.
5.  Fats are necessary to store energy.

This diagram shows the differences between estrogen (the female hormone,) and testosterone (the male hormone.  They only differ in chemical groups, but are otherwise very similar.

Ten Key Terms:

Isomers - compounds with the same formula but different structures.

Hydrophilic - water loving.

Hydrophobic - water fearing.

Hydroxyl Group - a hydrogen atom bonded to an oxygen atom, which is bonded to the carbon skeleton.

Carbonyl Group - a carbon atom is linked to an oxygen atom.

Carboxyl Group - a carbon double-bonded to an oxygen and also bonded to a hydroxyl gorup.

Amino Group - a nitrogen bonded to two hydrogen atoms and the carbon skeleton.

Phosphate Group - a phosphorous atom bonded to four oxygen atoms.

Methyl Group - a carbon bonded to three hydrogens.

Monosaccharides - the carbohydrate monomer (single-unit sugars.)

Sickle-cell Anemia Video: http://www.youtube.com/watch?v=8RYLu2j0Qy0

This chapter all about the molecules of cells and proteins.  It explained how and why the arrangement of around 20 amino acids can make thousands of different actions and reactions possible.  It showed the basic structures of proteins, which are composed of four layers.  It also explained how some molecules instinctively know to put the hydrophilic portions of itself on the outside, while hiding the hydrophobic particles within the structure, shielding it from any water that it could come in contact with.  This chapter was all about how the structure of molecules makes life possible.