Chapter 2 - Review Questions

What is the molar concentration of 80g of glucose dissolved in sufficient water to make 2L of solution?

40g/L

How many covalent bonds can be formed by atoms of carbon, nitrogen, oxygen and hydrogen?

Each type of atom forms a characteristic number of covalent bonds: Hydrogen 1 Oxygen 2 Nitrogen 3 Carbon 4

What determines a molecule's solubility or lack of solubility in water?

Having a number of polar bonds and/or ionized groups will dissolve in water (aka Hydrophilic). Electrically neutral covalent bonds do not dissolve in water (aka hydrophobic).

Describe the distinguishing characteristics of the three classes of essential chemical elements found in the body.

Major elements - 99.3% of total atoms in the body Mineral elements - 0.7% of total atoms in the body Trace elements - less than 0.01% of total atoms in the body

Describe the electrical charge, mass and location of the three subatomic particles in an atom.

Negatively charged electrons orbit around a nucleus consisting of positively charged protons and uncharged neutrons. Protons and neutrons have similar mass and all three particles combined equal the atomic mass.

Define IONIC BOND

Strong electrical attraction between two oppositely charged ions

What distinguishes a weak acid from a strong acid?

acids which are completely (or nearly completely) ionized in solution is a strong acid. Acids that do not ionize in a solution are weak acids.

Define ION

Atom or small molecule containing an unequal number of electrons and protons and therefore carrying a net positive or net negative electrical charge.

Define FREE RADICAL

Atom that has an unpaired electron in its outermost orbital; molecule containing such an atom.

Name the four classes of organic molecules in the body.

Carbohydrates, Lipids, Proteins, Nucleic Acids

Which four kinds of atoms are most abundant in the body?

Carbon (9%), Hydrogen (63%), Oxygen (26%), Nitrogen (1%)

What property of molecules allows them to change their three-dimensional shape?

Polarity

Describe the three subclasses of carbohydrate molecules.

Polysaccharides (made of many monosaccharides) disaccharides (made of 2 monosaccharides) monosaccharides (simplest sugar)

Describe the polar characteristics of a water molecule.

The outside of the hydrogen atom tends to be positively charged. The oxygen atom has eight electrons. Most of those tend to stay away from the hydrogen atoms, and cause the outside of the oxygen atom to have a negative charge. When two water molecules get close together, the polar forces work to draw the molecules together. The oxygen atom of one water molecule will bond with several hydrogen atoms of other water molecules.

Describe the organization of amphipathic molecules in water.

These molecules have both a polarized region at one site and a non-polar region at another site. These aggregate into spherical clusters.

Describe the subclasses of lipids.

Triglycerides - Phospholipids -