BIO 111: FOUNDATIONS OF BIOLOGY

LECTURE 2: "Chemistry of Life"

Assumed Knowledge:

Chapter 2.

Study Questions for Chapter 2 and Chapter 3:

• Define "element", "compound", and "atom".
• What are the relative masses and charges on protons, neutrons, and electrons?
• What do you get if you add a proton to an atom? What do you get if you add a neutron? What if the numbers of protons and electrons is unequal?
• How does potential energy content vary with the location of electrons in orbital shells?
• Are energy transformations in an atom continuous or discrete?
• What are valence electrons?
• How many electrons can fit in the first three shells?
• What do you call an element in which the outermost shell is full? Is it reactive? Give an example.
• Describe how a covalent bond between hydrogen atoms affects the electron-occupancy of their valence shells, and draw a picture (using an electron distribution model, see fig. 2.12.).
• Oxygen gas (O2) and hydrogen gas(H2) are non-polar molecules, and the bond holding the atoms together is a non-polar covalent bond. Explain these terms in terms of electronegativity.
• Oxygen and hyrogen form polar covalent bonds in a water molecule; explain what a polar covalent bond is, and the concept of 'partial charge'.
• These partial charges can cause atoms to be attractted to one another, in a realtionship called _________.
• How do ions and ionic bonds form?
• What are van der Waals interactions?
• Draw the structure of a water molecule (using an electron distribution model), and identify where the partial charges exist.
• How does water's polar nature explain the poperties of adhesion and cohesion? How are these properties valuable in the movement of water in a tree?
• How is surface tension related to cohension?
• Define heat and temperature in relation to kinetic energy.
• Water has a high specific heat. What does this mean, and what effect does this property have on water as an internal and external environment for life?
• Water also has a high heat of vaporization. What effect does this haveon living systems?
• Water has a maximum density at 4oC...what effect does this have on life?
• What types of compounds dissolve in water and why?
• Whater dissociates into ions. How does the concentration of free H+ ions related to the pH scale?