BIOL 2401
STUDY POINTS HANDOUT –Chapter 2
1.
Practice identifying the elements of the Periodic Table of Elements.
Use the elements on the index cards.
2. Write the electron configurations for C, O, Na, Cl, Ar
C 2/4 O 2/6 Na 2/8/1 Cl 2/8/7 Ar 2/8/8
3. What is the principal difference between an ionic bond and a covalent bond?
Ionic bonds transfer the electrons. Covalent bonds share the electrons.
4. What are cations and anions?
Cations are positively charged ions. Anions are negatively charged ions.
5. Write the chemical notation for MOLECULES of water.
H2 + O2 = H2O
6. Describe the difference between sodium chloride in solution and glucose in solution
Ionic compounds (NaCl) dissociate in water as the polar water molecules break the ionic bonds in the large crystal
structure. Each ion in solution is surrounded by water molecules, creating hydration spheres. Hydration spheres
also form around an organic molecule containing polar covalent bonds. If the molecule binds water strongly, as
does glucose, it will be carried into solution—in other words, it will dissolve. Note that the molecule does not
dissociate, as occurs for ionic compounds.
7. Which pH is more acidic: 6.82 or 9.17? Which pH is closer to neutral: 8.41 or 5.59?
6.82 is more acidic. The are equal distance from neutral.
8. How many hydroxyl groups does a molecule of glucose have? How many carbon atoms are part of glucose’s
carbon skeleton?
5 OH groups and 6 Carbon atoms.
9. Which body cells store glycogen?
Muscle cells.
10. What is the danger of a diet high in cholesterol?
Clogged arteries and other cardiovascular diseases.
11. Which portion of a phospholipid is hydrophilic, and which portion is hydrophobic?
Polar head is hydrophilic and the non-polar tails are hydrophobic.
12. Differentiate between essential amino acids and non-essential amino acids.
The essential amino acids are those that we cannot make. The non-essential amino acids are supplied in food.
13. Do all proteins have a quaternary structure?
No. Proteins consisting of a single polypeptide chain do not have a quaternary structure.
14. Which bases always pair with each other?
A to T C to G
15. Name the dissolved gases and give their functions.
O, C, N
Critical Thinking Question: During chemistry lab, Maria places sucrose (table sugar) in a glass beaker, adds water and
stirs. As the table sugar disappears, she loudly proclaims that she has chemically broken down the sucrose into
fructose and glucose. Is Maria’s chemical analysis correct?
Simply adding water to the table sugar does not cause it to break spart into monosaccharides. The water acts as a
solvent, dissolving the sucrose and forming a sugar-water solution. To complete the breakdown of table sugar to
glucose and fructose would require the presence of the enzyme sucrose.