BIO 106

What is the difference between covalent bonds and ionic bonds?

• Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms.

• Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms.

• Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms.

• Covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms.

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by ____.

• hydrogen bonds

• nonpolar covalent bonds

• polar covalent bonds

• ionic bonds

One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+), as noted below.

H2CO3 <--> HCO3- + H+

If the pH of blood drops, one would expect ____.

• a decrease in concentration of H2CO3 and an increase in the concentration of HCO3-.

• the concentration of bicarbonate ions (HCO3-) to increase

• the HCO3- to act as a base and remove excess H+ by the formation of H2CO3

• the HCO3- to act as an acid and remove excess H+ by the formation of H2CO3

The complexity and variety of organic molecules is due to ____.

• chemical versatility of carbon atoms

• variety of rare elements in organic molecules

• diverse bonding patterns of nitrogen

• their interaction with water

How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?

• 10

• 20

• 19

• 40

The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecular made by linking three glucose molecules together by dehydration reactions?

• C6H10O5

• C18H30O15

• C18H36O18

• C18H32O16

Phospholipids and triglycerides both ____.

• have three fatty acids

• have a glycerol backbone

• contain serine or some other organic compound

• have a phosphate

The label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. Hydrogenated vegtable oil ____.

• has more "kinks" in the fatty acid chains

• has fewer trans fatty acids

• is less likely to clog arteries

• is solid at room temperature

Which parts of the amino acids X and Y are involved in the formation of a peptide bond?

X-Y

• amino group of X and carboxyl group of Y

• carboxyl group of X and side chain of Y

• side chains of both X and Y

• carboxyl group of X and amino group of Y

OH -- H ---> H2O

• results in a peptide bond

• links two polymers to form a monomer

• hydrolysis reaction

• joins two fatty acids together