Introductory Biology
Sample Questions, Exam I                     Name__________

Multiple Choice: Circle the best answer.

1. The main chemical elements found in biological molecules are:
     a. carbon, oxygen, calcium, sulfur
     b. hydrogen, sodium, nitrogen, oxygen
     c. potassium, hydrogen, carbon, oxygen
     d. carbon, oxygen, hydrogen, nitrogen

2. The formation of a peptide bond involves:
          I. two monosaccharides
         II. two amino acids
        III. a condensation reaction
     a. I only
     b. II only
     c. III only
     d. I and III
     e. II and III

3. Simple proteins and DNA are similar in that they both contain all
    of  the following except:
     a. oxygen
     b. hydrogen
     c. nitrogen
     d. phosphorus
     e. carbon

4.  ______ are the subunits of nucleic acids and  ______ are the
     subunits of proteins.
      a. nucleotides, amino acids
      b. bases, polypeptides
      c. polypeptides, sugars
      d. amino acids, nucleic bases 

5. The backbone of organic compounds is formed  by the chemical
     bonding of ______ atoms into chains and rings.
     a. hydrogen
     b. carbon
     c. oxygen
     d. nitrogen
     e. phosphorus

6. Which of the following would not be included in the family of
     a. glucose
     b. sucrose
     c. adenine
     d. chitin
     e. glyceraldehyde

7.  The type of reaction in which organic compounds  are formed
      from their subunits is called:
      a. hydrolysis 
      b. dehydration
      c. oxidation
      d. saturation

8. Ionic bonds:
      a. involve a sharing of electrons between two atoms
      b. form only between two anions or two cations
      c. result from the complete transfer of electrons from one atom to another
      d. are very weak
      e. occur between groups of nonpolar molecules

9. Polyunsaturated fatty acids:
      a. contain phosphorous and nitrogen
      b. contain several double bonds
      c. are solid at room temperature
      d. always have an odd number of carbon atoms 

10. Atoms of the same element containing the same number of
      protons but different  numbers of neutrons are termed:
      a. covalent bonds
      b. ionic bonds
      c. salts
      d. isotopes
      e. acids

11. The amount of energy required to change one gram of liquid
       water to one gram of water vapor is termed the ______ of
      a. specific heat
      b. ionization
      c. cohesion
      d. heat of vaporization
      e. adhesion

12. Which of the following statements is not true?
      a. bases are proton donars
      b. a buffer consists of a weak acid and a salt of that acid
      c. a buffer consists of a weak base and a salt of that base
      d. acids are proton donars
      e. electrolytes include salts, acids, or bases dissolved in water

13. All of the following except ________ belong to the four families
      of small organic molecules that serve as building blocks for
      large biological molecules or as energ sources.
      a. fatty acids
      b. simple sugars
      c. lipids
      d. nucleotides
      e. amino acids

14. In ______ reactions, small molecules become covalently linked,
      and water can also form.
      a. symbiotic
      b. hydrolysis
      c. condensation
      d. ionic

15. In an atom the electrons:
      a. closest to the nucleus have the most energy
      b. in the outermost energy level determine the chemical properties of the atom
      c. in the outer level have the least amount of energy
      d. can be found in the space between energy levels

16. The high specific heat and cohesive forces characteristic of
      water are a result of:
      a. covalent bonds between the O and two H's of
          the water molecule
      b. ionic bonds between H+ and OH-
      c. hydrogen bonding between water molecules
      d. dissociation of H2O into H+ and OH-

17. The helical structure of a polypeptide represents the:
      a. primary structure
      b. secondary structure
      c. tertiary structure
      d. quaternary structure

18. The atomic number of an atom is the number of
      a. electrons
      b. protons
      c. neutrons
      d. protons and neutrons
      e. electrons and protons

19. An acid is a
      a. proton acceptor
      b. proton donar
      c. electrolyte
      d. a and c are correct
      e. b and c are correct

20. Which of the following compounds is not considered a lipid?
      a. oils
      b. fats
      c. waxes
      d. steroids
      e. enzymes

Matching: Match the organic molecules appropriately.

___b___ maltose
___e___ fibroin
___d___ collagen
___a,g__ deoxyribose
___c___ glycogen
______ glycerol
______ palmitic acid

a. monosaccharide
b. oligosaccharide
c. polysaccharide
d. alpha-helically coiled protein
e. beta-pleated sheet protein
f. triose
g. pentose

Essay: Answer the questions in the space provided. The value of
each question is indicated.

1. Draw the structure of a triacylglcerol. (6 pts)

. H2
. .I
. .C - O - CO - CH2 - CH2 ------- CH3
.. I
HC - O - CO - CH2 - CH2 ------- CH3
. . I
. .C - O - CO - CH2 - CH2 ------- CH3
. . I
. .H2

2. What is a radioisotope? Give an example. (6 pts)

An isotope in which one of the neutron decays releasing a proton and electron. Tritium.

3. Define an ionic bond. Give a specific example of an ionic bond.
     (4 pts)

electrons are completely transferred from one atom to another. NaCl.

4. With respect to water, what is adhesion? What is responsible for
     water having this property?  What other properties of water
    does  adhesion explain? (5 pts)

Adhesion is water attracted to molecules other than itself. Hydrogen bonding causes this. Explains capillary action, imbibition, and solvent properties of water.

5. Why does water have a high specific heat? (2 pts)

due to hydrogen bonding. Must break hydrogen bonds before molecules can move faster.

6. Define the following terms and give an example of each (8 pts):

     monomer-building blocks of polymers. e.g. amino acids for proteins.

     unsaturated fatty acid-missing 2 hydrogens (one double bond). oleic acid.

     wax-esters of long chain alcohols and long chain fatty acids. e.g. cutin, suberin.

7. Explain the steps of the scientific method (6 pts).

be able to explain or recognize all of the terms provided in case 1 (null hypothesis, directional alternative and nondirectiona alternative hypotheses, control and experimental groups, how test for random error, how test for systematic error, prediction, inductive and deductive reasoning, statistical and biological conclusions, Type I error.