BIO 171 - First Exam - 2019

Multiple Choice.
Place the letter of the choice that best answers the question on the line to the left.
Two Points Each. NOTE: “e” answers are never the correct answer.

_______ 1. When comparing a solution of pH 13 to one of pH 11, the pH 11 solution is
                    a. Twice as basic             b. Twice as acidic             c. 100 times more basic
                    d. 100 times less basic                         e. Not as tasty

_______ 2. Which type of molecular bond has the smallest role in living systems?
                    a. Ionic             b. Polar             c. Covalent            d. Hydrogen
                                                    e. Super Glue

_______ 3. Hydrogen atoms are transferred in most
                    a. Oxidation reactions             b. Membrane pumps            c. Osmotic transfers
                    d. Exergonic Reactions            e. Stock transactions - it’s in the very small print

_______4. In an enzyme-catalyzed process that combines three substrates to get one
                                        product, the process can be stopped with least effort by removing

                    a. The product                              b. Any one of the substrates
                    c. All three substrates                    d. The membrane confinement
                                                e. Its will to live

_______5. In biological systems, group transfer potential most often involves
                    a. Oxidation                     b. Amino acids                     c. Reduction
                    d. Phosphates                   e. Boy bands

_______6. D-glyceraldehyde dehydrogenase, if broken down, would yield
                    a. Sugars                     b. Amino acids                     c. Nucleotides
                    d. Water                      e. If you threatened it

_______7. Chaperonins are involved in
                    a. DNA translation to protein                     b. Protein secondary structure
                    c. Protein tertiary structure                        d. Building nuclei
                                    e. Very violent parties in historical Japan

_______8. An active site is a kind of
                    a. Domain                 b. Prosthetic group                 c. Cofactor
                    d. Complex                                 e. Site of activity

_______9.  The main difference between digestible plant starch and indigestible
                                        plant fiber like cellulose is

                    a. Only the fiber has a ring structure
                    b. In their hydrophilic areas
                    c. How the amino acids interact on the secondary level
                    d. In the linkages between the sugars
                    e. How they affect certain unmentionable processes

_______10. The R group of an amino acid attaches to
                    a. The Carboxyl group             b. The Amino group            c. The Central or alpha carbon
                    d. All of these                          e. The closest molecule with money and a hot car

_______11. Artificial sweeteners taste sweet but are not broken down by enzymes for
                                        absorption because of variations in
                    a. Overall charge             b. Stereospecificity            c. Carbohydrate content
                    d. Hydrophobicity                    e. How serious the diet is

_______ 12. A Q10 is a relationship between
                    a. Reaction rate and substrate                     b. Enzyme and substrate
                    c. Reaction rate and temperature                 d. Enzyme and temperature
                                                            e. A “Q” and a “10"

_______13. Producers, compared to consumers, have
                    a. Equal biomass and numbers of species             b. More biomass and fewer species
                    c. Less biomass and more species                        d. Less biomass and fewer species
                                e. Does this ecosystem make by biomass look fat-?

_______14. NAD, when it moves electrons to new acceptors, would be a(n)
                    a. Enzyme                 b. Reducing agent                 c. Oxidizing agent
                    d. Inhibitor                             e. Moving company

_______15. Liquid water is most dense
                    a. At its freezing point, 0oC                     b. At its boiling point, 100oC
                    c. It’s always equally dense                     d. At 4oC
                            e. In the brains of exam-taking biology students

_______16. A gene relates to _______ protein structure in a ________ base-to-amino acid ratio.
                    a. ....Primary...3 to 1                     b. ...Secondary...3 to 1
                    c. ....Primary...1 to 3                     d. ...Secondary...1 to 3
                        e. ....some sort of...I-don’t-care to you-can’t-make-me

_______17. Carbon dating uses
                    a. Radioactive isotopes to determine the ancientness of biological materials
                    b. The bonding properties of carbon to determine an organism’s age
                    c. The breakdown ratio of water and DNA
                    d. Rates of electron loss to neutron number
                    e. One of the Internet’s weirdest chatrooms

_______18. When a reaction reaches equilibrium,
                    a. It stops
                    b. Both forward and backward rates are the same
                    c. Substrate and product concentration is the same
                    d. All of these
                    e. It usually puts in for retirement

Short Answer.

Pick NINE questions to answer in the spaces provided.

NOTE: if you answer MORE than nine, only the first nine will be corrected.
Four Points each. Partial credit is possible.

1. Explain why a Michaelis-Menten curve levels off.

2. Give the components (and how many of each) of a typical lipid molecule.

3. Other than their initials, what are two sets of significant differences between DNA and RNA?



4. Show the nucleotides on the other strand of the DNA -
DNA       T  G  C  T  A  C  C  G  T  A  T  T  G  G  C  G  A  G  T  C  A  T  C  G
Other DNA
Strand:     ________________________________________________________________________________

5. Briefly explain what a hydration shell is.

6. What are two different major biological molecule types that are polymers?


7. Briefly explain the nature of the double bond in O2.

8. What are two things in non-coding DNA that are still some kind of code?


9. What is it about molecules like amino acids and nucleic acids be considered acids?

10. What are two reasons why the dynamic equilibrium point would be significantly different for an enzyme-mediated reaction, as opposed to the non-enzyme version.


11. If two molecules are isomers, what does that mean?

12. What are two of the three components of a nucleotide?


13. What are two different protein classes that are communication signals?


14. What are two general, different functions based upon a match-up of complementary shapes that are commonly performed by proteins?


15. What is meant by a turnover number?

16. A saturated organic molecule, compared to an unsaturated one, would have


Long Answer.

Select and answer completely any four of the following questions.

Note: if you answer more than four, only the first four will be corrected.
Seven Points Each. Partial credit is possible.
1.  For four functional organic molecule groups, give the name, then show the arrangement of atoms in enough detail to demonstrate completely how each group works.

2.  All for the most common isotope –




# 9

Column 7

How many


How many



How many
(Radical form)

3.  Name three basic different properties of water and for each, briefly explain a role that property plays in biological systems (this could be an example).
PROPERTY Role in biological systems




4. Briefly describe three different ways that enzymes can be inhibited.


5.  Using the numbers of bonds as a guide, fill in the symbols for either Carbon, Hydrogen, Nitrogen, or Oxygen.
 Can't recreate the original hand drawing.  Practice by filling in bonds...

O           O           O

          O              O           O           O
                    O                                       O           O
          O               O

6.  Below is a graph showing how enzyme activity, measured through the rate of the reaction catalyzed by the enzyme, reacts to changes in pH (NOT temperature!). Fill in: A) The name given to the pH where the graph peaks; B) Why the graph peaks there; C) and D) What's happening to the enzyme molecules as the rate drops off (C) below the peak; and (D) above the peak.

                                                                          *   A
                                                                  *                *
                                                              *                        *
Reaction                                      C    *                             *   D
Rate                                                 *                                   * 
                                                       *                                       *
                                                  *                                                    *
                                         *                                                                       *
                          *****                                                                                         ******

                                                                    pH ---->

7.  Name and give a brief description for the four levels of protein structure.

Link to Answer Key

BONUS QUESTIONS. Answer as many or as few as you wish. You can't lose points on the rest of the exam by getting these wrong. Partial credit is possible.

How did Mendeleev, the “periodic table guy,” get to where his talents could be best expressed? Three Points.

You have to figure this out – why do different types of radiation emitted from unstable nuclei have very different abilities to penetrate biological tissue? Three Points.

Water is commonly used in hydraulic systems because it is essentially incompressible. Why would this be true? Three Points.

How would the pOH scale work? Three Points.

Which functional organic groups have recently become known to be very important to cellular chemistry? Three Points Each.

Why, probably, is almost every organism’s actin close to identical? Three Points.

In the lab, why did the Benedict’s test require added heat? Three Points.

Although many catalysts work on a reaction in both forward and backward directions, many enzymes do not. For Three Points, why?

Why would an enzyme’s affinity increase with a drop in temperature? Three Points.

What was Mr. McDarby’s job between high school and college? Three Points.


BIO 171

Michael McDarby


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